DRAFT UGANDA STANDARD   
  DUS 1756 -3:2017  
First Edition  
2017 -mm-dd 
 
 
 Reference number  
DUS 1756 -3: 2017  
© UNBS 2017  
  
Commercial blasting explosives — Specification — Part 3: Part 
Ammonium Nitrate for explosives  
 DUS 1756 -3: 2017  
ii © UNBS 2017  – 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 correct application  
© UNBS 2017   
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 photo copying and microfilm, without prior written 
permission 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 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 1756 -3:2017  
© UNBS 2017  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Grades  ................................ ................................ ................................ ................................ ....................  1 
5 Requirements  ................................ ................................ ................................ ................................ .........  2 
5.1 Physical requirements  ................................ ................................ ................................ ..........................  2 
5.2 Anti-caking agents  ................................ ................................ ................................ ................................  2 
5.3 Chemical requirements  ................................ ................................ ................................ .........................  2 
5.4 Bulk density  ................................ ................................ ................................ ................................ ...........  3 
6 Inspection and sampling  ................................ ................................ ................................ ......................  3 
6.1 General  ................................ ................................ ................................ ................................ ...................  3 
6.2 Inspection  ................................ ................................ ................................ ................................ ...............  4 
6.3 Sampling  ................................ ................................ ................................ ................................ ................  4 
7 Packaging and labelling ................................ ................................ ................................ ........................  4 
7.1 Packaging  ................................ ................................ ................................ ................................ ...............  4 
7.2 Labelling  ................................ ................................ ................................ ................................ .................  4 
Annex  A (normative)  Determination of moisture using air -oven method  ................................ ...................  5 
A.1 Proc edure  ................................ ................................ ................................ ................................ ...............  5 
A.2 Calculation  ................................ ................................ ................................ ................................ .............  5 
B.1 Procedure  ................................ ................................ ................................ ................................ ...............  6 
B.2 Calculation  ................................ ................................ ................................ ................................ .............  6 
Annex C (normative)  Determination of non -volatile matter  ................................ ................................ ..........  7 
C.1 Procedure  ................................ ................................ ................................ ................................ ...............  7 
C.2 Calculation  ................................ ................................ ................................ ................................ .............  7 
Annex D (normative)  Determination of chlorides  ................................ ................................ ..........................  8 
D.1 Outline of the Method  ................................ ................................ ................................ ............................  8 
D.2 Reagents  ................................ ................................ ................................ ................................ ................  8 
D.3 Procedure  ................................ ................................ ................................ ................................ ...............  8 
D.4 Calculation  ................................ ................................ ................................ ................................ .............  8 
Annex E (normative)  Determination of nitrite  ................................ ................................ ................................ . 9 
E.1 General  ................................ ................................ ................................ ................................ ...................  9 
E.2 Colorimetric method  ................................ ................................ ................................ .............................  9 
E.2.1  Reagents  ................................ ................................ ................................ ................................ ................  9 
E.2.2  Procedure  ................................ ................................ ................................ ................................ ...............  9 
E.2.3  Calculation  ................................ ................................ ................................ ................................ .............  9 
E.3 Volumetric method  ................................ ................................ ................................ ..............................  10 
E.3.1  Reagents  ................................ ................................ ................................ ................................ ..............  10 
E.3.2  Procedure  ................................ ................................ ................................ ................................ .............  10 
E.3.1  Calculation  ................................ ................................ ................................ ................................ ...........  10 
Annex F (normative)  Determination of acidity of nitric acid  ................................ ................................ ....... 11 
F.1 Outline of the method  ................................ ................................ ................................ .........................  11 
F.2 Reagents  ................................ ................................ ................................ ................................ ..............  11 
F.3 Procedure  ................................ ................................ ................................ ................................ .............  11 
F.4 Calculation  ................................ ................................ ................................ ................................ ...........  11 
Annex G (normative)  Determination of iron  ................................ ................................ ................................ .. 12 DUS 1756 -3: 2017  
iv © UNBS 2017  – All rights reserved  
 G.1 Outline of the method  ................................ ................................ ................................ .........................  12 
G.2 Reagents  ................................ ................................ ................................ ................................ ..............  12 
G.3 Procedure  ................................ ................................ ................................ ................................ ............  12 
G.4 Calculation  ................................ ................................ ................................ ................................ ...........  12 
Annex H (normative)  Determination of calcium  ................................ ................................ ..........................  14 
H.1 Outline of the method  ................................ ................................ ................................ .........................  14 
H.2 Reagents  ................................ ................................ ................................ ................................ ..............  14 
H.3 Procedure  ................................ ................................ ................................ ................................ ............  14 
H.4 Calculation  ................................ ................................ ................................ ................................ ...........  14 
Annex I (normative)  Determination of pH  ................................ ................................ ................................ ..... 16 
Annex J (normative)  Determination of organic matter  ................................ ................................ ...............  17 
J.1 Procedure  ................................ ................................ ................................ ................................ ............  17 
J.2 Calculation  ................................ ................................ ................................ ................................ ...........  17 
Annex K (normative)  Determination of grit  ................................ ................................ ................................ .. 18 
K.1 Procedure  ................................ ................................ ................................ ................................ ............  18 
K.2 Calculation  ................................ ................................ ................................ ................................ ...........  18 
Annex L (normative)  Determination of purity on dry basis  ................................ ................................ ........  19 
L.1 Outline of the method  ................................ ................................ ................................ .........................  19 
L.2 Reagents  ................................ ................................ ................................ ................................ ..............  19 
L.3 Procedure  ................................ ................................ ................................ ................................ ............  19 
L.4 Calculations  ................................ ................................ ................................ ................................ .........  19 
Annex M (normative)  Determination of determination of metals and compounds of metals other 
than alkali metals, calcium andiron  ................................ ................................ ................................ .. 21 
M.1 Procedure  ................................ ................................ ................................ ................................ ............  21 
Annex N (normative)  Determination of pyridine  ................................ ................................ ..........................  22 
N.1 Pyridine  ................................ ................................ ................................ ................................ ................  22 
N.2 Procedure  ................................ ................................ ................................ ................................ ............  22 
Annex O (normative)  Determination of thiocyanate  ................................ ................................ ....................  23 
Annex P (normative)  Determination of prussian  blue and allied products  ................................ ..............  24 
Annex Q (normative)  Determination of oil absorption  ................................ ................................ ................  25 
Q.1 Procedure  ................................ ................................ ................................ ................................ ............  25 
Q.2 Calculation  ................................ ................................ ................................ ................................ ...........  25 
Annex R (normative)  Determination of bulk density  ................................ ................................ ...................  26 
R.1 Apparatus  ................................ ................................ ................................ ................................ ............  26 
R.2 Procedure  ................................ ................................ ................................ ................................ ............  26 
R.3 Calculation  ................................ ................................ ................................ ................................ ...........  26 
Annex S (normative)  Determi nation of total nitrogen  ................................ ................................ .................  28 
S.1 Outline of the method  ................................ ................................ ................................ .........................  28 
S.2 Apparatus  ................................ ................................ ................................ ................................ ............  28 
S.3 Reagents  ................................ ................................ ................................ ................................ ..............  28 
S.4 Procedure  ................................ ................................ ................................ ................................ ............  28 
S.4 Calculation  ................................ ................................ ................................ ................................ ...........  29 
Annex T (normative)  Determination of sulphates  ................................ ................................ .......................  30 
T.1 Outline of the Method  ................................ ................................ ................................ .........................  30 
T.2 Apparatus  ................................ ................................ ................................ ................................ ............  30 
T.3 Reagents  ................................ ................................ ................................ ................................ ..............  30 
T.4 Procedure  ................................ ................................ ................................ ................................ ............  30 
Bibliography  ................................ ................................ ................................ ................................ .....................  31 
 
. DUS 1756 -3:2017  
© UNBS 2017  – All rights reserved  v 
 Foreword  
Ugan da 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 In ternational 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  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda St andards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interes ted parties.  
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 Ug anda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS /TC 5, Chemicals and 
Environment  
US 1285  consists of the following parts, under the general title Commercial blasting explosives — 
Spec ification  
  Part 1: Emulsion Explosive   
  Part 2: Ammonium Nitrate – Fuel Oil Explosive  
  Part 3: Ammonium Nitrate - For explosives  
  Part 4: Soduim Nitrate - For explosives  
 DARFT UGANDA STANDARD  DUS 1756 -3: 2017  
 
© UNBS 2017 – All rights reserved  1 
 Commercial blasting explosives  — Specification  — Part 3: Part 
Ammonium Nitrate for explosives  
1 Scope   
This Draft Uganda S tandard specifies  requirements , sampling and test methods for Ammonium Nitrate 
intended primarily  for use in explosives.  
NOTE  The requirements of this standard should be read in conjunction with the Act of 1964 cap  309 and /or other 
applicable regulations . 
2 Normative references   
The following referenced documents referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dated references, only the edition c ited applies. For undated 
references, the latest edition of the referenced document (including any amendments) applies.  
DUS 1776 , light metal in hazardous location at mines — Guidelines for use  
DUS 1757 , Commercial blasting explosives — Terminology  
DUS ISO  7010 , Graphical symbols — Safety colours and safety signs — Registered safety signs  
3 Terms and definitions  
For the purposes of this document, the terms and definitions given in DUS 1757 and the following apply   
3.1  
anti-caking agents  
an additive placed  in powder ed or granulated materials, to prevent the formation of lumps (caking) and for 
easing packaging, transport, and consumption . 
4 Grades  
The material shall be of any of the following  three grades namely;  
a) Grade 1 — for Ammonium Nitrate Fuel Oil (ANFO ); 
b) Grade 2 — for slurry type explosives ; or 
c) Grade 3 — for Nitroglycerine based explosives .  
2 © UNBS 2017  – All rights reserved  
 5 Requirement s 
5.1 Physical requirements  
5.1.1  The material shall be in the form of prills, lumps or crystals, as agreed to between the purchaser and 
the supplier, a nd colourless or showing only a brownish tint. It shall be free from grit, foreign matter and visible 
impurities.  
5.1.2  The different grades of material shall conform to the sizes given in Table 1.  
Table 1 — Grade sizes  
Grade  Size 
mm 
Grade 1  0.65 – 2.8 
Grade 2  2.9 – 100 
Grade 3  As agreed to between the purchaser 
and the supplier.  
 
5.2 Anti-caking agents  
Where anti -caking agents are added they shall be compatible with the explosives and shall not cause undue 
frothing in the manufacturing process of explo sives and the quantity and nature of the agent shall be declared 
by the supplier  
5.3 Chemical requirements  
All permitted ammonium nitrate intended primarily for use in explosives, in addition to meeting the general 
requirements stipulated is clause 5.1 abo ve, and shall  comply with chemical specification as specified in the 
table 2 below.  
Table  2 — Chemical requirements of Ammonium Nitrate  
NO. Characteristic/  
parameter  Grade  
% Test method  
Grade 
1 Grade 
2 Grade 3  
1 Moisture, precent by mass, (Max)  0.3 3.0 0.1 Annex A  
2 Matter insoluble in water, percent by 
mass, (Max)  0.3 0.05 0.01 Annex B  
3 Non-volatile matter, percent by mass, 
(Max)  0.2 - 0.1 Annex C  
4 Chlorides (as Cl), percent by mass, 
(Max)  - 0.05 0.006  Annex D  
5 Nitrites (as Ammonium Nitrite ), 
percent by mass, (Max)  - 0.02 0.0005  Annex E  
6 Acidity (as Nitric  acid), percent by 
mass, (Max)  - 0.01 0.01 Annex F  
7 Iron (as Fe), percent by mass, (Max)  - 0.002  0.002  Annex G  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  3 
 8 Calcium (as calcium nitrite), percent 
by mass, (Max)  - 0.5 - Annex H  
9 pH of 10 percent aqueous solution  ≥ 4 5 - 6 4 -7 Annex I  
10 Organic matter, percent by mass, 
(Max)  0.5 Nil 0.1 Annex J  
11 Grit, percent by mass, (Max)  - Nil Nil Annex K  
12 Purity (on dry basis), percent by 
mass, (Min)  99.2 99.0 99.8 Annex L  
13 Metals and compounds of metals 
other thana lkali metals, calcium and 
iron, percent by mass, (Max)  - - 0.02 Annex M  
14 Pyridine, percent by mass, (Max)  - - Nil Annex N  
15 Thiocyanate (as ammonium 
thiocyanate), percent by mass, (Max)  - - Nil Annex O  
16 Prussian blue and allied compounds 
(as Prussi an blue), percent by mass, 
(Max)  - - Nil Annex P  
17 Oil absorption, percent by mass, 
(Min)  7 - - Annex Q  
18 Total nitrogen, percent by mass, 
(Min)  34.5 - - Annex R  
19 Sulphates (as ammonium sulphate), 
percent by mass, (Max)  - - 0.03 Annex T  
 
5.4 Bulk d ensity  
When determined in accordance with Annex R, the bulk density of the Ammonium Nitrate for the respective 
grades shall be as that given in table 3 below  
Table  3 — Bulk density of ammonium nitrate  
Grade  Bulk density  
g/cm3 
Grade 1  0.65 – 0.85 
Grade 2  - 
Grade 3  0.92 – 1.02 
 
6 Inspection and sampling  
6.1 General  
Owing to the dangerous nature of ammonium nitrate  intended primarily for use in explosives, extreme care 
and caution shall be exercised during the inspection, sampling and testing of ammonium nitrate . All safety 
precautions and procedures laid down in the relevant national legislations shall be strictly followed.   
4 © UNBS 2017  – All rights reserved  
 6.2 Inspection  
Inspect the ammonium nitrate for compliance with the requirements of clause 5 . 
6.3 Sampling  
In a single consignment of the material all the containers of the same, type and size and drawn from the same 
batch of manufacture shall constitute a lot. If a consignment is known to consist of different batches of 
manufacture or of different types and sizes of containers, the cont ainers belonging to the same batch type and 
size shall be grouped together and each such group shall constitute a separate lot.  
The number of containers to be selected at random from lots of different sizes shall be in accordance with 
Table 4.  
Table 4 — Sample sizes to be considered  
Lot size  Sample size  
Up to 15  3 
16 to 25  4 
26 to50  5 
51 to100  7 
101 and above  10 
7 Packaging and labelling  
7.1 Packaging  
The material shall be packed in polyethylene lined bags or in such other containers as agreed to betw een the 
purchaser and the supplier. The polyethylene sheet shall not be less than 0.05 mm thick  
7.2 Labelling  
7.2.1  Each package shall also be marked with appropriate safety symbol as specified in US IS0 7010.  
7.2.2  Each package shall be legibly and indel ibly marked with the following information : 
a) name and grade of the material;  
b) manufacturers' name or his recognized trade -mark, if any;  
c) year of manufacture and expiry date ; 
d) lot/ batch number ; 
e) country of origin ; and  
f) gross and net weight . 
In addition to the ab ove, the following cautionary note shall also appear on the label in red ink:  “HIGHLY 
EXPLOSIVE. HANDLE WITH UTMOST CARE.  DO NOT BRING ANY SPARK OR FLAME NEAR THE 
PACKAGE. DO NOT STORE , TRANSPORT OR STOCK WITH THE DETONATORS .” DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  5 
 Annex  A 
(normative)  
 
Determin ation  of moisture  using air-oven method  
A.1 Procedure  
A.1.1  Weigh rapidly 10 g of the material and transfer it to a weighing dish with a close fitting lid.  
A.1.2  Close the dish and weigh it accurately.  
A.1.3  Lift the lid and expose the material in an oven at 100 °C ± 2 °C for 2 h.  
A.1.4  Then close the lid, remove the dish to a desiccator for about half an hour to cool and reweigh it.  
A.1.5  Repeat the operation till a constant mass is obtained.  
A.2 Calculation  
Moisture, percent by mass = 
M MM M

12 1100  1 
where 
M1 is the mass in g of the material and the dish before heating ; 
M2 is the mass in g of the material and the dish after heating ; 
M is the mass in g of empty dish.   
6 © UNBS 2017  – All rights reserved  
 Annex  B 
(normative)  
 
Determination of matter insoluble in water  
B.1 Procedure  
B.1.1 Take 100 g of the sample in a 500 -ml beaker and dissolve in about 200 ml of hot water.  
B.1.2  Filter the residue through What -man No. 40 filter paper . 
B.1.3  Wash the residue with water till free from all soluble matter.  
B.1.4  Dry in an oven maintained a t 100 °C ± 2 °C.  
B.1.5  Brush out the residue in a weighed silica crucible and weigh.  
B.1.6  Deduct the quantity of the declared anti -caking agent insoluble in water, if any, from the dried residue.  
B.2 Calculation  
Matter insoluble in water, percent by mass  
MM1100  2 
where 
M1 is the mass in g of the dried residue, and  
M is the  mass in g of the material taken for the test.  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  7 
 Annex C  
(normative)  
 
Determination of non -volatile matter  
C.1 Procedure  
C.1.1  Heat a porcelain or silica basin with cover about  6 cm in diameter in an oven at 100 °C ± 2 °C for half 
an hour.  
C.1.2  Cool it  in a desiccator and weigh.  
C.1.3  Place about 10 g of the material in the dish,  moisten the ammonium nitrate with sulphuric acid, 
replace the cover  and weigh accurately.  
C.1.4 Uncover the dish and heat the sample initially  over low flame till the fume subsides and finally over 
strong flame having  a temper ature of 800 °C ± 20 °C for 1 h.  
C.1.5  Remove the burner and replace  the cover, cool the basin and the cover in a desiccator  to room 
temperature  and weigh.  
C.1.6  Repeat the operation till constant mass is obtained.  
C.2 Calculation  
Calculate the non -volatile matter as follows:  
Non-volatile matter, percent by mass
1 21 3 ) ( 100
M MM M
  
where 
M1 mass in g of the empty dish and the cover ; 
M2 mass in g of the dish and the cover with the sample taken ; and  
M3 mass  in g of the dish and the cover with the sample  after heating.   
8 © UNBS 2017  – All rights reserved  
 Annex D  
(normative)  
 
Determination of chlorides  
D.1 Outline of th e Method  
Chloride is completely precipitated as  silver chloride by the addition of an excess of standard silver nitrate  
solution and the excess is back titrated with ammonium thiocyanate.  
D.2 Reagents  
1) Silver Nitrate Solution – 0.1 N ; 
2) Ammonium Thiocyanate — 0.1 N ; 
3) Concentrated Nitric Acid ; 
4) Ferric Alum Indicator — 40 %; and  
5) Nitrobenzene  
D.3 Procedure  
D.3.1  Weigh about 10 g of the sample accurately in a  250-ml conical flask. Dissolve with heating in 100 ml 
of water.  
D.3.2  Add 5 ml of concentrated nitric acid followed by 25 ml silver nitrate solution  through a pipette.  
D.3.3  Shake for two minutes and titrate against 0.1 N  thiocyanate using 2 ml of ferric alum indicator and 5 
ml of nitrobenzene  till there is a persistent colour change.  
D.3.4  Run a blank with all  the reagents  and water but without the sample . 
D.4 Calculation  
Chlorides, percent by mass  
MNBA100
100045.35  4 
where 
A volume of ammonium thiocyanate consumed for blank titration ; 
B volume of ammonium thiocyanate consumed for sam ple titration ; 
N normality of ammonium thiocyanate solution ; and 
M mass in g of sample taken for the test.  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  9 
 Annex E  
(normative)  
 
Determination of nitrite  
E.1 General  
Two methods are prescribed, namely, colorimetric method and volumetric method. Colorimetric  method is 
recommended for routine analysis. In case of dispute, volumetric method shall be the referee method . 
E.2 Colorimetric method  
When dilute solutions of sulphanilic acid and α -naphthylamine are acted upon by nitrous acid, a red 
colouration is produ ced which may be used for the colorimetric determination of nitrites. The full colour does 
not appear at once. A satisfactory colour comparison can be made after 10  min - 15 min provided the sample 
and standard are treated in the same manner.  
E.2.1  Reagent s 
E.2.1.1  Sulphanilic acid reagent  (solution 1 ) — Dissolve 0.6 g of sulphanilic acid in 100 ml of 20 % (v/v) 
dilute hydrochloric acid.  
E.2.1.2  α-Naphthylamine reagent  (solution 2 ) — Dissolve 0 .48 g of α-naphthylamine in 100 ml of 20 
percent (v/v ) dilute hydrochloric acid.  
E.2.1.3  Standard nitrite solution  — Dissolve 4.93 g of sodium nitrite in water and dilute with deionized 
water. Dilute 10 ml o f standard solution to one litre with deionized water.  
E.2.1.4  Sodium acetate (2 M ) — Dissolve 16.4 g of anhydrous sodium acetate in water and dilute to 100 
ml with water.  
E.2.2  Procedure  
E.2.2.1  Place the qu antity of the sample containing about 0.03 mg or  less of nitri te in a 50  ml volumetric 
flask.  
E.2.2.2  Add 1 ml  of sulphanilic acid reagent, mix well an d allow to stand at least for 3 minutes but not 
more than 10 minutes at room temperature in diffused light. Introduce 1 ml of α -naph thylamine reagent and 1 
ml of 2 M sodium acet ate solution to act as buffer ( pH 2 to 2.5 ).  
E.2.2.3  Dilute to volume and mix well. Use a photoelectric colo rimeter with a green filter and measure 
transmittance. Construct a ref erence curve with known nitrate standards, preferably in the nitrite -nitrogen 
range of the sample and measure the concentration of the nitrite in the sample solution from the reference 
curve.  
E.2.3  Calculation  
The concentrat ion of nitrite is directly read from the reference curve and calculated as ammonium nitrite.   
10 © UNBS 2017  – All rights reserved  
 E.3 Volumetric method  
E.3.1  Reagents  
1) Potassium permanganate solution — N/50.  
2) Sulphuric acid  
E.3.2  Procedure  
E.3.2.1  Weigh accurately about 3 0 g of sample and transfer to a 100-ml volumetric flask and dissolve with 
shaking in 40 ml of water.  
E.3.2.2  Make up the volume to the mark with wat er. Stopper the flask and shake well. Take up the 
solution in a burette.  
E.3.2.3  Take 2.5 ml of freshly prepa red N/50 potassium permanganate solution in a conical f lask. Add 5 
ml of sulphuric acid ( 1:1) 
E.3.2.4  Dilute to 40 ml with water and heat to around 60°C and titrate against sample solution taken in 
the burette till the pink colour disappears.  
E.3.1  Calculation  
1 ml of 1 N potassium perma nganate = 0 032 0 g of ammonium nitrite.  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  11 
 Annex F  
(normative)  
 
Determination of acidity of nitric acid  
F.1 Outline of the method  
The dried m aterial is dissolved in neutral acetone, water added to the solutio n and then titrated with sodium 
hydroxide solution . 
F.2 Reagents  
1) Acetone — Neutralized to methyl red indicator  
2) Standard Sodium Hydroxide Solution  — 0.01 N.  
3) Methyl Red Indicator  — Dissolve 1 g of methyl red ( water soluble ) in wat er and dilute the solution to 
1 litre 
F.3 Procedure  
F.3.1  Add about 2 to 10 g of the dried material weighed accurately to 0.01 g, to 100 ml of acetone. Shake 
the mixture  vigorously for several minutes until solution is complete.  
F.3.2  Add 100 ml of water to solution with constant stirring. Boil o ff the acetone on a water bath, cool, filter 
through a filt er paper ( Wha tman No. 1 or its equivalent ), wash with two 10 ml portions of water  and titrate the 
filterate with standard sodium hydroxide solution using methyl red as indicator . 
F.3.3  Run a blank determinati on using the same quantities of reagents  
F.4 Calculation  
Acidity ( as nitric acid ), percent by mass 
MNV V ) (3.61 2  5 
where 
V1 = volume in ml of sta ndard sodium hydroxide solution required by the blank,  
V2 = volume in ml of sta ndard sodium hydroxide solution required by the material,  
N = normality  of standard sodium hydroxide solution, and  
M = mass in g of the dried material taken for the test.   
12 © UNBS 2017  – All rights reserved  
 Annex G  
(normative)  
 
Determination of iron  
G.1 Outline of the method  
Ferric (bu t not ferrous) iron reacts with thiocyanate to give a series of intense ly red  coloured complexes which 
remain in true solution. In the colori metric determination, excess of thiocyanate should be used since this 
increases the intensity and also stability of the colour. Strong acid (hydrochlor ic or nitric acid concentration 
0.052 to 0.05 M ) should be presen t to suppress the hydrolysis of ferric iron.  
G.2 Reagents  
1) Potassium Thiocyanate Solution  — Dissolve 20 g of potassium thiocyanate in 100 ml of water.  
2) Concentrated Nitric Acid  
3) Standard Solution of Iron (Ferric)  — Dissolve 0.864 g of  Ferric Ammonium Sulphate in water, add 
10 ml  of concentrated nitric acid and dilute it to one litre . 1 ml of this solution is equivalent to 0.1 mg of 
iron (as Fe).  
G.3 Procedure  
G.3.1  Dissolve accurately 5 g of the material in 1:1 waternitric acid mixture  and evaporate to nearly dryness 
to expel excess of acid. Dilute slightly with water, oxidize any ferrous ion to the ferric state with dilute 
potassium permanganate solution (2g/l ), adding slowly dropwise until a slight pink colour remains after stirring 
well. Make up the solution to 250 ml or other suitable volume.  
G.3.2 Place 50 ml of the solution in a Nessler cylinder, add 5 ml of thiocyanate solution and 2 to 4 ml of 4 N 
nitric acid. Add the same amounts of reagents to 50 ml of water contained in a simi lar Nessler cylinder and run 
in standa rd iron solution from burette ( use long glass ro d with flattened end for mixing ) until colours are 
matched. Note the exact volume (X ml ) of the standard iron solution added.  
G.3.3 Repeat determination using 50 - X ml o f water. Comparison of the standard and unknown should be 
made soon after preparation since the colour may fade on standing for a long time.  
G.3.4 For estimating the concentration of ferric iron more accurately, the use of photoelectric colorimeter 
may be resorted to. A filter showing maximum transmission at or near 480 nm should be used. Standard 
solutions of ferric iron which are in the range of the concentration of ferric iron likely to be present in the 
sample are prepared and the transmittance of each such solution measured with photoelectric colorimeter.  
G.3.5 A reference curve is then prepared by plotting the concentration versus transmittance. Now the 
transmittance of the sample solution is also measured and from the reference curve, the co ncentratio n of 
ferric iron as [ Fe (NO 3)3] is directly read . 
G.4 Calculation  
Ferric iron as [Fe (NO 3)3] percent by mass
100Mm  6 DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  13 
 where 
m = mass in g of ferric iron [ as Fe ( NO3)3] as found out from the reference curve, and 
M = mass in g of the material taken for the test.   
14 © UNBS 2017  – All rights reserved  
 Annex H  
(normative)  
 
Determination of  calcium  
H.1 Outline of the method  
Calcium, like some other metal ions, is complexed by Disodium Dihydrogen Ethylene Diamine Tetra -Acetate 
(EDTA ) by choosing the proper pH and indicator. Using calcon  as indicator, calcium can be estimated in the 
presence of magnesium since magnesium is precipitated quantitatively as magnesium hydroxide in the pH 
range of the reaction  
H.2 Reagents  
1) Diethylamine  
2) Calcon Indicator  — prepared  by dissolving 0.2 g of the dyes tuff in 50 ml of methyl alcohol.  
3) Standard Disodium Dihydrogen Ethylenediamine Tetra Acetate ( EDTA ) Solution  — Weigh 
3.772 5 g of EDTA, dissolve in water free from polyvalent ions ( distilled water for this purpose should 
be passed through a column of cat ion exchange resins in the sodium form ) and make up to a volume 
of 1 000 ml. Concentration of the resulting solution will be 0.01 M. (If the EDTA is not of analytical 
reagent grade, then the solution prepared needs to be standardised against standard zinc  chloride 
solution or magnesium chloride solution which is prepared from analytical reagent grade material or 
corresponding metal pellets of analytical reagent grade).  
4) Sample solution  — Weigh about 1 g of the material accurately, dissolve in water from fre e polyvalent 
ions, filter and make up to 100 ml.  
H.3 Procedure  
H.3.1 Pipette out 10 ml of the sample solution (see A .9.2.4)  into 250 ml conical flask.  
H.3.2 Add about 40 ml of water and 5 ml of diethylamine, giving the mixture a pH of about 12.5. Under the se 
conditions, magnesium, if present, precipitates quantitatively as the hydroxide.  
H.3.3 Add four drops of calcon indicator to the solution and titrate with standard EDTA solution with shaking 
until the colour changes from pink to a pure blue . 
H.4 Calcul ation  
Calcium [ as Ca ( NO3)2], percent by mass
AVM*64.1  7 
where; 
V = volume in ml of standard EDTA solution,  
M = molarity of standard EDTA solution, and  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  15 
 A = mass in g  of material taken for the test.   
16 © UNBS 2017  – All rights reserved  
 Annex I  
(normative)  
 
Determination of pH 
Dissolve 10.0 g of the material in 100 ml of water and measure the pH of the solution by means of a suitab le 
pH meter using glass electrodes . DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  17 
 Annex J  
(normative)  
 
Determination of organic matter  
J.1 Procedure  
J.1.1  Weigh about 50 g of the sample accurately in a tall sintered -glass grade 2 thimble with a sm all hole at 
the top of wall for tying a small piece of wire.  
J.1.2  Put the thimble g ently in the soxhlet extraction chamber with the help of the wi re.  
J.1.3  Take 200 ml of the suitable solvent ( dichlorometha ne, diethyl ether, acetone, N -butyl acetate, etc ) in 
the flask containing a few glass beads.  Fit the apparatus on a boiling water bath and continue the extract ion 
for three hours.  
J.1.4  Remove the condenser and take out the thimble.  
J.1.5  Replace the co ndenser and continue boiling till majority of the solvent is recover ed in the flask to a 
tared flat bottom glass basin with cover. Rinse th e flask twice with the suitable solvent and transfer in the 
basin.  
J.1.6  Put the basin in a boiling water bath  at 95  °C ± 2 °C for two hours.  
J.1.7  At the end of this period, replace the cover, cool the basin and the cover in a desiccator to room 
temperatu re and weigh. Repeat the drying operation till constant mass is obtained.  
NOTE  When required, the manufacturers shall inform  about the name of the solvent to be used.  
J.2 Calculation  
Organic matter, percent by mass 
100*
12
MM  8 
where 
M2 = mass in g of the residu e after complete evaporation of the solvent extract, and  
M1 = mass in g of the material taken for test.  
18 © UNBS 2017  – All rights reserved  
 Annex K  
(normative)  
 
Determination of grit  
K.1 Procedure  
K.1.1  Weigh about 50 g of the material into a 500 -ml beaker, dissolve in adequate quantity of  water and 
allow to stand until the insoluble material settles.  
K.1.2  Decant th e supernatent liquor  and filter the rest using a filter paper. Ignite the fil ter paper with the 
residue in a muffle furnace. Boil the residue for a bout 30 minutes with 20 ml aqua regia.  
K.1.3  After cooling the mixture, drain off the aqua regia and wash the thoroughly with wat er. 
K.1.4  Dry the r esidue in an air oven and sieve it through 125 μm IS -sieve.  
K.1.5  Weigh the portion retained on the sieve and test for soda glass scratching. If it scratch es soda glass 
then report it as percent grit.  
K.2 Calculation  
Grit, percent by mas s
1100*
MM  9 
Where; 
M = mass in g of the residue retained on 125 μm IS -sieve, and  
M1 = mass in g of  the material taken for test  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  19 
 Annex L  
(normative)  
 
Determination of purity on dry basis  
L.1 Outline of the method  
Ammonia from ammonium nitrate  (NH 4NO 3) reacts quantitatively with excess of formaldehyde  (HCHO ) to 
produce nitric acid  (HNO 3). 
4NH 4NO 3 + 6HCHO                    (CH2 )5 N4 + 4HNO 3 + 6H 2O 
This nitric acid can be titrated against standard alkali  
L.2 Reagents  
1) Sodium Hydroxide  — 0.2 N.  
2) Hydr ochloric Acid  — 0.2 N.  
3) Phenolphthaline — 1 % in alcohol.  
4) Formaldehyde 1:1 — Mix equal volu mes of AR grade formaldehyde (37 percent m/m ) and water. 
Add few drops of phenolphthaline indicator and titrate against standard alkali to its lightpink end point  
L.3 Procedure  
L.3.1  Weigh exactly 0.4 g of sample into a 250  ml conical flask and dissolve in 20 ml of water.  
L.3.2  Add 50 ml of formaldehyde 1: 1 reagent and warm the flask.  
L.3.3  Cool to room temperature and titrate against standard alkali till permanent lig ht pink colour appears.  
L.3.4  Drain another 2 ml of alkali and note down the volume  (V1). 
L.3.5  Keep it for 10 minutes and titrate against standard hydrochloric acid usin g a microburette till the 
solut ion becomes  colourless and note down the volume  (V2). 
L.3.6 Repeat the same experiment till concordant values are obtained . 
L.4 Calculations  
Volume of sodium hydroxide required 
12 2)(NNVV V  10 
Percent purity of ammonium nitrate
MNV 005.81  11  
20 © UNBS 2017  – All rights reserved  
 Purity (on dry basis), percent  by mass
percent moistureabove obtainedas purity
100100  12 
Where; 
N1 = normality of sodium hydroxide,  
N2 = normality of hydrochloric acid, and  
M = mass of the sample  (g). DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  21 
 Annex M  
(normative)  
 
Determination of determination of metals and compounds of metals 
other than alkali metals, calcium andiron  
M.1 Procedure  
M1.1  Treat 5 g of the material in a porcelain crucible with 1 ml of concentrated sulphuric acid.  
M.1.2  Drive off the excess acid by gentle heating and heat the residue strongly.  
M.1.3  Extract the residue with dilute hydrochloric acid and te st qualitatively for the presence of metallic 
radica ls (other than alkali metals, iron and calcium ) like lead, copper zinc and manganese.  
M.1.4  If any metallic impurity is detected, estimate quantitatively by a standard colorimetric method   
22 © UNBS 2017  – All rights reserved  
 Annex N  
(normat ive) 
 
Determination of pyridine  
N.1 Pyridine  
Triturate a little powdered bora x rapidly with about 5 g of the material in  a mortar. If the odour of pyridine is 
detected, estimate the  amount of pyridine present as follows  
N.2 Procedure  
N.2.1  Dissolve 100 g of the  material in 300 ml of water in a 500 -ml flask and add a few drops of methyl 
orange solution.  
N.2.2  Fit the flask with a rubber stopper through which passes a  tap-funnel and a glass outlet tube.  
N.2.3  The outlet tube incor porating a bulb or other d evice to guard against a suck back, leads into a 500-ml 
conical flask containing sodium hydroxide solution and 4 ml  of bromine, and dips below the surface of this 
solution.  
N.2.4  Close the coni cal flask with a rubber stopper through which also passes a di stilling trap  attached to a 
water condenser.  
N.2.5  Attach to the exit tube of the condenser a 2 50-ml conical flask as receiver containing a little water and 
fitted with guard tube of mo istened glass. beads.  
N.2.6  Add 5 ml of 1 N sodium hyd roxide solution t o the ammonium nitrate solution through the tap funnel 
and distil the solution slowly into the hypobromite solution. When abou t 50 ml of the ammonium nitrate 
solution has been distilled, steam dis til the hypobromite solution by warming the flask of hypobro mite and 
continuing the distillation of the ammonium nitrate solution. Titrate t he pyridine so collected in the receiver with 
0.1 N hydrochloric acid using methyl orange as indicator  
N.2.7  Calculate the factor to be us ed in calculating the amount of pyridi ne present from the results of 
titration of aqueous solutions, containing known quantities of pyridine.  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  23 
 Annex O  
(normative)  
 
Determination of thiocyanate  
O.1 Dissolve 5 g of  the material in about 80 ml of water. Filter the solution, if necessary , and make it up to 
100 ml in a Nessler cylinder. Prepare similarly a series o f standard solutions containing 5 g of pure 
thiocyanate free  ammonium nitrate and different known amounts of ammonium thiocyanate.  
O.2 Add 2 ml of 10 percent ferric alum solution ( containi ng 50 ml of  concentrated nitric acid/litre ) to the 
contents of each cylinder, with  stirring.  
O.3 Determine the amount of thiocyanate present in the material  by comparing the colour of the solution 
under test with the standard solutions   
24 © UNBS 2017  – All rights reserved  
 Annex P  
(normative)  
 
Determination of prussian blue and allied products  
P.1 Warm 10 g, approximately, of the material with about 20 ml of 1 N nitric acid solution. If the resulting 
solution is coloured blue or contains blue coloured particles, estimate the prussianblue as fo llows.  
P.2 Dissolve 100 g of the material in about 100 ml of water and acidify the solution with 20 ml of 1 N nitric 
acid. Heat for 5 minutes and then filter. Treat the residue of prussian blue on the filter paper with 100 ml of 1 N 
potassium hydroxide s olution, added in consecutive small portions and make up the resulting filtrate, 
containing potassium ferrocyanide, to a volume of 200 ml.  
P.3 Transfer a suitable aliquot portion of the ferrocyanide solution to a Nessler cylinder and add a 2 ml 
excess of  1 N nitric acid. Dilute the solution to 100 ml and add 5 ml of 10 percent ferric alum solution with 
stirring  
P.4 Prepare similarly a series of standard solutions in Nessler cylinders, containing the same quantities of 
alkali, acid and ferric alum as in the fi rst Nessler cylinder but with different known quantities of potassium 
ferrocyanide.  
P.5 Determine the amount of prussian blue present in the material by comparing the colour of the solution 
under test with the standard solutions.  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  25 
 Annex Q  
(normative)  
 
Determination of oil absorption  
Q.1 Procedure  
Q.1.1 10 g of sample to be tested is placed in a dry 50  ml beaker.  
Q.1.2 Ten ml of diesel oil is added to the sample in the beaker and th e contents are left for exactly 10 
minutes.  
Q.1.3 The contents of the beaker a re then  transferred to a porcelain buchner funnel ( 6 cm internal dia meter ) 
equipped with a Whatman No. 1 filter paper.  
Q.1.4 A suction o f 150 mm mercury is applied for three minutes.  
Q.1.5 The oiled sample is t hen transferred to a previously weighed watch glass.  
Q.1.6 The mass of the oiled sample is calculated from the combined masses of the sample and t he watch 
glass. The percent oil absorption is calculated as follows . 
Q.2 Calculation  
Oil absorption, percent by mass 
100*
11 2
MM M  13 
Where; 
M2 = mass in g of oiled sample, and  
M1 = mass in g of original sample   
26 © UNBS 2017  – All rights reserved  
 Annex R  
(normative)  
 
Determination of bulk density  
R.1 Apparatus  
Assemble the apparatus a s shown in Fig ure 1 (All dimensions in millimetres )  
The measuring cylind er A shall be of 20 ml capacit y, base of the measuring cyl inder shall be ground flat. and 
the distance between the flat -ground pa rt of the base of the measuring cylinder A and the rubber base pad B , 
when the measuring cylinder A is raised to the full height, shall be 25 mm ± 2 mm.  
 
Figure 1 — Apparatus for determination of bulk density  
The rubber base pad B shall have a shore hardness of 42 to 50.  
Pans of the balance hall be at least 10 cm in diameter and the balance shall be sensitive to less than 0.1 g.  
R.2 Procedure  
Place 50 g of the  material in the graduated cylinder fitted in the apparatus and tap it until a constant volume of 
the material is obtained. Note down the volume of the material  
R.3 Calculation  
Bulk density, g/cm3
VM 14 
Where; DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  27 
 M = mass in g of the materi al taken for the test, and  
V = volume of  the material in the cylinder.   
28 © UNBS 2017  – All rights reserved  
 Annex S  
(normative)  
 
Determination of total nitrogen  
S.1 Outline of the method  
Ammonia is distilled off from an alkalin e solution and absorbed in standard h ydrochloric acid. The excess of 
acid is titrated with standard hydroxide solution.  
S.2 Apparatus  
Ammonia distillation apparatus  as shown in Fig ure 2 
S.3 Reagents  
1) Sodium Hydroxid e solution  — 30 percent ( m/v).  
2) Standard hydrochloric a cid — 0.5 N.  
3) Standard Sodium Hydroxide solution  — 0.5 N. 
4) Mixed Methyl Red Indicator solution  — Dissolve 0.1 g of methyl red in 50 ml of ethyl alcohol and 
0.05 g of methylene blue in 50 ml of ethyl alcohol and mix the two solutions  
5) Devarda's Alloy  — Containing 45 parts of aluminium, 50  parts of copper and 5 pa rts of zinc  
S.4 Procedure  
S.4.1 Weigh accurately 2.0 g of the prepared sample and transfer to the Kjeldahl flask, adding about 150 ml 
of water and a few porcelain beads. Add 6 to 7 g Devarda's alloy. Connect the apparatus as shown in Fig ure. 
2.  
S.4.2 Meas ure into the beaker exactly 125 ml of standard hydrochloric acid and add 4 to 5 drops of the 
mixed indicator solution.  
S.4.3 Place the beaker so that the end of the delivery tube is below the surface of the acid. Pour about 25 
ml of sodium hydroxide soluti on (30 percent ) into the tap funnel. Slowly drop the sodium hydroxide solution 
into the Kjeldahl flask by opening the tap of the funnel. Close the tap after delivering the entire quantity of 
sodium hydroxide.  
S.4.4 Start heatingthe Kjeldahl flask and circ ulate water in the condenser. After distilling about 150 ml into 
the receiver, remove the beaker and titrate the excess acid using 0.5 N sodium hydroxide solution. The end 
point is orange to green. Suggested indicator solution for the above determination i s methyl red and 
bromocresol green solution . It is prepared by dissolving 0.1 g of methyl red in 50 ml of ethyl alcohol and 
mixing the two solutions.  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  29 
 
 
Figure  2 — Apparatus for determination of nitrogen  
S.4 Calculation  
Total nitrogen (as N ), percent by mas s
MNVNV ) (*401.1 2 2 1 1  15 
Where; 
V1 = volume in ml of standard hydrochloric add used,  
N1 = normality of standard hydrochloric acid,  
V2 = volume in ml of standard sodium hydroxide, solution,  
N2 = normality of standard sodium hydroxide solution, and  
M = mas s in g of the material taken for the test.   
30 © UNBS 2017  – All rights reserved  
 Annex T 
(normative)  
 
Determination of sulphates  
T.1 Outline of the Method  
Sulpha tes are determined by comparing the turbidity produced with barium sulpha te solution, against a 
standard turbidity in Nessler cylinde rs 
T.2 Apparatus  
1) Nessler Cylinders  — 50-ml capacity  
T.3 Reagents  
1) Sodium Carbonate — Solid  
2) Dilute Hydrochloric Acid — Approximately 2 N  
3) Standard Sulphuric Acid — 0.002 N  
4) Barium Sulphate Reagent — Dissolve 2.0 g of barium chloride in 75 ml of water, add 20 m l of 95 
percent  (v/v) ethyl alcohol and 5 ml of standard sulphuric acid. It shall be prepared afresh  
T.4 Procedure  
T.4.1 Weigh accurately 10 g of the prepared sample into a porcelain dish and dissolve in 40 ml of water. 
Add 0.05 g of sodium carbonate and h eat on a sand -bath at about 120  °C to volatilize water and then heat 
over a very low flame until the evolution of white fumes has ceased. Finally heat the dish at 600°C in a 
furnace for 15 min. Cool, dissolve the residue in 10 ml of water, add 1 ml. of dil ute hydrochloric acid and filter 
through a Whatman No. 41 filter paper.  
T.4.2 Transfer the filtrate to a Nessler cylinder, add 10 ml of water and 1 ml of barium sulphate reagent. Mix 
well and allow to stand for 5 min.  
T.4.3 Prepare a series of sulphate sta ndard turbidities with different known volumes of standard sulphuric 
acid and 1 ml of barium sulphate reagent in the similar manner and compare the turbidities.  
T.4.4 Calculate the sulphate content as ammonium sulphate in the sulphate standard in which the  turbidity 
most closely matches with that in the solution of the material.  DUS  1756 -3: 2017  
© UNBS 2017  – All rights reserved  31 
 Bibliography  
[1] IS 4668  – 1985  Specification for Ammonium Nitrate for  explosives  
 DUS 1756 -3: 2017  
© UNBS 2017 – All rights reserved  33 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda Nationa l Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certificat ion Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda  Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme o f the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Stan dards.  
 
 DUS 1756 -3: 2017    
 
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