FINAL DRAFT UGANDA 
STANDA RD  
  FDUS EAS 148-2 
First  Edition  
2018-mm-dd 
 
 Reference number  
FDUS EAS 148-2: 2017 
© UNBS 201 8 
  
Cement — Test me thods — Part 2: Chemical analysis  
 US EAS  148-2:2017 
ii                © UNBS  2018 - All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its corr ect application  
© UNBS 20 18 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written 
permis sion from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 7 333 2 50/1/2 
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  
 US EAS 148-2:2017 
© UNBS  2018 - All rights reserved                 iii National foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade, Industry and 
Cooperatives established under Cap 327, of the Laws of Uganda, as amended.  UNBS is  mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT Agre ement of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of representatives of 
consumers, traders, academicians, manufacturers, government and other stakeholders.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
This Uganda Standard, US EAS 148-2: 2017, Cement — Test me thods — Part 2: Chemical analysis , is 
identical with  and has been reproduced from a n East African  Standard , EAS 148-2: 2017, Cement — Test 
methods — Part 2: Chemical analysis , and adopt ed as a Uganda Standard.  
The committee responsible for this document is Technical Committee UNBS/TC 3, Building and construction . 
This s tandard cancels and replaces US 100-2:2016, Cement — Test me thods — Part 2: Chemical analysis , 
which has been technically revised.  
Wherever the words, “ East African  Standard"  appear, they should be replaced by "Uganda Standard."  
 
   EAS 148-2: 201 7 
ICS 91.100.10  
© EA C 2017                                                                                                                         Second  Edition 2017  
 
  EAST AFRICAN STANDARD   
Cement — Test methods  — Part 2: Chemical analysis  
EAST AFRICAN COMMUNITY  
 
 
 
 EAS 148-2:201 7 
i © EAC 2017 – All rights reserved  
 Copyright notice  
This EAC document is copyright -protected by EAC. While the reproduction of this document by 
participants in the EAC standards development p rocess is permitted without prior permission from EAC, 
neither this document nor any extract from it may be reproduced, stored or transmitted in any form for 
any other purpose without prior written permission from EAC.  
Requests for permission to reproduce this document for the purpose of selling it should be addressed 
as shown below or to EAC’s member body in the country of the requester:  
© East African Community  2017 — All rights reserved  
East African Community  
P.O.Box 1096  
Arusha  
Tanzania  
Tel: 255 27 2504 253/8  
Fax: 255 27 2504481/2504255  
E-mail: eac@eachq.org  
       Web: www.eac -quality.net  
Reproduction for sales purposes may be subject to royalty payments or a licensing agreement.  
Violators may be persecuted  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  ii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ......................  iii 
1 Scope  ................................ ................................ ................................ ................................ ................  1 
2 Normative references  ................................ ................................ ................................ .......................  1 
3 General requirements for testing  ................................ ................................ ................................ .... 1 
3.1 Number of tests  ................................ ................................ ................................ ................................  1 
3.2 Repeatability and reproducibilit y ................................ ................................ ................................ .... 2 
3.3 Expression of masses, volumes, factors and results ................................ ................................ ..... 2 
4 Ignitions  ................................ ................................ ................................ ................................ ............  2 
4.1 General  ................................ ................................ ................................ ................................ .............  2 
4.2 Reagents  ................................ ................................ ................................ ................................ ...........  3 
4.3 Apparatus  ................................ ................................ ................................ ................................ ....... 14 
4.4 Analysis procedure  ................................ ................................ ................................ ........................  18 
4.5 Determination of major elements  ................................ ................................ ................................ .. 23 
5 Chemical analysis by X -ray fluorescence  ................................ ................................ .....................  44 
5.1 Reagents and reference materials  ................................ ................................ ................................ . 44 
5.2 Apparatus  ................................ ................................ ................................ ................................ ....... 45 
5.3 Flux ................................ ................................ ................................ ................................ .................  46 
5.4 Determination of loss on ignition and the change in mass on fusion of the cement  ..................  47 
5.5 Factoring test results and correcting total analyses for presence of sulfides and halides  ........  49 
5.6 Preparation of fused beads and pressed pellets  ................................ ................................ ..........  51 
5.7 Calibration and validation  ................................ ................................ ................................ ..............  53 
5.8 Calculation and expression of results  ................................ ................................ ..........................  62 
5.9 Performance criteria (repeatability, accuracy and reproducibility limits)  ................................ ... 63 
 
 EAS 148-2:201 7 
iii © EAC 2017 – All rights reserved  
 Foreword  
Development of the East African Standards has been necessitated by the need for harmonizing requirements 
governing quality of products and services in the East African Community. It is envisaged that through 
harmonized standardization,  trade barriers that are encountered when goods and services are exchanged 
within the Community will be removed.  
In order to achieve this objective, the Community established an East African Standards Committee mandated 
to develop and issue East African S tandards.   
The Committee is composed of representatives of the National Standards Bodies in Partner States, together 
with the representatives from the private sectors and consumer organizations. Draft East African Standards 
are circulated to stakeholders t hrough the National Standards Bodies in the Partner States. The comments 
received are discussed and incorporated before finalization of standards, in accordance with the procedures 
of the Community.  
East African Standards are subject to review, to keep pac e with technological advances. Users of the East 
African Standards are therefore expected to ensure that they always have the latest versions of the standards 
they are implementing .  
EAS 148-2 was prepared by Technical Committee EASC/TC/026, Cement , lime, clay and related products . 
In the preparation of this East African Standard, reference was made to the following standard:  
EN 196 -2: 20 13, Methods testing cement — Part 2: Chemical analysis  
The assistance derived from the above source is hereby acknowledge d with thanks.  
This second  edition cancels and replaces the first  edition (EAS 148-2: 2000 ), which has been technically 
revised.  
EAS 148 consists of the following parts, under the general title Cement  — Test methods : 
Part 1: Determination of strength  
Part 2: Chemical analysis  
Part 3: Determination of setting times and soundness  
Part 4: Quantitative determination of constituents  
Part 5: Pozzolanicity test for pozzolanic cement  
Part 6: Determination of fitnes s 
Part 7: Methods of taking and preparing samples of cement  
Part 8: Heat of hydration  — Solution method  EAST AFRICAN STANDARD  EAS 148-2:201 7 
 
1 © EAC 2017 – All rights reserved  
 Cement — Test methods  — Part 2: Chemical analysis  
1 Scope  
This East African Standard specifies the methods for the chemical analysis of cement . 
The standard describes the reference methods and, in certain cases, an alternative method which can be 
considered to be equivalent. In the case of dispute, only the reference methods are used.  
The standard also describes methods which apply principally to cem ents, but which can also be applied to 
their constituent materials and other materials.  
An alternative performance -based method using X -ray fluorescence (XRF) is described for SiO 2, Al2O3, Fe2O3, 
CaO, MgO, SO 3, K2O, Na 2O, TiO 2, P2O5, Mn 2O3, SrO, Cl and Br.   
NOTE 1  When correctly calibrated according  to the specified procedures and reference materials, it provides 
a method equivalent to the reference methods but has not been validated for use yet as a reference 
procedure for conformity and dispute purposes.  It can be applied to other relevant elements when adequate 
calibrations have been established. This method is based on beads of fused samples and analytical validation 
using certified reference materials, together with performance criteria. A method based  on pressed pellets of 
un-fused samples can be considered as equivalent, providing that the analytical performance satisfies the 
same criteria.  
NOTE 2  Any other methods may be used provided they are calibrated, either against the reference methods 
or against internationally accepted reference materials, in order to demonstrate their equivalence.  
2 Normative references  
The following referenced documents are indispensable for the application of this document. For dated 
references, only the edition cited appl ies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
EAS 148 -7, Cement — Test m ethods  — Part 7: Methods of taking and preparing samples  
ISO 385, Laboratory glassware — Burettes  
ISO 835, Laboratory glassware — Graduated pip ettes  
ISO Guide 30 , Reference materials — Selected  terms and definitions used in connection with reference 
materials  
ISO Guide 31 , Reference materials — Contents of certificates and labels  
3 General requirements for testing  
3.1 Num ber of tests  
Analysis of cement  may require the determination of a number of its chemical properties . For each 
determination, one or more tests shall be carried out in which the number of measurements to be taken shall 
be as specified in the relevant claus e of this document .  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  2 
 Where the analysis is one of a series subject to statistical control, the determination  of each chemical property 
by a single test shall be the minimum required.  
Where the analysis is not part of a series subject to statistical control , the number of tests for determination of 
each chemical property shall be two (see also 3.3 and 5.8).  
In the case of a dispute, the number of tests for determination of each chemical property shall be two (see 
also 3.3).  
3.2 Repeatability and reproducibil ity 
Repeatability  is precision under conditions where independent test results are obtained with the same method 
on identical test items (material) in the same laboratory by the same operator using the same equipment 
within short intervals of time . 
Reprodu cibility  is precision under conditions where test results are obtained with the same method on 
identical test items (material) in different laboratories with different operations using different equipment . 
Repeatability  and reproducibility in this document  are expressed as repeatability standard deviation(s) and 
reproducibility standard deviation(s) in for example absolute percent, grams  according to the property tested.  
3.3 Expression of masses, volumes, factors and results  
Express masses in grams to the n earest 0 .0001 g and volumes from burettes in millilitres to the nearest 0 .05 
mL. 
Express the factors of solutions, given by the mean of three measurements, to three decimal places.  
Express the results where a single test result has been obtained, as the me an of the results, as a percentage 
generally to two decimal places.  
Express the results where two test results have been obtained, as the mean of the results, as a percentage 
generally to two decimal places.  
If the two test results  differ by more than twic e the standard deviation of repeatability, repeat the test and take 
the mean of the two closest test results.  
The results of all individual tests shall be recorded.  
4 Ignitions  
4.1 General  
4.1.1  Procedure for ignitions  
Place the filter paper and its conten t into a crucible which has been previously ignited and tared.  
Dry it, then incinerate slowly in an oxidising atmosphere in order to avoid immediate flaming, where ensuring 
complete combustion. Ignite the crucible and its contents at the stated temperatur e then allow to cool to the 
laboratory temperature in a desiccator. Weigh the crucible and its content.  
4.1.2  Determination of constant mass  
Determine constant mass by making successive 15 -min ignitions followed each time by cooling and then 
weighing. Cons tant mass is reached when the difference between two successive weighings is less than 
0.000 5 g.  EAS 148-2:201 7 
3 © EAC 2017 – All rights reserved  
 4.1.3  Check for absence of chloride ions (silver nitrate test)  
After generally five to six washes of a precipitate, rinse the base of the filter stem with a f ew drops of water. 
Wash the filter paper and its contents with several millilitres of water and collect this in a test tube. Add several 
drops of silver nitrate solution (4.2.44). Check the absence of turbidity or precipitate in the solution. If present , 
continue washing while carrying out periodic checks until the silver nitrate test is negative.  
4.1.4  Blank determinations  
Carry out a blank determination without a sample, where relevant, following the same procedure and using the 
same amounts of reagents. Correct the results obtained for the analytical determination accordingly.  
4.1.5  Preparation of a test sample of cement  
Before chemical analysis, treat the laboratory sample, taken in accordance with EAS 148-7, as follows to 
obtain a homo geneous test sam ple. 
Take approximately 100 g of the laboratory sample by means of a sample divider or by quartering. Sieve this 
portion on a 150 -µm or 125 -µm sieve until the residue remains constant. Remove metallic iron from the 
material  retained on the sieve by means o f magnet (see Note 1). Then grind the iron -free fraction of the 
retained material so that it completely passes the 150 -µm or 125 -µm sieve. Transfer the sample to a clean dry 
container with an airtight closure and shake vigorously to mix it thoroughly.  
Carry out all operations as quickly as possible to ensure that the test sample is exposed to ambient air only for 
the minimum time.  
NOTE 1  Where the analysis is one of a series subject to statistical control and the level of the metallic iron content has 
been shown to be insignificant in relation to the chemical properties to be determined then it is not necessary to remove 
metallic iron.  
NOTE 2  Where the sample is to be used for XRF analysis and it contains quartz, it might be necessary t o grind the 
sample to pass a 90 -µm sieve in order to obtain a satisfactory fusion (see 5.6). The time and temperature required to 
obtain a satisfactory fusion is affected by the fitness of the sample.  
NOTE 3  Where the sample is to be used for XRF analysis using pressed pellets,  accuracy can be improved by grinding 
the sample more finely.  
4.2 Reagents  
4.2.1  General  
Only reagents of analytical quality  shall be used .  
NOTE 1  References to water mean distilled or de -ionised water having an electrical conductivity ≤ 0.5 mS/m.   
NOTE 2  Unless otherwise stated,  percent  (%) means percent by mass.  
Unless otherwise stated, the concentrated liquid reagents used in this document have the following densities 
(ρ) (in g/cm3 at 20° C): 
hydrochloric acid   1.18 - 1.19     acetic acid    1.05 - 1.06 
nitric acid    1.40 - 1.42     phosphoric acid   1.71 - 1.75 
perchloric acid   1.60 - 1.67     ammonium hydroxide  0.88 - 0.91 
The degree of dilution is always given as a volumetric sum, for example: dilute hydrochloric acid 1 + 2 means  
that 1 volume of concent rated hydrochloric acid is to be mixed with 2 volumes of water.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  4 
 4.2.2  Types of reagents  
4.2.2.1  Concentrated hydrochloric acid (HCl)  
4.2.2.2 Dilute hydrochloric acid (1 + 1)  
4.2.2.3 Dilute hydrochloric acid (1 + 2)  
4.2.2.4 Dilute hydrochloric acid (1 + 3)  
4.2.2.5 Dilute hydrochloric acid (1 + 9)  
4.2.2.6 Dilute hydrochloric acid (1 + 11)  
4.2.2.7 Dilute hydrochloric acid (1 + 19)  
4.2.2.8 Dilute hydrochloric acid (1 + 99)  
4.2.2.9 Dilute hydrochloric acid of pH (1 .60 ± 0 .05). Prepare by adjusting the pH of two litres of water to 
(1.60 ± 0 .05) by adding five or six drops of concentrated  hydrochloric acid. Control using the pH meter 
(4.3.18.1). Store the solution in a polyethylene container.  
4.2.2.10 Concentrated hydrofluoric acid (> 40 %) (HF)  
4.2.2.11 Dilute hyd rofluoric acid (1 + 3)  
4.2.2.12 Concentrated nitric acid (HNO 3) 
4.2.2.13 Dilute nitric acid (1 + 2)  
4.2.2.14 Dilute nitric acid (1 + 100)  
4.2.2.15 Concentrated sulfuric acid (>98 %) (H 2SO 4) 
4.2.2.16 Dilute sulfuric acid (1 + 1)  
4.2.2.17 Dilute sulfuric aci d (1 + 4)  
4.2.2.18 Concentrated perchloric acid (HClO 4) 
4.2.2.19 Concentrated phosphoric acid (H 3PO 4) 
4.2.2.20 Dilute phosphoric acid (1 + 19) ; Store this solution in a polyethylene container.  
4.2.2.21 Boric acid (H 3BO 3) 
4.2.2.22 Concentrated acetic acid ( CH 3COOH)  
4.2.2.23 Amino -acetic acid (NH 2CH 2COOH)  
4.2.2.24 Metallic chromium (Cr), in powder form  
4.2.2.25 Concentrated ammonium hydroxide (NH 4OH) 
4.2.2.26 Dilute ammonium hydroxide (1 + 1)  
4.2.2.27 Dilute ammonium hydroxide (1 + 10)  
4.2.2.28 Dilute ammoniu m hydroxide (1 + 16)  EAS 148-2:201 7 
5 © EAC 2017 – All rights reserved  
 4.2.2.29 Sodium hydroxide (NaOH)  
4.2.2.30 Sodium hydroxide solution (4 mol/ L). Dissolve 160 g of sodium hydroxide (4.2. 2.29) in water and 
make up to 1 000 mL. Store in a polyethylene  container.  
4.2.2.31 Sodium hydroxide solution (2 mol /L). Dissolve 80 g of sodium hydroxide (4.2. 2.29) in water and 
make up to 1 000 mL. Store in a polyethylene  container.  
4.2.2.32 Ammonium chloride (NH 4Cl) 
4.2.2.33 Tin (II) chloride (SnCl 2.2H 2O) 
4.2.2.34 Potassium iodate (KIO 3) dried to constant mass at (12 0 ± 5) °C  
4.2.2.35 Potassium periodate (KIO 4) 
4.2.2.36 Sodium peroxide (Na 2O2) in powder form  
4.2.2.37 Sodium chloride (NaCl) dried to constant mass at (110 ± 5) °C  
4.2.2.38 Potassium chloride (KCl)  dried to constant mass at (110 ± 5) °C  
4.2.2.39 Sodium ca rbonate (Na 2CO 3) dried to constant mass at (250 ± 10) °C  
4.2.2.40 Mixture of sodium carbonate and sodium chloride . Mix 7 g of sodium carbonate (4.2. 2.39) with 1 
g sodium chloride (NaCl) (4.2. 2.37). 
4.2.2.41 Barium chloride solution . Dissolve 120 g of bariu m chloride (BaCl 2.2H 2O) in water and make up to 
1 000 mL. 
4.2.2.42 Silver nitrate (AgNO 3) dried to constant mass at (150 ± 5)  o C 
4.2.2.43 Silver nitrate solution  Dissolve 5 g of silver nitrate (AgNO 3) (4.2. 2.42) in water, add 10 mL of 
concentrated nitric acid (HNO 3) (4.2. 2.13) and make up to 1 000 mL with water.  
4.2.2.44 Silver nitrate solution (0 .05 mol/ L). Dissolve (8 .494 0 ± 0 .000 5) g of silver nitrate (AgNO 3) 
(4.2.2.42) in water in a 1 000 mL volumetric flask and  make up to the mark. Store in a brown glass container 
and protect from the light.  
4.2.2.45 Sodium carbonate solution . Dissolve 50 g of anhydrous sodium carbonate (4.2. 2.39) in water and 
make up to 1 000 mL. 
4.2.2.46 Potassium hydroxide solution  Dissolve 250 g of potassium hydroxide (KOH) in wa ter and make up 
to 1 000 mL. Store in a polyethylene  container.  
4.2.2.47 Ammoniacal zinc sulfate solution . Dissolve 50 g of zinc sulfate (ZnSO 4.7H 2O) in 150 mL water 
and add 350 mL of concentrated ammonium  hydroxide (4.2. 2.25). Leave to stand for at least 24 h and filter.  
4.2.2.48 Lead acetate solution . Dissolve approximately 0 .2 g of lead acetate (Pb(CH 3COO) 2.3H 2O) in water 
and make up to 100 mL. 
4.2.2.49 Starch solution . To 1 g of starch (water soluble), add 1  g of potassium iodide (KI), dissolve in water  
and make up to 100 mL. Use within two weeks.  
4.2.2.50 Polyethylene oxide solution . Dissolve 0 .25 g of polyethylene oxide ( -CH 2-CH 2-O-)n of average 
molecular mass 200 000 to 600 000, in  100 mL water while stirring vigorously. Use within two weeks.  
4.2.2.51 Boric acid solution , saturated . Dissolve approximately 50 g of boric acid (H 3BO 3) in water and 
make up to 1 000 mL. EAS 148-2:201 7 
© EAC 2017 – All rights reserved  6 
 4.2.2.52 Citric acid solution . Dissolve 10 g of citric acid (C 6H8O7.H2O) in water and make up to 100 mL. 
4.2.2.53 Calcium carbonate (CaCO 3), dried to constant mass at (200 ± 10) °C (of purity > 99 .9 %) 
4.2.2.54 Ammonium molybdate solution . Dissolve 10 g of ammonium molybdate (NH 4)6Mo 7O24.4H 2O in 
water and make up to 100 mL. Store the  solution in a polyethylene flask. Use within one week.  
4.2.2.55 Copper sulfate solution . Dissolve 0 .45 g of copper sulfate (CuSO 4.5H 2O) in water and make up to 
50 mL in a volumetric flask.  
4.2.2.56 Ammonium acetate solution . Dissolve 250 g of ammonium acetate (CH 3COONH 4) in water and 
make up to 1 000 mL. 
4.2.2.57 Triethanolamine [N(CH 2CH 2OH) 3], (> 99 %) diluted to 1 + 4 solution  
4.2.2.58 Reducing solution . Dissolve 1 g of tin (II) chloride (SnCl 2.2H 2O) (4.2. 2.33) in water to which has 
been added 1 mL of concentrated  hydrochloric acid (4.2.2 .1). Make up to 100 mL with water. Use within one 
day. 
4.2.2.59 Buffer solution  of pH 1. 40. Dissolve (7 .505 ± 0 .001) g of amino -acetic acid (4.2. 2.23) and (5 .850 ± 
0.001) g of sodium chloride (NaCl)  (4.2.2.36) in water and make up to 1 000 mL. Dilute 300 mL of this solution 
to 1 0 00 mL with hydrochloric acid 1 + 99 (4.2. 2.8). 
4.2.2.60 Standard potassium iodate solution , approximately 0 .016 6 mol/ L. 
4.2.2.60.1 Weigh, to ± 0 .000 5 g, (3 .6 ± 0 .1) g, of potassium iodate (KIO 3) (4.2. 2.34) (m1) and place in a 1 
000 mL volumetric flask. A dd 0.2 g of sodium hydroxide (4.2. 2.29), 25 g of potassium iodide (KI), dissolve all 
the solids  in freshly boiled and cooled water and make up to the mark using the same water.  
4.2.2.60.2 Calculate the factor , F, of the potassium iodate solution from the f ollowing formula:  
3.56681mF
 (1) 
where  
m1 is the mass of the portion of potassium iodate, in grams . 
4.2.2.61 Sodium thiosulfate solution , approximately 0 .1 mol/ L 
4.2.2.61.1 Preparation  
Dissolve  (24.82 ± 0. 01) g of sodi um thiosulfate (Na 2S2O3.5H 2O) in water and make up to 1 000 mL. Before  
each test series, determine the factor f of this solution as described in 4.2. 2.61.2. 
4.2.2.61.2 Standardization  
4.2.2.61.2.1 Standardization using potassium iodate solution  
4.2.2.61.2.1.1 This standardization is carried out preferably using the standard potassium iodate solution 
(4.2.2.60). For this  standardization, pipette 20 mL of the standard potassium iodate solution (4.2. 2.60) into a 
500 mL conical flask  and dilute with approximate ly 150 mL of water. Acidify with 25 mL of hydrochloric acid 
1+1 (4.2. 2.2) and titrate  with the approximately 0 .1 mol/ L sodium thiosulfate solution (4.2. 2.61.1) to a pale 
yellow colour. Add 2 mL of the  starch solution (4.2. 2.49) and continue the titration u ntil the colour changes 
from blue to colourless.  
4.2.2.61.2.1.2 Calculate the factor f of the sodium thiosulfate solution from the formula:  EAS 148-2:201 7 
7 © EAC 2017 – All rights reserved  
 
1 1 x20
 x 3.5668 x 214.01 x 0.01667 x 20
VF
VFf   (2) 
where  
F is the fact or of the standard potassium iodate solution (4.2. 2.60); 
V1 is the volume of the approximately 0 .1 mol/ L sodium thiosulfate solution used for the titration, in  
millilitres;  
3.5668  is the mass of potassium iodate corresponding to a solution with exactly 0 .016 67 mol/ L of 
potassium iodate, in grams;  
214.01 is the molecular mass of KIO 3, in grams.  
4.2.2.61.2.2 Standardisation using a known quantity of potassium iodate  
4.2.2.61.2.2.1  The standardization may alternatively be carried out using a known quantity of  potassium 
iodate. For this  standardization, weigh, to ± 0 .000 5 g, (0 .070 ± 0 .005) g of potassium iodate (4.2. 2.34) (m2) 
and place in a  500-mL conical flask. Dissolve in approximately 150 mL of water. Add about 1 g of potassium 
iodide, acidify  with 25 mL of hydrochloric acid 1+1 (4.2. 2.2) and titrate with the approximately 0 .1 mol/ L 
sodium thiosulfate  solution (4.2. 2.61.1) until a pale yellow colour is obtained. Then add 2 mL of the starch 
solution (4.2. 2.49) and  titrate until the colour changes from blue to colourless.  
4.2.2.61.2.2.2 Calculate the factor f of the sodium thiosulfate solution from the formula:  
Vm
Vmf
22
22 x 280.3634
 x 3.5668 x 000 1 
 (3) 
where  
m2 is the mass of potassium iodate, in grams;  
V2 is the volume of the approximately 0 .1 mol/ L sodium thiosulfate solution used for the titration, in  
millilitres;  
3.5668 is the mass of potassium iodate corresponding to a solution with exactly 0 .016 67 mol/ L of 
potassium iodate, in grams.  
4.2.2.62 Standard manganese solution  
4.2.2.62.1 Anhydrous manganese sulfate  
Dry hydrated manganese sulfate (MnSO 4.xH 2O) to constant mass at (250 ± 10) °C. The composition of the  
product obtained corresponds to the formula MnSO 4. 
4.2.2.62.2 Preparation  
Into a 1 00 0-mL volumetric flask, weigh, to ± 0 .000 5 g, (2 .75 ± 0 .05) g of anhydrous manganese sulfate ( m3); 
dissolve in water and make up to the mark. Calculate the content G of manganese (II) ions of this solution,  
expressed in milligrams of Mn  2+ per millilitre, from the formula:  
2.7485mG3
 (4) 
where  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  8 
 m3 is the mass of anhydrous manganese sulfate, in grams.  
4.2.2.62.3 Construction of the calibration curve  
4.2.2.62.3.1 Into each of two volumetric flasks, respectively 500 mL (No. 1) and 1 000 mL (No. 2), pipette 20 
mL of the  standard manganese solution. Make up to the mark with water. Into each of three volumetric flasks,  
respectively 200 mL (No. 3), 500 mL (No. 4) and 1 000 mL (No. 5) pipette 100 mL of the solution from flask 
No. 2 and make up to the mark with water.  
4.2.2.62.3.2 Take 100 mL of each solution from flasks 1 to 5 and pipette each portion into a 400 -mL beaker. 
Add 20 mL of concentrated nitric acid (4.2. 2.12), 1.5 g of potassium periodate (4.2. 2.35) and 10 mL of 
phosph oric acid (4.2. 2.19), heat to boiling and boil gently for 30 min.  Allow to cool to room temperature and 
transfer the c ontents of each beaker to a 200 -mL volumetric flask and  make up to the mark with water. 
Measure the absorbance of the solutions using a ph otometer (4.3.10) at a  wavelength of around 525 nm, 
against water (use one or more cells (4.3.11) of appropriate sizes). Record the  absorbance values to three 
decimal places.  
4.2.2.62.3.3 For each cell optical length, construct a separate curve of the abso rbance of these calibration 
solutions E1 to  E5 as a function of the corresponding manganese concentrations in milligrams of Mn per 200 
mL. The  corresponding manganese concentrations are given in Table 1. They can be used as given if the 
content G obtained in accordance with 4.2. 2.62.2 has the value 1 .000 0. Otherwise, multiply the manganese  
concentrations in Table 1 by the value of G calculated from Formula (4).  
Table 1 — Concentrations of manganese calibration solutions  
Calibration solution  E1 E2 E3 E4 E5 
Concentration of manganese in mg of Mn per 200 mL  4.0 2.0 1.0 0.4 0.2 
 
4.2.2.63 Standard silica solution  
4.2.2.63.1 Silica (SiO 2), of purity >  99.9 % after ignition to constant mass at (1 175 ± 25) °C  
4.2.2.63.2 Basic solution  
4.2.2.63.2.1 Weigh (0 .200 0  ± 0.000 5) g of freshly ignited silica (4.2. 2.63.1), in a platinum crucible already 
containing  (2.0 ± 0 .1) g of anhydrous sodium carbonate (4.2. 2.39). 
4.2.2.63.2.2 Heat the mixture and fuse it at a bright -red heat for at least 15 min. After cooling to roo m 
temperature, place  the fused solid in a polyethylene beaker and dissolve it in water, then transfer the solution 
quantitatively to a  200-mL volumetric flask and make up to the mark with water.  
4.2.2.63.2.3 Store the solution in a polyethylene container.  This solution contains 1 mg of SiO 2 per mL. 
4.2.2.63.3 Standard solution  
Pipette 5 mL of the basic solution into a 250 -mL volumetric flask and make up to the mark with water. Store 
the solution in a polyethylene container. This solution contains 0 .02 mg si lica per  mL. Use within one week.  
4.2.2.63.4 Compensating solutions  
Prepare the compensating solutions according to the procedure adopted in the determination of silica content  
(4.5.3 to 4.5.5) by dissolving the amounts of the reagents given in Table 2 in water and making up to 500 mL. 
4.2.2.63.5 Construction of the calibration curve  
4.2.2.63.5.1 Add from a burette the volumes of the silica calibration solutions given in Table 3 into 100 - mL 
polyethylene  beakers each containing a magnetic stirrer bar. Add 2 0 mL of the compensating solution by 
pipette and make  up to 40 mL with water from a burette. The volumes required for this are also given in Table EAS 148-2:201 7 
9 © EAC 2017 – All rights reserved  
 3. While stirring  with a magnetic stirrer, add 15 drops of hydrofluoric acid 1+3 (4.2. 2.11). Stir for at leas t 1 min. 
Then pipette  15 mL of the boric acid solution (4.2. 2.51) into the solution . 
Table 2 — Composition of the compensating solutions for a volume of 500 mL 
Reagent  Precipitation by 
double evaporation 
(4.5.3)  Precipitation by 
polyethylene oxide 
(4.5.4)  Decomposition by HCI 
and NH 4CI (4.5.5)  
HCI conc , mL 75 70 15 
H2SO 4 1 + 1 , mL 1 1 - 
HNO 3 conc , mL - - 1 
Polyethylene oxide solution , mL - 5 - 
NH 4CI, g - - 1 
Na2CO 3, g 1.75 1.75 1.75 
NaCI , g 0.25 0.25 0.25 
Na2O2, g 3 3 - 
 
Table 3 — Composition of th e silica calibration solutions and their silica content  
Silica calibration solutions  Sample  
Blank  1 2 3 4 
Standard SiO 2 solution , mL 0 2 5 10 20 
Water , mL 20 18 15 10 0 
Silica content , mg SiO 2/100 mL  0 0.04 0.10 0.20 0.40 
 
4.2.2.63.5.2 Add from a pip ette 5 mL of the ammonium molybdate solution (4.2. 2.54). Adjust the pH of this 
solution to  (1.60 ± 0 .05) by adding, drop by drop, sodium hydroxide solution (4.2. 2.30) or hydrochloric acid 1 + 
2 (4.2. 2.3) using the pH meter (4.3.18.1) calibrated with a buff er solution of similar pH for example  1.40 see 
4.2.2.59. Transfer the  solution to a 100 -mL volumetric flask and rinse the beaker with dilute hydrochloric acid 
(4.2.2.9). After 20 min,  add from a pipette 5 mL of the citric acid solution (4.2. 2.52), stir and  leave to stand for 
5 min. Then add from a  pipette 2 mL of the reducing solution (4.2. 2.58). (Time 0).  
4.2.2.63.5.3 Make up to the mark with dilute hydrochloric acid (4.2. 2.9) and mix. At time (0 + 30) min, measure 
the absorbance with the photometer (4.3.1 0) using a cell (4.3.11) of 1 cm optical length against the blank 
solution  prepared in the same way, using the wavelength 815 nm. Construct a curve giving the measured 
absorbance  as a function of the corresponding silica contents given in Table 3.  The blan k solution used in 
constructing the calibration curve may be used as the blank solution here. The  calibration curve enables the 
silica content in mg SiO 2/100 mL to be determined.  
4.2.2.64 Standard calcium ion solution, approximately 0 .01 mol/ L 
Weigh, to ± 0.000 5 g, (1 .00 ± 0 .01) g of calcium carbonate (4.2. 2.53) (m4) and place it in a 40 -mL beaker with  
approximately 100 mL of water. Cover the beaker with a watch glass and carefully introduce approximately  10 
mL of hydrochloric acid 1 + 2 (4.2. 2.3). Stir wi th a glass rod and ensure that dissolution is complete, bring to  
the boil in order to expel the dissolved carbon dioxide. Cool to room temperature, transfer to a 1 000 -mL 
volumetric flask, washing the beaker and watch glass carefully, and make up to the ma rk with water.  
4.2.2.65 EDTA solution , approximately 0 .03 mol/ L 
4.2.2.65.1 Ethylenediaminetetra -acetic acid disodium salt dihydrate (EDTA)  
4.2.2.65.2 Dissolve (11 .17 ± 0 .01) g of EDTA in water and make up to 1 000 mL. Store in a polyethylene 
container.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  10 
 4.2.2.65.3 Standardization  
4.2.2.65.3.1 Pipette 50 mL of the standard calcium ion solution (4.2. 2.64) into a beaker suitable for the 
measuring apparatus  (4.3.12). Then dilute with water to a volume suitable for the operation of the apparatus.  
4.2.2.65.3.2 Using the pH meter (4.3.18.1), adjust the pH of this solution to (12 .5 ± 0 .2) with either of the 
sodium hydroxide  solutions (4.2. 2.30 or 4.2. 2.31). 
4.2.2.65.3.3 Determine the end -point using one of the following two methods : 
a) Photometric determination of the e nd-point (reference method)  
 Add, without weighing, about 0 .1 g of murexide (4.2. 2.69) or of mixed calcein and methylthymol blue 
indicator  (4.2.2.75). Place the beaker in the apparatus (4.3.12) set at 620 nm when using murexide 
or at 520 nm when  using the mixed indicator and, while stirring continuously, titrate with the 
approximately 0 .03 mol/ L EDTA  solution. In the vicinity of the indicator colour change, construct a 
curve giving the absorbance values as a  function of the volume of EDTA added. The volume V3 used 
is determined from the intersection of the line of  greatest slope near the colour change and the line of 
almost constant absorbance after the colour change.  Calculate the factor fD of the EDTA solution 
from the formula:  
34 4 x 16.652
 x0.03 x 100.09 x 50
3DVm
Vm
f  
 (5) 
where  
m4 is the mass of calcium carbonate taken to prepare the standard calcium ion solution (4.2. 2.64), in 
grams;  
V3 is the volume of the EDTA solution used for the titration, in millilitres.  
b) visual determination of the end -point (alternative method)  
 Add, without weighing, about 0 .1 g of either the calcon indicator (4.2. 2.71) or the Patton and Reeders 
indicator  (4.2.2.76). Stir and titrate with the approximately 0 .03 mol/ LEDTA sol ution (4.2. 2.65) until 
the colour changes from  pink to blue (calcon) or purple to blue (Patton and Reeders), volume V3, and 
one drop in excess does not  further increase the intensity of the blue colour. Calculate the 
standardization factor fD of the EDTA s olution  using Formula (5).  
4.2.2.66 Copper complexonate solution  
4.2.2.66.1 Pipette 25 mL of the copper sulfate solution (4.2. 2.55) into a 400 -mL beaker and add from a 
burette an equivalent  volume V5 of the approximately 0 .03 mol/ L EDTA solution (4.2. 2.65). Determine the 
required volume V5 of EDTA  solution as follows.  
4.2.2.66.2 Pipette 10 mL of the copper sulfate solution (4.2. 2.55) into a 600-mL beaker. Dilute to 
approximately 200 mL with water and add 10 mL of concentrated ammonium hydroxide (4.2. 2.25) and, 
without weighing, about 0 .1 g of  murexide indicator (4.2. 2.69). Titrate with the approximately 0 .03 mol/ L EDTA 
solution (4.2. 2.65) until the colour  changes from pink to violet ( V4). 
4.2.2.66.3 Calculate the volume V5 of the approximately 0 .03 mol/ L EDTA solution to be added to 25 mL of 
the copper  sulfate solution to obtain copper complexonate from the formula:  
V V 4 5  x 2.5
 (6) 
where  EAS 148-2:201 7 
11 © EAC 2017 – All rights reserved  
 V4 is the volume of the approximately 0 .03 mol/ L EDTA solution for the titration, i n millilitres.  
4.2.2.67 EGTA solution,  approximately 0 .03 mol/ L 
4.2.2.67.1 Ethyleneglycolbis (aminoethylether) tetra -acetic acid (EGTA)  
4.2.2.67.2 Preparation  
Dissolve (11 .4 ± 0 .01) g of EGTA in 400 mL of water and 30 mL of the sodium hydroxide solution (4 .2.2.31) in 
a 600-mL beaker. Heat the mixture until the EGTA is completely dissolved. Allow to cool to room temperature.  
Using the pH meter (4.3.18.1), adjust the pH to (7 .0 ± 0 .5), by adding, drop by drop, hydrochloric acid 1 + 2  
(4.2.2.3). Transfer the s olution quantitatively to a 1 000 -mL volumetric flask and make up to the mark with 
water.  Store the solution in a polyethylene container.  
4.2.2.67.3 Standardization  
4.2.2.67.3.1 Pipette 50 mL of the standard calcium ion solution (4.2. 2.64) into a beaker su itable for the 
measuring apparatus  (4.3.12). Then dilute with water to a volume suitable for the correct operation of the 
apparatus. Add 25 mL of the triethanolamine 1 + 4 solution (4.2. 2.57). 
4.2.2.67.3.2 Using the pH meter (4.3.18.1), adjust the pH of th is solution to (12 .5 ± 0 .2) with either of the 
sodium hydroxide  solutions (4.2. 2.30 or 4.2. 2.31). 
4.2.2.67.3.3 Add, without weighing, about 0 .1 g of murexide (4.2. 2.69) or of calcein indicator (4.2. 2.70). Place 
the beaker in the  apparatus (4.3.12) set at 6 20 nm when using murexide or at 520 nm when using calcein 
and, while stirring  continuously, titrate with the approximately 0 .03 mol/ L EGTA solution. In the vicinity of the 
indicator colour  change, take note of the absorbance values and the correspondent vo lumes of EGTA added 
and construct a  curve of absorbance versus volume of titrant. The volume V6 used is determined from the 
intersection of the  line of greatest slope near the colour change and the line of almost constant absorbance 
after the colour  change . 
4.2.2.67.3.4 Calculate the factor f G of the EGTA solution from the formula:  
65 5 x 16.652
 x0.03 x 100.09 x 50
6GVm
Vm
f  
 (7) 
where 
m5 is the mass of calcium carbonate taken to prepare the standard calcium ion solution (4.2. 2.64), in 
grams;  
V6 is the volume of the EGTA solution used for the titration, in millilitres.  
4.2.2.68 DCTA solution, approximately 0 .01 mol/ L 
4.2.2.68.1 1.2-diaminocyclohexane tetra -acetic (DCTA)  
4.2.2.68.2 Preparation  
Dissolve (3.64 ± 0 .01) g of DCTA in about 400 mL of water and 10 mL of sodium hydroxide solution (4.2. 2.31) 
in a 600 -mL beaker. Heat the mixture until the DCTA is completely dissolved. Allow to cool to room 
temperature.  Using the pH meter (4.3.18.1), adjust the pH to (7 .0 ± 0 .5) by adding hydrochloric acid 1 + 2 
(4.2.2.3), drop by  drop. Transfer the sol ution quantitatively to a 1 000 -mL volumetric flask and make up to the 
mark with water.  Store this solution in a polyethylene container.  
 
 EAS 148-2:201 7 
© EAC 2017 – All rights reserved  12 
 4.2.2.68.3 Standardization  
4.2.2.68.3.1 Pipette 50 mL of the standard calcium ion solution (4.2. 2.64) into a beaker appropriate for the 
measuring  apparatus (4.3.12). Then dilute with water to a volume suitable for the correct operation of the 
apparatus.  
4.2.2.68.3.2 Using the pH met er (4.3.18.1), adjust the pH of this solution to (10 .5 ± 0 .2) with concentrated 
ammonium  hydroxide (4.2. 2.25). 
4.2.2.68.3.3 Add, without weighing, about 0 .1 g of murexide (4.2. 2.69) or of calcein indicator (4.2. 2.70). Place 
the beaker in the  apparatus (4.3 .12) set at 620 nm when using murexide or at 520 nm when using calcein 
and, while  continuously stirring the solution, titrate with the approximately 0 .01 mol/ L DCTA solution. In the 
vicinity of the  colour change of the indicator, take note of the absorbanc e values and the correspondent 
volumes of DCTA  added and construct a curve of absorbance versus volume of titrant. The volume V7 used is 
determined by the  intersection of the line of greatest slope near the colour change and the line of almost 
constant abs orbance  after the colour change.  
4.2.2.68.3.4 Calculate the factor fC of the DCTA solution from the formula:  
76 6 x 49.995 
 x0.01 x 100.09 x 50
1cVm
Vm
f  
 (8) 
where  
m6 is the mass of calcium carbonate t aken to prepare the standard calcium ion solution (4.2. 2.64), in 
grams;  
V7 is the volume of the DCTA solution used for the titration, in millilitres.  
4.2.2.69 Murexide indicator . Prepare by grinding (1 .0 ± 0 .1) g of murexide (ammonium purpurate, 
C8H4N5O6.NH4) with (100 ± 1) g of  sodium chloride (NaCl).  
4.2.2.70 Calcein indicator . Prepare by grinding (1 .0 ± 0 .1) g of calcein (bis [(bis (carboxymethyl) -amino -
methyl)] –2’, 7’ -fluorescein,  Fluoresceindi -(methylimino diacetic acid) sodium salt) with (100 ± 1) g of 
potassium nitrate (KNO 3). 
4.2.2.71 Calcon indicator . Prepare by grinding (1. 0 ± 0 .1) g of calcon (sodium 2 -hydroxy -4-(2-hydroxy -1-
naphthylazo) naphthalene -1-sulfonate, EriochromeBlue -Black R) with (100 ± 1) g of anhydrous sodium sulfate 
(Na 2SO 4). 
4.2.2.72 Sulfosalicylic acid indicator (5 -sulfosalicylic acid dihydrate)  
4.2.2.73 PAN indicator . Prepare by dissolving (0 .10 ± 0 .01) g of PAN (1 -(2-pyridylazo) -2-naphthol, 
C15H11N3O) in (100 ± 1) mL ethanol  (C2H5OH, density = 0 .79). 
4.2.2.74 Methylthymol blue in dicator . Prepare by grinding (1 .0 ± 0 .1) g of methylthymol blue (sodium salt of 
3’, 3’’ -bis- [bis (carboxy -methyl)  - aminomethyl] -thymolsulfophthalein, C 37H41N2O13SNa 3) with (100 ± 1) g of 
potassium nitrate (KNO 3). 
4.2.2.75 Mixed calcein and methylthymol b lue indicator . Prepare by grinding (0 .20 ± 0 .02) g of calcein 
(see 4.2. 2.70) and (0 .10 ± 0 .01) g of methylthymol blue  (see 4.2. 2.74) with (100 ± 1) g of potassium nitrate 
(KNO 3). 
4.2.2.76 Patton and Reeders reagent . Prepare by mixing (1 .0 ± 0 .1) g of 2 -hydroxy-1-(2-hydroxy -4-sulfo -1-
napthylazo) -3-napthoic acid  (C21H14N2O7S) with (100 ± 1) g of anhydrous sodium sulfate (Na 2SO 4). 
4.2.2.77 Mixed indicator . Prepare by mixing (0 .10 ± 0 .01) g o-cresophthalein complexone ( o-
cresolphthaleindi -(methyliminodi -acetic  acid), C32H32N2O12), (0.020 ± 0 .001) g methyl red indicator ( o-EAS 148-2:201 7 
13 © EAC 2017 – All rights reserved  
 carboxybenzene -azodimethyl -aniline,  C15H14N3NaO 2) and (0 .030 ± 0 .001) g naphthol green B 
(C30H15FeN 3Na3O15S3) with (10 .0 ± 0 .1) g of sodium  chloride (4.2. 2.37). 
4.2.2.78 Ammonium thiocyanate (N H4SCN)  
4.2.2.79 Ammonium thiocyanate solution,  approximately 0 .05 mol/ L. Prepare by dissolving (3 .8 ± 0 .1) g of 
ammonium thiocyanate (4.2. 2.78) in water and making up to 1 000 mL. 
4.2.2.80 Ammonium iron (III) sulfate, (NH 4Fe(SO 4)2.12H 2O) 
4.2.2.81 Indicator  solution . Prepare by adding 10 mL of nitric acid 1 + 2 (4.2. 2.13) to 100 mL of a cold 
saturated water solution of ammonium  iron (III) sulfate (4.2. 2.80). 
4.2.2.82 Copper (II) sulfate (CuSO 4.5H 2O) 
4.2.2.83 Saturated water solution of copper (II) sulfate  
4.2.2.84 Absorbent for hydrogen sulfide . Place a weighed quantity of dried pumice stone with a grain size 
between 1 .2 mm and 2 .4 mm into a flat dish  and cover with a volume of saturated copper sulfate solution 
(4.2.2.83) so the mass of the copper sulfate  solution is approximately half of that of the pumice stone. 
Evaporate the mixture to dryness, while stirring  frequently with a glass rod. Dry the contents of the dish for at 
least 5 h in an oven at a temperature of  (150 ± 5) °C. Allow the solid mixture to coo l in a desiccator and store 
in an airtight bottle.  
4.2.2.85 Absorbent for water . Anhydrous magnesium perchlorate (Mg(ClO 4)2) with a particle size between 
0.6 mm and 1 .2 mm.  
4.2.2.86 Absorbent for carbon dioxide . Synthetic silicates with a particle size bet ween 0 .6 mm to 1 .2 mm 
impregnated with sodium hydroxide (NaOH)  (4.2.2.29). 
NOTE  This absorbent can be obtained ready for use.  
4.2.2.87 Mercuric (II) chloride (HgCl 2) 
4.2.2.88 Alkali stock solution . Weigh (0 .566 0 ± 0 .000 5) g of sodium chloride (4.2. 2.37) and (0 .475 0 ± 
0.000 5) g of potassium chloride  (4.2.2.38) and place in a 600 mL beaker. Add approximately 150 mL of water 
and allow the salts to dissolve.  Transfer the solution quantitatively, rinsing the b eaker with water, to a 1 000 -
mL volumetric flask and make up  to the mark with water. Mix the contents of the flask thoroughly. This solution 
contains 0 .300 g each of sodium  oxide (Na 2O) and potassium oxide (K 2O). 
4.2.2.89 Acid stock solution, (HCl/H 3PO 4). To approximately 500 mL of water, placed in a 1 0 00-mL 
volumetric flask, add 50 mL of concentrated  hydrochloric acid (4.2.2 .1) and 50 mL of concentrated phosphoric 
acid (4.2. 2.19). Allow to cool then make up to  the mark with water and mix thoroughly.  
4.2.2.90 Calcium  stock solution . Weigh (11 .25 ± 0 .01) g of calcium carbonate (4.2. 2.53) into a 600 - mL 
beaker. Add 100 mL of water and dissolve  the calcium carbonate by cautiously adding 25 mL of concentrated 
hydrochloric acid (4.2.2 .1). After the reaction  is completed, bring slowly to boiling in order to exp el the 
dissolved carbon dioxide and then cool. Transfer the  solution, rinsing the beaker with water, into a 1 000 -mL 
volumetric flask, make up to the mark with water and  mix thoroughly.  
4.2.2.91 Alkali stock solution ( alternative  method) . Dissolve (0 .2542 ± 0.0005) g of sodium chloride 
(4.2.2.37) and (0 .190 7 ± 0 .000 5) g of potassium chloride  (4.2.2.38) in water in a 1 000 -mL volumetric flask 
and make up to the mark. (See Note to 4.2. 2.94.) 
4.2.2.92 Caesium chloride (CsCl)  
4.2.2.93 Aluminium nitrate (Al(NO 3)3.9H 2O) EAS 148-2:201 7 
© EAC 2017 – All rights reserved  14 
 4.2.2.94 Buffer solution . Dissolve 50 g of caesium chloride (4.2. 2.92) and 250 g of aluminium nitrate 
(4.2.2.93) in water and make up to  1 000 mL. (See Note).  
NOTE  These solutions can be obtained made up ready for use.  
4.3 Apparatus  
4.3.1  Balance (s), capable  of weighing to an accuracy of ± 0 .000 5 g  
4.3.2  Crucibles  
4.3.2.1  Porcelain and/or platinum crucibles, 20 mL - 25 mL capacity. The methods specify where 
platinum crucibles are to be used. Unless platinum is specified, porcelain  crucibles may b e used.  
4.3.2.2  Lids, suitable lids to be fitted to crucibles (4.3.2.1) where required  
4.3.3  Fire proof ceramic support(s) . For preventing overheating of the crucible, it shall be in thermal 
equilibrium with the furnace at the moment the  crucible is introd uced.  
4.3.4  Porcelain evaporating dish , of approximately 200 mL 
4.3.5  Electric furnaces(s), naturally ventilated and capable of being set at the following temperatures:  (500 
± 10) °C, (950 ± 25) °C and (1 175 ± 25) °C  
4.3.6  Laboratory oven(s), capable of b eing set at the following temperatures: (110 ± 5) °C, (120 ± 5) °C,  
(150 ± 5) °C, ( 200 ± 10) °C, and (250 ± 10) °C  
4.3.7  Desiccator(s), containing anhydrous magnesium perchlorate (Mg(ClO 4)2) or silica gel.  Where self -
indicating silica gel is used, a non -toxic indicator is recommended  
4.3.8  Bulb condenser  
4.3.9  Apparatus for determining sulfide . A typical apparatus is shown in Figure 1. A Woolf bottle may be 
added to control the flow of gas.  The connecting tubes shall be made of a material free from sulfur ( polyvinyl 
chloride, polyethylene, etc.).  
 
Key 
1 lead acetate solution (4.2. 2.48) 
2 air, nitrogen or argon  
3 ammoniacal solution of zinc sulfate (4.2. 2.47) 
4 reaction flask  
Figure 1 — Typical apparatus for the determination of sulphide  EAS 148-2:201 7 
15 © EAC 2017 – All rights reserved  
 4.3.10 Photometer(s), for measuring the absorbance of a solution in th e vicinity of 525 nm and 815 nm  
4.3.11  Cells, for the photometer  
4.3.12  Apparatus for measuring the absorbance, at 520 nm and 620 nm of a solution contained in a  
titration beaker, while sti rring  
4.3.13  Stirrer, for example  magnetic stirrer, with inert, for example  PTFE, covered ba r 
4.3.14  Evaporation apparatus, controlled at (105 ± 5) °C, for example  water bath or hot plate  
4.3.15  Sand bath or hot plate, controlled at approximately 400 °C  
4.3.16 Ashless filter papers  
NOTE  Filter papers with a mean pore diameter of around 2 µm are termed fine, those with  a mean pore diameter of 
around 7 µm are termed medium and those with a mean pore diameter of around 20 µm are termed coarse.  
4.3.17  Volumetri c glassware , of analytical accuracy, that is . class A as defined in ISO 385 and ISO 835  
4.3.18  pH measuring equipment  
4.3.18.1  pH meter, capable of measuring to an accuracy of ± 0 .05 
4.3.18.2  pH indicator paper(s), capable of measuring pH in the 0 – 14 ran ge. 
4.3.19  Apparatus for the determination of the carbon dioxide (reference method)  
4.3.19.1  Figure 2 shows a typical apparatus which can be fitted with either a cylindrical pressure container, 
a small  electrical compressor or a suitable suction pump which  will ensure an even flow of gas or air. The gas 
(air or  nitrogen) entering the apparatus has previously had its carbon dioxide removed by first being passed 
through  an absorbent tube or tower containing the carbon dioxide absorbent (4.2. 2.86). The apparat us 
consists of a  100-mL distillation flask (14) fitted with a three neck adaptor. Neck (5) is connected to a dropping 
funnel (4),  neck (6) to a connecting tube and neck (8) to a water cooled condenser. The funnel onto (5) and 
the connecting tube onto (6) a re joined together by means of a Y -piece (1), so that the carbon dioxide -free air 
can flow either through the connecting tube or the funnel by means of a Mohr clip (2).  
4.3.19. 2 After the condenser (9), the gas is passed through concentrated sulfuric acid (4.2.2.15) (10), then 
through  absorption tubes containing the absorbent for hydrogen sulfide (4.2. 2.84) (11) and for water (4.2. 2.85) 
(12) and  subsequently through two absorption tubes (13) which can be weighed and which are three -quarters 
filled with  the absorbent for carbon dioxide (4.2. 2.86) and a quarter with the absorbent for water (4.2. 2.85). 
The absorbent  for carbon dioxide (4.2. 2.86) is placed upstream of the absorbent for water (4.2. 2.85) with 
respect to the gas flow.  Absorption tubes (13) are foll owed by an additional absorption tube (15), which also 
contains the absorbent  for carbon dioxide and water, which is fitted in order to protect second absorption tube 
(13) against  penetration by carbon dioxide and water from the air.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  16 
  
 
Key 
1 Y-piece  
2 Mohr clip  
3 absorption tower containing carbon dioxide absorbent (4.2. 2.86) 
4 dropping funnel  
5 dropping funnel connector  
6 connecting tube connector  
7 three -armed still head  
8 condenser connector  
9 condenser  
10 wash bottle with concentrated sulfuric acid (4 .2.2.15) 
11 absorption tube with absorbent for hydrogen sulfide (4.2. 2.84) 
12 absorption tube with absorbent for water (4.2. 2.85) 
13 absorption tubes with absorbents for carbon dioxide (4.2. 2.86) and water (4.2. 2.85) 
14 100-mL distillation flask  
15 absorpt ion tubes with absorbents for carbon dioxide (4.2. 2.86) and water (4.2. 2.85) 
Figure 2 — Typical apparatus for the determination of carbon dioxide (reference method)  
4.3.19. 3 The absorption tubes (13) which are to be weighed may have, for example, the follo wing 
approximate sizes : 
a) external distance between branches             45 mm ; 
b) internal diameter                 20 mm ; 
c) distance between the lower part of the tube and the upper part of the ground section  75 mm ; and  EAS 148-2:201 7 
17 © EAC 2017 – All rights reserved  
 d) Tube wall thickness                1.5 mm . 
4.3.20  Apparatus for the determination of the carbon dioxide content (alternative method)  
4.3.20 .1 A typical apparatus is shown in Figure 3. A small vacuum pump is used to generate reduced 
pressure in the  apparatus.  
4.3.20 .2 Paraffin may be used instead of sulfuric acid in the final wash bottle (Figure 3) as this bottle only 
serves as a  bubble counte r 
 
Key 
1 dropping fu nnel for sulfuric acid (4.2. 2.17) 
2 condenser  
3 absorption tubes containing absorbent for  water (4.2. 2.85) 
4 absorption tubes containing abs orbent for carbon dioxide (4.2. 2.86) and water (4.2. 2.85) 
5 absorption tubes with absorbents for carbon dioxide (4.2. 2.86) and water (4.2. 2.85) 
6 to the vacuum pump  
7 100-mL distillation flask  
8 absorption tower containing absorbent  for carbon dioxide (4.2 .2.86) 
9 washing bottle (empty)  
10 washing bottle containing concentrated  sulfuric acid (4.2. 2.15) or paraffin  
Figure 3 — Typical apparatus for the determination of carbon dioxide (alternative method)  
4.3.21  Flame photometer , of sufficient stability and ca pable of measuring the intensities of the sodium line 
at 589 nm and the potassium  line at 768 nm. In order to avoid any interference of the determination by 
alkaline earths, the flame photometer  shall be operated with a relatively low temperature by using a propane -
air or butane -air flame.  
4.3.22  Platinum dish  
4.3.23  Filter paper, medium filter paper (4.3.16), prewashed with hot water  
4.3.24  Stirrer, resistant to hydrofluoric acid, for example  platinum  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  18 
 4.3.25  Heating lamp, capable of evaporating to dryness samples in aqueous solution  
4.4 Analysis procedure  
4.4.1  Determination of loss on ignition  
4.4.1.1  Principle  
The loss on ignition is determined in an oxidising atmosphere. By igniting the sample in air at (950 ± 25) °C  
the carbon dioxide and water are driv en off and any oxidisable elements present are oxidised to some extent.  
A correction for the influence of this oxidation on the loss on ignition is described. The error resulting from the  
oxidation of metallic iron, bivalent iron, or bivalent manganese is usually considered to be negligible and only  
the correction for the extent of oxidation of any sulfides is applied (see 4.4.1.4).  
4.4.1.2  Procedure  
Weigh, to ± 0 .000 5 g, (1 .00 ± 0 .05) g of cement ( m7) into a crucible which has been previously ignited and  
tared. Place the covered crucible in the electric furnace (4.3.5) controlled at (950 ± 25) °C. After heating for  5 
min, remove the lid and leave the crucible in the furnace for a further 10 min. Allow the crucible to cool to  room 
temperature in the desicca tor. Determine constant mass ( m8) in accordance with 4.1.2.  
NOTE  For cements containing sulfides, a more accurate determination of the loss on ignition can be obtained by  
determining the sulfate contents before and after ignition. The correction applicable  to these cements is given in 4.4.1.4.  
4.4.1.3  Calculation and expression of results  
Calculate the observed loss on ignition , L, in percent from the formula:  
100 x  - 
78 7
mm mL
 (9) 
where  
m7 is the mass  of the test portion, in grams;  
m8 is the mass of the ignited test portion, in grams.  
4.4.1.4  Correction for oxidation of sulfides  
Calculate the correction for the extent of oxidation of sulfide that occurs during the determination of loss on  
ignition by d etermining the sulfate present before ignition, SO 3 (initial), and after ignition, SO 3 (final), from the  
following relationships:  
a) SO 3 (final) - SO 3 (initial) = SO 3 resulting from the oxidation of sulfides;  
b) oxygen taken up = 0 .8 (SO 3 from oxidation of  sulfide) = correction;  
c) corrected loss on ignition = observed loss on ignition ( L) + oxygen taken up;  
where  in a), b) and c) all values are expressed in percent ages  based on the initial mass(es) of unignited test  
portion(s).  
Any corrections applied shal l be indicated in the test report.  
4.4.1.5  Repeatability and reproducibility  
4.4.1. 5.1 The standard deviation for repeatability is 0 .04 %.  Field  Code  ChangedEAS 148-2:201 7 
19 © EAC 2017 – All rights reserved  
 4.4.1. 5.2 The standard deviation for reproducibility is 0 .08 %.  
4.4.2  Determination of sulfate  
4.4.2.1  Principle  
4.4.2.1.1  Sulfate ions, produced by the decomposition of cement with hydrochloric acid, are precipitated at 
a pH  between 1 .0 and 1 .5 by a solution of barium chloride. The precipitation of barium sulfate is carried out at  
boiling point.  
4.4.2.1. 2 The determinat ion is then completed gravimetrically and sulfate expressed as SO 3. 
4.4.2.2  Procedure  
4.4.2.2.1  Weigh, to ± 0 .000 5 g, (1 .00 ± 0 .05) g of cement (m 9), place in a 250 -mL beaker, and add 90 mL 
of water. While  stirring the mixture vigorously, add 10 mL of con centrated hydrochloric acid (4.2.2 .1). Heat the 
solution gently  and crush the sample with the flattened end of a glass stirring rod until decomposition is 
complete. Allow the  solution to digest for 15 min at a temperature just below boiling.  
4.4.2.2. 2 Filter the residue on a medium filter paper (4.3.16) into a 400 -mL beaker. Wash thoroughly with 
hot water until  free from chloride ions, tested by the silver nitrate test (4.1.3).  
4.4.2.2. 3 Adjust the volume to about 250 mL; if necessary, adjust the pH of the solution to between 1 .0 and 
1.5 with  hydrochloric acid 1 + 11 (4.2. 2.6) or ammonium hydroxide 1 + 16 (4.2. 2.28). 
4.4.2.2. 4 Bring to the boil and boil for 5 min. Check that the solution is clear; if not, start the determination 
again using a  new test portio n. While stirring vigorously, maintain the solution at boiling point and add drop by 
drop 10 mL of the barium chloride solution (4.2. 2.41) heated to just below boiling. Maintain the solution at just 
below boiling  point for at least 30 min, ensuring that th e volume is kept between 225 mL and 250 mL, and 
then allow the  covered beaker to stand at room temperature for 12 h - 24 h before filtration.  
4.4.2.2. 5 Filter the precipitate on a fine filter paper (4.3.16) and wash with boiling water until free from 
chlor ide ions,  tested by the silver nitrate test (4.1.3).  
4.4.2.2. 6 Ignite (4.1.1) at (950 ± 25) °C to constant mass (4.1.2) ( m10). 
NOTE  In general, an ignition period of 15 min is sufficient to achieve constant mass.  
4.4.2.3  Calculation and expression of resul ts 
Calculate the sulfate content, expressed as SO 3, in percent from the formula:  
9 9310 10 x34.3100 x 0.343x 
mm
mm
SO 
 (10) 
where  
m9 is the mass of the test portion, in grams;  
m10 is the mass of bariu m sulfate, in grams.  
4.4.2.4  Repeatability and reproducibility  
4.4.2.4.1  The standard  deviation  for repeatability is 0 .07 %.  
4.4.2.4. 2 The standard deviation for reproducibility is 0 .08 %.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  20 
 4.4.3  Determination of residue insoluble in hydrochloric acid and s odium carbonate  
4.4.3.1  Principle  
This is a method in which the insoluble residue in cement is obtained by treatment with dilute hydrochloric acid  
in order to minimise the precipitation of soluble silica. The residue from this treatment is treated with a b oiling  
solution of sodium carbonate in order to re -dissolve traces of silica which may have been precipitated. After  
ignition the residue is determined gravimetrically.  
4.4.3.2  Procedure  
4.4.3.2.1  Weigh, to ± 0 .000 5 g, (1 .00 ± 0 .05) g of cement (m 11), pla ce in a 250 -mL beaker, add 90 mL of 
water and, while  stirring the mixture vigorously, add 10 mL of concentrated hydrochloric acid (4.2.2 .1). 
4.4.3.2. 2 Heat the solution gently and crush the sample with the flattened end of a glass stirring rod until 
decomp osition  is complete. Allow the solution to digest for 15 min at a temperature just below boiling.  
4.4.3.2. 3 Filter the residue on a medium filter paper (4.3.16) and wash thoroughly with almost boiling water. 
Transfer  the filter paper and its contents back to the reaction beaker and add 100 mL of the sodium carbonate 
solution  (4.2.2.45). Boil for approximately 30 min. Filter on a medium filter paper and wash with almost boiling 
water,  then four times with hot hydrochloric acid 1 + 19 (4.2. 2.7) until pH < 2 b y indicator paper (4.3.18.2) is 
obtained  and with almost boiling water until free from chloride ions, tested by the silver  nitrate test (4.1.3).  
4.4.3.2. 4 Ignite (4.1.1) at (950 ± 25) °C to constant mass (4.1.2) ( m12). 
NOTE  In general, an ignition period o f 30 min is sufficient to achieve constant mass.  
4.4.3.2. 5 If a cloudy filtrate is observed, filter again on a fine filter paper, wash thoroughly with hot water 
and combine  the two residues on their filter papers to ignite them. If in spite of this operati on the filtrate 
remains cloudy, its  effect on the insoluble residue may be neglected.  
4.4.3.3  Calculation and expression of results  
Calculate the insoluble residue in percent from the formula:  
Insoluble residue  
100 x  
1112
mm  (11) 
where  
m11 is the mass of the test portion, in grams;  
m12 is the mass of the ignited insoluble residue, in grams.  
4.4.3.4  Repeatability and reproducibility  
4.4.3.4.1  The standard deviation for repeatability is 0 .04 %.  
4.4.3.4.1  The standard d eviation for reproducibility is 0 .06 %.  
4.4.4  Determination of residue insoluble in hydrochloric acid and potassium hydroxide  
4.4.4.1  Principle  
This is a method in which the insoluble residue in cement is obtained initially by treatment with a hydrochloric  
acid solution. The residue from this treatment is then treated with a boiling solution of potassium hydroxide.  
After ignition, the residue is determined gravimetrically.  EAS 148-2:201 7 
21 © EAC 2017 – All rights reserved  
 4.4.4.2  Procedure  
4.4.4.2.1  Weigh, to ± 0 .000 5 g, (1 .00 + 0 .05) g of cement (m 13), place in a porcelain dish (4.3.4), add 25 
mL of water  and disperse using a glass stirring rod. Add 40 mL of concentrated hydrochloric acid (4.2.2 .1). 
Heat the solution  gently and crush the sample with the flattened end of a glass stirring rod until decompos ition 
is complete.  Evaporate to dryness on a water bath (4.3.14). Repeat the operation twice more with 20 mL 
concentrated  hydrochloric acid (4.2.2 .1). 
4.4.4.2. 2 Treat the residue from the third evaporation with 100 mL of hydrochloric acid 1 + 3 (4.2. 2.4). Re-
heat, filter on a  medium filter paper (4.3.16) and wash with almost boiling water until free from chloride ions, 
tested by the  silver nitrate test (4.1.3).  Transfer the filter paper and its contents to a 250 -mL conical flask fitted 
with a bulb condenser  (4.3.8) and add  100 mL of the potassium hydroxide solution (4.2. 2.46). Leave to stand 
for 16 h at room temperature and then  boil the solution under reflux for 4 h.  
4.4.4.2. 3 Filter on a medium filter paper (4.3.16) and wash with water then with 100 mL of hydrochloric acid 
1 + 9 (4.2. 2.5) and finally with almost boiling water until free from chloride ions, tested by the silver nitrate test 
(4.1.3).  
4.4.4.2. 4 Ignite (4.1.1) at (950 ± 25) °C to constant mass (4.1.2) ( m14). 
NOTE  In general, an ignition period of 30 min is sufficient to achieve constant mass.  
4.4.4.3  Calculation and expression of results  
Calculate the insoluble residue in percent from the formula:  
Insoluble residue  
100 x  
1314
mm  (12) 
where  
m13 is the mass  of the test portion, in grams;  
m14 is the mass of the ignited insoluble residue, in grams.  
4.4.4.4  Repeatability and reproducibility  
4.4.4.4.1  The standard deviation for repeatability is 0 .15 %.  
4.4.4.4. 2 The standard deviation for reproducibility is 0 .18 %. 
4.4.5  Determination of sulfide  
4.4.5.1  Principle  
The cement is decomposed by hydrochloric acid under reducing conditions. The sulfides are transformed into  
hydrogen sulfide, which is carried over by a gaseous stream into an ammoniacal solution of zinc sulfate. The  
amount of precipitated zinc sulfide is determined by iodometry.  
4.4.5.2  Procedure  
4.4.5.2.1  Use the apparatus described in 4.3.9. Weigh, to ± 0 .000 5 g, (1 .00 ± 0 .05) g of cement ( m15) (see 
Note 1),  place in a 250 -mL stoppered round bottom fla sk with a ground glass joint. Add about 2 .5 g of tin (II) 
chloride  (4.2.2.33) and 0 .1 g of chromium (4.2. 2.24) (see Note 2). Disperse in 50 mL of water. Fix the flask to 
the ground  neck of the dropping funnel and connect to the condenser the glass outlet t ube which dips into the 
beaker  containing 15 mL of ammoniacal zinc sulfate solution (4.2. 2.47) and 285 mL of water. Connect the gas 
supply  (air, nitrogen or argon) and adjust the flow to about 10 mL per min. Stop the flow of gas. Release 50 
mL of hydrochlo ric acid 1 + 1 (4.2. 2.2) from the dropping funnel ensuring that a small quantity of acid remains EAS 148-2:201 7 
© EAC 2017 – All rights reserved  22 
 in the  dropping funnel to provide a seal. Reconnect the gas supply, heat the contents of the flask to boiling 
and boil  for 10 min. Disconnect the outlet tube w hich can serve as a stirrer during the titration.  
4.4.5.2. 2 Cool to room temperature, add 10 mL of potassium iodate solution approximately 0 .016 6 mol/ L 
(4.2.2.60) by pipette and 25 mL of concentrated hydrochloric acid (4.2.2 .1). Titrate with sodium thiosu lfate 
solution (4.2. 2.61) until pale yellow. Then add 2 mL of starch solution (4.2. 2.49) and titrate until the colour 
changes from blue to  colourless . 
NOTE 1  If the sulfide content is low (<  0.10 %), the mass of the test portion will preferably be increase d in proportion.  
NOTE 2  Chromium assists in the decomposition of any pyrites (FeS 2) present in the cement.  
4.4.5.3  Calculation and expression of results  
Calculate the sulfide content in percent from the formula:  
159 8
158 9
mf)] V( - F) V[(
 x 0.1603 
m  x000 1100 1.603f)] (V -F) V([  
 
2S
 (13) 
where  
V8 is the volume of potassium iodate solution, in millilitres;  
F is the factor of the potassium iodate solution;  
V9  is the vo lume of the sodium thiosulfate solution used for the titration, in millilitres;  
f is the factor of the sodium thiosulfate solution;  
m15 is the mass of the test portion, in grams.  
4.4.5.4  Repeatability and reproducibility  
4.4.5.4.1  The standard deviation fo r repeatability is 0 .02 %.  
4.4.5.4. 2 The standard deviation for reproducibility is 0 .04 %.  
4.4.6  Determination of manganese  
4.4.6.1  Principle  
The manganese present is oxidised to permanganate (MnO 4-) by means of potassium periodate. The  
absorbance of the v iolet solution is measured at 525 nm. The ferric (Fe3+) ions are complexed with phosphoric  
acid which also assists the formation of MnO 4- and stabilises the colour of the solution.  
4.4.6.2  Procedure  
4.4.6.2.1  Weigh, to ± 0 .000 5 g, (0 .1 to 1 .0) g of cement  (m16) into a 250 -mL beaker. Disperse in about 75 
mL of water.  Stir, add cautiously 15 mL of nitric acid (4.2. 2.12) and boil in a fume cupboard until free from any 
hydrogen  sulfide (H 2S) present and all the cement (see Note) is decomposed.  
4.4.6.2. 2 For co ntents of manganese of the order of 0 .01 %, taking a test portion close to 1 g and varying 
its amount to  suit the probable manganese concentration is recommended.  
NOTE  For cements with a high insoluble residue, fusion of a separate test portion can be nece ssary to obtain  
complete solution. This is carried out by the method of sintering with sodium peroxide as described for the determination  
of the main constituents (see 4.5.2).  EAS 148-2:201 7 
23 © EAC 2017 – All rights reserved  
 4.4.6.2. 3 Filter through a medium filter paper (4.3.16) into a 400 -mL beaker. Wa sh the residue with hot 
water until the  volume of the filtrate is 120 mL. To this filtrate, add 10 mL of phosphoric acid (4.2. 2.19), mix 
and add 1 .5 g of  potassium periodate (4.2. 2.35). Heat to boiling until the characteristic pink colour of 
permanganate a ppears. If it  does not appear, reduce the acidity by adding a few drops of concentrated 
ammonium hydroxide (4.2. 2.25). 
4.4.6.2. 4 Once the colour has appeared, continue boiling gently for 30 min. Cool and transfer the contents 
of the beaker  to a 200 -mL volumetric flask. Cool to room temperature and make up to the mark with water.  
4.4.6.2. 5 Using a photometer (4.3.10 and 4.3.11), measure the absorbance of the solution against water at 
a wavelength of approximately 525 nm.  
4.4.6.2. 6 Record the absorbance value  to three decimal places. The absorbance read from the calibration 
curve  (4.2.2.62.3) corresponding to the cell used gives the concentration of manganese, C, in milligrams of  
manganese per 200 mL. Record the manganese concentration, C, to three decimal pla ces. 
4.4.6.3  Calculation of results  
Calculate the manganese content Mn in percent from the formula:  
16 x0.1 
 x 0001 x 
16mC
m100C
Mn  
 (14) 
where  
C is the manganese ( Mn) concentration of the solution, in milligram s per 200 mL; 
m16 is the mass of the test portion, in grams.  
4.4.6.4  Repeatability and reproducibility  
4.4.6.4.1  The standard deviation for repeatability is 0 .003 %.  
4.4.6.4. 2 The standard deviation for reproducibility is 0 .03 %.  
4.4.6.5  Expression of resu lts 
The manganese content is normally expressed as MnO or Mn 2O3. The following formulae are used in their  
calculation:  
MnO = 1.29 x Mn;  in percent;  (15) 
Mn 2O3 = 1.44 x Mn; in percent.  (16) 
4.5 Determination of major elements  
4.5.1  Principle  
4.5.1.1  The ana lysis is carried out after the cement is completely dissolved. The decomposition with 
hydrochloric acid  and ammonium chloride (alternative method) may be used for cement with an insoluble 
residue (as  determined in accordance with 4.4.3) not exceeding 1 .5 %. 
4.5.1. 2 The cement is decomposed by sintering with sodium peroxide or by treatment with hydrochloric 
acid in the  presence of ammonium chloride. In the first case, after dissolution of the sintered solid in 
hydrochloric acid,  the major part of the silica is precipitated either by double evaporation or by hydrochloric 
acid with coagulation  by polyethylene oxide; in the second case, the major part of the silica is separated by 
the treatment. The  impure silica precipitated is treated with hydrofluoric acid an d sulfuric acid to volatilise EAS 148-2:201 7 
© EAC 2017 – All rights reserved  24 
 silica; the residue,  treated with a mixture of sodium carbonate and sodium chloride, is dissolved in 
hydrochloric acid and added  to the silica filtrate.  
4.5.1. 3 In the case of the treatment with hydrochloric acid in the presen ce of ammonium chloride, if the 
residue  obtained after volatilisation of impure silica by means of hydrofluoric acid and sulfuric acid is greater 
than 0.5 %, the method is not applicable. In this case it is necessary to decompose the cement by sodium  
perox ide. 
4.5.1. 4 In the final solution, the soluble (residual) silica is determined by photometric determination, and 
iron (III)  oxide, aluminium oxide, calcium oxide and magnesium oxide are determined by complexometric 
methods.  
4.5.1. 5 The schematic diagram o f the chemical analysis is shown in Figure 4.  
4.5.1. 6 The relative amounts of impure, pure and soluble (residual) silica may vary depending on the 
procedure used,  but the same result for the total silica is obtained whichever path in Figure 4 is chosen.  EAS 148-2:201 7 
25 © EAC 2017 – All rights reserved  
 
 
Figure 4 — Schematic diagram for analysis of the major elements  
4.5.1. 7 If the residue insoluble in hydrochloric acid and sodium carbonate (see 4.4.3) is greater than 1 .5 
%, it is  necessary to use the method of decomposition by sodium peroxide.  
4.5.1. 8 When the ammonium chloride method is used, if the residue after volatilisation with hydrofluoric 
acid and  sulfuric acid exceeds 0 .5 %, it is necessary to recommence the analysis using the decomposition by 
sodium  peroxide.  
4.5.2  Decomposition with sodium perox ide 
4.5.2.1  Weigh, to ± 0 .000 5 g, (1 .00 ± 0 .05) g of cement ( m17) and place, with about 2 g of sodium 
peroxide (4.2. 2.36), into a platinum crucible (4.3.2.1); mix thoroughly with a spatula. Brush back into the EAS 148-2:201 7 
© EAC 2017 – All rights reserved  26 
 mixture any particles  adhering to the spatula . Cover the mixture with about 1 g of sodium peroxide. Carefully 
preheat the crucible  fitted with a lid (4.3.2.2) for about 2 min at the opening of the furnace (4.3.5) before 
placing it on its support  (4.3.3) in the heated zone controlled at a uniform temp erature of (500 ± 10) °C.  
4.5.2. 2 After 30 min, remove the crucible from the furnace and allow it to cool to room temperature. The 
sintered solid  mass should not stick to the sides of the crucible. If it does, then repeat the decomposition at a 
temperature  10 °C lower than was first used.  
4.5.2. 3 Transfer t he sintered solid mass to a 400 -mL beaker and rinse the crucible with 150 mL of cold 
water.  
4.5.2. 4 Cover the beaker with a watch glass and heat until the solid is completely dispersed. Then add 
cautiousl y 50 mL of concentrated hydrochloric acid (4.2.2 .1). The solution obtained shall be perfectly clear. If 
not, reject it  and repeat the decomposition by peroxide at a temperature increased by 10 °C or for double the 
time in the  furnace. Add to the solution 1  mL of sulfuric acid 1 + 1 (4.2. 2.16). Bring the solution to the boil and 
boil for  30 min.  
4.5.2. 5 This solution is ready for use for the precipitation of silica in accordance with 4.5.3 or 4.5.4.  
4.5.3  Precipitation and determination of silica — Double ev aporation method (reference method)  
4.5.3.1  Procedure  
4.5.3.1.1  Evaporate to dryness the solution prepared as described in 4.5.2 on evaporation apparatus 
controlled at  (105 ± 5) °C (4.3.14). Moisten with several drops of concentrated hydrochloric acid (4.2 .2.1). 
Leave for 1 h at  this temperature.  
4.5.3.1. 2 After cooling to room temperature, treat the residue with 10 mL of concentrated hydrochloric acid 
(4.2.2 .1). After  a few minutes, dilute with 50 mL of water, bring to the boil and filter the hot solution through a 
medium filter  paper (4.3.16) into a 500 -mL volumetric flask. Wash the filter and the residue three times with 
hot water.  Evaporate the filtrate and washings in the same way, treat with 10 mL of concentrated hydrochloric 
acid (4.2.2 .1) and dilute with 50 mL of water. Boil, and then  pass through the same filter into a 500 -mL 
volumetric flask. Where  filtration is difficult a second filter paper may be used in which case the following 
procedure shall be applied to  both filter papers and precipitated r esidue.  
4.5.3.1. 3 Wash the filter and precipitate with hot water until free from chloride ions, tested by the silver 
nitrate test  (4.1.3). Collect the washings in the same 500 -mL volumetric flask.  
4.5.3.1. 4 Ignite (4.1.1) the filter and precipitate, to con stant mass (4.1.2) ( m18), in a platinum crucible at (1 
175 ± 25) °C.  
NOTE  In general, an ignition period of 60 min is sufficient to obtain constant mass.  
4.5.3.1. 5 Volatilise the ignited precipitate as described in 4.5.6. Add the decomposed evaporation res idue 
solution  (4.5.7) to the f iltrate and washings in the 500 -mL volumetric flask. The combined solutions are used 
for the  colorimetric determination of soluble silica that is . the residual silica in solution (4.5.8) and for the  
complexometric determinatio ns of iron (III) oxide (4.5.10), aluminium oxide (4.5.11), calcium oxide (4.5.12 or  
4.5.14) and magnesium oxide (4.5.13 or 4.5.15).  
4.5.3.2  Calculation and expression of results  
Calculate th e impure silica content in percent from the formula:  
Impure  SiO 2
x100
1718
mm
  (17) 
where  Field  Code  ChangedEAS 148-2:201 7 
27 © EAC 2017 – All rights reserved  
 m17 is the mass of the test portion as in 4.5.2, in grams;  and 
m18 is the mass determined in accordance with 4.5.3.1, in grams.  
4.5.4  Precipitation and determination of si lica — Polyethylene oxide method (alternative method)  
4.5.4.1  Procedure  
4.5.4.1.1  Evaporate to dryness the solution prepared as described in 4.5.2. Allow the beaker to cool. Treat 
the residue  with 5 mL of water and 10 mL of concentrated hydrochloric acid ( 4.2.2 .1). While stirring, add some 
ashless filter  paper pulp to the mixture and then 5 mL of the polyethylene oxide solution (4.2. 2.50) ensuring 
that the  precipitate and the polyethylene oxide are thoroughly mixed, especially the precipitate adhering to th e 
sides of  the beaker. Stir the mixture thoroughly then add 10 mL of water, stirring briefly and leave to stand for 
5 min.  
4.5.4.1. 2 Filter through a medium f ilter paper (4.3.16) into a 500 -mL volumetric flask and rinse with hot 
hydrochloric acid  1 + 19 (4 .2.2.7). Remove any precipitate adhering to the sides of the beaker using a rubber 
or plastics scraper.  Wash the filter and precipitate at least five times with hot hydrochloric acid 1 + 19, then 
rinse with hot water,  ensuring that the residue in the filte r is broken up thoroughly during washing, until free 
from chloride ions,  tested by the silver nitrate test (4.1.3) . 
4.5.4.1. 3 Colle ct the washings in the same 500 -mL volumetric flask.  
4.5.4.1. 4 Ignite (4.1.1) the filter and the precipitate, to constant mas s (4.1.2) ( m19), in a platinum crucible at  
(1 175 ± 25) °C.  
NOTE  In general, an ignition period of 60 min is sufficient to obtain constant mass.  
4.5.4.1. 5 Volatilise the ignited precipitate as described in 4.5.6. Add the decomposed evaporation residue 
(4.5.7) to the  filtrate and washings in the 500 -mL volumetric flask. The combined solution is used for the 
colorimetric  determination of soluble silica that is  the residual silica in solution (4.5.8) and for the 
complexometric  determinations of iron (III) oxid e (4.5.10), aluminium oxide (4.5.11), calcium oxide (4.5.12 or 
4.5.14) and  magnesium oxide (4.5.13 or 4.5.15).  
4.5.4.2  Calculation and expression of results  
Calculate the impure silica content in percent from the formula:  
Impure  SiO 2
x100
1719
mm
  (18) 
where 
m17 is the mass of the test portion used in 4.5.2, in grams;  
m19 is the mass determined in accordance with 4.5.4.1, in grams.  
4.5.5  Decomposition with hydrochloric acid and ammonium chloride an d precipitation of silica  
(alternative method)  
4.5.5.1  General  
This method is to be used only where the insoluble residue, as determined in 4.4.3, does not exceed 1 .5 %. 
4.5.5.2  Procedure  
4.5.5.2.1  Weigh, to ± 0 .000 5 g, (1 .00 ± 0 .05) g of cement (m 20) and  place in a 100 -mL beaker. Add about 1 
g of ammonium chloride (4.2. 2.32) and mix thoroughly with a glass stirring rod. Cover the beaker with a watch Field  Code  ChangedEAS 148-2:201 7 
© EAC 2017 – All rights reserved  28 
 glass  and cautiously add 10 mL of concentrated hydrochloric acid (4.2.2 .1) taking care to let the acid run down 
the side  of the beaker. When effervescence has stopped, add 10 drops of nitric acid (4.2. 2.12) and stir with a 
glass  stirring rod crushing any lumps.  
4.5.5.2. 2 Place the beaker and its watch glass on a boiling water bath and leave for 30 min. Dilute t he 
contents of the  beaker with a small quantity of hot water and filter through a coarse f ilter paper (4.3.16) into a 
500-mL volumetric flask. Transfer the gelatinous precipitate to the filter as completely as possible without 
dilution, and  allow the solut ion to drain through the filter. Remove all precipitate adhering to the beaker by 
using a rubber or  plastics scraper.  
4.5.5.2. 3 Rinse the beaker and precipitate with hot hydrochloric acid 1 + 99 (4.2. 2.8). Then wash the 
precipitate and filter  with small am ounts of hot water until free from chloride ions, tested by the silver nitrate 
test (4.1.3).  
4.5.5.2. 4 Collect the washings in the same 500 -mL volumetric flask.  
4.5.5.2. 5 This is used, together with the evaporation residue decomposed as described in 4.5.7,  for the 
photometric  determination of soluble silica that is  residual silica in solution in accordance with 4.5.8.  Ignite 
(4.1.1) the filter and the precipitate, to constant mass (4.1.2) ( m21), in a platinum crucible at  (1 175 ± 25) °C.  
NOTE  In general, an  ignition period of 60 min is sufficient to obtain constant mass.  
4.5.5.2. 6 Volatilise the ignited precipitate as described in 4.5.6.  
4.5.5.3  Calculation and expression of results  
Calculate the impure silica in percent from the formula:  
 
Impure  SiO 2
x100
2021
mm
  (19) 
where  
m20 is the mass of the test portion used in 4.5.5.2, in grams;  
m21 is the mass determined in accordance with 4.5.5.2, in grams.  
4.5.6  Determination of pure silica  
4.5.6.1  Procedu re 
4.5.6.1.1  Moisten the precipitate, obtained in accordance with 4.5.3.1 ( m18) or 4.5.4.1 ( m19) or 4.5.5.2 ( m21), 
with about  0.5 mL - 1 mL of water, add approximately 10 mL of hydrofluoric acid (4.2. 2.10) then two drops of 
sulfuric acid  (4.2.2.15). Evapor ate in a fume cupboard over a sand bath or hot plate (4.3.15), then continue to 
heat until free  from white sulfuric acid fumes.  
4.5.6.1. 2 Ignite the crucible with the evaporation residue in an electric furnace (4.3.5) at (1 175 ± 25) °C for 
10 min,  leave t o cool to room temperature in a desiccator and weigh ( m22). 
4.5.6.1. 3 Decompose  the evaporation residue as described in 4.5.7. If the residue obtained by this method 
exceeds  0.5 %, restart the analysis using the method of decomposition with sodium peroxide  (4.5.2).  
4.5.6.2  Calculation and expression of results  
Calculate the pure silica content in percent from the formula:  Field  Code  ChangedEAS 148-2:201 7 
29 © EAC 2017 – All rights reserved  
 Pure  SiO 2 
x100
2322 24
mm-  m
  (20) 
where  
m22 is the mass determined in accordance with 4.5.6.1, in grams;  
m23 is the mass of the test portion used in 4.5.2 ( m17) or in 4.5.5.2 ( m20), in grams;  
m24 is the mass determined in accordance with 4.5.3.1 ( m18), 4.5.4.1 ( m19) or 4.5.5.2 ( m21), in grams.  
4.5.7  Decomposition of the evap oration residue  
4.5.7.1  To the evaporation residue, obtained in accordance with 4.5.6.1, add about 2 g of the sodium 
carbonate and  sodium chloride mixture (4.2. 2.40) and fuse to a bright red heat for example  using a gas 
burner. Swirl the melt  frequently un til the residue is completely dissolved.  
4.5.7. 2 Check visually that no part of the residue remains at the base of the crucible. Allow the crucible 
and its  contents to cool, transfer to a 250 -mL beaker, add about 100 mL water and acidify with a few millili tres 
of concentrated hydrochloric acid (4.2.2 .1). When the decomposed mass is completely dissolved, remove the  
platinum crucible from the solution and rinse it with water.  
4.5.7. 3 Check that the solution is clear. If not, filter through a medium filter pap er (4.3.16), wash, burn off 
the paper,  ignite and then repeat the decomposition as above. Transfer the solution to the 500 -mL volumetric 
flask containing the filtrate and washings from the precipitation of silica in accordance with 4.5.3.1 or 4.5.4.1 or  
4.5.5.2; make up to the mark with water.  
4.5.7. 4 After shaking the flask vigorously, this solution is ready to be used in the photometric 
determination of the  soluble silica (4.5.8) and also in the complexometric determinations of iron (III) oxide (4.5.10), 
aluminium oxide  (4.5.11), calcium oxide (4.5.12 or 4.5.14) and magnesium oxide (4.5.13 or 4.5.15).  
4.5.8  Determination of soluble silica  
4.5.8.1  Procedure  
4.5.8.1.1  Pipette 20 mL of the solution prepared in accordance with 4.5.7 from the 500 -mL volumetric flask 
into a  polyethylene beaker already containing a magnetic stirrer bar (4.3.13) and add 20 mL water. While 
stirring with  the magnetic stirrer (4.3.13), add 15 drops of to (1 .60 ± 0 .05) by adding, drop by drop, sodium 
hydroxide  (4.2.2.30) or hydrochlori c acid 1 + 2 (4.2. 2.3), using hydrofluoric acid 1 + 3 (4.2. 2.11). Stir again for 
at least 1 min.  Then pipette 15 mL of the boric acid solution (4.2. 250). Add from a pipette 5 mL of the 
ammonium molybdate  solution (4.2. 2.54) to the solution. Adjust the pH o f the solution a pH meter (4.3.18.1) 
calibrated with a buffer  solution of similar pH value for example  1.40 see 4.2. 2.59). 
4.5.8.1. 2 Transfer the solution to a 100 -mL volumetric flask and rinse the beaker with hydrochloric acid of 
pH 1 .60 (4.2.2.9). After 20 min, add from a pipette 5 mL of the citric acid solution (4.2. 2.52), stir and leave to 
stand for  5 min. Then add from a pipette 2 mL of the reducing solution (4.2. 2.58) (Time 0) . Make up to volume 
with dilute hydrochloric acid of pH 1 .60 (4.2. 2.9) and m ix. At time (0 + 30) min measure the  absorbance with 
the photometer (4.3.10) against a blank solution prepared in a similar way and using the  same wavelength 
and a cell (4.3.11) of the same optical length as used for the construction of the calibration  curve (4.2. 2.63.5). 
The silica concentration ( m25) in mg SiO 2/100 mL is read from the calibration curve.  
4.5.8.2  Calculation and expression of results  
Calculate the soluble silica content in percent from the formula:  
Soluble  SiO 2
2325 x2.5 
 x000 1 x 20100x  x 500
2325 
mm
mm
   (21) Field  Code  ChangedEAS 148-2:201 7 
© EAC 2017 – All rights reserved  30 
 where  
m23 is the mass of the test portion used in 4.5.2 ( m17) or 4.5.5.2 ( m20), in grams;  
m25 is the silica concentration of the solution in accordance with 4.5.8.1, in milligrams of SiO 2 in 100 mL. 
4.5.9  Determination of total silica  
4.5.9.1  Calculation and expression of results  
The total silica content, in percent, is the sum of the pure silica content (4.5.6) and the soluble silica content  
(4.5.8).  
4.5.9.2  Repeatabi lity and reproducibility  
4.5.9.2.1  The standard deviation for repeatability is 0 .10 %.  
4.5.9.2. 2 The standard deviation for reproducibility is 0 .25 %.  
4.5.10  Determination of iron (III) oxide  
4.5.10.1  General  
4.5.10.1.1  The presence of titanium affects the  speed of the titration of iron by EDTA. This cause of error 
can be  overcome by proceeding slowly, for example with the help of an automatic burette. It is equally 
possible to  mask the titanium by adding 2 mL of sulfuric acid 1 + 1 (4.2. 2.16) to the soluti on before titration.  
4.5.10.1. 2 This method uses photometric determination of the end -point. It is also possible to make visual 
observation of  the titration although with less precision. Sulfosalicylic acid (4.2. 2.72) is a suitable indicator 
(colour change s from violet to clear yellow).  
4.5.10.2  Procedure  
4.5.10.2.1  Pipette 100 mL of the solution prepared in acc ordance with 4.5.7 from the 500 -mL volumetric 
flask into a beaker  compatible with the measuring apparatus (4.3.12). Then make up with water to a vol ume 
suitable for the  correct operation of the equipment.  
4.5.10.2. 2 Add 0 .5 g amino -acetic acid (4.2. 2.23) and 0 .3 g - 0.4 g of sulfosalicylic acid indicator (4.2. 2.72). 
4.5.10.2. 3 Using a pH meter (4.3.18.1), adjust the pH of this solution to (1 .5 ± 0 .1) with the ammonium 
hydroxide 1 + 1  (4.2.2.26) and 1 + 10 (4.2. 2.27). 
4.5.10.2. 4 Heat to (47 .5 ± 2 .5) °C. Place the beaker in the apparatus (4.3.12) set at 520 nm and, while 
stirring the  solution, titrate with the approximately 0 .03 mol/ L EDTA solution (4.2. 2.65). In the vicinity of the 
indicator colour  change, construct a curve of the readings from the measuring apparatus as a function of the 
volume of EDTA  solution added. Record the total volume Vtot of EDTA solution added. The volume at the end 
point V10 is determined from the intersection of the line of greatest slope in the region of the colour change and 
the line of  almost constant absorbance after the colour change. The excess volume VEx of EDTA solution 
added is  determined as volume Vtot less volume V10. 
4.5.10.2. 5 During the titration, the temperature of the solution shall not exceed 50 °C. Otherwise the 
determination shall  be repeated.  
4.5.10.2. 6 This titrated solution is retained for the determination of aluminium oxide content in accordance 
with 4.5 .11.1.  EAS 148-2:201 7 
31 © EAC 2017 – All rights reserved  
 4.5.10.3  Calculation and expression of results  
Fe2O3
23D x 1.1977  100 x 
 x 100 x 000 1 x 2x  x 500 x 159.692 x 0.03
2310 D 
mf x V
mV10f   (22) 
where  
V10  is the volume of the approximately 0 .03 mol/ L EDTA solution used for the titration, in millilitres;  
fD  is the factor of the approximately 0 .03 mol/ L EDTA solution determined in accordance with  4.2.2.65; 
m23  is the mass of the test portion used in 4.5.2 ( m17) or 4.5.5.2 ( m20), in grams.  
4.5.10 .4 Repeatability and reproducibility  
4.5.10.4.1  The standard deviation for repeatability is 0 .08 %.  
4.5.10.4. 2 The standard deviation for reproducibility is 0 .15 %.  
4.5.11  Determination of aluminium oxide  
4.5.11.1  Procedure  
4.5.11.1.1  Cool the solution retained from 4.5.10.2 to room temperature. Then add 5 mL of acetic acid 
(4.2.2.22) then, drop  by drop, the ammonium acetate solution (4.2. 2.56) so as to obtain a pH of (3 .05 ± 0 .05). 
This range shall be  strictly observed and controlled by m eans of the pH meter (4.3.18.1). The pH shall not 
exceed 3 .10. Bring to  the boil add three drops of the copper complexonate solution (4.2. 2.66) and 2 mL of 
PAN indicator (4.2. 2.73). 
4.5.11.1. 2 During the titration, keep the solution gently boiling (work in  a fume cupboard). Titrate with the 
approximately  0.03 mol/ L EDTA solution (4.2. 2.65) until the colour changes from violet -pink to pale yellow. 
When the pink  colour reappears, add the EDTA solution drop by drop until the yellow colour persists for at 
least  1 min.  
4.5.11.2  Calculation and expression of results  
Calculate the aluminium oxide content in percent from the formula:  
Al2O3 
23D   x 0.7647  100 x  x 100 x 000 1 x 2fx  x 500 x 101.961 x 0.03
23D 11
mf x V
mV11   (23)  
where  
V11  is the volume of the approximately 0 .03 mol/ L EDTA solution used for the titration plus the  excess 
volume VEx (see 4.5.10.2), in millilitres;  
fD  is the factor of the 0 .03 mol/ LEDTA solution determined in accordance with 4.2. 2.65.3; 
m23  is the mass of the test portion used in 4.5.2 ( m17) or 4.5.5.2 ( m20), in grams.  
4.5.11.3  Repeatability and reproducibility  
4.5.11.3.1  The standard deviation for repeatability is 0 .10 %.  
4.5.11.3. 2 The standard deviation for reproducibility is 0 .25 %.  Field  Code  ChangedEAS 148-2:201 7 
© EAC 2017 – All rights reserved  32 
 4.5.12  Determination of calcium oxide by EGTA (reference method)  
4.5.12.1  General  
This method uses photometric determination of the end -point. It is possible to make visual observations of the  
titration, although with less precision. The mixed calcei n and methylthymol blue indicator (4.2. 2.75) is suitable  
(colour change from pale green to pink) for both photometric and visual methods.  
NOTE  In this method any strontium oxide is determined and expressed as calcium oxide.  
4.5.12.2  Procedure  
4.5.12.2.1  Pipette 25 mL of the solution prepared in accordance with 4.5.7 from the 500 -mL volumetric flask 
into a beaker  compatible with the measuring apparatus (4.3.12) and make up to the same volume as in 
4.2.2.67.3 with water  and then add 25 mL of the triethanolami ne solution 1 + 4 (4.2. 2.57). Using the pH meter 
(4.3.18.1), adjust the pH of this solution to (12 .5 ± 0 .5) with sodium hydroxide solution (4.2. 2.30). Add, without 
weighing, about 0 .1 g of  murexide (4.2. 2.69) or calcein indicator (4.2. 2.70). Place the beak er in the apparatus 
(4.3.12) set at 520 nm when  using calcein or at 620 nm when using murexide and, while stirring, titrate with 
the approximately 0 .03 mol/ L EGTA solution (4.2. 2.67). 
4.5.12.2. 2 In the vicinity of the colour change, construct a curve of th e readings from the measuring 
apparatus as a  function of the volume of EGTA solution added. The volume V12 used is determined from the 
intersection of  the line of greatest slope in the region of the colour change and the line of almost constant 
absorbance after the colour change.  
4.5.12.3  Calculation and expression of results  
Calculate the calcium oxide content in percent from the formula:  
23 x 3.3648  100 x 
 x 25 x 000 1x  x 500 x 56.08 x 0.03
2312G 
mf x V
mf V
CaOG 12 
 (24) 
where  
V12  is the volume of the approximately 0 .03 mol/ L EGTA solution used for the titration, in millilitres;  
fG  is the factor of the approximately 0 .03 mol/ L EGTA solution determined in accordance with  
4.2.2.67.3; 
m23  is the mass o f the test portion used in 4.5.2 ( m17) or 4.5.5.2 ( m20), in grams.  
4.5.12.4  Repeatability and reproducibility  
4.5.12.4.1  The standard deviation for repeatability is 0 .18 %.  
4.5.12.4. 2 The standard deviation for reproducibility is 0 .37 %.  
4.5.13  Determinati on of magnesium oxide by DCTA (reference method)  
4.5.13.1  General  
This method uses photometric determination of the end -point. It is possible to make visual observations of the  
titration, although with less precision. Methylthymol blue (4.2. 2.75) is a suit able indicator (colour change from  
blue to grey).  EAS 148-2:201 7 
33 © EAC 2017 – All rights reserved  
 4.5.13.2  Procedure  
4.5.13.2.1  Pipette 50 mL of the solution prepared in accordance with 4.5.7 from the 500 -mL volumetric flask 
into a beaker  compatible with the measuring apparatus (4.3.12), add 50 mL of triethanolamine solution 1 + 4 
(4.2.2.57) and a  volume V13 of the EGTA solution (4.2. 2.67). Calculate the volume V13 required in millilitres 
from the formula : 
V13 = (2 x V12) + 1.5  (25) 
where  
V12 is the volume of the EGTA  solution used for titration in accordance with 4.5.12.2, in millilitres;  
V13 is the calculated volume of the EGTA solution, in millilitres.  
4.5.13.2. 2 After addition of the calculated volume of EGTA solution, dilute with water to a volume suitable for 
the correct  operation of the apparatus. Using the pH meter (4.3.18.1), adjust the pH of this solution to (10 .5 ± 
0.5) with  concentrated ammonium hydroxide (4.2. 2.25). 
4.5.13.2. 3 Add, without weighing, about 0 .1 g of methylthymol blue indicator (4.2. 2.74). 
4.5.13.2. 4 Place the beaker in the apparatus (4.3.12) set at 620 nm and, while stirring the solution, titrate 
with the  approximately 0 .01 mol/ L DCTA solution (4.2. 2.68). In the vicinity of the colour change of the 
indicator, construct  a curve of the absorbanc e values as a function of the volume of DCTA solution added. 
The volume V14 used is  determined from the intersection of the line of greatest slope in the region of the colour 
change and the line of  almost constant absorbance after the colour change.  
4.5.13 .3 Calculation and expression of results  
Calculate the magnesium oxide content in percent from the formula:  
MgO  
  x 0.4031  100 x 
 x 50 x 000 1fx  x 500 x 40.311 x 0.0114
23C
14 
23C
mf V
mV
   (26) 
where  
V14  is the volume of the approximately 0 .01 mol/ L DCTA solution used for the titration, in millilitres;  
fC  is the factor of the approximately 0 .01 mol/ LDCTA solution determined in accordance with  4.2.2.68.3; 
m23  is the mass of the test portion use d in 4.5.2 ( m17) or 4.5.5.2 ( m20), in grams.  
4.5.13.4  Repeatability and reproducibility  
4.5.13.4.1  The standard deviation for repeatability is 0 .15 %.  
4.5.13.4. 2 The standard deviation for reproducibility is 0 .15 %.  
4.5.14  Determination of calcium oxide by  EDTA (alternative method)  
4.5.14.1  General  
This method uses photometric determination of the end -point. It is possible to determine the end -point of the  
titration visually. In this case Calcon (4.2. 2.71) (colour change from pink to blue), mixed calcein an d 
methylthymol blue indicator (4.2. 2.75) (colour change pink to yellow) or Patton and Reeders reagent (4.2. 2.76) 
(colour change from purple to clear blue) are suitable indicators . 
NOTE  In this method, any strontium oxide is determined and expressed as calc ium oxide.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  34 
 4.5.14.2  Restriction on the method  
This method can be used for determination of calcium oxide in the presence of manganese. Where the  
method is to be used in conjunction with the method of determination of magnesium oxide by EDTA (see  
4.5.15), i t shall be preceded by the determination of manganese content (see 4.4.6) for comparison with the  
limit given in 4.5.15.2 for manganese oxide.  
4.5.14.3  Procedure  
4.5.14.3.1  Pipette 50 mL of the solution prepared in accordance with 4.5.7 from the 500 -mL volumetric flask 
into a beaker  compatible with the measuring apparatus (4.3.12). Then dilute with water to a volume suitable 
for the correct  operation of the equipment. Add 50 mL of the triethanolamine solution 1 + 4 (4.2. 2.57). 
4.5.14.3. 2 Using the pH meter (4.3.18.1), adjust the pH of this solution to (12 .5 ± 0 .5) with sodium hydroxide 
solution  (4.2.2.30). 
4.5.14.3. 3 Add, without weighing, about 0 .1 g of murexide (4.2. 2.69), calcein indicator (4.2. 2.70) or mixed 
calcein and  methylthymol blue indicator (4.2. 2.75). Place the beaker in the apparatus (4.3.12) set at 620 nm 
when using  murexide or at 520 nm when using calcein and, while stirring the solution, titrate with the 
approximately  0.03 mol/ L EDTA solution (4.2. 2.65). In the vicinity of the colour change of  the indicator, 
construct a curve of the  absorbance values as a function of the volume of EDTA added. The volume V15 used 
is determined from the  intersection of the line of greatest slope in the region of the colour change and the line 
of almost constant  absorbance after the colour change.  
4.5.14.4  Calculation and expression of results  
Calculate the calcium oxide content in percent from the formula:  
CaO 
  x 1.6824  100 x 
 x 50 x 000 1x  x 500 x 56.08 x 0.03
23D 15 D
2315 
mfV
mf V 
   
 (27) 
where  
V15  is the volume of the approximately 0 .03 mol/ L EDTA solution used for the titration, in millilitres;  
fD  is the factor of the approximately 0 .03 mol/ L EDTA solution determined in accordance with  4.2.66.3;  
m23  is the mass of the test portion used in 4.5.2 ( m17) or 4.5.5.2 ( m20), in grams.  
4.5.14.5  Repeatability and reproducibility  
4.5.14.5 .1 The standard deviation for repeatability is 0 .15 %.  
4.5.14.5 .2 The standard deviation for reproducibility is 0 .43 %.  
4.5.15 Determination of magnesium oxide by EDTA (alternative method)  
4.5.15.1  General  
This method uses photometric determination of the end -point. It is possible to determine the end -point of the  
titration visually. In this case mixed calcein and methylthymol  blue indicator (4.2. 2.75) (colour change from 
pink to colourless) or mixed indicator (4.2. 2.77) (colour change from pink to colourless) or a dispersion of 1 g 
of phthalein purple in 100 g of solid NaCl (colour change from violet to pale pink) are suitable  indicators.  EAS 148-2:201 7 
35 © EAC 2017 – All rights reserved  
 4.5.15.2  Restriction on the method  
In the rare case where cement  has a manganese oxide (Mn 2O3) content greater than 0 .5 %, only the  method 
of determination of magnesium oxide by DCTA (4.5.13) is applicable.  
4.5.15.3  Procedure  
4.5.15.3.1  Pipett e 50 mL of the solution prepared in accordance with 4.5.7 from the 500 -mL volumetric flask 
into a beaker  compatible with the measuring apparatus (4.3.12). Then dilute with water to a volume suitable 
for the correct  operation of the equipment. Add 50 mL of the triethanolamine solution 1 + 4 (4.2. 2.57). 
4.5.15.3. 2 Using the pH meter (4.3.18.1), adjust the pH of this solution to (10 .5 ± 0 .5) with ammonium 
hydroxide 1 + 1  (4.2.2.26). 
4.5.15.3. 3 Using a burette, add the volume V15 of EDTA solution (4.2. 2.65) req uired for the titration of 
calcium oxide  previously determined in 4.5.14.3.  
4.5.15.3. 4 Then add, without weighing, about 0 .1 g of methylthymol blue (4.2. 2.74), mixed calcein and 
methylthymol blue  indicator (4.2. 2.75) or mixed indicator (4.2. 2.77). 
4.5.15.3 .5 Place the beaker in the apparatus (4.3.12) set at 620 nm and, while stirring the solution, titrate 
with the  approximately 0 .03 mol/ L EDTA solution (4.2. 2.65). In the vicinity of the colour change of the 
indicator, construct  a curve of the absorbance val ues as a function of the volume of EDTA solution added. The 
volume V16 used is  determined from the intersection of the line of greatest slope in the region of the colour 
change and the line of  almost constant absorbance after the colour change.  
4.5.15.4  Calculation and expression of results  
Calculate the magnesium oxide content in percent from the formula:  
MgO 
 
 -
 x 1.2093  100 x 
 x 50 x 000 1 x 500 x 40.311 x 0.03
2315 16 15 16
23-
mfV V
mD DfVV   (28) 
where  
V15  is the volume of EDTA solution required for the determination of calcium oxide as in 4.5.14.3, in  
millilitres;  
V16  is the volume of EDTA solution required for the determination of calcium oxide and magnesium  oxide 
determined in 4.5.15. 3, in millilitres;  
fD  is the factor of the approximately 0 .03 mol/ L EDTA solution determined in accordance with  
4.2.2.65.3; 
m23  is the mass of the test portion used in 4.5.2 ( m17) or 4.5.5.2 ( m20), in grams.  
4.5.15.5  Repeatability and reproducibility  
4.5.15.5.1  The standard deviation for repeatability is 0 .21 %.  
4.5.15.5. 2 The standard deviation for reproducibility is 0 .25 %.  
4.5.16  Determination of chloride  
4.5.16.1  Principle  
This method gives the total chloride plus bromide content and expresses the res ult as chloride ion (Cl-). 
Cement is treated with boiling dilute nitric acid to decompose it and to remove sulfides. The dissolved chloride  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  36 
 is precipitated using a known volume of a standard silver nitrate solution. After boiling, the precipitate is  
washed  with dilute nitric acid and discarded. The filtrate and washings are cooled to below 25 °C and the  
residual silver nitrate is titrated with a standardised ammonium thiocyanate solution using an iron (III) salt as  
indicator.  
4.5.16.2  Procedure  
4.5.16.2.1  Weigh, to ± 0 .000 5 g, (5 .00 ± 0 .05) g of cement ( m26) and place in a 400 \-mL tall form beaker; 
add 50 mL of water and, while stirring with a glass rod, 50 mL of nitric acid 1 + 2 (4.2. 2.13). Heat the mixture 
to boiling (in a  fume cupboard for samples cont aining sulfide), stirring occasionally, and boil for 1 min - 2 min, 
avoiding loss  of liquid. Remove from the source of heat and add 5 mL of silver nitrate solution (4.2. 2.44) by 
pipette (4.3.17)  into the solution. Then boil for not less than 1 min and not more than 2 min and filter through a 
coarse filter  paper (4.3.16), washed before use with nitric acid 1 + 100 (4.2. 2.14), into a 500 -mL conical flask. 
Wash the  beaker, glass rod and filter paper with nitric acid 1 + 100 until the volume of the filtrate and  the 
washings is  approximately 200 mL. Cool the filtrate and washings to below 25 °C in subdued light or in the 
dark.  
4.5.16.2. 2 Add up to 5 mL indicator solution (4.2. 2.81) and titrate with the ammonium thiocyanate solution 
(4.2.2.79) shaking  vigorously u ntil a drop of this solution produces a faint pink colouration which does not 
disappear on shaking.  Record the volume V17 of ammonium thiocyanate used in the titration. If V17 is less than 
0.5 mL, repeat the  procedure with half the sample mass.  
4.5.16.2. 3 Carry out the same procedure with no cement sample and record the volume, V18, of ammonium 
thiocyanate  solution used in the blank titration.  
4.5.16.3  Calculation and expression of results  
Calculate the chloride content in percent from the formula:  
CI¯
261817 18
1818
 x  ) - ( x 0.8865  100 x 
 x  x 000 1 ) - ( x 1.773
2617
m VV V
m VVV   (29) 
where  
m26  is the mass of the test portion, in grams;  
V17  is the volume of the ammonium thiocyanate soluti on used for the titration of the test solution, in  
millilitres;  and 
V18  is the volume of the ammonium thiocyanate solution used for the titration of the blank solution,  in 
millilitres.  
4.5.16.4  Repeatability and reproducibility  
4.5.16.4.1  The standard dev iation of repeatability is 0 .005 %.  
4.5.16.4. 2 The standard deviation of reproducibility is 0 .010 %.  
4.5.17  Determination of carbon dioxide (reference method)  
4.5.17.1  Principle  
The cement is treated with phosphoric acid to decompose the carbonate present.  The carbon dioxide liberated  
is entrained in a current of carbon dioxide -free gas or air through a series of absorption tubes. The first two  
remove hydrogen sulfide and water and the following absorb carbon dioxide. Two absorption tubes, each  
containing a  granular absorbent for carbon dioxide and anhydrous magnesium perchlorate to retain the water  
formed during the absorption reaction are weighed to determine the mass of carbon dioxide released.  EAS 148-2:201 7 
37 © EAC 2017 – All rights reserved  
 4.5.17.2  Apparatus  
A typical apparatus (4.3.19) is shown in F igure 2.  
4.5.17.3  Procedure  
4.5.17.3.1  Weigh, to ± 0 .000 5 g (1 .00 ± 0 .05) g of cement ( m27) and place it in a dry 100 mL distillation 
flask. Connect the  flask to the apparatus (4.3.19) as shown in Figure 2, but without the two absorption tubes 
(13). Pass a current  of carbon dioxide -free gas through the apparatus for 15 min at approximately three 
bubbles per second  (bubble counter) via the connecting tube onto (6) (branch onto (5), Mohr clip closed). 
Release the Mohr clip  and remove the gas supply from the funnel (4). Add 30 mL concentrated phosphoric 
acid (4.2. 2.19) into the  dropping funnel and reconnect the gas supply to fill the funnel (4).  
4.5.17.3. 2 Condition the closed absorption tubes (13) for 15 min in the balance case in order to achieve 
temperature  equilibrium. Then weigh each tube separately. Shut off the flow of gas and attach the tubes to the 
apparatus  as shown in Figure 2.  
4.5.17.3. 3 Care should be taken when handling the tubes to avoid affecting their weight, causing damage or 
sustaining  injury . It is advisable to wear protective gloves when carrying out this operation.  
4.5.17.3. 4 Reopen the gas flow. After 10 min close absorption tubes (13), remove them, place them in the 
balance case  for 15 min and then weigh them separately. Repeat the passag e of gas, removal and weighing 
of absorption  tubes (13) for as long as is required for the results of two successive weighings of a tube not to 
differ by more  than 0 .000 5 g.  
4.5.17.3. 5 If the change in mass of the absorption tubes (13) remains greater tha n 0.000 5 g, renew the 
absorbents in  tubes (11) and (12).  
4.5.17.3. 6 Attach the weighed absorption tubes (13) to the apparatus, as shown in Figure 2.  
4.5.17.3. 7 Open the funnel tap and allow the phosphoric acid to drop into the distillation flask (14). Aft er the 
reaction has  ceased, heat the contents of the flask to boiling and boil gently for 5 min. Maintain the gas flow 
through the  apparatus until the flask has cooled to room temperature.  
4.5.17.3. 8 Close absorption tubes (13), remove them and place them in the balance case for 15 min and 
then weigh  them separately. The increase in mass of each tube is used for the calculation of the carbon 
dioxide content  (see 4.5.17.4).  
4.5.17.3. 9 The carbon dioxide is practically completely absorbed by first tube (13). If the increase in mass of 
second tube  (13) exceeds 0 .000 5 g, renew the absorbent in first tube (13) and start the test again.  
4.5.17.4  Calculation and expression of results  
Calculate the carbon dioxide content as a percentage of the cement from the formu la: 
CO 2 
 100x   
2729 2
mm m8
  (30) 
where  
m27  is the mass of the test portion, in grams;  
m28  is the increase in mass of first tube (13) after absorption, in grams;  
m29  is the increase in mass of second tube (13) after absorption, in grams.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  38 
 If the carbon  dioxide content calculated from Formula (30) is less than 0 .5 %, repeat the determination with  
(2.00 ± 0 .05) g of cement, weighed to ± 0 .000 5 g. Alternatively, where the cement contains a high proportion  
of carbonate, the size of the sample should be dec reased appropriately.  
4.5.17.5  Repeatability and reproducibility  
4.5.17.5.1  The standard deviation of repeatability is 0 .07 %.  
4.5.17.5.1  The standard deviation of reproducibility is 0 .10 %.  
4.5.18  Determination of carbon dioxide (alternative method)  
4.5.1 8.1 Principle  
The carbon dioxide is driven off by treatment with sulfuric acid, absorbed by sodium hydroxide and determined  
gravimetrically. Any hydrogen sulfide present which may affect the results is absorbed by mercuric (II)  
chloride.  
4.5.18.2  Apparatus  
The apparatus (4.3.20) is shown in Figure 3. A small vacuum pump is used to generate reduced pressure in  
the apparatus.  
4.5.18.3  Procedure  
4.5.18.3.1  Weigh, to ± 0 .000 5 g, (1 .00 ± 0 .05) g of cement ( m30) into the 100-mL distillation flask (7) of the 
appa ratus  (4.3.20). Mix this cement with a small (about 50 mg) amount of mercuric (II) chloride (4.2. 2.87) 
using a spatula  and then add enough water to form a slurry. Connect the flask to the ground joint of the 
dropping funnel (1).  Then draw air for 15 min th rough the apparatus, passing the air through an absorption 
tower (8) filled with  absorbent (4.2. 2.86) to remove the carbon dioxide before the air passes into the flask.  
4.5.18.3. 2 Condition the closed absorption tubes (4) for 15 min in the balance case in order to achieve 
temperature  equilibrium. Then weigh each tube separately. Shut off the flow of gas and attach the tubes to the 
apparatus  as shown in Figure 3.  
4.5.18.3. 3 Care should be taken when handling the tubes to avoid affecting their weight, causing  damage or 
sustaining  injury. It is advisable to wear protective gloves when carrying out this operation.  
4.5.18.3. 4 Add 25 mL - 30 mL of sulfuric acid 1 + 4 (4.2. 2.17) from the dropping funnel (1) into the flask. 
Take care to  ensure that some of the acid remains in the dropping funnel as a seal.  
4.5.18.3. 5 Turn the vacuum pump on again, so that the current of air carries the liberated carbon dioxide 
through the  condenser (2) and the first two absorption tubes (3), filled with magnesium perchlorate (4.2. 2.85) 
for the  purposes of drying the air, to the two previously weighed absorption tubes (4) filled with absorbents 
(4.2.2.85 and 4.2. 2.86). An absorption tube (5) filled with magnesium perchlorate (4.2. 2.85) and absorbent 
(4.2.2.86) is fitted  after these tub es in order to prevent penetration by the ambient air. Gas washing bottle (9) 
empty and (10),  filled with concentrated sulfuric acid (4.2. 2.15) or paraffin, as a bubble counter are connected.  
4.5.18.3. 6 After about 10 min, heat the contents of the flask to  boiling and boil gently for 5 min. Maintain the 
air flow  through the apparatus until the flask has cooled to room temperature. Close the taps and remove the  
absorption tubes (4), place them in the balance case for 15 min in order to achieve temperature eq uilibrium  
and then weigh them.  
4.5.18.4  Calculation and expression of results  
Calculate the carbon dioxide content in percent from the formula:  EAS 148-2:201 7 
39 © EAC 2017 – All rights reserved  
 CO 2 
 100x  100 x 
3031
mm
  (31) 
where  
m30  is the mass of the test portion, in grams;  
m31  is the inc rease in mass of the absorption tubes (4) after absorption, in grams.  
If the carbon dioxide content calculated from Formula (31) is less than 0 .5 %, repeat the determination with  
(2.00 ± 0 .05) g of cement, weighed to ± 0 .000 5 g. Alternatively, where the c ement contains a high proportion  
of carbonate the size of the sample should be decreased appropriately.  
4.5.18.5  Repeatability and reproducibility  
4.5.18.5.1  The standard deviation of repeatability is 0 .07 %.  
4.5.18.5.1  The standard deviation of reproducib ility is 0 .10 %.  
4.5.19  Determination of alkali (reference method)  
4.5.19.1  Principle  
A butane, propane or acetylene flame is used to excite the alkali metals to emit their characteristic spectrum in  
the visible range. The emission is proportional to the a lkali content at low concentrations. The influence of  
large quantities of calcium in the sample on the sodium determination is suppressed by means of phosphoric  
acid. The influence of phosphoric acid on the potassium emission from the calibration solutions  is suppressed  
by adding calcium to the calibration solutions.  
4.5.19.2  Reagents  
Whenever a new batch of any reagent is used, determine the alkali content by means of this method. If the  
alkali content of a reagent exceeds 0 .01 %, either replace the batch with a new one, which shall be verified in  
the same way, or prepare new calibration solutions.  
4.5.19.3  Preparation of calibration solutions and calibration curves  
Prepare the calibration solutions using the volumes of alkali stock solution, acid stock sol ution and calcium  
stock solution listed in Table 4. Make up the volumes listed in lines 1 to 7 to 1 000 mL with water and mix  
thoroughly. Store these calibration solutions in polyethylene bottles. Spray the calibration solutions into the  
flame of the flame  photometer (4.3.21). Spray the blank solution (Table 4, S1) first and set the indication on  
the apparatus to zero. Spray the solution of greatest concentration (S7) and set the indication on the  
apparatus to maximum intensity. Spray the other calibration solutions in the order of increasing concentration  
(S2 to S6). Measure the intensities for Na 2O at 589 nm and for K 2O at 768 nm.  Construct curves of the 
measured intensities against the corresponding concentrations of Na 2O and K 2O in the calibration soluti ons. EAS 148-2:201 7 
© EAC 2017 – All rights reserved  40 
 Table 4 — Volumes of solutions for the preparation of calibration solutions and their sodium oxide  
and potassium oxide concentrations  
Calibration 
solution  Alkali stock  solution 
(4.2.2.88) 
mL Acid stock  solution 
(4.2.2.89) 
mL Calcium stock  
solution (4 .2.2.90) 
mL Na2O and K 2O 
concentrations  
mL 
S1 - 100 100 0.0 
S2 5 100 100 1.5 
S3 10 100 100 3.0 
S4 20 100 100 6.0 
S5 30 100 100 9.0 
S6 40 100 100 12.0 
S7 50 100 100 15.0 
4.5.19.4  Dissolution of the test portion  
4.5.19.4.1  Cements with an insoluble residue not exceeding 3 %  
Weigh (0 .500 0 ± 0 .000 5) g of cement into a 250 -mL beaker, make into a slurry with 50 mL of water and add  
50 mL of hydrochloric acid 1 + 19 (4.2. 2.7). Warm the mixture until the cement has decomposed, crushing any  
lumps with a gl ass rod. Then allow the suspension to cool to ambient temperature. Transfer the contents of  
the beaker, rinsing the beaker with water, into a 500 -mL volumetric flask. Add 50 mL of phosphoric acid 1 + 19  
(4.2.2.20), make up to the mark with water and mix th oroughly. Filter, without washing, sufficient solution  
through the filter paper (4.3.23) into a clean, dry beaker, before spraying solution into the flame.  
NOTE  This method is applicable to cements which have insoluble residue content, determined in accord ance with  
Clause 9, not exceeding 3 %.  
4.5.19.4.2  Cements with an insoluble residue exceeding 3 %  
WARNING 1  Carry out the following evaporation procedures in an appropriate fume cupboard (see  WARNING 2) 
because the vapours from nitric acid (4.2.13), perchl oric acid (4.2.19) and hydrofluoric acid  (4.2.2.10) are 
hazardous. In addition, wear eye protection and suitable rubber or plastics gloves when handling  or agitating 
these acids or their mixtures.  
Where the content of insoluble residue, determined in accor dance with 4.4.3, exceeds 3 %, the method  
described below should be used.  
Weigh (0 .500 0 ± 0 .000 5) g of cement into a platinum dish (4.3.22) and add 15 mL of nitric acid (4.2. 2.12). 
Heat  the mixture, for example  on a hot -plate, and evaporate to dryness. D isperse the residue from 
evaporation in 15 mL of water, add 5 mL of perchloric acid (4.2. 2.18) and then add 25 mL of hydrofluoric acid 
(4.2.2.10). 
WARNING 2  Perchloric acid vapours form explosive mixtures with organic materials. It is therefore necessary  to 
take special precautionary measures when working with perchloric acid, for example  the use of fume cupboards  
flushed with water and a general ban on the use of organic substances in the same fume cupboard.  
Heat the mixture and evaporate to dryness. Preve nt overheating by frequent agitation by means of the HF  
resistant stirrer (4.3.24). Add 10 mL of water and 50 mL of hydrochloric acid 1 + 19 (4.2. 2.7) to the residue 
from evaporation and heat until the residue has dissolved. Allow the suspension to cool to  room temperature.  
Transfer the contents of the platinum dish, rinsing the dish with water, into a 500 -mL volumetric flask. Add  50 
mL of phosphoric acid 1 + 19 (4.2. 2.20) to the solution, make up to the mark with water and mix thoroughly . 
Filter, without w ashing, sufficient solution through the filter paper (4.3.23) into a clean, dry beaker, before  
spraying solution into the flame . EAS 148-2:201 7 
41 © EAC 2017 – All rights reserved  
 4.5.19.5  Procedure  
4.5.19.5.1  Spray the sample solution produced as described in 4.5.19.4.1 or 4.5.19.4.2 into the flame of the  
flame  photometer (4.3.21). Measure the intensity of the sodium line at 589 nm and the potassium line at 768 
nm. Obtain the sodium oxide or potassium oxide concentration in the solution respectively by means of a 
linear  interpolation from the intensities a nd the associated concentrations of the calibration solutions 
measured as  described in 4.5.19.3.  
4.5.19.5. 2 Use the curves constructed in accordance with 4.5.19.3 to obtain the sodium oxide and 
potassium oxide  concentrations of the solution in milligrammes  per litre or use the intensities and the 
associated concentrations of the calibration  solutions with the next higher and the next lower intensity for the 
calculation as follows.  
4.5.19.5. 3 Calculate the sodium oxide CNa2O  or potassium oxide CK2O concentra tion of the sample from the 
intensities  INa2O  or IK2O respectively using the following formulae:  
C Na2O 
    x ) ( 
Bn BhBnNa2O
Bn Bh BnIII IC C C  (32) 
C K2O  
    x ) ( 
Bn BhBnK2O
Bn Bh BnIII IC C C  (33) 
where  
CBn  is the concentration of the sodium oxide or potassium oxide respectively in the calibration  solution 
having a lower concentration than the sample solution, in milligrams per litre;  
CBh  is the concentration of the sodium oxide or potassi um oxide respectively in the calibration  solution 
having a higher concentration than the sample solution in milligrams per litre;  
IBn  is the intensity of the calibration solution having a lower concentration than the sample solution;  
IBh  is the intensity  of the calibration solution having a higher concentration than the sample  solution.  
4.5.19.6  Calculation and expression of results  
4.5.19.6.1  Sodium oxide and potassium oxide content  
Calculate the sodium oxide or potassium oxide content in percent from th e following formulae using the  
corresponding concentrations as determined in accordance with 4.5.19.5.  
Na2O = 0.1 x CNa2O (34) 
K2O = 0.1 x CK2O (35) 
where  
CNa2O is the sodium oxide concentration of the sample solution as calculated by Formula (32), in  milligrams 
per litre;  and 
CK2O is the potassium oxide concentration of the sample solution as calculated by Formula (33), in  
milligrams per litre.  
4.5.19.6.2  Sodium oxide equivalent  
Calculate the sodium oxide equivalent content in percent by converting the pot assium oxide content to the  
equivalent sodium oxide content and adding the measured sodium oxide content using the formula:  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  42 
 Sodium oxide equivalent = Na 2O + 0 .658 K 2O  (36) 
NOTE  The sodium oxide equivalent, determined in accordance with this standard, is s ometimes referred to as the  
acid soluble alkali content to differentiate from determinations carried out using other extraction methods for example  
water  soluble alkali content.  
4.5.19.7  Repeatability and reproducibility  
4.5.19.7.1  The standard deviation o f repeatability is:  
0.01 % for the determination of Na 2O; 
0.02 % for the determination of K 2O. 
4.5.19.7. 2 The standard deviation of reproducibility is:  
 
0.02 % for the determination of Na 2O; 
0.03 % for the determination of K 2O. 
4.5.20  Determination of alka li (alternative method)  
4.5.20.1  Principle  
Cements, with an insoluble residue not exceeding 3 %, determined in accordance with 4.4.3, are treated with  
hydrochloric acid. Cements, with an insoluble residue greater than 3 %, are first evaporated with hydrofl uoric  
acid/sulfuric acid. The alkali contents of the solutions are determined by means of flame photometry.  
4.5.20.2  Reagents  
Whenever a new batch of any reagent is used, determine the alkali content by means of this method. If the  
alkali content of a reag ent exceeds 0 .01 % either replace the batch with a new one, which shall be verified in  
the same way or prepare new calibration solutions.  
4.5.20.3  Construction of the calibration curves  
4.5.20.3.1  In the case of cements with an insoluble residue not exceed ing 3 %, evaporate 20 mL of 
hydrochloric acid  1 + 9 (4.2. 2.5) to dryness. In the case of cements with an insoluble residue greater than 3 %, 
evaporate 15 mL of hydrofluoric acid (4.2. 2.10) and 5 mL of sulfuric acid (4.2. 2.15) to dryness for the 
purposes of  preparing the  calibration solutions for each calibration point.  
4.5.20.3. 2 In both cases, dissolve the residue from evaporation with 2 mL of hydrochloric acid 1 + 9 (4.2. 2.5) 
and 3 mL of water. Transfer the solution to a 100 - mL volumetric flask and add 1 0 mL of buffer solution 
(4.2.2.94). Add the  quantities of the alkali stock solution (4.2 2.91) to the individual volumetric flasks shown in 
Table 5 using a  burette (4.3.17).  
Table 5 — Quantities of stock solution to be added to flasks  
Volumetric flasks  1 2 3 4 5 6 7 
Stock solution (m L) 0 1 3 5 10 20 30 
 
4.5.20.3. 3 Then make up the volumetric flasks to the mark with water.  
4.5.20.3. 4 For an original test portion of 0 .200 0 g, the values measured for flasks 1 to 7 correspond to the 
Na2O and  K2O contents show n in Table 6 . EAS 148-2:201 7 
43 © EAC 2017 – All rights reserved  
 Table 6 — Alkali contents of stock solutions in flasks  
Volumetric flasks  1 2 3 4 5 6 7 
Na2O content (%)  0 0.07 0.20 0.34 0.67 1.35 2.02 
K2O content (%)  0 0.06 0.18 0.30 0.60 1.20 1.81 
 
4.5.20.3. 5 Spray the calibration solutions into the fl ame of the flame photometer (4.3.21). Spray the blank 
solution 1 first  and set the indication on the apparatus to zero.  
4.5.20.3. 6 Then spray the other calibration solutions in order of increasing alkali content (2 to 7). Measure 
the intensities  for Na 2O at 589 nm and for K 2O at 768 nm. Construct curves of the measured intensities 
against the  corresponding contents of sodium oxide and potassium oxide in the calibration solutions.  
4.5.20.4  Procedure  
4.5.20.4.1  Cements with an insoluble residue not exceeding 3 % 
NOTE  This procedure is applicable to cements which have an insoluble residue content, determined in accordance 
with 4.4.3, not exceeding 3 %.  
4.5.20.4.1.1  Weigh, to ± 0 .000 5 g, (0 .200 0 ± 0 .005) g of cement into the platinum dish (4.3.22), make into 
a slurry with  3 mL of water and evaporate to dryness after adding 20 mL of hydrochloric acid 1 + 9 (4.2. 2.5). 
Add hot water  and 2 mL of hydrochloric acid 1 + 9 to the residue and filter through the filter paper (4.3.23) into 
a 100 -mL volumetric flask which already contains 10 mL of the buffer solution (4.2. 2.94). Wash the residue 
with hot water  until the volumetric flask is almost filled to the mark. Then cool to room temperature and make 
up to the mark  with water.  
4.5.20.4.1. 2 Measure the solution in the fl ame photometer (4.3.21). The scale values read off in 
conjunction with the  calibration curves (4.5.20.3) give the contents of Na 2O and K 2O in percent respectively, 
uncorrected in the  case where a test portion different in mass from 0 .200 0 g has been taken  (see 4.5.20.3 
and 4.5.20.5).  
4.5.20.4.2  Cements with an insoluble residue exceeding 3 %  
WARNING  1 Carry out the following evaporation procedures in an appropriate fume cupboard because the  
vapours from sulfuric acid (4.2. 2.15) and hydrofluoric acid (4.2. 2.10) are hazardous. In addition, wear eye  
protection and suitable rubber or plastics gloves when handling or agitating these acids or their mixtures.  
Where the content of insoluble residue, determined in accordance with 4.4.3, exceeds 3 %, the procedure  
described below should be used.  
Weigh, to ± 0 .000 5 g, (0 .200 ± 0 .005) g cement into the platinum dish (4.3.22). Make into slurry  with 3 mL of 
water and evaporate after adding 5 mL of sulfuric acid (4.2. 2.15) and 15 mL of hydrofluoric acid (4.2. 2.10). 
Evapor ate to dryness under the heating lamp (4.3.25). Mix the residue with hot water and 2 mL of hydrochloric  
acid 1 + 9 (4.2. 2.5) and continue the procedure, from the filtering operation onwards, as described in 
4.5.20.4.1.  
4.5.20.5  Calculation and expression o f results  
4.5.20.5.1  Calculate the content of each alkali oxide as a percentage for an original test portion of 0 .200 0 g 
by dividing  each value obtained, in percent, in 4.5.20.4.1 or 4.5.20.4.2 by the actual mass of the test portion 
and multiplying by 0 .2. 
4.5.20.5. 2 Express the result as described in 4.5.19.6.  
4.5.20.6  Repeatability and reproducibility  
4.5.20.6.1  The standard deviation of repeatability is:  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  44 
  % for the determination of Na 2O; 
 % for the determination of K 2O. 
4.5.20.6.2  The standard deviation o f reproducibility is:  
 0.02 % for the determination of Na 2O; 
 0.03 % for the determination of K 2O. 
5 Chemical analysis by X -ray fluorescence  
5.1 Reagents and reference materials  
5.1.1  Pure reagents  
5.1.1.1  Reagents shall be of analytical quality and, whereve r possible, pure oxides or carbonates, except 
for the calibration of such elements as sulfur, chlorine, bromine or phosphorus, which do not form stable 
oxides or carbonates, where some guarantee of stoichiometry is required.  
5.1.1. 2 Reagents shall be free of (or corrected for) the presence of water (and, in the case of oxides, 
carbon dioxide) when weighed out for fusion. Furthermore, the reagents shall be in a known oxidation state. 
The specified procedure ensures that the correct oxidation state is obtaine d. 
5.1.1. 3 The reagents used to prepare the standard beads for calibrations shall be pure oxides or 
carbonates of at least 99.95 % purity (excluding moisture or CO 2). 
5.1.1. 4 Reagents shall be used in a known stoichiometry in terms of content. In order to achieve this, 
they can be treated before use as follows:  
a) determine the loss on ignition for silicon dioxide (SiO 2), aluminium oxide (Al 2O3) and magnesium oxide 
(MgO) as follows:  
(i) ignite the reagent at, for example, (1 175  ±  25) °C and maintain  at this t emperature for 30 min;  
(ii) cool in a desiccator to room temperature and reweigh;  
(iii) after allowing for this loss, weigh the appropriate amount of the unignited material to prepare the 
bead.  
b) dry manganese oxide (Mn 2O3) and titanium(IV) oxide (TiO 2) as follows:  
(i) ignite the reagent at, for example, (1 000 ± 25) °C and maintain  at this temperature for 30 min;  
(ii) cool in a desiccator  to room temperature before use;  
c) dry iron (III) oxide (Fe 2O3) as follows:  
(i) ignite the reagent at, for example, (700  ± 25) °C and maintain  at this temperature for 30 min;  
(ii) cool in a desiccator to room temperature before use.  
d) dry calcium carbonate (CaCO 3), strontium carbonate (SrCO 3), potassium carbonate (K 2CO 3) and sodium  
carbonate (Na 2CO 3). 
(i) heat the reagent at, for example, (250 ± 10) °C and maint ain at this temperature for 2 h;  
(ii) cool in a desiccator to room temperature before use.  EAS 148-2:201 7 
45 © EAC 2017 – All rights reserved  
 5.1.2  Reference materials  
5.1.2.1  Certified reference materials  
5.1.2.1.1  Certified reference materials (CRMs) are materials, for example  cement, supplied by an 
organisation conforming to  the requirements for the competence of reference material producers in 
accordance with ISO Guide 30.  
5.1.2.1. 2 CRMs shall be supplied with a certificate of analysis giving information on the average value and 
standard  deviation i n accordance with ISO Guide 31.  
5.1.2.2  Industrial reference materials  
Industrial reference materials (IRMs) are materials, for example  cement, prepared and homogenised by a 
laboratory.  The reference analysis of an IRM shall be the average result from inte r-laboratory co -operative 
testing  involving at least four laboratories able to meet the performance criteria given in 5.7.3.  
5.1.3  Calibration standards  
Calibration standards are prepared in the laboratory from pure, analytical -grade reagents, IRMs, CRMs o r a 
combination of these. They shall be formulated to provide a series of calibration standards covering the range  
of maximum to minimum values for each element being analysed and shall be evenly distributed between  
those limits. The variation in concentra tions of the elements shall be independent of each other. There shall  
be a minimum of seven calibration standards in a series.  
5.1.4  Binding agent  
A binding agent, for example wax, whose influence on the elements being analysed has been determined, is 
used  in the grinding of samples during the preparation of pressed pellets. Carry out a pellet -preparation 
monitoring  check (see 5.7.5) whenever the batch of binding agent is changed.  
5.2 Apparatus  
5.2.1  Balance, capable of weighing to an accuracy of ± 0.000 5 g. 
5.2.2  Fusion vessels and casting moulds, of a non -wetted platinum alloy, such as Pt/5 % Au or Pt/Rh.  
Vessels that serve both as a fusion vessel and as a casting mould that is . a combined fusion mould may be  
used. If moulds become distorted in use, then they shall be reshaped by pressing in a suitable former. If the  
bottom (flat) surface of the bead is used for analysis, it is necessary that the internal base of the mould also be  
kept flat and free from blemishes.  
NOTE  Cleanliness of fusion vessels is imp ortant in achieving accurate analyses. This can be achieved, for example,  
by boiling in dilute hydrochloric acid, 1:10 by volume or citric acid, 100 g/ L. 
5.2.3 Lids, optional, of a platinum alloy (not necessarily non -wetted).  
5.2.4  Furnace, for e xample  an electric resistance, muffle or high -frequency induction furnace, capable of 
operating  at (250 ± 10) °C, (700 ± 25) °C, (950 ± 25) °C, (1 000 ± 25) °C and (1 175  ± 25) °C.  
5.2.5  Automatic fusion apparatus, for use in automatic bead preparation (see 5.6.4).  An automatic fusion 
apparatus may be used, provided that the performance criteria in 5.7.3 can be met.  
5.2.6  Cooling apparatus, consisting of any device, such as a narrow jet of air that can be directed to the  
centre of the base of the casting mould (for e xample, by the base of a B unsen burner without a barrel) or a  water -
cooled metal plate.  
NOTE  Normally, cooling in air is sufficient but some difficult samples can require a cooling apparatus in order to cool  
the melt rapidly. This is necessary to obtain a homogeneous bead and to free the melt from the casting mould.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  46 
 5.2.7  Heat reservoir, for the casting mould, required in special circumstances when using moulds of small  
sizes, so that the mould does not cool too rapidly when removed from the furn ace 
5.2.8  Spectrometer, X-ray fluorescence, capable of meeting the perf ormance criteria given in 5.7.3  
NOTE  It is important to set appropriate measuring conditions to satisfy the performance criteria based on the type of  
samples, the type of apparatus, elements being  analysed and their content, etc.  
5.2.9  Flow gas, maintained at as constant at room temperature as possible.  The temperature of the flow 
gas cylinder and of the connecting pipework is critical in order to prevent drift in  sensitivity of the flow 
proportion al counters. Pipework shall be as short as practical and run, whenever  possible, within the 
temperature -controlled room in which the spectrometer is housed. Where this is not  possible, the cylinder 
shall be kept in a temperature -controlled cabinet (room te mperature  ± 2 °C) or otherwise  maintained at a 
constant room temperature. For the same reason, new cylinders shall be allowed to  equilibrate for at least 2 h 
to room temperature before use.  
NOTE  The flow gas is used in the gas flow proportional counter of the XRF spectrometer.  
The composition of gas can change as the cylinder becomes exhausted. Cylinders should be replaced before  
they become completely empty.  
5.2.10  Grinding equipment, capable of grinding the sample, with binding agent if necessary, to a su itable  
fineness.  
5.2.11  Pellet press, capable of applying a pressure suitable for production of pellets with a consistent,  
consolidated surface to meet the performance requirements given in 5.7.3.  
5.2.12  Mould, usually of steel, of suitable strength to wit hstand the press without distortion and of suitable  
size to produce a pellet to fit the spectrometer.  
5.3 Flux 
5.3.1  Choice of  flux 
5.3.1.1  General  
One of the advantages of the XRF fused cast bead method is that a wide variety of fluxes may be chosen. For  
a given calibration, the same flux shall be used throughout. The conditions given in 5.3.1.2 to 5.3.1.4 shall be  
met for any flux used.  
NOTE 1  Fluxes used with success in the analysis of cement are given in Annex A. Pre -fused fluxes have the  
advantage of a lower moisture content.  
NOTE 2  Reducing the particle size of the flux has been shown to improve fusion at a given temperature.  
5.3.1.2  Dissolution  
Under the conditions of preparation used, the sample shall be totally dissolved by the flux and shall not c ome 
out of solution in the casting procedure.  
5.3.1.3  Heavy -element absorber  
A heavy -element absorber, such as lanthanum or vanadium oxide, may be incorporated into the flux,  
provided:  
a) it does not reduce sensitivities to the point that the performance c riteria given in 5.7.3 cannot be met;  and 
b) the heavy element does not have a line overlap with any of the elements being determined.  EAS 148-2:201 7 
47 © EAC 2017 – All rights reserved  
 NOTE  Lanthanum oxide assists the formation and stabilisation of glass but reduces the intensity of the emitted  X-
rays.  
WARNING  There are restrictions on the use of heavy -metal chemicals in some countries. Care should be  taken in 
the handling of these and national safety rules observed.  
5.3.1.4  Flux purity  
5.3.1.4.1  The flux shall be pure with respect to the elements being de termined.  
5.3.1.4. 2 Most reagents sold as “flux” grade quality by reputable manufacturers meet this requirement, but 
an analysis  shall be obtained for each batch of flux supplied. Carry out a bead -preparation monitoring check 
(see 5.7.5)  when a batch of fl ux is changed.  
5.3.2  Moisture in flux  
Pre-molten fluxes having a loss on ignition not exceeding 0 .50 % mass fraction are preferred. However, if the  
flux contains moisture, it shall be dried at a suitable temperature.  
5.3.3  Flux-to-sample ratio  
5.3.3.1  The flux-to-sample ratio selected shall be such that the performance criteria given in 5.7.3 are 
met. The mass  fraction ratio, R, of flux to sample used for the calibration shall be used for subsequent 
analyses.  
NOTE  As the flux -to-sample mass fraction ratio i s greater than one, impurities in the flux can have a negative  
influence on the measured result. The greater the ratio of the flux to sample, the greater the influence . 
5.3.3. 2 The total mass of sample and flux shall be chosen for the particular casting mo uld type used, and 
this mass  shall always remain the same.  
5.3.4  Anti-wetting agent  
A small amount of anti -wetting agent may be used, if necessary. An anti -wetting agent, such as lithium  
bromide, ammonium bromide, lithium iodide, lithium iodate or ammonium  iodide, may be added to the melt to  
assist in preventing the cracking of the fused beads on cooling and to aid in the release from the mould.  
Where an anti -wetting agent is used, all beads shall be prepared using the same anti -wetting agent added in  
the s ame quantity and at the same stage of bead preparation.  
NOTE  Bromine or iodine in the anti -wetting agent can remain in the bead under some fusing conditions. It is  
important to check for residual bromine or iodine, since these elements can cause line overl apping, such as Br  Lα on Al 
Kaα or I ß2 on Ti  Kα 
5.4 Determination of loss on ignition and the change in mass on fusion of the cement  
5.4.1  Principle  
5.4.1.1  In order to be able to total (to 100 % mass fraction) any oxide analysis of cement, the 
determination of the loss  on ignition, that is  the amount of any combined water and carbon dioxide, is 
required. In addition, in order to be  able to convert an oxide analysis obtained on the fused -basis using fused -
bead XRF, to an oxide analysis on  the as -received basis, an “observed” loss on ignition is also required.  
NOTE  Where the sample contains no oxidisable species, the loss on ignition and the “observed” loss on ignition are  
the same.  
5.4.1. 2 The “observed” loss on ignition (see 5.4.3.1) is a very close approximation to the “chan ge in mass 
on fusion”  that occurs when a sample is prepared as a fused bead for analysis by XRF. This “observed” loss 
on ignition  is used in this method to calculate a factor, f, (see 5.5) to convert test results obtained on the fused 
basis to  the as -recei ved basis.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  48 
 5.4.1. 3 The traditional loss -on-ignition determination carried out in an oxidising atmosphere by igniting in 
air can be  used to determine both the loss on ignition and the “observed” loss on ignition. Where any 
oxidisable species  are present, in  particular sulfide or sulfur -containing species, a correction can be applied to 
the “observed”  loss in order to derive a “corrected” loss on ignition for use in totalling the oxide analysis. 
However, any error  resulting from the oxidation of any metallic iron, bivalent iron or bivalent manganese is 
usually considered to  be negligible and only the correction for the extent of oxidation of sulfides is applied in 
the correction.  
5.4.1. 4 An alternative method, for example  automatic equipment, may be used, prov ided that it can be 
demonstrated that the  performance criteria given in 5.7.3 are satisfied.  
5.4.2  Procedure  
5.4.2.1 Weigh, to ± 0.000 5 g, (1 .00 ± 0.05) g of cement into a crucible which has been previously ignited 
and tared.  Record this mass as m1. Place  the covered crucible in the furnace (5.2.4) controlled at (950  ± 25) 
°C. After  heating for 5 min, remove the lid and leave the crucible in the furnace for a further 10 min. Allow the 
crucible  to cool to room temperature in a desiccator. Determine constant  mass by making successive 15 min 
ignitions  followed each time by cooling and then weighing, and record as m2. Constant mass is reached when 
the difference between two successive weighings is less than 0 .000 5 g.  
NOTE  For cements containing sulfides, a mor e accurate determination of the loss on ignition can be obtained by  
determining the sulfate content before and after ignition.  The correction applicable to these cements is given in 5.4.3.2.  
5.4.2.2 When vacuum desiccators are used, the appropriate desicca tor inlet trap should be used when 
any vacuum is  released. Phosphorus pentoxide should be avoided where surface -active materials are being 
stored, since  P2O5 can be absorbed by the sample, particularly under vacuum conditions.  
5.4.3  Calculation and express ion of results  
5.4.3.1  Observed loss on ignition  
Calculate the observed loss on ignition that is  the change in mass on fusion, L, expressed as a percentage  
mass fraction, as given in Formula (37):  
L 
 100x   m
121
mm  (37) 
where  
m1  is the mass of the test portion, expressed in grams;  
m2  is the mass of the ignited test portion, expressed in grams.  
5.4.3.2  Correction to the observed loss on ignition for the oxidation of sulfides  
5.4.3.2.1  Calculate the correction to the “observed” loss on ignition for the extent of oxidation of sulfides, by 
determining  the sulfate present before and after ignition (see 4.4.2).  
5.4.3.2. 2 The amount of SO 3, wS,up, resulting from the oxidation of sulfides, expressed as a percentage 
mass frac tion, is  calculated as given in Formula (38):  
W W W iS,fS,upS,  - 
 (38) 
where  
wS,f  is the final SO 3 value, expressed as a percentage mass fraction;  
wS,i  is the initial SO 3 value, expressed as a percentage mass fraction . EAS 148-2:201 7 
49 © EAC 2017 – All rights reserved  
 A correction, wO,up, for the oxygen taken up by the test portion, expressed in percent, is given by Formula (39):  
 0.8 upS,upO, W W
 (39) 
The corrected loss on ignition, Lcor, is calculated as given in Formula (40):  
 upO,cor WLL
 (40) 
where  
L is the observed loss on ignition, expressed as a percentage mass fraction.  
Indicate any corrections applied in the test report.  
5.4.4  Repeatability and reproducibility for loss on ignition  
5.4.4.1 The standard deviation for repeatability is 0 .04 % mass fraction.  
5.4.4. 2 The standard deviation for reproducibility is 0 .08 % mass fraction.  
5.5 Factoring test results and correcting total analyses for presence of sulfides and halides  
5.5.1  General  
5.5.1.1  Analyses may be carried out on a fused -bead or pressed -pellet test portion. In the case of 
analysis using  fused beads, it is necessary to determine the change in mass that occurs during fusion (see 
5.4.3.1) in order  to derive a multiplying factor fo r converting test results obtained on the fused basis to 
analytical results  reported on the as -received basis.  
5.5.1. 2 In addition, where sulfide, chloride or bromide are present, it is also necessary to correct the total 
oxide  analysis of a cement for the  fact that, traditionally, these species are also expressed as if they were 
oxygen  (combined with calcium) in the analytical result reported for calcium oxide. This latter correction also 
applies to  analyses carried out using pressed pellets.  
5.5.2  Factori ng test results obtained from fused -bead analysis  
5.5.2.1  Principle  
Where fusion is employed, it is necessary to determine the change in mass that occurs during fusion in order  
to derive a multiplying factor for converting test results obtained on the fuse d basis to analytical results on the  
as-received basis.  The change in mass that occurs during fusion is determined by igniting, in air, a weighed 
test portion to  constant mass at (950  ± 25) °C and calculating the “observed” loss on ignition; see 5.4.3.  
NOT E 1 The change in mass occurring during fusion in air is normally a loss as, generally, water and carbon dioxide  
are released. Where, however, the sample contains oxidisable species, there is an increase in mass of these species  
during fusion resulting fro m oxygen uptake. This might or might not lead to an overall increase in mass of the test portion  
depending on the balance of mass lost versus mass gained. The oxidisable species that can lead to an overall gain in  
mass of a test portion is sulfur, generall y present as sulfide (typically calcium sulfide) in test portions that contain a 
blastfurnace  slag constituent. Other oxidisable species, where present, such as metallic iron, bivalent iron or bivalent  
manganese, are generally present in small amounts and make only a minor contribution to mass change.  
NOTE 2  The presence of sulfide in a sample also leads to restrictions on the scope of the analysis that can be  
undertaken using the XRF technique based upon fused beads. In particular, sulfate (SO 3) cannot be determined directly  
from such a fused bead because of the contribution to the concentration from the unknown amount of sulfide. In addition,  
sulfide cannot be determined directly (or accurately, indirectly) because of the contribution of the unknown amount  of 
sulfate to the analysis and from the possibility that some sulfide could have been lost by volatilisation during fusion.  
Consequently, the method in 4.4.5, is the reference method for determining the sulfate content of samples containing  
sulfide specie s. EAS 148-2:201 7 
© EAC 2017 – All rights reserved  50 
 5.5.2.2  Calculating the factor for converting the results obtained using fused beads  
Calculate the factor, fLOI, for converting test results obtained on the fused basis to analytical results on the  as-
received basis, from the observed loss on ignition, L, (see 5.4.3.1) as given in Formula (41):  
 
) (
100100
LOILf  (41) 
where  
L is expressed as a percentage mass fraction.  
When L is a negative number, which occurs when the test portion has undergone an overall gain in mass,  
preserve the sign together with L in Formula (41).  
5.5.2.3  Use of the conversion factor, fLOI 
Convert all test results obtained on the fused basis to analytical results on the as -received basis by multiplying  
each result by the fac tor, fLOI. 
5.5.3  Correcting total oxide analysis for sulfides and halides  
5.5.3.1  Correcting total oxide analysis for sulfides  
5.5.3.1.1  Irrespective of whether the analysis was carried out on a fused (bead) or pressed (pellet) test 
portion,  determine the sulfide content of the cement, on the as -received basis, in accordance with the method 
for sulfide determination in 4.4.5.  
5.5.3.1. 2 The factor, fS, to correct the total analysis of cement containing sulfide species, is calculated as 
given in  Formula (42):  
 2sO, totO, w W  Lcor 2swfs
 (42) 
where  
ws2-  is the sulfide content, expressed as a percentage mass fraction;  
Lcor  is the “corrected” loss on ignition, expressed as a percentage mass fraction; (see 5.4.3.2);  
wO,tot   is the sum of all oxides, expressed as a percentage mass fraction; (see 3.3);  
wO,s2-  is the oxygen equivalent of sulfide, expressed as a percentage mass fraction, which is  
calculated as given in Formula (43):  
  2s2 w0.5 sO,w
 (43) 
5.5.3.2  Correcting total oxide analysis for halides  
5.5.3.2.1  Correcting total oxide analysis for chloride  
Irrespective of whether the analysis has been carried out on a fused (bead) or pressed (pellet) test port ion, 
calculate the factor, fCl, to correct the total analysis of cement containing chloride as given in Formula (44):  
w w wfcl    toto, c
clO,corL l
 (44) 
where  EAS 148-2:201 7 
51 © EAC 2017 – All rights reserved  
 wCl  is the chloride content, expressed as  a percentage mass fraction;  
wO,Cl  is the oxygen equivalent of chloride, expressed as a percentage mass fraction, which is  
calculated as given in Formula (45):  
clW0.2 WclO,
 (45) 
NOTE  Any correction for the presenc e of chloride is generally very small and is usually ignored.  
5.5.3.2.2  Correcting total oxide analysis for bromide  
Irrespective of whether the analysis has been carried out on a fused (bead) or pressed (pellet) test portion,  
calculate the factor, fBr, to correct the total analysis of cement containing bromide as given in Formula (46):  
w- w L wfBr  toto,BrO,corBr
 (46) 
where  
wBr  is the bromide content, expressed as a percentage mass fraction;  
wO,Br   is the oxygen equivalent of bromide, expressed as a percentage mass fraction, which is 
calculated  as given in Formula (47):  
Brw W BO,r 10
 (47) 
NOTE  Any correction for the presence of bromide is generally very small and is usually ignored.  
5.6 Preparation of fused beads and press ed pellets  
5.6.1  General  
5.6.1.1  At several of the stages, a choice of procedures is given. Once a choice has been made, the 
procedure shall  be adhered to throughout calibration and analysis, unless a new calibration is carried out in 
accordance with  5.7. 
5.6.1. 2 The bead or pellet preparation conditions shall be set such that the criteria given in 5.7.3 are met.  
5.6.2  Conversion of the sample to bead form  
5.6.2.1  Weighing of the sample  
5.6.2.1.1  General  
Weigh the sample, the flux and any anti -wetting agent  to the nearest 0 .000 1 g and to the ratio, R, selected.  
Add the anti -wetting agent, when used as a solution, using a micro -pipette. The sample being used shall be  
weighed as given in either 5.6.2.1.2 or 5.6.2.1.3.  
5.6.2.1.2  Unignited samples  
The required mass, m3, expressed in grams, of the unignited sample is calculated as given in Formula (48):  
)
100(1 4
3Lmm

 (48) 
where  
m4  is the mass of fused sample (see 5.3.3) required to prepare a bead, expressed in gram s; EAS 148-2:201 7 
© EAC 2017 – All rights reserved  52 
 L is the observed loss on ignition, expressed in percent (see 5.4.3.1).  
5.6.2.1.3  Ignited samples  
5.6.2.1.3.1  Prepare the sample in accordance with 5.4.2 but, in this case, the appropriate amount of the 
sample may be  used. A constant mass is reached whe n the difference between two successive weighings is 
less than 0 .05 %  mass fraction. Store ignited samples in a desiccator.  
5.6.2.1.3. 2 When preparing a bead using the ignited sample, carry out weighings as quickly as possible 
to avoid  contamination.  
5.6.2 .1.3.3 Where the sample contains significant amounts of carbonate that can result in loss of material 
through  spurting, or where it contains carbides, iron or other metals that can interact with platinum and 
damage the  crucible, the ignited sample should b e used in the preparation of beads.  
5.6.2.1.3. 4 The amount of the sample should not be more than 5 g, because it is difficult with a larger 
sample to reach a  constant mass without repeated ignitions. However, if a large amount of sample is being 
used, lump s in the  sample should be broken up after the first ignition.  
5.6.2.2  Fusion procedure  
5.6.2.2.1  Thoroughly mix the sample, the flux and any anti -wetting agent before fusion. Where the anti -
wetting agent is  added as a solution, it shall be added after plac ing the mixture of sample and flux into the 
fusion vessel and  evaporating all moisture at a low temperature before the fusion. Fuse the mixture for the 
prescribed time, for example  10 min, at the selected, controlled temperature with occasional swirling un til the 
sample dissolves and the melt  is homogeneous.  
NOTE  The volatilisation of sulfur trioxide becomes  significant for samples fused at temperatures in excess of  1 100 
°C. Where sulfur trioxide is being determined, it is essential to keep the temperature  below this level.  
5.6.2.2. 2 The fusion temperature may be specified according to cement or element type. For more volatile 
elements,  for example  sulfate, sulfide, chloride or alkalis, fusion at reduced temperature or the use of pressed 
pellets can be  nece ssary to achieve the required precision.   
Increasing the temperature in two stages has been shown to improve precision.  
5.6.3  Casting of the beads  
5.6.3.1  General  
Cast the beads using one of the methods  below . Beads produced shall be free from blemishes on  the 
analytical measuring surface:  
a) outside the furnace: after 5 min, remove the casting mould (and the heat reservoir) from the furnace and  
place on a horizontal surface. Remove the lid from the fusion dish, remove the dish from the furnace and  
immediat ely pour the melt into the casting mould ; 
b) in the furnace: after 5 min, remove the lid from the fusion dish and pour the melt into the casting mould  
inside the furnace, ensuring that as much of the melt is transferred to the casting mould as possible.  
Remove the casting mould from the furnace and place on a horizontal surface.  
c) combined fusion mould: after 5 min, remove the fusion mould from the furnace and by swirling ensure the  
transfer of the whole of the melt into the mould part of the dish ; 
d) mould heated over burner: after preparation of the melt, pour the melt into the preheated casting mould  
and turn the burner off ; and  
e) inside the fusion mould: after completion of the fusion, leave the melt inside the fusion dish and remove it  
from the furnac e. EAS 148-2:201 7 
53 © EAC 2017 – All rights reserved  
 5.6.3.2  Cooling of the beads  
5.6.3.2.1  Allow the casting mould to cool on a horizontal surface.  
5.6.3.2. 2 If rapid cooling is required, when the melt has cooled from red heat, transfer the casting mould to 
an air jet  (5.2.6) (or alternatively, a water -cooled plate). The melt can be molten or solid at this stage. Hold the 
dish in a  horizontal position above the air jet so that the air is directed onto the centre of the base of the 
mould. When  the bead has solidified and released itself, turn off the air j et. 
NOTE  It can be necessary to encourage the release of the beads at this stage by gently tapping the casting mould on  
a solid surface.  
5.6.4  Automatic bead preparation  
An automatic fusion apparatus (5.2.5) may be used to prepare beads.  
5.6.5  Storage  
5.6.5.1 Protect beads from deterioration caused by adverse temperature and humidity conditions, for 
example  by storage in a  polyethylene self -seal container. If the laboratory environment is suitably controlled 
for example  air-conditioned, then  the container s hall be stored in a desiccator. Alternatively, if the environment 
is not controlled, the containers  shall be stored in a tempera ture-controlled oven at 25 °C - 30 °C.  
5.6.5. 2 Where pressed pellets are being stored for a limited period, they may be placed u nwrapped in a 
desiccator.  
5.6.5. 3 The containers themselves can cause surface contamination due to the use of “anti -blocking 
agents” (the  effect being more apparent for the lighter elements). After long -term storage, thoroughly clean the 
measuring  surfaces  of beads before use, for example  by washing with ethanol or acetone or by polishing.  
NOTE  Reported sources of contamination are as follows: sulfur from vacuum oil in the spectrometer or from the  
laboratory atmosphere; sodium and chlorine from manual conta ct and the atmosphere if the laboratory is near the sea;  
sodium and potassium from cigarette smoke.  
5.6.6  Pressed pellets  
Weigh, to the nearest 0 .1 g, a quantity of sample suitable to fill the mould to excess. Grind to a suitable  
fineness, with a binding a gent (5.1.4) if necessary. Place the ground sample into the pellet mould (5.2.12) and  
spread evenly. Apply pressure at a rate and for a time shown to be suitable to ensure that the criteria given in  
5.7.3 are met. Store in accordance with 5.6.5 until requi red. 
NOTE  In automated pellet preparation, the sample is dosed volumetrically.  
5.7 Calibration and validation  
5.7.1  Principles  
The calibration equations and inter -element corrections are established using calibration standards produced  
using beads or pelle ts made from pure reagents, CRMs, IRMs or any combination of these (see 5.1). The  
validity of the calibration is confirmed by analysing one or more CRMs, representative of the range of analyses  
being undertaken. The ongoing calibration monitoring for inten sity, bead preparation and calibration drift is  
determined immediately after calibration and at intervals during the analytical process. Typical ranges for  
calibration standards for analysis of CEM I cements are given in Annex B. Performance criteria are s et out in 
5.9. EAS 148-2:201 7 
© EAC 2017 – All rights reserved  54 
 5.7.2  Calibration and validation samples  
5.7.2.1  Calibration standards  
5.7.2.1.1  Prepare a series of beads or pellets from pure reagents, IRMs, CRMs or combinations of these 
(see 5.1) as  calibration standards. The series shall cover the rang e from the minimum to the maximum values 
for each  element being analysed and shall be evenly distributed between those limits. The variations in the  
concentration of each element in the calibration standard shall be independent of each other. The minimum  
number of standards is seven.  
5.7.2.1. 2 An example of a series of calibration standards suitable for the analysis of cements of type CEM 
I, in accordance with  EAS 18-1, is given in Annex B. Other reagents may be added to cover the scope of the  
elements be ing determined.  
5.7.2.1. 2 Where ten standards or fewer are used, duplicate beads or pellets should be prepared. Where a 
larger  number of standards is used, single preparation can be sufficient.  
5.7.2.1. 3 For pellet analysis, a calibration made from IRMs or  CRMs can provide unsatisfactory results due 
to mineralogical effects. In this case, the calibration may be done with secondary standards, made from 
samples  routinely analysed by the laboratory, that have been characterised with at least one analysis by 
reference  methods or by X -ray fluorescence using fused beads.  
5.7.2.2  Calibration validation of a CRM or IRM  
5.7.2.2.1  Prepare one or more CRMs, not used in the calibration standard (5.7.2.1) and having a 
composition within the  calibration range for each ele ment being analysed.  
5.7.2.2. 2 When only one validation CRM is being used, select a sample in the middle of the concentration 
ranges.  Where several validation CRMs are used, select samples covering high and low values.  
5.7.2.2. 3 If no suitable CRM is avail able, choose an IRM that satisfies the above criteria. It is 
recommended that each  IRM be validated by at least four laboratories.  
5.7.2.2. 4 In the case of pressed pellets, and especially for composite cements, variations in mineralogy can 
affect the  accur acy. In such cases, it is essential to use an IRM matching closely each type of sample being 
analysed,  and preferably made from the samples routinely analysed by the laboratory.  
5.7.2.3  Intensity correction samples  
NOTE 1  These are sometimes referred to as  “monitor” samples.  
5.7.2.3.1  Use one or more samples, (glass beads or other stable material) each having a composition 
giving an  intensity level similar to the calibration range for each element being analysed. If several samples 
are used,  select high and  low values for each element. These samples shall be different from the calibration 
standards  (see 5.7.2.1). Store these samples for future reference. Excessive exposure to the X -ray beam shall 
be avoided to prevent ageing.  
NOTE 2  Samples stored as pellets  are subject to rapid ageing and, therefore, it is preferable that fused beads or glass  
be used for intensity control, even where the analysis predominantly uses pellet calibrations.  
5.7.2.3. 2 The samples shall be used to calculate a correction factor to a pply to the raw intensity 
measurements, to take  account of the ageing of the apparatus (X -ray tube, detectors ) (see 5.7.4.3).  
5.7.2.4  Re-calibration standards  
5.7.2.4.1  Select two of the calibration standards (5.7.2.1), having high and low values for each element of 
interest, and  store for future reference.  
NOTE  Depending on the equipment, it might be required to define re -calibration standards at the time of the initial  
calibration.  EAS 148-2:201 7 
55 © EAC 2017 – All rights reserved  
 5.7.2.4. 2 They shall be used to adjust the equation of the calibration cur ve in the event that the drift of the 
apparatus is  not sufficiently corrected by the intensity correction procedure (see 5.7.4.2).  
5.7.2.5  Spectrometer control samples  
5.7.2.5.1  Control for bead analysis  
5.7.2.5.1.1  Prepare and store one or more beads with in, or close to, the calibration range. Calibration 
validation samples  (see 5.7.2.2) are suitable.  
5.7.2.5.1. 2 A replacement bead may be prepared if ageing is suspected.  
5.7.2.5.2  Control for pellet analysis  
Due to the more rapid ageing of pellets, it is n ot possible to ensure control of the spectrometer using pellets.  
Therefore, the spectrometer control for pellet analysis shall be made using a fused bead or glass sample.  
5.7.2.6  Preparation procedure control sample  
Prepare a new bead or pellet of the cali bration validation samples (see 5.7.2.2) as a control for the preparation  
procedure.  
5.7.3  Initial calibration  
5.7.3.1  Calibration procedure  
5.7.3.1.1  Establish the calibration relationship  between the intensity of measured X -rays and the element 
concentra tion, including corrections for any mass absorption and line overlap effects.  
5.7.3.1. 2 At a reasonable counting time for example  3 min - 5 min, measure and record the intensities for 
each element being  determined in all of the calibration beads or pellets . Using regression analysis, establish 
the calibration curve  for each element being determined.  
NOTE  Increasing the counting time on the measurement of the standards can improve the accuracy of the  
calibration.  
5.7.3.2  Calibration for inter -element effects  
Where inter -element effects significantly influence the accuracy of the calibration, for example  the influence of  
potassium on calcium, it can be necessary to establish a correction. For each inter -element correction applied,  
prepare at least one addition al calibration standard bead or pellet.  
5.7.3.3  Validation of calibration  
5.7.3.3.1  Validate the accuracy of the calibration for the elements being determined by analysing, in 
duplicate, at least  one accuracy validation sample [see 5.7.2.2 (CRM or IRM)].  
5.7.3.3. 2 When selecting a CRM or IRM for validation, it is recommended that the series of analyses used 
to produce  the certified analysis be examined in relation to the criteria for repeatability, reproducibility and 
accuracy  (see 5.9).  
5.7.3.3. 3 The calib ration is valid if all the elements being determined satisfy the accuracy limits set down in 
Table 8.  
5.7.3.3. 4 If the calibration is not valid:  
a) consider the need for a calibration adjustment for inter -element effects (see 5.7.3.2);  
b) consider whether the set of standards used is adequate;  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  56 
 c) determine other cause(s), and take appropriate corrective action; or,  
d) repeat initial calibration in accordance with 5.7.3, as appropriate.  
5.7.3.4  Validation of repeatability  
5.7.3.4.1  General  
Validate the repea tability of analysis for a new spectrometer when there has been any major modification of  
the preparation procedure or the spectrometer.  
5.7.3.4.2  Repeatability of the spectrometer  
5.7.3.4.2.1  Measure, over a period of not more than one week, the same bead  of the spectrometer 
control sample (see  5.7.2.5) at least ten times. Record the average and calculate the standard deviation of 
these measurements.  To validate the spectrometer repeatability, the standard deviation shall be less than 
one-third of the  repeatability limits defined in Table 7.  
5.7.3.4.2. 2 The limits in Table 7 allow for the overall procedure repeatability. The repeatability of the 
spectrometer itself  should be lower, to ensure the required repeatability of the method.  If the repeatability of 
the spectrometer is not validated, implement one of the following and repeat the  repeatability validation:  
a) check the stability of the apparatus (gas fl ow, temperature regulation ); 
b) increase the counting time;  and 
c) increase the sample -to-flux ratio f or the bead to improve sensitivity.  
5.7.3.4.3  Repeatability of the method  
5.7.3.4.3.1  Prepare and analyse, over an appropriate period of time (for example,  at least two weeks), at 
least ten different  preparations of the preparation procedure control sample  (see 5.7.2.6). Record the average 
and the  calculated standard deviation.  
5.7.3.4.3. 2 The repeatability of the method is valid if the difference in results for each new preparation, 
compared with the  previous example, is within the repeatability limits def ined in Table 7.  
5.7.3.4.3. 3 If the repeatability of the method is not validated:  
a) check the stability of the apparatus (gas flow, temperature regulation . 
b) increase the counting time;  
c) increase the sample -to-flux ratio for the bead to improve sensiti vity; 
d) increase the fineness of the sample;  
e) adjust the temperature and/or duration of the fusion for beads;  
f) consider the use of a grinding agent or binding wax for pellets;  and 
g) increase the duration and/or pressure on the press for pellets.  EAS 148-2:201 7 
57 © EAC 2017 – All rights reserved  
 
 
Figure 5 — Calibration validation  
5.7.3.5  Initial values of the intensity correction samples  
At the time of the initial calibration, record the initial values of the intensity correction samples (“monitors”; see  
5.7.2.3).  
NOTE  It is generally possible to sto re these values in the software.  Store the corresponding samples for future 
reference.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  58 
 5.7.3.6  Initial values of the re -calibration standards  
At the time of the initial calibration, record the initial values of the re -calibration standards (see 5.7.2.4) . 
 
NOTE  It is generally sufficient in the software to define two of the calibration standards (see 5.7.2.1) as the  re-
calibration standards.  
5.7.3.7  Initial values of the spectrometer control sample  
5.7.3.7.1  At the time of the initial calibration, record the  average value, calculated in accordance with 
5.7.3.4.2, of the  spectrometer control sample (see tolerance limits in 5.7.4.2).  
5.7.3.7. 2 If ageing of the spectrometer control sample is suspected, a new bead is prepared, and new initial 
values are  establish ed. 
5.7.3.8  Initial values of the preparation procedure control sample  
At the time of the initial calibration, record the average calculated in 5.7.3.4.3 as the initial value of the  
preparation procedure control sample (see 5.7.2.6 and preparation repeatab ility validation limits in 5.7.5.1).  
5.7.4  Spectrometer follow -up 
5.7.4.1  Principle  
5.7.4.1.1  Introduction  
5.7.4.1.1.1  The main bias in X -ray fluorescence is the intensity drift due to ageing. The consistency of the 
results is  monitored by measuring the sp ectrometer control sample (see 5.7.2.5), before carrying out each 
series of  sample analyses.  
5.7.4.1.1. 2 In the first instance, this intensity drift is corrected using the intensity correction samples 
(5.7.2.3). Where this  is not sufficient, correction fac tors may be applied to the calibration equation using the 
re-calibration  standards. Alternatively, a full re -calibration may be necessary.  
5.7.4.1.1. 3 After each action that modifies the result pr ovided by the spectrometer (for example,  drift 
correction or  re-calibration),  the accuracy shall be assessed again in accordance with 5.7.3.3.  
5.7.4.1.2  General  
If the spectrometer control sample is within the limits set out below, or if the calibration has been re -validated  
in accordance with 5.7.3.3, then the spe ctrometer is ready for analysis. If the analysis is not valid, apply the  
decision diagram in Figure 6.  
5.7.4.1.3  Re-validation of bead calibration  
The bead calibration remains valid if the results, compared with the initial values (see 5.7.3.7), are equal to or 
less than three times the standard deviation for the spectrometer determined in 5.7.3.4.2.  
5.7.4.1.4  Re-validation of pellet calibration  
5.7.4.1.4.1  Depending on the capabilities of the software used, record the measurements:  
a) as a corrected intens ity, taking into account the intensity drift correction (see 5.7.4.2);  and 
b) as a concentration.  EAS 148-2:201 7 
59 © EAC 2017 – All rights reserved  
 5.7.4.1.4. 2 The pellet calibration remains valid if the results, compared with the initial values (see 
5.7.3.7), are equal to or  less than three times the sta ndard deviation for the spectrometer determined in 
5.7.3.4.2.  
 
 
*Apply successively one or several of the proposed corrective actions. If several actions are necessary, apply 
in the following order:  
1. correction for intensity drift;  
2. recalibration; and  
3. renew  initial calibration.  
Figure 6 — Analysis validation decision scheme Instrument check  
Carry out the following checks, as necessary, when any automatic fine adjustment, present in software on  
some spectrometers, has been made:  
c) gas flow;  
d) temperature re gulation;  
e) counter resolution problems;  
f) 2-theta angle settings;  and 
g) high-voltage settings of the detector.  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  60 
 5.7.4.2  Correction for intensity drift  
5.7.4.2.1  Where necessary (see Figure 6), a correction factor is calculated for each element to compen sate 
for the drift  in intensity due to a geing of the tube, detector . Subsequently, the corrected intensities are then 
used in  the calibration equation to derive the concentrations.  
NOTE  In most software applications, this correction is applied to all calib rations for each element.  
5.7.4.2. 2 The intensity drift should be small and regular with time. A sudden change in intensity indicates 
an instrumental problem, and correction by this intensity drift method is not appropriate.  
5.7.4.3  Re-calibration  
5.7.4.3. 1 Where necessary (see Figure 6), if the intensity correction (see 5.7.4.2) is insufficient to achieve 
accurate  results for the analysis validation (see 5.7.4.1), it is possible to apply correction factors to the 
calibration  curves using the re -calibration  standards.  
5.7.4.3. 2 The modifications in the calibration equation due to instrumental drift should be small and regular 
with time.  Any rapid or major bias in the analytical results can indicate an instrumental or analytical problem, 
and correction by thi s re-calibration method is not appropriate.  
5.7.5  Preparation procedure follow -up 
5.7.5.1  Bead and pellet preparation validation  
On a regular basis, the whole analysis method shall be checked, including preparation of the bead or pellets  
and the measuremen t on the spectrometer.  Prepare a new preparation procedure control sample (see 
5.7.2.6). The preparation is valid if:  
a) the results of the new analysis, compared with the initial values (see 5.7.3.8), are within the limits for  
repeatability set down in Ta ble 7;  and 
b) the ongoing average values for new analyses, compared with the certified values of the CRM or IRM, are  
within the limits for accuracy set down in Table 8.  
5.7.5.2  Remedial action for preparation bias  
5.7.5.2.1  If the analysis fails to satisfy  the repeatability or accuracy limits set down in 5.7.5.1, check 
whether:  
a) the loss on ignition of the flux has increased;  
b) drift could have occurred due to the preparation apparatus (check temperature, fineness, quality of  
sample surface ) 
c) a new bat ch of flux has been introduced;  
d) a new bead or pellet preparation apparatus has been installed;  
e) the sample preparation procedure has been changed or modified, for example  from manual to automatic;  
f) a new type of flux or new sample -to-flux ratio has been used;  and 
g) other procedural or apparatus changes have been introduced.  
5.7.5.2. 2 In the first two cases, take remedial action and re -check the analysis. In all other cases, carry out 
a full  re-calibration, including new preparation of all of the sam ples in accordance with 5.7.2.  EAS 148-2:201 7 
61 © EAC 2017 – All rights reserved  
  
Table 7 — Repeatability limits for analysis validation  
Element mean value , 
% mass fraction  Repeatability limit  for “normal” performance , 
% mass fraction absolute  Repeatability limit for  “expert” 
performance , 
% mass fraction  absolute  
0 - 0.49 0.057 0.023  
0 50 - 0.99 0.080  0.032  
1.00 - 1.99 0.110  0.044  
2.00 - 3.99 0.135  0.054  
4.00 - 4.99 0.155  0.062  
5.00 - 6.99 0.172  0.069  
7.00 -9.99 0.202  0.081  
10.00 - 14.99  0.240  0.096  
15.00 - 19.99  0.290  0.116  
20.00 - 24.99  0.335  0.134  
25.00 - 29.99  0.372  0.149  
30.00 - 34.99  0.405  0.162  
35.00 - 39.99  0.437  0.175  
40.00 - 44.99  0.465  0.186  
45.00 -49.99 0.492  0.197  
50.00 -54.99 0.517  0.207  
55.00 - 59.99 0.542  0.217  
60.00 -64.99 0.565  0.226  
65.00 - 69.99  0.587  0.235  
70.00 - 74.99 0.610  0.244  
75.00- 79.99  0.630  0.252  
80.00 - 100 0.650  0.260  
NOTE  All values of repeatability are expressed on the basis of fused, that is  loss-on-ignition -free, samples.  
 
Table 8 — Accuracy limits for validation  
Content of e lement 
species , 
% mass fraction 
absolute  Accuracy  limit for “normal” performance , 
% mass fraction absolute  Accuracy limit for “expert” 
performance , 
% mass fraction absolute  
0 - 0.49 0.05 0.02 
0 50 - 0.99 0.08 0.03 
1.00 - 6.99 0.20 0.08 
7.00 - 14.99  0.30 0.12 
15.00 - 29.99  0.38 0.15 
30.00 - 49.99  0.50 0.20 
50.00 - 79.99  0.63 0.25 EAS 148-2:201 7 
© EAC 2017 – All rights reserved  62 
 Content of e lement 
species , 
% mass fraction 
absolute  Accuracy  limit for “normal” performance , 
% mass fraction absolute  Accuracy limit for “expert” 
performance , 
% mass fraction absolute  
80.00 - 100 0.75 0.30 
NOTE  All values of accuracy  are expressed on the basis of fused, that is  loss-on-ignition -free, samples.  
 
Table 9 — Reproducibility limits achieved using certified referenc e materials  
Element mean value , 
% mass fraction  Reproducibility limit for “normal” performance , 
% mass fraction  Reproducibility limit for  “expert” 
performance , 
% mass fraction  
0.5 0.112 0.045 
1.0 0.150 0.060 
2.0 0.225 0.090 
3.0 0.262 0.105 
4.0 0.300 0.120 
5.0 0.352 0.135 
7.0 0.412 0.165 
10 0.487 0.195 
15 0.562 0.225 
20 0.675 0.270 
25 0.750 0.300 
30 0.825 0.330 
35 0.862 0.345 
40 0.937 0.375 
45 0.975 0.390 
50 1.050 0.420 
55 1.087  0.435 
60 1.125  0.450 
65 1.162  0.465 
70 1.237  0.495 
75 1.275 0.510 
80 1.312 0.525 
NOTE  All values of reproducibility are expressed on the basis of fused, that is  loss-on-ignition -free, samples.  
 
5.8 Calculation and expression of results  
5.8.1  Calculate the concentrations on a fused basis from the calibration cur ve (see 5.7.3.1), corrected, 
where  necessary, for any inter -element effect (see 5.7.3.2).  
5.8.2 Calculate the results, where a single test result has been obtained, as a percentage mass fraction to 
four significant figures when the value exceeds 1 .00 % mas s fraction, or to three decimal places for values 
below  1.00 % mass fraction.  EAS 148-2:201 7 
63 © EAC 2017 – All rights reserved  
 5.8.3 Calculate the results, where two test results have been obtained, as the mean of the results, as a 
percentage  mass fraction to four significant figures when the value excee ds 1.00 % mass fraction, or to three 
decimal  places for values below 1 .00 % mass fraction.  
5.8.4 If the two test results differ by more than the appropriate repeatability limits set out in Table 7, repeat 
the test  and take the mean of the two closest test results.  
5.8.5 Convert test results on a fused basis to results on the as -received basis using the factor, fLOI, in 
accordance  with 5.5.2.3.  
5.8.6 Where the sample contains oxidisable sulfur species, or any chloride or bromide, see 5.5.3 with 
regard to  totalling the oxide analysis.  
5.8.7 The results of all individual tests shall be recorded.  
5.8.8 Express the results, generally as the oxide, to two decimal places.  
5.9 Performance criteria (repeatability, accuracy and reproducibility limits)  
Performance crit eria are given in Tables 7, 8 and 9.  
 EAS 148-2:201 7 
© EAC 2017 – All rights reserved  64 
 Annex  A 
(informative)  
 
Examples of fluxes  
There are three examples of fluxes that have proved suitable : 
a) 66 % lithium tetraborate +34 % lithium metaborate; purity 99 .95 % (minimum);  
b) 100 % lithium  tetraborate; nominal pu rity 100 %; and  
c) lithium tetraborate /lithium metaborate, in ratios of 100 :0 - 0:100 %; purity 99.98 %.  EAS 148-2:201 7 
65 © EAC 2017 – All rights reserved  
 Annex  B 
(informative)  
 
Examples of calibration standards and monitor beads and pellets  
Table B.1 — Calib ration standards for the calibration of analysis of CEM I cements  
Reagent  Mass of reagents required for each fusion , 
g 
Bead number  
1 2 3 4 5 6 7 
SiO 2 0.240 0  0.195 0  0.204 0  0.223 0  0.180 0  0.187 0  0.214 0  
Al2O3 0.072 0  0.081 0  0.026 0  0.054 0  0.045 0  0.063 0  0.036 0  
Fe2O3 0.015 0  0.061 0  0.068 0  0.042 0  0.053 0  0.023 0  0.034 0  
CaCO 3 1.042 2  1.091 2  1.096 0  1.148 7  1.135 4  1.188 6  1.199 2  
MgO  0.011 0  0.017 0  0.040 0  0.026 0  0.022 0  0.032 0  0.005 0  
K2CO 3 0.014 7  0.005 9  0.002 9  0.011 7  0.008 8  0.017 6 — 
CaSO 4 0.068 0  0.030 6  0.045 9  0.003 4  0.057 8  0.017 0  0.039 1  
Total  1.462 9  1.481 7  1.482 8  1.508 8  1.502 0  1.528 2  1.527 3  
 
Table B.2 — Composition of the calibration standards listed in Table B.1 
Reagent  Composition , 
% mass fraction  
Bead number  
1 2 3 4 5 6 7 
SiO 2 24.0 19.5 20.4 22.3 18.0 18.7 21.4 
Al2O3 7.2 8.1 2.6 5.4 4.5 6.3 3.6 
Fe2O3 1.5 6.1 6.8 4.2 5.3 2.3 3.4 
CaO 61.2 62.4 63.3 64.5 66.0 67.3 68.8 
MgO  1.1 1.7 4.0 2.6 2.2 3.2 0.5 
K2O 1.0 0.4 0.2 0.8 0.6 1.2 0.0 
SO 3 4.0 1.8 2.7 0.2 3.4 1.0 2.3 
Total  100.0  100.0  100.0  100.0  100.0  100.0  100.0  EAS 148-2:201 7 
© EAC 2017 – All rights reserved  66 
 Bibliography  
[1] ISO 5725 -1, Accuracy (trueness and precision) of measurement methods and results — Part 1: 
General principles and definitions  
[2] ISO/TR 12389 Methods of testing cement — Report of test programme — Chemical analysis by x -ray 
fluorescence  
[3]  EN 196 -2: 20 13; Methods testing cement — Part 2: Chemical analysis  
 EAS 148 -2: 201 7   
 
© EAC 20 17 – All rights reserved