Dispersion Characteristics of 

Montmorillonite, Kaolinite, 

and Hike Clays in Waters of 

Varying Quality, and Their 

Control with Phosphate 

Dispersants

By B. N. ROLFE, R. F. MILLER, and I. S. McQUEEN

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

GEOLOGICAL SURVEY PROFESSIONAL PAPER 334-G

Prepared in cooperation with 

Colorado State University

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1960
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. SEATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington 25, D.C. - Price 40 cents (paper cover)
CONTENTS

Page

Abstract._ ________________________________________ 229

Introduction.______________________________________ 229

Personnel._____________________________________ 230

Acknowledgments _______________________________ 230

Materials----------------------_---__---_----_--__- 231

Clay minerals._________________________________ 231

Phosphate deflocculents_--_-_______-_-__--______ 231

Waters.--____-----_--_--___-_-__--_-________ 231

Methods_______________________._________ 233

Water synthesis_________-_-____,.___----______ 233

Exchange complex saturation of clays _________________ 233

Treatment with deflocculents___________________ 234

Hydrometer analysis._____--_-_-___-_----_______ 234

Results and discussion_______________________

Sodium montmorillonite in distilled water.. 

Calcium montmorillonite in distilled water. 

Sodium montmorillonite in soft water. 

Calcium montmorillonite in soft water__. 

Sodium montmorillonite in hard water_____

Calcium montmorillonite in hard water.__ 

Sodium kaolinite in distilled water. _-____-

Calcium kaolinite in distilled water. ___._. 

Sodium kaolinite in soft water___________-

Calcium kaolinite in soft water.__________

Sodium kaolinite in hard water.__________

Calcium kaolinite in hard water._________

Sodium illite in distilled water__________

Calcium illite in distilled water.__________

Sodium illite in soft water_ -________-___.

Calcium illite in soft water._________-_._.

234

235

235

237

237

237

237

239

239

239

241

241

241

241

241

241

241

Results and discussion Continued Page 

Sodium illite in hard water_______________________ 241

Calcium illite in hard water._____________________ 243

Volclay in distilled water._______________________ 243

Volclay in medium-hard water- _-_-_-_---_.___ 243 

Kaolinite (78.8 percent sodium saturated) in distilled 

water ___-_-____--_-__-__-------_-_---_--____ 246

Kaolinite (78.8 percent sodium saturated) in mediumhard water...________________________________ 246

Illite (78.8 percent sodium saturated) in distilled

water.. _________________..._._.____ 246

Illite (78.8 percent sodium saturated) in mediumhard water_ _________-___-__-__--_-___---___ 248

Summary of conclusions.________--__-____-----_-___- 248

Properties of clay minerals, by B. N. Rolfe. ___________ 248

Kaolinite. _____________________________________ 249

Montmorillonite. _______________________________ 249

Illite__.-____-____---_-_-_____--_--_-_-_-_-_--_ 250

Discussion of the hydrometer method, by I. S. McQueen. 250 

Advantages of the hydrometer method-___________ 251

Disadvantages of the hydrometer method.--.------ 251

Theory of clay mineral behavior in dilute suspensions, by

R. F. Miller-_____----__----_...------__------__-- 252

Factors that control the degree of dispersion.______ 252

Dispersion and clay minerals._-----______________ 254

Mechanism of dispersion control-_________________ 255

Tables of data and dispersion indices __________________ 255

Filter-loss test of clay suspensions, by I. S. McQueen____ 269

Selected references__________________________________ 270

Index_____-___-____---__---_------_-_-_-__-_-_-___ 273

ILLUSTRATIONS

FIGURE 37. Dispersion characteristics 

	(Cand D)_________

38. Dispersion characteristics

39. Dispersion characteristics

40. Dispersion characteristics

41. Dispersion characteristics

42. Dispersion characteristics

43. Dispersion characteristics

44. Dispersion characteristics

45. Dispersion characteristics

46. Dispersion characteristics

47. Dispersion characteristics

48. Nature of zone measured

of sodium- and calcium-saturated montmorillonite in distilled (A and B) and soft water

of sodium- and calcium-saturated montmorillonite in hard water____________-_-___-

of sodium- and calcium-saturated kaolinite in distilled water______________________

of sodium- and calcium-saturated kaolinite in soft water._________________________

of sodium- and calcium-saturated kaolinite in hard water. ________________________

of sodium- and calcium-saturated illite in distilled water._________________________

of sodium- and calcium-saturated illite in soft water.____-_-__-_-_-_---.--__-----

of sodium- and calcium-saturated illite in hard water.___--__-_____---_-_---------

of Volclay in distilled and medium-hard water.____________-____-_--____-------

of kaolinite (78.8 percent sodium saturated) in distilled and medium-hard water____

of illite (78.8 percent sodium saturated) in distilled and medium-hard water________

by a hydrometer.__________ ________.._-___-_-_____---_-_----_----------------

m

Page

236

238

239

240

242

243

244

245

246

247

247

251
IV CONTENTS

TABLES

Page

TABLE 1. Properties of the phosphate deflocculents used in the study, ______-__________-_-____--__--__--___-___--_-- 232

2. Hydrometer data: Montmorillonite and sodium tripolyphosphate-___________________________________________ 256

3. Hydrometer data: Montmorillonite and sodium hexametaphosphate_________________--__-__--_-___-----__- 257

4. Hydrometer data: Montmorillonite and sodium hexametaphosphate plus sodium carbonate.____--___-_----_-- 258

5. Hydrometer data: Kaolinite and sodium tripolyphosphate..______________________-_-_-__--__---_-_-_-___-- 259

6. Hydrometer data: Kaolinite and sodium hexametaphosphate-__________________________-____-_-_-----__-_ 260

7. Hydrometer data: Kaolinite and sodium hexametaphosphate plus sodium carbonate__,______.__-___-_-_____- 261

8. Hydrometer data: Illite and sodium tripolyphosphate_________________-___-__--__---_-__---------_-_--- 262

9. Hydrometer data: Illite and sodium hexametaphosphate-______________________--__-____--_---_-------_-- 263

10. Hydrometer data: Illite and sodium hexametaphosphate plus sodium carbonate._-_________-__-__-----_--_-- 264

11. Hydrometer data: Volclay and sodium tripolyphosphate-__________________--__--__----_----------------- 265

12. Hydrometer data:, Volclay and sodium hexametaphosphate----------------------------------------------- 265

13. Hydrometer data: Volclay and tetrasodium pyrophosphate--___________-_______--__--__--_--------------- 266

14. Hydrometer data: Kaolinite and sodium tripolyphosphate-__________---_-__---_---_------_----_-------_-- 266

15. Hydrometer data: Kaolinite and sodium hexametaphosphate__-_-____-__------_----------_----_---------- 267

16. Hydrometer data: Kaolinite and tetrasodium pyrophosphate__________-___-.-_______-_______-__---.-___-- 267

17. Hydrometer data: Illite and sodium tripolyphosphate__________---_--_-----.------------------------------ 268

18. Hydrometer data: Illite and sodium hexametaphosphate-______-___--_-__-_-------_--_----_-------------- 268

19. Hydrometer data: Illite and tetrasodium pyrophosphate-_______________________-__________---_---.------ 269

20. Results of filter-loss tests,______.______._____...___..______.-__._._.--.._...--_-.._---....-----.---.-- 270
SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

DISPERSION CHARACTERISTICS OF MONTMORILLONITE, KAOLINITE, AND ILLITE CLAYS 

IN WATERS OF VARYING QUALITY, AND THEIR CONTROL WITH PHOSPHATE DISPERSE NTS

By B. N. ROLFE, R. F. MILLER, and I. S. McQuEEN

ABSTRACT

This study is concerned with the dispersion characteristics of 

montmorillonite, kaolinite, and illite clay minerals in waters of 

different hardness and the relation of these characteristics to the 

control of canal seepage by artificial sedimentation. The effect of 

dehydrated sodium phosphates on dispersion was also investigated. The importance of recognizing colloidal suspensions as 

ternary systems (colloid, water, ionized salt) is emphasized.

Representative samples of montmorillonite, kaolinite, and illite 

clays, were saturated with either calcium or sodium and then prepared as 1 percent suspensions in distilled, hard, and soft waters. 

This provided extreme clay-water environments with respect to 

an investigation of the control of dispersion through the injection 

of sodium polyphosphate-type dispersants. Intermediate conditions were also provided by using a water of intermediate quality 

between hard and soft extremes. A native montmorillonite clay 

was selected for use as the prototype of calcium-sodium exchange 

relation and was replicated on the kaolinite and illite clays. The 

dispersion characteristics of the clay minerals under the preceding 

environments are involved in sediment transport in natural 

streams and play a decisive role in sediment-lining procedures. 

The deflocculents used in the investigation were sodium tripolyphosphate (NasPsOio), tetrasodium pyrophosphate (Na4P2O7), sodium hexametaphosphate (NaPOa) n, and sodium hexametaphosphate plus soda ash (Na2COs) in a 50-50 by weight mixture. 

The deflocculents varied in dispersion efficiency depending upon 

the interaction of the clay-water-phosphate systems. These 

variations were related to dissociation of sodium and length 

of polymer chains. A specific deflocculent for each clay, water, 

ionized salt system was indicated by the data.

The percentage of dispersion was measured by sensitive hydrometers, reading from 0-10 grams of colloid per liter. This 

instrument gave generally acceptable results, except where conditions did not conform to the limitations imposed by basic 

theories of hydrometer analysis. The greatest source of trouble 

was in montmorillonite suspensions which produced anomalous 

increases in the hydrometer readings. This was attributed to 

consolidation of uniformly sized particles in the hydrometer jar, 

producing a greater apparent specific gravity in the zone measured by the hydrometer. The increase was usually accompanied 

by phenomena similar to gelation.

As an aid in comparing the many hydrometer analyses (consisting of 3,156 hydrometer readings), the index of dispersion concept was introduced. This value totals selected ordinates under 

a dispersion curve and compares the sum to a base value obtained 

by the same method for selected ordinates under a standard curve 

representing sodium-saturated clays in distilled water. Thus,

for each clay mineral there is a standard value against which all 

deflocculating treatments may be compared.

The results indicate the importance of understanding the chemistry of the ternary system (clay, water, ionized salt). T* e dependence of dispersion on the interaction of these three factors is 

great. Each clay-mineral group has specific properties and characteristics in the system. Not only does montmorillonite show 

the greatest colloidal yield but it is the most responsive to cl anges 

in chemical environment. It is far more difficult to sodium 

saturate a calcium clay than a hard calcium water. Although 

repulsion between like negative surfaces is the basis of dispersion, 

the location, source and amount of negativity of the varior^ clay 

minerals determine the best deflocculent for effecting dispersion.

The general implications of the study have a bearing on several 

fields of sedimentation. With respect to sediment lining of 

canals, the investigation indicated the relative superiority of montmorillonite-type clays for the penetration and filling of small 

voids. With respect to filling of joints, cracks, burrow?, and 

other relatively large openings, kaolinite and illite clays n^ay be 

suitable as mortaring agents.

INTRODUCTION

Irrigation is practiced in areas where precipitation 

is insufficient to produce a profitable crop. It is also 

used to a limited extent where supplemental apnlications of water are needed to offset irregularities in 

rainfall distribution. More than 100 million aero-feet 

of water is diverted annually for irrigation purposes 

in the 17 Western States (exclusive of Alaska). The 

amount of water that reaches the user is reduced during 

transport by a minimum of 25 percent (Dirmeyer, 

1955). Most of this loss may be attributed to seepage 

from unlined canals. In addition to the actual decrease 

in available water supply, there is the problem of 

damage to cropland adjacent to seeping irrigation 

canals, such as waterlogged soil, drowned crops, and 

zones of salt accumulation. Investigation has therefore been centered on possible means of decreasirg the 

losses.

Canal seepage has been diminished by treating the 

leaking bed material to reduce its permeability. These 

treatments consist of lining the canals with materials

229
230 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

such as concrete, plastics, bentonite, and asphalt 

membranes, and compacted earth. The cost of such 

treatment ranges from $0.15 to $5 per square yard of 

canal bed. None of these treatments has satisfactorily 

supplied a low-cost canal lining. Sediment lining seems 

to offer great promise, and the present investigation is 

the outgrowth of the need for low-cost canal lining. 

Canal lining by sedimentation is very appealing 

because little special equipment is required.

Sediment lining of canals was originally a natural 

phenomenon connected with the early history of 

irrigation farming. Irrigation waters were first diverted directly from natural streams. The spring 

floodflows at the start of the growing season normally 

carried enough suspended sediment to serve as a 

natural seepage control through sedimentation. The 

only drawback to this means of seepage control was its 

transient stability. Clear irrigation water, diverted 

during the middle and latter parts of the season broke 

up the sediment cake and carried it away in suspension. 

As irrigation progressed the installation of reservoirs 

as sources of irrigation waters terminated the favorable 

natural sedimentation of former years by intercepting 

the sedimenting material.

An artificially introduced sedimenting material should 

be more stable than the temporary sediment cake of 

the past. Seepage control by sedimentation probably 

could be improved, either by increasing the stability 

or toughness of the filter cake at the surface of the bed 

material, or by adding a fine-grained sediment below 

the bed surface as a void filler.

If the sedimenting material is to be used as a void 

filler below the surface of the canal bed, it should be 

transportable by the canal water. This imposes 

certain limits on the size and transportability of the 

particles. The particles probably should be colloidal 

in size (less than 1 micron in diameter), and the chemistry of the clay-water system should be controlled so 

that the particles do not coagulate and form clumps 

of particles that will not enter the soil voids. A native 

Wyoming bentonite that apparently conformed to the 

above requirements was used for sediment lining by the 

U.S. Bureau of Reclamation on its Kendrick project at 

Casper, Wyo. This was a bentonitic clay that had a 

median particle diameter of 0.5 micron.

It was found early in the work at Kendrick, however, 

that this bentonite was equally responsive to both 

flocculating and dispersing environments. If the canal 

waters were of such a chemical quality as to promote 

floe formation, the transport of the introduced sedimenting material was shortlived. The bentonite suspension failed to cover the desired extent in the canal 

because the particles generally precipitated a short 

distance from the starting point. Also, floes of

bentonite with a sedimentation diameter larger than the 

desired 0.5 micron were formed; there would not 

penetrate the voids of canal-bed material.

There seemed to be a need for a disposing medium 

or chemical control to insure the suspension of bentonite 

in. differing canal waters. It was at thi« stage in the 

sediment-lining investigation that the Geological Survey 

was approached on the subject of a possirT e cooperative 

project with Colorado Agricultural and Mechanical 

College.

The transport of sediment by water may be influenced 

by the kind of sediment and the chemical quality of the 

water. Therefore a basic study into the dispersion 

characteristics of several clay minerals in waters of 

differing chemical quality was of mutual interest to the 

Geological Survey and to investigators into canal 

lining by sedimentation.

The need for chemical additives to maintain a 

dispersion medium led to discussions with representatives from chemical companies. The several phosphate deflocculents available seemed to offer the 

greatest promise of success so the study was designed 

to investigate these in conjunction with the ternary 

system (clay, water, ionized salt).

PERSONNEL

The investigation was made by the Geological Survey 

in cooperation with Colorado Agricultural and Mechanical College, now Colorado State University. The 

investigation was started in 1954 at Colorado Agricultural and Mechanical College, where laboratory space 

was provided for the Geological Survey, and was completed in 1956 in the soils laboratory of the Geological 

Survey at the Denver Federal Center. The investigation by Geological Survey personnel was under the 

administrative direction of R. W. Davenport, chief 

Technical Coordination Branch succeeded by C. C. 

McDonald, chief General Hydrology Branch, and under 

the supervision of H. V. Peterson, project hydrologist 

and later branch area chief, General Hydrology Branch, 

Denver, Colo.

B. N. Rolfe, soil scientist, was in immediate charge of 

the investigation until his resignation in 1956. Reuben 

F. Miller, soil scientist, and I. S. McQueen, hydraulic 

engineer, assisted in the research and completed the 

report.

ACKNOWLEDGMENTS

There were many formal and informal conferences 

during the study. The names that follcw are those of 

people who contributed much to the etudy but any 

omissions do not imply lesser contributions by others to 

the overall problem. The writers are indebted to many 

faculty members at Colorado State Uriversity, espe-
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 231

cially to Dr. D. F. Peterson, R. D. Dirmeyer, Jr., R. B. 

Curry, and Dr. M. L. Albertson of the Civil Engineering Department, to Dr. R. S. Whitney of the Soils 

Department, and Dr. C. G. H. Johnson of the Chemistry 

Department. Valuable counsel was received also from 

Dr. S. R. Olsen and Dr. C. V. Cole of the regional phosphate laboratory of the Agricultural Research Service, 

U.S. Department of Agriculture, stationed at Colorado 

State University.

Several chemical companies were generous with time, 

data, and suggestions. Representing the companies 

were R. P. Gates, Victor Chemical Works; Clark Sumner, A. R. Maas, R. N. Thompson and W. C. Bennett, 

Calgon, Inc.; and John Deming, L. V. Sherwood and 

R. A. Ruehrwein, Monsanto Chemical Co. These men 

contributed very helpful counsel and furnished supplies 

of deflocculents for the testing program.

The clay companies were also generous with time, 

data, and samples. Paul Bechter, American Colloid 

Co., supplied samples as well as technical information. 

Messrs. S. C. Lyons and R. E. Lehman of Georgia Kaolin Co. helped by furnishing pertinent data on the kaolin used in the investigation. For the Baroid Co., 

Messrs. Huebotter, Neznayko, Weintritt, and the late 

F. J. Williams offered technical advice and information 

on many aspects of the study.

The writers also wish to acknowledge the fine cooperation given by Engineering Laboratories Division of 

the U.S. Bureau of Reclamation at Denver, Colo. 

Messrs. Hunter, Jones, Mielenz, and the late M. E. King 

were always gracious in exchanging ideas and information during the course of the investigations.

MATERIALS 

CLAY MINERALS

The materials used were components of the ternary 

system; clays, water, and ionizable salts. 

The clays used were:

1. Kaolinite, supplied by Georgia Kaolin Co., Dry 

Branch, Ga.

2. Montmorillonite, trade name "Volclay" supplied 

by American Colloid Co., Belle Fourche, S. Dak.

3. Illite, an illite-bearing shale from Fithian, 111.

A discussion of clay mineral properties by B. N. 

Rolfe is presented on p. 248.

PHOSPHATE DEFLOCCULENTS

Three phosphate deflocculents were selected for the 

investigation. Each was studied to determine its effect 

on the control of dispersion in the different clay-water 

systems utilized in the experiments.

The various phosphates have several common properties, but differ in efficiency as to specific reactions (Chu

and Davidson, 1955; Tchillingarian, 1952; Whitehouse 

and Jeffrey, 1955; Wintermyer and Kinter,1955). The 

results of this investigation indicate only the relative capabilities of three phosphate reagents, all of which were 

dehydrated sodium phosphates, in dispersing three different types of clay minerals. The chemical composition and general characteristics of the compounds used 

are given in table 1.

There is apparently some confusion concerning phosphate nomenclature. The terms in this report are those 

in common usage in the phosphate industry. The term 

"molecularly dehydrated phosphates" refers to certain 

complex salts formed by the high temperature del ydration of monosodium orthophosphate, disodium orthophosphate, or an intermediate mixture. The phosphates 

differ significantly in P2O6 content, chemical formula, 

and atomic arrangement. As is shown in table 1, sodium tripolyphosphate, tetrasodium pyrophosphate, and 

sodium hexametaphosphate are separate entitle-* and 

represent distinct phosphate salts with individual^ different characteristics.

Table 1 was compiled from literature furnished by 

Victor Chemical Works and Calgon, Inc. Ther^ has 

been no effort to edit these statements. The vriters 

have merely arranged the information for easy comparative reading.

Sodium tripolyphosphate and sodium hexametf.phosphate were used during both years of the study whereas 

tetrasodium pyrophosphate was used only during the 

second year. A 50-50 mixture, by weight, of sodium 

hexametaphosphate and soda ash (Na2CO3) was tried 

during the first year of the study. This was done in 

response to a suggestion by personnel at Calgon, Inc., on 

the basis of their experience in the paper industry 

with dispersing kaolinite clays.

WATERS

The chemical quality of the waters used in the study 

varied greatly with respect to hardness (calcium, magnesium content). The relative amounts of the metallic 

ions, calcium, magnesium, and sodium are of paramount importance to the dispersion characteristics 

of the various clay minerals. Two prototype waters, 

a hard and a soft water, were selected from a tf.ble of 

representative irrigation waters described in the U.S. 

Department of Agriculture Salinity Handbool- (Richards, and others, 1954). This was in accord with the 

objective of the work for the first year wherein endmember relations such as sodium- versus calcium saturated clays were to be studied.

The plan for the second year decided upon by interested parties in conferences held at Fort Collins in 

early 1955 was to study the dispersion characteristics 

of a clay commercially available in water of interm ediate
to

COto

TABLE 1. Properties of the phosphate deflocculents used in the study

Deflocculent

Sodium tripolyphosphate.

Tetrasodium pyrophosp'hate.

Sodium hexametaphosphate.

Chemical composition

NasPsCho __ -

Na4P2 07 (anhydrous) .

(NaP03)n -

Pj Os content (percent)

57.8

53.0 

67.0

Physical appearance

Powdered, granular.

_---_do----___-

Glass plates %- 

1 inch flat 

side, Me-J^ 

inch thick.

Solubility in 100 

parts water

Temperature (°F)

50 

70 

160 

212

50 

70 

160 

212

(')

Parts

14 

15 

22 

34

3 

4 

14 

21

(')

Stability to reversion

10 hr at 100°F solution contains 

98 percent sodium 

tripolyphosphate 

(unchanged 

1.2 percent pyrophosphate, 0.8 

percent orthophosphate) .

10 hr at 160°F, 

little hydrolsis, 

solutions contain 

100 percent original tetrasodium 

py rophosphate .

To effect complete 

reversion in solution requires 

autoclaving 

with strong acid 

or strong alkali.

Sequestration activity

Solubilizes calcium 

and magnesium.

Solubilizes magnesium soaps,disperses calcium 

soaps.

Solubilizes calcium 

and magnesium 

soaps, forms soluble complexes 

with most polyvalent metals.

pH of a l 

percent 

solution

9.6

10.2 

6.9

Uses

Water softening,builder for detergents and soaps, including bar 

and chip soap (nonblooming) , 

industrial cleaners, dispersant 

for pitch control in paper manufacture, clay dispersing, textile processing, conditioning 

drilling mud.

Water softening, builder for soaps 

and detergents, conditioning 

drilling muds, industrial cleaners subjected to high temperature for long periods, stabilizing peroxide bleach baths, clay 

dispersing, textile processing, 

de-inking newsprint ,tin plating.

Threshold treatment for iron stabilization and corrosion and 

scale control, water softening, 

builder for detergents, dispersant for pitch in paper 

manufacturing, dispersant for 

clay and pigments, textile and 

leather processing, conditioner 

for drilling muds, and processing food products.

i Infinitely soluble.
DISPERSION CHARACTERISTICS, MONTMORILLONTTE, KAOLINITE, ILLITE CLAYS 233

quality. A Wyoming bentonite (Volclay) and water 

from the Tri-County Canal in central Nebraska, were 

selected as prototypes for the clays and waters used 

during the second year's investigation.

Distilled water was the first aqueous medium in which 

the various clays were dispersed. Any addition of 

deflocculent to such a clay-water system would merely 

serve to counter the influence of any hard (Ca++ or 

Mg++) ions in exchange positions on the clay. Under 

such a premise, a sodium-saturated clay in distilled 

water should represent maximum dispersion potential, 

and the dispersion index discussed later is based on 

this condition.

The composition of the hard water was selected from 

a field prototype to represent an extreme in flocculating 

effect. The synthetic model contained the following in 

milliequivalents per liter: Calcium, 17; magnesium, 

8; and sodium, 17. This is an admittedly unusual water 

because of its high electrolyte content and high calcium, magnesium values. Anions were not regarded 

as significant during the design stage of this study 

but proved to be, as will be described later.

The soft water, as with the hard water, was selected 

from a field prototype to represent the other extreme 

in waters. The synthetic model contained the following, in milliequivalents per liter: Calcium, 3; magnesium, 2; and sodium, 15.5. This is a highly sodic 

water and is probably an end member in the range that 

might be expected in irrigation waters.

Water from the Tri-County Canal in central Nebraska was selected as a prototype for the study because its 

chemical compositon fell midway between those of the 

hard and soft waters. The synthetic model contained 

the following, in milliequivalents per liter: Calcium, 

6.2; magnesium, 3.6; and sodium, 6.3.

METHODS

WATER SYNTHESIS

The synthetic waters of varying degrees of hardness 

were assembled in the laboratory by adding the proper 

amounts of calcium, magnesium, and sodium salts to 

distilled water. As indicated previously, there was a 

different experimental procedure for each year of study. 

This was true for the clays and waters. It is, therefore, 

convenient to discuss the water synthesis in chronological order.

The analyses of the waters for 1954-55 have been 

reported in the previous section. Only the sources 

of the cations are noted here. Sodium was derived 

from reagent grade sodium chloride (NaCl); calcium 

from reagent grade calcium sulfate (CaSO4 -2H2O); and 

magnesium from reagent grade magnesium sulfate 

(MgSO4-7H2O).

530716 O 60 2

During the second year (1955-56) the sodium ions 

were derived from reagent grade sodium chloride. 

However, to provide calcium, calcium chloride was used 

instead of calcium sulfate in order to avoid the possible 

formation of an insoluble precipitate as occurred in the 

investigation of the hard water.

EXCHANGE COMPLEX SATURATION OF CLATS

The clay minerals were treated to saturate their 

exchange complexes with either calcium or sodium or a 

combination of the two. In the first year's investigation the clay minerals were made homoionic with 

respect to calcium and sodium. In the second year 

the clays were ionically adjusted to simulate the 

exchange complex of a native Wyoming bentonite 

(Volclay).

Homoionic clays were prepared as follows:

1. 10-gram portions of air-dry clay were placed in 100 mHliliter 

glass centrifuge tubes.

2. 100 milliliters of 1 N calcium acetate or sodium chloride were 

added and mixed with the clay.

3. The centrifuge tubes were placed in beakers containing water 

and warmed gently overnight on a hot plate.

4. The suspensions were then centrifuged and the supernatant 

liquid decanted.

5. The above procedure was repeated three times.

6. The clays were washed three times with distilled water, 

centrifuged and decanted between each washing.

7. The washed clays were transferred into hydrometer jars and 

filled to 1 liter with the proper aqueous medium.

During the second year's investigation, instead of 

using homoionic clays, the cation-exchange conplex 

of Volclay was used as a prototype from which calciumsodium percentages were calculated. As presented in 

the American Colloid Co. Circular, Data No. 202, the 

ionic content of Valclay (per 100 grams) is as follows:

MiUiequimkntt

Sodium.___-_____--__---------_-_ -_ -- -._ 85. 5

Calcium._________________________________.__._-_ 22. 0

Magnesium________________________________________ 1. 0

Total__-___________-__-______ 108. 5

In calculating the percentage of saturation with 

respect to calcium and sodium, magnesium was grouped 

with calcium. Therefore, the sodium saturation is 

equal to 85.5-^-108.5X100 or 78.8 percent, and the 

calcium saturation is 100 percent minus 78.8 percent 

or 21.2 percent.

The percentage of exchangeable cations was simulated 

on the kaolinite and illite as follows:

1. Homoionic sodium and calcium clays were prepared as 

described previously.

2. Instead of transferring the clays to hydrometer jars (step 6), 

they were air-dried and stockpiled.
234 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

3. 7.88 grams of air-dry sodium clay was mixed with 2.12 grams 

of calcium clay.

4. The mixtures (10 grams) were put into hydrometer jars 

which were filled to 1 liter with the desired water.

TREATMENT WITH DEFLOCCULENTS

The phosphate deflocculents were added progressively 

in small increments to each clay-water system to 

determine the quantity producing the maximum 

dispersion. The dispersion attained in a phosphatedistilled water medium was considered the maximum 

obtainable for each type of clay.

The increments of phosphate were added to the 

system at the end of each hydrometer test sequence, 

stirred, and allowed to soak for about 20 hours. The 

hydrometer procedure was followed and the phosphate 

addition repeated. The time required to attain 

maximum dispersion varied with the clay-water system 

and took as long as 3 weeks in the calcium-clay hardwater system. The possible effect of the time element 

on the validity of the results was recognized but the 

described procedure was adopted because of the space 

limitations of the laboratory and the time allotted to the 

study. The objection to this method was the 

possibility of the phosphate reverting to PO4 ionization 

products of phosphoric acid an orthophosphate in the 

time elapsed during the experiment. However, some 

checks that were made using single optimum 

applications of phosphates to clay-water systems, 

showed no appreciable differences in the results. Also, 

the temperatures involved in the study were of such a 

range as to restrict reversion to a minimum. The 

latter statement agrees with published statements by 

phosphate manufacturers.

The method described above was followed during 

both years of the investigation. It proved expedient 

and allowed for a greater number of tests than would 

have been possible otherwise.

HYDROMETER ANALYSIS

The hydrometer test procedures used were patterned 

after standard wet mechanical analysis methods with 

modifications to adapt them to the objectives of this 

investigation (see the section "Discussion of the hydrometer method"). The procedure was as follows:

1. 10 grams of air-dry colloid was placed in each hydrometer 

cylinder.

2. Each cylinder was filled to the 1 liter mark with either distilled water or previously prepared synthetic water. The 

mixture was allowed to stand for 24 hours with occasional 

mixing.

3. A cylinder was filled with the same water as that used in the 

test, to act as a check on temperature and other effects.

4. The hydrometer was inserted into the check cylinder, and the 

reading recorded.

5. The samples were thoroughly mixed for a period of 1 minute 

by one of the following methods:

a. The hydrometer cylinder was covered with the palm 

of the hand and the suspension mixed by vigorous 

end-over-end shaking of the cylinder, 

b. A mixing tool was inserted (a large rubber stopper 

fixed to the end of a glass rod) into the cylinder and 

moved rapidly up and down.

6. A clock or stopwatch was started as the mixing was stopped.

7. The hydrometer was carefully inserted into the suspension.

8. The percentage of clay in suspension was read and recorded 

1 minute and 4 minutes after mixing.

9. The hydrometer was placed in the check cylinder and the 

observed reading recorded, thereby accounting for changes 

in temperature and electrolyte effects. This value was 

applied to the readings in the sample as a correction.

10. Additional readings were made on the sample and the check 

cylinder 19, 60, 435, and 1,545 minutes after mixing.

11. Specified amounts of deflocculent were added to the sample 

and to the check cylinder and steps 4 through 10 were 

repeated.

The hydrometer used was an ultrasensitive instrument that measures 10 grams of soil per liter at maximum reading. This instrument was u^ed to enable 

work in the same range of concentration (about 1 

percent) as was used in field experiments on sediment 

lining. When the salt concentration in the water was 

high and the amount of deflocculent was large, readings 

were beyond the range of the sensitive hydrometer and 

it was necessary to use a standard hydrometer calibrated 

to 60 grams of suspended material per liter.

RESULTS AND DISCUSSION

Many attempts have been made to devise a universal 

means of comparing the results from hydrometer tests 

and from other methods of mechanical analysis. Where 

large numbers of analyses were made, no rapid visual 

method of comparing the results was available. The 

primary deterrent was the lack of a suital^ standard of 

comparison.

In the present investigation, interest centered on the 

relative efficiency of the various phosphate deflocculents. By adoption of one set of data as a standard of 

comparison, the relative dispersion characteristics of 

one clay in different phosphate-water systems could be 

evaluated. The numerical relation between the standard and the individual set of data is referred to as "the 

index of dispersion."

The data for sodium-saturated clays in distilled 

water with no deflocculent were selected as the standard 

of comparison for computation of dispersion indices.

Each sequence of tests on each clay type started 

with no deflocculent added. Because there was a 

sequence for each of three types of deflocculent using 

distilled water, this provided 3 runs on each clay that 

were duplicates, that is the same amount of clay dis-
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITB, ILLITB CLAYS 235

persed in identical liquid media. This provided a 

usable standard with several advantages:

1. There were duplicate tests that could be averaged.

2. Sodium-saturated clays in distilled water represent near 

optimum dispersion.

3. The aqueous medium is salt free and does not introduce any 

extraneous electrolytic effects into the system.

4. The individual size distribution curves for a given clay were 

similar. Therefore the standard should be reproducible.

In the test procedure used, hydrometer readings 

were made 1, 4, 19, 60, 435, and 1,545 minutes after 

mixing the sample. As the grain-size distribution for 

all samples of a given type of clay was presumably the 

same, the sum of these readings would represent the 

relative dispersion of the sample. The average of the 

sum of the readings for 3 runs on each sodium-saturated 

clay in distilled water with no deflocculent was used 

as a standard or 100 percent dispersion. For Volclay, 

a montmorillonite-type clay, the average sum was 532; 

for kaolinite it was 453; and for illite it was 395. The 

dispersion indices were computed as in the following 

example.

For calcium-saturated Volclay in distilled water 

with 0.5 grams per liter of sodium tripolyphosphate 

added, the corrected hydrometer readings at the 

specified times were 90, 83, 69, 52, and 41 percent of 

dispersed weight. The total is 404 and the dispersion 

index is 404-^-532X100=75.9 percent.

Thus each test run was compared on a percentage 

basis with the standard for the type of clay being tested.

The computation of dispersion indices requires that 

there be no missing data. The hydrometer readings 

in the standard at 1, 4, 19, 60, 435, and 1,545 minutes 

must be matched by readings at the same time intervals 

in the hydrometer run being studied. However, 1 or 

more of these readings were omitted during several 

tests, the reasons being time, expediency and apparent 

end to sequence. Examination of the data and the 

laboratory procedures used indicated that the missing 

readings lay within narrow definable limits and could 

be supplied with reasonable accuracy by extrapolation 

and interpolation. The following criteria were followed 

in substituting for missing data:

1. Missing values were assumed to be equal to or less than those 

preceding them in a series.

2. Incomplete curves were compared with complete size distribution curves in the same system and the missing data was 

chosen to make their curve shapes conform.

3. Notes on original data sheets such as references to clear 

surface breaks and floe formation, were used as guides in 

determining the extrapolated values.

4. Dispersion indices for a given system were plotted and any 

significant deviation from a norm was rechecked.

The results of the hydrometer analyses are presented 

in the section "Tables of Data and Dispersion Indices"

in tables 2 through 19 and are summarized for discussion 

in figures 1 to 11. Figures 1 to 11 are graphs of the 

dispersion indices versus the amount of deflocculent 

as listed in the tables of base data. The dispersion 

indices are plotted as ordinates with the abscissa of 

the point being the amount of deflocculent. Both are 

on linear scales as indicated. All graphs are labeled 

to indicate the colloid, type of water and ion saturation. 

The deflocculent used is indicated by the type of line 

in the individual graphs. The line coding used consistently through all of the summary curves is as 

follows:

Sodium tripolyphosphate 

Sodium hexametaphosphate 

Sodium hexametaphosphate plus sodium carbonate 

Sodium tetrapyrophosphate 

SODIUM MONTMORILLONITE IN DISTILLED WATER

Sodium montmorillonite was in a well-dispersed 

state when at equilibrium with distilled water (fig. 37 A). 

This was in accord with dispersion theories (See section 

"Theory of clay-mineral behavior in dilute suspension", by R. F. Miller.) in that there is no electrolyte 

contribution from the water and the inherent negativity 

of the montmorillonite particles is at equilibrium with 

sodium, the least opposing cation to dispersion. The 

introduction of phosphate deflocculents into the system 

increased the index of dispersion beyond that of the 

standard. There was little difference among the three 

reagents in their effect on percentage of dispersion.

The improvement in dispersion of the system was 

probably due to sequestration of multivalent cations 

still present on the sodium saturated clay surfaces. 

The energy relations between ions and surfaces preclude 

the complete replacement by mass action of multivalent ions by sodium. Sequestration reduces thb difficulty and increases the degree of sodium saturation. 

It is also possible, but less likely, that dispersion may 

have been improved by increasing the negativity of 

the montmorillonite particles by phosphate anion 

adsorption to clay edges.

CALCIUM MONTMORILONITE IN DISTILLED WATER

The calcium montmorillonite was in a flocculent 

state when at equilibrium with the distilled water 

(fig. 37J5). Unlike sodium saturation, calcium saturation may be completely effected by mass action. Thus, 

the exchange complex of the clay was probaWy 100 

percent calcium and these closely held, divalert ions 

decreased the intensity of the clay negativity. The 

particles could then approach each other to the point 

where attractive forces become effective, thereby 

inducing floe formation and more rapid settling 

velocities.
236 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

120

100

80

O 60 

C/5 tr

A. Sodiumsaturated 

clay

20

0.05 0.1 0

B. Calcium-saturated clay

0.5 1

GRAMS DEFLOCCULENT

120

100

80

O 60 

C/5 tr

UJ 

Q_

£ 40 

O

20

0.05 0.1 0 0.5 1

GRAMS DEFLOCCULENT 

EXPLANATION

1.5

Sodium tripolyphosphate Sodium hexametaphosphate

FIGUKE 37. Dispersion characteristics of sodium- and calcium-saturated montmorillonite in distilled and soft water. A, B, distilled water; C, D, soft water.

Sodium hexametaphosphate 

plus sodium carbonate
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLESTITE, ILLITE CLAYS 237

The introduction of phosphate deflocculents into 

this system improved dispersion. The slope of the 

index curve was greatest up to 70 percent; beyond this 

point there was a smaller increase in dispersion per unit 

weight of deflocculent. This point of maximum 

efficiency (70 percent) corresponds to 5 percent deflocculent per unit weight of clay.

At the 70 percent dispersion index there was little 

difference among the dispersants. Below this point, 

the reagents in the order of their efficiency in increasing 

the percentage of dispersion were: Sodium hexametaphosphate, sodium hexametaphosphate plus sodium 

carbonate, and sodium tripolyphosphate. Beyond the 

70 percent dispersion index, sodium tripolyphosphate 

had a slight advantage over the other two.

The greater efficiency of sodium hexametaphosphate 

up to the 70 percent dispersion index was probably a 

function of its long chain polymer structure. Because 

the calcium montmorillonite-distilled-water system 

represented a high degree of neutralization of clay negativity, long chain hexametaphosphate polymeric anions 

could probably get closer to the clay edges than in 

other systems. Such contact may have facilitated the 

adsorption of these anions to the clay particle by contact with exposed positive charges (Al+++) at these 

edges. This could improve dispersion by increasing 

the negative charge of the clay particles and by facilitating sequestration of the tightly bound Ca++ ions.

The apparent supremacy of sodium tripolyphosphate 

above the 70 percent index may be attributable to its 

greater supply of dissociated Na+. Displacement of 

Ca++ by Na+ is by mass action and it may require 

more Na+ in this range than can be supplied by the 

hexametaphosphate. Sequestration facilitates dispersion but a calcium-saturated system also requires mass 

action displacement by sodium.

SODIUM MONTMORILLONITE IN SOFT WATER

Sodium montmorillonite was in a semidispersed state 

when at equilibrium with soft water (fig. 37 C). The 

system seemed dispersed because of the turbidity 

throughout the hydrometer columns. However, a 

clear-water break soon developed at the surface (before 

a 24-hour period) and indicated that maximum dispersion had not been attained. Apparently, the ion 

concentration about each clay particle permissible for 

maximum dispersion had been exceeded and consolidation had taken place wherein porous floes of material 

were compressed, leaving clear water at the surface.

The introduction of phosphate deflocculents into this 

system did not improve dispersion; in fact, the depth 

of clear-water breaks increased directly with the amount 

of deflocculent added. This was probably due to

electrolytic concentrations and compression of the diffuse cloud of cations about the clay particles. Sodium 

tripolyphosphate and the mixture of hexametaphosphate plus sodium carbonate was least detrimental to 

dispersion in this system.

CALCIUM MONTMORILLONITE IN SOFT WATER

The calcium montmorillonite was flocculated when 

at equilibrium with the soft water (fig. 37 D). This 

system showed properties similar to that of the calcium 

montmorillonite in distilled water. The high electrolyte content of the soft water apparently served to 

repress the dispersive tendency of the montmorillonite 

clay.

Introduction of phosphate deflocculents into this 

system improved dispersion. The phosphate dispersants ranked in efficiency in the order of possible displacement of calcium by sodium as follows: sodium 

tripolyphosphate, sodium hexametaphosphate, and 

sodium hexametaphosphate plus sodium carbonate. 

Sodium tripolyphosphate with the highest percent 

sodium per unit weight of salt was superior. This 

system contained hard (calcium) clays requiring massaction displacement by sodium ions.

SODIUM MONTMORILLONITE IN HARD WATER

The sodium montmorillonite at equilibrium in hard 

water (fig. 38A) was in a semiflocculent state. The 

dispersion index at zero deflocculent was 80 ard was 

accompanied by a clear-water break at the surface. 

This system could be better described as a high floe. 

Calcium ions apparently displaced sodium from ion 

exchange surfaces, reducing the negativity of the montmorillonite particles and compressing the diffuse, outer 

layer of associated cations.

The introduction of phosphate deflocculents into 

this system improved dispersion only slightly. This 

was probably due to the increase in electrolyte content 

from the added dispersant counteracting any possible 

benefit from replacing Ca++ ions with Na+ ions.

CALCIUM MONTMORILLONITE IN HARD WATER

The calcium montmorillonite in hard water (fig. 38J5) 

was in a flocculent state at equilibrium. Introduction 

of phosphate deflocculents improved dispersion up to a 

maximum at 30 percent deflocculent per weight of 

clay. Dispersant addition not only increased dispersion but caused the formation of a white precipitate. 

Analysis of the precipitate by X-ray diffraction and 

spectrography indicated that it was a comp^x of 

gypsum and phosphate.

The formation of this precipitate may be explained 

by review of the electrolyte content of the system. The
238

120

100

X

UJ 80 

Q

O 60

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

A- Sodium-saturated clay

cr

UJ 

Q_

40

20

234

GRAMS DEFLOCCULENT

120

100

80

O 60 

(/) DC

UJ 

Q.

<2 40 

Q

20

B. Calcium-saturated clay

234

GRAMS DEFLOCCULENT 

EXPLANATION

Sodium tripolyphosphate Sodium hexametaphosphate

FIGURE 38. Dispersion characteristics of sodium- and calcium-saturated montmorillonite in hard water.

Sodium hexametaphofohate 

plus sodium carbonate

anions of the calcium and magnesium salts in the hard 

water were sulf ate (SO"!). The composition of the water 

was such that the solubility product of gypsum (CaSO4 - 

2H2O) was close to its limit. The addition of electrolyte in the form of phosphate deflocculents possibly 

caused the system to exceed the solutior limit of the 

gypsum-phosphate complex, thereby causing it to precipitate. The complex may be the result of the affinity
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINTTE, ILLITE CLAYS 239

of the phosphate polyanions for Ca++ ions causing them 

to be carried down with the calcium sulphate. The removal of Ca++ ions from the system by sequestration 

and precipitation apparently softened the water and 

improved the dispersion.

Sodium tripolyphosphate seemed most efficient, 

probably because of its greater content of dissociated 

sodium concurrent with its sequestering capacity. The 

dissociated sodium is needed to replace exchangeable 

calcium from the clay. Dehydrated sodium phosphates 

are poor sources of sodium for displacement of calcium 

from exchange surfaces by mass action.

SODIUM KAOLINITE IN DISTILLED WATER

Sodium kaolinite was dispersed when at equilibrium 

with distilled water (fig. 39^1). The addition of phosphate deflocculents improved dispersion probably by 

sequestering any stray multivalent cations still in the 

system and by increasing clay negativity through sorption 

onto clay edges.

CALCIUM KAOLINITE IN DISTILLED WATER

Calcium kaolinite was flocculated when at equilibrium 

with distilled water (fig. 395). The phosphate deflocculents improved dispersion in the following 

order: Sodium hexametaphosphate, then sodium carbonate plus sodium hexametaphosphate, and last, 

sodium tripolyphosphate. The superiority of the 

sodium hexametaphosphate treatments indicate? that 

increased negativity from adsorption of polyanions 

helped increase the dispersability of kaolinite in this 

system above the dispersion attainable from Ca++ ion 

sequestation alone

SODIUM KAOLINITE IN SOFT WATER

Sodium kaolinite was partly flocculated when at 

equilibrium with soft water (fig. 40 A). Thh was 

probably due to the effect of the high salt content and 

the 5 milliequivalents per liter of Ca++ plus Mg++ in the 

soft water. Addition of phosphate deflocculents to the 

sytem increased dispersion. The order of efficiency of 

the three reagents was: Sodium hexametaphosphate 

plus sodium carbonate, sodium tripolyphosphate, and 

last, sodium hexametaphosphate. The fact that the 

degree of dispersion was greater in the two alkaline systems indicates that dissociation of OH~ ion from alumina sheets increased the negativity of clay particles The 

superiority of sodium hexametaphosphate buffered by

INDEX DISPERSION 

§8 Sgo

A. Sodiumsaturated 

clay

^ 

9~~ 

B. Calcium-saturated clay

0.05 0.1 0 0.5 1

GRAMS DEFLOCCULENT 

EXPLANATION

Sodium hexametaphosphate

1.5

Sodium tripolyphosphate

FIGURE 39. Dispersion characteristics of sodium- and calcium-saturated kaolinite in distilled water

Sodium hexametaphosphate 

plus sodium carbonate
240

120 r

100

80

O 60

CO 

OH

UJ

40 

Q

20

t

120

100

X

UJ 8o

O 60

CO

OH

UJ

40

20

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

A. Sodium-saturated clay

0.5 1.5

GRAMS DEFLOCCULENT

B. Calcium-saturated clay

0.5 1

GRAMS DEFLOCCULENT 

EXPLANATION

1.5

Sodium tripolyphosphate Sodium hexametaphosphate

FIGUEE 40. Dispersion characteristics of sodium- and calcium saturated kaolinlte in soft water.

Sodium hexametaphosphate 

plus sodium carborate
DISPERSION CHARACTERISTICS, MONTMORILLONTTE, KAOLINITE, ILLITE CLAYS 241

sodium carbonate indicates that increased negativity 

from adsorption of polyanions also was effective in 

dispersing the system.

CALCIUM KAOLINITE IN SOFT WATER

Calcium kaolinite was flocculated when at equilibrium with soft water (fig. 405). Phosphate deflocculents increased dispersion in the following order: 

Sodium tripolyphasphate, sodium hexametaphosphate, 

and sodium hexametaphosphate plus sodium carbonate. 

The reaction order indicates that sequestration of Ca++ 

ions and replacement of these ions with monovalent 

Na+ ions was effective in dispersing this system.

SODIUM KAOLINITE IN HARD WATER

Sodium kaolinite was flocculated when at equilibrium 

with hard water (fig. 41.4). The introduction of 

phosphate deflocculents into the system caused a 

gradual increase in degree of dispersion. The increase 

in dispersion was coincident with formation of a 

precipitate similar to that formed in montmorillonitehard-water system, that is, a complex of gypsum and 

phosphate.

There was little difference between the reagents with 

respect to dispersion efficiency. The sodium tripolyphosphate, however, produced a slightly higher index 

than the other two, reflecting its greater capacity for 

sequestering Ca++ ions. The high electrolyte content 

of this system apparently prevented it from attaining 

as high a degree of dispersion as existed in the standard 

sodium kaolinite distilled water system.

CALCIUM KAOLINITE IN HARD WATER

Calcium kaolinite was flocculated when at equilibrium 

with hard water (fig. 415). Both clays and water were 

dominated by the calcium ion and the environment was 

especially conducive to flocculation.

The introduction of phosphate deflocculents improved 

dispersion coincident with the formation of a gypsumphosphate precipitate. Sodium tripolyphosphate was 

most efficient, followed by the sodium hexametaphosphate-sodium carbonate mixture with sodium 

hexametaphosphate last. The superiority of the two 

alkaline buffered dispersants over acid sodium 

hexametaphosphate indicates that the negativity of 

kaolinite may have been increased in the alkaline systems by dissociation of OH~ ions in the alumina sheet.

SODIUM ILLITE IN DISTILLED WATER

Sodium illite was dispersed when at equilibrium with 

distilled water (fig. 42A). The colloidal yield of the 

dispersed standard was only 25 percent, that is, only

one-fourth of the mass had a diameter of less than one 

micron.

The introduction of phosphate deflocculents into the 

system increased dispersion. This was probably due to 

sequestration of any stray multivalent ions still present. 

There was little or no difference in efficiency between the 

phosphates.

CALCIUM ILLITE IN DISTILLED WATEI

Calcium illite was flocculated when at equilibrium 

with distilled water (fig. 425). Phosphate deflbcculents did not improve dispersion in this system.

SODIUM ILLITE IN SOFT WATER

Sodium illite had a dispersion index of a little more 

than 60 percent when at equilibrium with soft water 

(fig. 43-4). This decrease of dispersion in distilled water 

must be attributed to the high salt content of the soft 

water and the effect of the divalent ions, Ca++ and 

Mg++, in the water.

The introduction of phosphate deflocculents into the 

system produced an increase in degree of dispersion. 

Only treatments containing long chain polymers (hexametaphosphates) progressively improved dispersion, 

indicating benefits from increased negativity from 

adsorption of long chain polyanions to clay surfaces. 

The ineffectiveness of sodium tripolyphosphate indicates little benefit to the system by the sequestration 

mechanism. The increase in dispersion efficiency of 

sodium tripolyphospbate, after this chemical became 

more concentrated in the system, cannot be explained 

on the basis of available data.

CALCIUM ILLITE IN SOFT WATER

The calcium illite was in a flocculent condition when 

at equilibrium with soft water (fig. 435). The addition of phosphate reagents did not materially increase 

the dispersion of the system. This indicates th^t it is 

impractical to improve the dispersibility of a crlciumsaturated clay by the use of sequestering agents. The 

relative efficiencies of the deflocculents in this system 

were the same as those observed when sodium-saturated 

illite was studied in the soft water. The similarity 

between curves in both systems indicates tho same 

factors were effective with both the sodium- and 

calcium-saturated clays in the soft water.

SODIUM ILLITE IN HARD WATER

Sodium illite in hard water (fig. 44A) was flocculent 

and showed a dispersion index of slightly more than 40 

percent when at equilibrium with hard water. This 

system exhibited dispersion characteristics similar to 

those of the sodium illite in soft water, indicating the

530716 O 60 -3
242

120

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

A. Sodium-saturated clay

234

GRAMS DEFLOCCULENT

120

100

X

LU 80 

Q

O 60 

(/)

cr

LU

Q_

(/> 40

Q

20

B. Calcium-saturated clay

Sodium tripolyphosphate

3 4

GRAMS DEFLOCCULENT 

EXPLANATION

Sodium hexametaphosphate Sodium hexametaphosphate 

plus sodium carbonate

FIQURE 41. Dispersion characteristics of sodium- and calcium-saturated kaolinite in hard water.
DISPERSION CHARACTERISTICS, MONTMORILLONTTE, KAOLENITE, ILLITE CLAYS 243

§

8

NDE §

z 

o 

</) 

cc

UJ 

Q- c/)

Q

§

20

A. Sodiumsaturated 

clay

£=**

f

- 

B. Calcium-saturated clay

0.05 0.1 0 0.5

GRAMS

i 

DEFLOCCULENT

1.5

EXPLANATION

Sodium tripolyphosphate Sodium hexametaphosphate

FIGURE 42. Dispersion characteristics of sodium- and calcium-saturated illite In distilled water.

Sodium hexametaphosphate 

plus sodium carbonate

prevailance of similar factors in both systems. Apparently, long chain polymers were most effective in 

dispersing the system. The initial depression of dispersion in the sodium tripolyphosphate system could be 

related to an increase in the salt concentration without 

benefit from polyanion adsorption.

CALCIUM ILLITE IN HARD WATER

Calcium illite at equilibrium with hard water (fig. 

445) was flocculated. The increase in dispersion index 

through use of phosphate reagents was small, from 

about 20 percent to between 40 and 50 percent. Large 

quantities of the dispersants had to be added before 

dispersion was improved. The superiority of sodium 

tripolyphosphate at this point indicates that availability 

of Na+ ions for displacement of Ca++ ions and ability 

to sequester Ca++ ions were most effective in improving 

dispersion. The data further indicate that it is impractical to attempt to disperse a calcium-saturated 

system with phosphate dispersants.

The illite and kaolinite used in the following phases 

of the study were treated to simulate ion saturation on 

a Wyoming bentonite sold by American Colloid Co. 

as Volclay. Circular 202 of this company indicates

that the relative sodium and calcium plus magnesium 

percentages in Volclay are 78.8 and 21.2 respectively. 

The dispersion characteristics of the above-treated 

clays were examined in distilled water and in a synthetic water of medium hardness, based on a prototype 

water from the Tri-County Canal system in central 

Nebraska. This water contained 6.2, 3.6, and 6.3 

milliequivalents per liter respectively of calcium, magnesium, and sodium.

VOLCLAY IN DISTILLED WATER

Volclay was dispersed when at equilibrium with distilled water (fig. 45A). Not only was the water relatively free from cations but the exchangeable cations 

were in such proportion as not to effectively reduce the 

negativity of the montmorillonite particles.

The addition of phosphate deflocculents did not improve dispersion. The increase in electrolyte content 

probably counteracted any possible benefit by sequestration or polyanion adsorption.

VOLCLAY IN MEDIUM-HARD WATER

The dispersion index of the native montmorillonite 

medium hard water system (fig. 45J3) was about 75 per-
244

120

100

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

A. Sodium-saturated clay

Q 

Z

80

z

O 60

(/) 

01 

LiJ 

Q_ 

CO 40

Q

20

Calgon

0.5 1

GRAMS DEFLOCCULENT

1.5

120

100

B. Calcium-saturated clay

80 Q 

Z

z

O 60 

CO

¥1 40 

O

20

0.5 1

GRAMS DEFLOCCULENT 

EXPLANATION

1.5

Sodium tripolyphosphate Sodium hexametaphosphate Sodium hexametaphosphate 

plus sodium carbonate

FIGURE 43. Dispersion characteristics of sodium- and calcium-saturated fllite in soft water.
120

100

X

UJ 80

O 60

(/)

OC

UJ

Q_

<2 40 

Q

20

DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS

A. Sodium-saturated clay

245

120

234

GRAMS DEFLOCCULENT

B. Calcium-saturated clay

234

GRAMS DEFLOCCULENT 

EXPLANATION

Sodium tripolyphosphate Sodium hexametaphosphate

FKJUBE 44. Dispersion characteristics of sodium- and calcium-saturated Ulite to hard water.

Sodium hexametaphosphate 

plus sodium carbonate
246

120

100

UJ 80

Q

Z

g 60 

cc

Ld

CO 40 

Q

20

A. Distilled water

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

B. Medium-hard water

0.05 0.1 0 0.5 1

GRAMS DEFLOCCULENT

EXPLANATION

1.5

Sodium tripolyphosphate Sodium hexametaphosphate Tetrasodium pyrophosphate 

FIGURE 45. Dispersion characteristics of Volclay in distilled and medium-bard water.

cent when at equilibrium. This was probably due to 

the flocculating effect of the divalent cations and the 

salt content of the water.

The introduction of phosphate deflocculents into the 

system improved dispersion. This may be attributed 

to displacement of multivalent ions by monovalent Na+ 

ions, and sequestration of the multivalent ions. There 

was little difference between the deflocculents with respect to dispersion efficiency; but the dispersants did 

rank in the order of their sodium composition per unit 

weight, as follows: 1. tetrasodium pyrophosphate, 2. sodium tripolyphosphate, 3. hexametaphosphate.

KAOLINITE (78.8 PERCENT SODIUM SATURATED) 

IN DISTILLED WATER

This kaolinite was dispersed when at equilibrium 

with distilled water (fig. 46-4). Again the environment 

was conducive to dispersion.

The introduction of phosphate deflocculents into the 

system did little to increase dispersion. The slight increase may be attributed to sequestration of divalent 

cations and possibly polyanion adsorption to clay edges 

The latter possibility is remote because physicochemical 

consideration of the system indicate that the phosphate 

anions would have some difficulty in approaching the 

clay particles when the latter were surrounded by diffuse 

clouds of Na+ ions; the more diffuse the clouds of ions

about the particles the more difficult the approach of 

negative ions to the clay surface.

KAOLINITE (78.8 PERCENT SODIUM SATURATED) 

IN MEDIUM-HARD WATER

The dispersion index of this system (fig. 46J5) was 40 

percent when at equilibrium. The electrolyte and divalent cation content of the water was sufficient to 

partly flocculate the system.

The introduction of phosphate deflocculents into the 

system improved dispersion. The partly flocculated 

system apparently allowed the approach of polyanions 

to the clay surfaces. This hypothesis is supported by 

the order of efficiency of the reagents, namely, sodium 

hexametaphosphate, sodium tripolyphofiohate, tetrasodium pyrophosphate. The above order is that of decreasing length of polymer chain, which characteristic 

is related to efficiency in dispersing kaolinite through 

increasing the negativity of the clay by adsorption of 

polyanions to exposed edges.

ILLITE (78.8 PERCENT SODIUM SATURATED) IN 

DISTILLED WATER

The illite was dispersed when at equilibrium with distilled water (fig. 47 A). However, it imrt be remembered that only 30 percent of the matenal was less 

than 1 micron in diameter when fully dispersed.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 

A. Distilled water B. Medium-hard water

247

DISPERSION INDEX

i§ gs

0.05 0.1 0 0.5 1 1.5

GRAMS DEFLOCCULENT

EXPLANATION

Sodium tripolyphosphate Sodium hexametaphosphate Tetrasodium pyrophosphatFIGUEE 46. Dispersion characteristics of kaolinite (78.8 percent sodium saturated) in distilled and medium-hard water.

A. Distilled water B. Medium-hard water

120

100

X

UJ 80 

O

O 60 

</)

ce

UJ 

CL

<£ 40 

Q

20

0.05 0.1 0 1

GRAMS DEFLOCCULENT 

EXPLANATION

Sodium tripolyphosphate Sodium hexametaphosphate Tetrasodium pyrophosphate 

FIGURE 47. Dispersion characteristics of illite (78.8 percent sodium saturated) in distilled and medium-hard water.
248 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

The addition of phosphate deflocculents into the system did not materially increase the dispersion. There 

was no marked difference among the reagents with 

respect to dispersion efficiency

ILLITB (78.8 PERCENT SODIUM SATURATED) IN 

MEDIUM-HARD WATER

The illite was flocculated when at equilibrium with 

medium-hard water (fig. 475). The data indicate that 

the degree of flocculation was not as great as in the calcium-illite hard-water system.

The addition of phosphate deflocculents into the system increased dispersion. Sodium tripolyphosphate was 

better than sodium hexametaphosphate and tetrasodium pyrophosphate was 1he least efficient. The order 

of the dispersants probably reflects the relative efficiency 

of the dispersants as sequestering agents. Tetrasodium 

pyrophosphate was superior only in systems where sodium was needed to displace Ca++ ions from exchange 

surfaces, which was apparently not needed in this 

system.

SUMMARY OF CONCLUSIONS

1. It is not practical to attempt to disperse calciumsaturated clays with hexametaphosphate, tripolyphosphate, or tetrasodium pyrophosphate.

2. Only clays that are easily dispersed in distilled 

water without the use of deflocculents should be used 

for sediment lining of canals if control "of dispersion is a 

requirement.

3. Hexametaphosphate, tripolyphosphate, and tetrasodium pyrophosphate can control the degree to which 

clay particles are dispersed in waters varying in hardness (calcium and magnesium content) if the total salt 

content is not excessive.

4. The mechanism whereby the phosphate deflocculents disperse clay suspensions is probably a function of 

either divalent ion sequestration or increasing the negative charge of clay particles by adsorption of polyanions, or both.

5. Montmorillonite clays are apparently the best 

source of colloidal particles for sediment lining of canals 

if control of dispersion and penetration of small voids 

are required.

6. Tripolyphosphate was the most efficient dispersing agent for control of montmorillonite dispersion in 

waters oi low to medium hardness.

7. Sodium hexametaphosphate was generally superior for dispersion of kaolinite The kaolinite tested 

was, however, easily dispersed by all the phosphate 

dispersants tested.

8. Illite was difficult to disperse and keep in suspension. When sodium saturated, however, it formed

a sticky paste, which may make it useful for filing cracks 

and large voids.

9. If the electrolyte (salt) content of the canal water 

is too high it may prevent the dispersion of clays even 

with the use of phosphate dispersants.

10. The point of complete sequestration of calcium 

and magnesium by phosphate dispersants WPS measured 

by using dye indicators normally used for calcium and 

magnesium determinations. However, the quantities 

of sequestering agent required for practical dispersion 

of clay in canal waters seldom coincided with total 

sequestration. The only practical method found for 

determining the quantity of sequestering agent required 

is to add different quantities to samples of fresh water 

and measure dispersion with a hydrometer. Fresh 

water is specified because the chemical composition of 

a stream varies with time, or calcium may precipitate 

out as calcium carbonate as the water becomes stagnant 

and cause an underestimation of the quantity of sequestering agent needed. The effects of org-anic matter 

dissolved in the water would also express itself and 

could be compensated for.

PROPERTIES OF CLAY MINERALS

By B. N. ROLFE

This section of the report discusses the clay minerals 

used in the investigation. It is not intended as a primer 

on clay mineralogy but as background material for a 

better understanding of the experimental data. The 

reader is referred to Grim (1953) for a more detailed 

treatment of the subject. A discussion of the behavior 

of clay minerals in suspensions is presented in the section 

"Theory of Clay Mineral Behavior in Dilnte Suspensions" by R. F. Miller.

As the present study was designed to investigate 

basic dispersion characteristics of colloidal clays, it 

seemed expedient to simplify the problem by restricting 

the study to monomineralic clays. Therefore, three 

representative clay minerals were selected for the investigation of the dispersion characteristics of possible 

sedimenting materials.

Clay minerals are usually classified on the basis of 

structure and composition. Structurally, two units 

are included in the atomic lattices of most cKy minerals. 

One unit is comprised of two sheets of closely packed 

oxygen or hydroxyl ions between which aluminum and, 

less frequently, magnesium or iron atoms are embedded 

in octahedral coordination, that is, each metallic atom 

is equidistant from six oxygen or hydroxyl ions. This 

arrangement of sheets will hereinafter be referred to as 

the octahedral unit.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 249

The second unit is built of silica tetrahedrons in 

which a silicon atom is equidistant from four oxygen or 

hydroxyl ions. The silicon atoms apparently lie in a 

a plane and form a hexagonal network. This sheet 

arrangement will be hereinafter referred to as the tetrahedral unit.

These two units form the building blocks for the 

formation of clay minerals. Classification is based on 

the arrangement of these units and on deviations from 

modal atomic composition. The three main types of 

clay minerals will be discussed, in relation to the clay 

materials used during the investigation.

KAOLINITE

Kaolinite is the most prominent member of the kaolin 

group of clays among which are kaolinite, dickite, 

nacrite and halloysite. Clays in this group are called 

1:1 layer minerals because unit cells are composed of 

one tetrahedral unit joined to one octahedral unit. 

There is little or no atomic substitution in the units, 

and kaolinite may be regarded as consisting of model 

sheet units of silica tetrahedra and alumina octahedra. 

Because of the dimensional similarity between structural units along the a, and b crystallographic axes, 

unit cells of octahedra and tetrahedra are readily formed 

and are fairly stable.

Substitution of one ion for another, called isomorphous substitution in clay mineralogy, is rare in the 

kaolinite minerals and the kaolinite clays are generally 

electrostatically neutral. Charge deficiencies at the 

broken edges of the a and b planes are both negative 

and positive. Anionic deficiencies along these broken 

edges are the probable sources of anion attraction and 

probably are the point of phosphate ion adsorption as 

is explained later. Slight irregularities in the cation 

composition of kaolinite, as well as cationic deficiencies 

at broken edges, may be sources of positive charge 

deficiencies. The cation exchange capacity of kaolinite 

minerals generally ranges from 3 to 15 milliequivalents 

per 100 grams of kaolinite material.

Kaolinite minerals generally occur in the upper size 

diameters of clays. They may be found as discrete 

particles with diameters as large as 20 microns but the 

median diameter is generally about 1 micron. The 

specific dispersion characteristics of kaolinite are discussed on page 254 but deflocculation is probably effected by increasing clay negativity via anion sorption 

of complex polyphosphates along the broken edges.

MONTMORILLONITE

Montmorillonite is the dominant member of the 

montmorillonite group of clay minerals, among which 

are montmorillonite, beidellite, hectorite, saponite

530716 O 60 4

and nontronite. The clay used in the present study 

is commonly called bentonite and occurs abundantly in 

some parts of Western United States. The highswelling bentonite, produced extensively in Wyoming, 

is usually composed mostly of sodium montmorillonite 

together with traces of cristobalite and volcanic ash, 

and it has the ability to absorb large quantities of 

water.

The montmorillonite group of clay minerals is 

classified as 2:1 layer minerals the unit cells are 

composed of two tetrahedral units enclosing a single 

octahedral unit. Isoinorphous substitution is common 

to both units. This substitution phenomenon results 

in an imbalance of charge within the montmorillonite 

lattice and is characteristic of the mineral. Substitution in either unit may be partly compensated by 

substitution in the other unit. However, subst: tutions 

in the montmorillonite lattice yield a net regative 

charge on the lattice. This negative charge is balanced 

by exchangeable cations, such as Ca++ or Na+, adsorbed 

between the layers and around their edges.

Discrete montmorillonite particles grow by continuous extension along the a and 6 axes and by 

stacking in the c direction. Bonding between unit 

cells is weak by comparison with kaolinite and is the 

reason for the small size of discrete montmorillonite 

particles, generally under 0.5 micron in diameter. 

Only cation exchange is assumed to take place on the 

planar surfaces of the montmorillonite particles whereas 

both cation and anion exchange occur at the edges. 

The probable ratio of planar to edge surfaces may be 

indicated by cation-anion exchange capacity ratios 

of 6.7 to 1.0. A similar comparison for kaolinite shows 

a ratio of 0.5 to 1.0 (cation exchange capacity divided 

by anion exchange capacity) (Kelley, 1948). While 

the edge surface in kaolinite is more important than 

planar surfaces as a source of charge, the reverse is 

true in montorillonite. However, the greater total 

surface exposed by the smaller montmorillonite particles 

balances their comparative anion exchange capacities 

on a gravimetric basis. That is, 1 gram of montmorillonite, which has about an acre of total surface 

area, may have the same anion exchange capac; ty as a 

gram of kaolinite, in spite of the dominance of edge 

surfaces in the kaolinite.

The montmorillonite minerals are highly responsive 

to chemical environments, probably because of their 

colloidal size and structural peculiarities. A stable 

dispersion of this type mineral produces a high colloidal 

yield. It is likely that provision of a proper sodium 

environment is sufficient to enhance the inherent 

negativity of the montmorillonite particles to a point 

of adequate dispersion.
250 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

ILLITE

Elite includes a broad group of micalike clay minerals 

which to date have not been subdivided. Illites, like 

micas and montmorillonites are 2:1 layer minerals; 

that is, two silica tetrahedra units enclose one octahedral 

unit. Illites, however, differ from the mica minerals 

in several ways: in illites one-sixth of the Si++++ ions 

are replaced by Al+++ ions whereas in true micas 

one-fourth of the Si++++ ions are so replaced; the 

unbalanced cation deficiency is less, being 1.3 per unit 

cell as contrasted to 2.0 in micas; less potassium is 

adsorbed in interface position in illites but some 

Ca++ and Mg++ ions are adsorbed. Particles of illite 

generally are small, less than 1 to 2 microns. This 

may be attributed to weaker bonding brought about by 

less fixed K+ in interface positions.

Illites generally as the fine-grained component of 

marine shales and are not as free from mineral contamination as the other two clay groups. Whereas the 

kaolinite and montmorillonite minerals used in the 

present study may be considered monomineralic, 

the illitic mineral is polymineralic, because of its 

intimate mixture with shale fragments.

The previously mentioned cation deficiency gives 

illite a weak negative charge, as indicated by its cation 

exchange capacity of but 10-40 milliequivalents per 

100 grams. Anion exchange occurs at edge surfaces, 

and the ratio of cation to anion exchange capacities 

is approximately 2.3 to 1.0 (Kelley, 1948). One may 

postulate that dispersion characteristics of illite are 

somewhere between those of kaolinite and montmorillonite. If so, it should be possible to effect moderate 

deflocculation of illite particles by anion adsorption at 

clay edges and by increasing inherent negativity 

through replacement of adsorbed Ca++ arid Mg++ ions 

by Na+ ions.

DISCUSSION OP THE HYDROMETER METHOD

By I. S. McQtTEEN

The hydrometer has been used extensively as a means 

of determining the particle-size distribution of soils 

and sediments. Like most methods of wet mechanical 

analysis, the hydrometer method is based on Stokes' 

law, defined in 1845 by Sir George Stokes, a British 

mathematician and physicist. Stokes' law states that 

the terminal fall velocity of a solid spherical particle 

in quiet water is defined by the following relation:

r radius of particle in centimeters

p density of particle in grams per cubic centimeter

Po=density of fluid in grams per cubic centimeter

n=viscosity of fluid in poises (dyne-second per 

square centimeter)

If a point is chosen at a given depth, H (centimeters), 

and time, t (minutes), after mixing in a column of 

uniform spherical particles dispersed in water (for 

which />0=1)J the above expression can be solved for 

the diameter of the coarsest particle remaining in 

suspension at the given depth and time. Substituting

F=^rr and 1"=^ for time in minutes and diameter of 

particle in millimeters, gives:

Where

V velocity of fall in centimeters per second 

g=acceleration due to gravity (981 centimeters 

per second squared)

g(P-l)t

There are several requirements in any method that 

uses Stokes' law to determine the diameter of particles:

1. The depth of fall, H, must be defined and measurable.

2. The density and viscosity of the fluid must be constant and 

known.

3. The specific gravity of the particles must be known.

4. The particles should be spherical.

5. The concentration of particles in suspension should be low 

enough to minimize the interference betweer particles yet 

high enough to produce measurable differences in the specific 

gravity of the suspension.

6. The particles must be completely dispersed as discrete particles and must remain so throughout the te^t.

In standard hydrometer analysis methods, these 

conditions are all assumed to have been met. Krynine 

(1941, p. 477) describes the theory of grain-size 

measurement with a hydrometer as follows:

Since at the start of the hydrometer test the suspension is 

thoroughly mixed there are, at each horizontal section of the 

graduate, particles of all sizes present in the given sample in 

their natural concentration. As sedimentation proceeds, all 

grains of a given diameter settle with equal velocity; hence their 

concentration at all horizontal sections of the graduate is the 

same. Owing to the limited supply of particler from above, 

coarser particles gradually fall out. Thus at a gfven time moment there are at a given horizontal section of the graduate, 

particles finer than a given diameter only, though in their 

natural concentration.

A hydrometer consists of a hollow glass chamber or 

bulb, weighted at the bottom and having a graduated 

stem at the top. It has a constant masg ; and when 

placed in a liquid it sinks until it displaces ite own weight 

of liquid.

In conventional hydrometer analyses the depth of fall 

of a particle is assumed to be the distance from the water 

surface to the center of the hydrometer bulb. The hydrometer, however, does not measure the specific grav-
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 251

ity of the fluid or suspension at a point (Puri, 1949, p. 

245). It averages the specific gravity in a zone, the 

nature of which depends upon the shape and depth of 

submergence of the hydrometer. This characteristic of 

the hydrometer may bring errors into an analysis.

ADVANTAGES OF THE HYDROMETER METHOD

Two important advantages of the hydrometer method 

over other types of wet mechanical analysis are its convenience and the rapidity with which observations can 

be made. Results are available as soon as the settling 

time for the smallest size fraction to be determined has 

passed. There is no problem of evaporating large numbers of samples to dryness. Each point on the size distribution curve, or each size fraction to be determined, 

merely requires that a reading be made of the hydrometer at a specified time.

There is also a saving in space and equipment, because 

the hydrometer method does not require the pipette 

rack, drying oven, balance, and evaporating dishes that 

are used in the pipette method.

Another advantage of the hydrometer method is that 

the sample remains intact. There is no removal of parts 

of the sample as the test proceeds. This makes it possible to use the same sample for successive increments of 

deflocculents, resulting in a saving in time and material 

and eliminating some inaccuracies resulting from differences in samples. It is not necessary to prepare and 

disperse a separate sample for each increment of deflocculent. In the present work it was desirable and important that the sample remain intact so that successive 

amounts of deflocculent could be added to the same 

sample. If it had been necessary to use separate 

samples, small differences among samples possibly could 

have masked the effects of the deflocculent.

DISADVANTAGES OF THE HYDROMETER METHOD

The theory of hydrometer analyses assumes that the 

density of the suspension is being measured at a point. 

Actually, the hydrometer averages the specific 

gravity in a zone. If the specific gravity varied 

uniformly through the measured zone, the value 

at the center of the zone and the average value would 

coincide. This is generally true with materials that 

have a wide distribution of grain sizes in suspension. In 

suspensions with a narrow range of grain size the average density through the measured zone may not be the 

same as the density at the center of the hydrometer.

The exact nature of the zone measured by a given 

hydrometer can be determined by a simple experiment. 

Prom a balance, suspend a hydrometer in a hydrometer 

jar or cylinder. Gradually fill the hydrometer jar with 

water and record the weight of the hydrometer and the

depth of submergence at small intervals. Curve a of 

figure 48-4 is a plot of the data that may be obtained 

from such an experiment. The relative buoyancy of 

the hydrometer at each horizontal section will b? a function of the rate of change of hydrometer weight with 

depth of submergence and hence will be a furction of 

the slope of curve a. Curve b of figure 48-4 is derived 

from curve a 1 and represents the relative buoyancy of 

the fluid on the hydrometer at each horizontal section.

4(h

35-

1.000 10062 

A SPECIFIC GRAVITY

B

FIGURE 48. Nature of zone measured by a hydrometer. A, diagraramatic representation of zone 1 measured by hydrometer: B, hypothetical curves illustrating 

different types of suspensions.

Figure 48J5 represents the theoretical distribution 

of specific gravities of different types of suspensions in 

a hydrometer jar. Curve a shows a suspensior immediately after mixing. Curve b represents a material 

with a wide range of grain sizes after a period of settling. 

On this curve, if the specific gravities are averaged over 

the zone measured by the hydrometer, a value is 

obtained that is very near the value at the depth of 

the center of the hydrometer bulb. Curve c represents 

a material with a verry narrow range of grein sizes. 

If the particles are discrete they all have about the 

same settling velocity and clear solution is left above 

them. If the hydrometer measured the specific gravity 

at a fixed point, the readings would change fr^m maximum to a minimum almost immediately as the last 

particles pass the measuring point. However, as the 

hydrometer measures a zone and also sinks deeper as 

the particles settle, it takes an appreciable time interval

i Curve 6 of figure 4&4 represents the cosine of the angle between cirve a and the 

a>axis plotted against the depth. Curve 6 also corresponds to the sha*>e of the hydrometer used and defines the zone measured by it.
252 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

for the readings to change and the grain size distribution curve may be distorted. The materials used in 

this investigation tend toward narrow ranges of grain 

sizes, and hence may have distorted grain size distribution curves. Montmorillonite clays seem to be 

special in that, under certain conditions, they do not 

settle as discrete particles but form loose floe structures 

that undergo consolidation. This condition is represented by curve d and the anomalous results obtained 

from it are discussed more fully in the section on tables 

of data and dispersion indices.

The behavior of the hydrometer in suspensions with 

a narrow range of grain sizes is the principal disadvantage in the method. This disadvantage was minimized in the current investigations, because it was not 

pertinent to determine the grain size of discrete particles. 

The purpose of the investigation was to measure 

differences in dispersion characteristics and the 

hydrometer method proved to be well suited for this 

purpose.

THEORY OP CLAY MINERAL BEHAVIOR 

IN DILUTE SUSPENSIONS

By R. F. MILLER

The primary objectives of a canal sedimenting 

program are to transport the clay material by canal 

waters to the areas where seepage losses occur and to 

allow the clay material to penetrate and seal the 

openings through which seepage takes place.

The efficiency of clay transport and penetration is 

a function of the effective size of the clay materials. 

The effective size of clay particles suspended in water 

may vary with the type of clay and the chemical 

environment in the water system.

One of the objectives of this investigation was to 

study the dispersion characteristics of three basic types 

of clay minerals in waters of different chemical composition. These characteristics are a function of physicochemical reactions in the clay-water system. A brief 

review of the interactions operative in a clay-water 

system follows. It is presented here as a guide to 

evaluating the observations on clay-water systems 

noted during the study.

The dispersion of clays in water involves the separation of the clays into their finest discrete particles and 

maintaining them in suspension. Clays that are dispersed can be transported more easily by water and 

can penetrate small voids more readily. A dispersed 

clay-water system is related to the physical law that 

like charges repel and unlike charges attract.

There are many theories on the mechanism of dispersion. The discussion that follows is a composite of

these theories that explains the observations made 

during this investigation.

The various clay minerals are negatively charged to 

some degree. The mechanism of the dispersion of clay 

particles in water is a function of this negative charge.

The literature on clay minerals generally attributes 

the negative charge on the surface of clay particles to 

isomorphous substitution, dissociation of lattice hydroxyl (OH~) ions, and anion adsorption.

Isomorphous substitution is the substitution of ions 

of similar size for each other during the formation of 

the crystal lattice of a clay mineral. An example of 

isomorphous substitution is the substitution of divalent 

magnesium (Mg++) ions for trivalent aluminum (Al"*"*"1"). 

This type of substitution results in an imbalance of 

positive and negative charges within the structure of a 

clay particle yielding a cation deficiency and a negative 

charge expressed at the surface. The intercity of this 

negative charge is proportional to the amount of cation 

deficiency resulting from isomorphous substitution. 

This influences the number of cations that are adsorbed 

to each clay particle to balance the negative charge. 

Isomorphous substitution is discussed in more detail by 

Marshall (1949), Grim (1953), and Kelly (1948).

Dissociation of lattice OH~ ions as a source of negative charge for clay particles is summarized by Russell 

(1950, p. 117) as "Negative charges developed by hydrogen ions dissociating from bydroxyls attached to 

silicon atoms at the broken edges of oxygen sheets, 

which compose the clay mineral." This reaction can 

be written, Si-OH+H2O^Si-O-+H3O+. It only 

occurs appreciably under neutral or alkaline conditions, 

and the more alkaline the conditions the greater is the 

negative charge developed.

Anion adsorption is the electrostatic attraction of 

negatively charged anions to positively char-red cations 

exposed at the broken edges of clay particles. This 

reaction adds to the total negative charge expressed at 

the surface of clay particles, if the adsorbed anion is 

more highly charged than the attracting cation. This 

source of charge is discussed in more detail by Ruehrwein (1953) and Olphen (1950).

FACTORS THAT CONTROL THE DEGREE OF DISPERSION

If negatively charged clay particles and distilled 

water were the only components of a clay-wrter system, 

the system would be easy to understand. The negatively charged particles would repel each other and disperse throughout the system, since like charges repel. 

Also, since water molecules tend to be pos: tive at one 

end and negative at the other, they could be expected 

to orient themselves about the charged clay particles
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 253

in concentric shells. The water shells could act as 

barriers between particles and the net result would 

probably be a dispersed system. However, a claywater system is not this simple, for water contains 

salts in solution which ionize into positively charged 

cations such as calcium (Ca++), magnesium (Mg++), 

and sodium (Na+), and negatively charged anions such 

as chloride (Cl~), sulfate (SO4 ), and phosphate 

(PO4 -). These charged ions react with the clay, 

the water, and each other and complicate clay dispersion.

The maintenance of a dispersed system or a degree of 

dispersion in a complex clay, water, ionized salt system 

may be described as control of repelling and attracting 

forces. These forces are affected by:

1. The negative charge of the clay particle.

2. The valence or negative charge carried by the anions 

in the solution.

3. The valence or positive charge carried by the cations 

in the solution. , 4. The concentration of the cations in solution.

5. Hydration of ions in solution.

6. The mobility of the cations in solution.

7. Osmotic pressure differences in the clay-water 

system.

Any one or all of these factors could influence dispersion 

when a clay is placed in a canal water in a sedimentlining operation. A discussion of each of the above 

factors follows:

Negative charge on the surface of clay particles. The« 

negative charge on the surface of clay particles provides 

a repellent force between clay particles but also attracts 

and holds the exchangeable cations. The quantity of 

exchangeable cations associated with a clay particle is 

directly proportional to the negative charge of the particle. The clays in order of magnitude of the negative 

charge expressed at their surfaces are: (a) montmorillonite, (b) illite, (c) kaolinite. To illustrate the magnitude of the attractive force that may be expressed on a 

single clay surface, Kelley (1948) estimates that a montmorillonite-type clay (bentonite) with plate dimensions 

of 1 ju X 0.4 n could have about 600,000 exchangeable 

monovalent ions per lattice layer. This type of clay 

would have an exchange capacity of approximately 1 

milliequivalent per gram of clay and 1 milliequivalent 

of a monovalent ion such as sodium, contains 6.023 X 

1020 ions.

Valence of the negative ions (anions). The negative 

valency of the anions in solution in a complex clay, 

water, ionized salt system may affect the control of 

dispersion in the system. Polyvalent anions may 

replace anions with less charge from anion exchange

positions at the broken edges of clay particles, thus 

increasing the negative charge.

Multivalent anions may add a negative charg? to a 

clay particle but no charge is added by monovalent 

anions. Only part of the negative charge associated 

with a multivalent anion is used by attraction to the 

exposed cation. The increase in dispersion potential 

of a clay-water system through the absorption of negatively charged ions on the clay particle is roughly proportional to the unused valency of the anions. For 

example, much more negative charge would be added 

to a clay surface by the adsorption of a long chain 

polyanion of high negative valence than by the adsorption of a simple anion, such as orthophosphate (PO4 ).

Valence oj the positive ions (cations). The positive 

valency of the cations is also an important factor in the 

control of dispersion in a clay, water, ionized salt system.

The cations attracted to a negatively charged clay 

particle form a positively charged shell or cloud around 

each clay particle. The attracted cations tend to form 

two layers about each particle, a closely held inner layer 

and a more loosely held or diffuse outer layer. The 

diffuseness or depth of the outer layer or cloud of cations 

is related to the charge or valency of its component 

cations. Multivalent cations are more strongTy attracted to the clay than are monovalent cations; therefore, an outer shell of monovalent cations is more diffuse 

than one of multivalent cations. This results in j\ shell 

or barrier of positively charged monovalent ions at 

greater distance from the clay particle than when 

multivalent cations comprise the shells.

The shells of positively charged ions surrounding 

each clay particle in a clay-water system tend to repel 

one another. Therefore, the diffuseness of the outer 

ring of associated cations is an important factor in the 

control of clay dispersion in a clay, water, ionized salt 

system. Generally, the greater the diffuseness of the 

clouds of cations about each clay particle in the system, 

the greater the dispersion in the system.

Concentration oj the cations in solution. The concentration of the cations in solution in a clay-water system 

is another of the factors that controls the depth of the 

diffuse shell of cations that surround a clay particle. 

Increasing the concentration of positively charged ions 

crowds more cations into the zone between clay particles 

and, in effect, helps to neutralize the negative charge of 

a clay particle closer to the particle. This in turn 

decreases the diameter, or depth of the shells of positive 

ions surrounding the clay particles. Thus, dispersion 

in a clay, water, ionized salt system may be reduced by 

decreasing the diameter of the repelling shells of cations 

about each clay particle, through increased cation 

concentration.
254 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Conversely, Bolt,2 found that dispersion of the system may be obtained even if Ca++ or Mg++ are the 

dominant ions, but that the concentration of these ions 

in the system must be much more dilute to achieve 

dispersion than is necessary when Na+ is the predominant ion in solution.

Hydration of cations in solution. The hydration 

of cations in solution is the result of electrostatic 

attraction of concentric shells of dipole water molecules 

about each cation. These shells of dipole water 

molecules vary in depth with the size, valency, and 

mobility of the cations. If cations become hydrated 

the shells of water may affect the efficiency of their 

positive charge, for the intensity of an electrostatic 

charge varies inversely with the square of the distance 

from the source of the charge. For example, if two 

cations of equal charge were hydrated to different 

degrees, the cation with the smaller shell of attracted 

water would be the more efficient in neutralizing the 

negative charge of a clay particle in a clay-water 

system. Thus, hydration along with valency and 

concentration may affect the diffuse cloud of cations 

about each clay particle and affect control of 

dispersion.

Mobility of the cations in solution. The mobility 

of the cations in solution in a clay-water system may 

also affect the diffuseness of the repelling shell or cloud 

of cations about each clay particle. The mobility of a 

cation in solution may be considered as the speed with 

which the cation moves or oscillates about in solution. 

A highly mobile cation such as sodium may not be as 

easily attracted to a negatively charged clay particle 

as a less mobile cation such as calcium or magnesium. 

Therefore, mobility could effect the efficiency with 

which a cation neutralized the negative charge of the 

clay particle. This may result in diffuse shells of 

cations about each of the clay >articles and thus 

influence the control of dispersion in a clay-water 

system.

Osmotic pressure. Osmotic pressure may aid in 

attaining dispersion in a clay-water system. The 

concentration of ions in the diffuse cloud of ions 

around each clay particle is greater than the concentration of ions in the part of the solution not 

affected by electrostatic forces from the clay particles. 

There is a tendency for ions in solution to come to 

equilibrium and eliminate differences in concentration. 

While the two systems are attempting to reach equilibrium, convection currents may be set up which could 

aid the other forces in the system in attaining dispersion. 

This aid to dispersion would no longer exist after 

equilibrium had been attained.

'Bolt, Q. H., 1954, Physico-chemical properties of the electric double layer on 

planar surfaces: Ph. D. thesis, Cornell Univ., Ithaca, N.Y., 106 p.

Forces other than those mentioned 1 <>re may be 

effective in controlling dispersion in a clay, water, 

ionized salt system, but those discussed are perhaps 

the most dominant interacting in the sys terns studied 

in these experiments.

DISPERSION AND CLAY MINES ALS

Montmorillonite, "illite", and kaolirite are the 

three dominant clay-mineral types that iray be available for sediment-lining operations. Fach of the 

above clays has associated with it seme negative 

charge. The negative charge of clay particles affects 

the degree to which they may be dispersed in a claywater system. As previously stated, three sources of 

negative charge on clay surfaces are isomorphous 

substitution (cationic deficiency), dissociation of lattice 

hydroxy (OH~) ions, and anion adsorption. These 

sources of negative charge may be common to all types 

of clay but are effective to different degrees.

Montmorittonite4ype clays. Montmorillonite -type 

clays are more highly charged and finer textured than 

the other two clays. Isomorphous substHution is the 

predominant source of the negative charge on 

montmorillonite-type clays. Grim (1953, p. 132) 

attributes about 20 percent of the exchange capacity 

to broken bonds. This includes possible negative 

charge from dissociation of lattice OH~ ions, or adsorption of high valence anions. Because of the more 

intense negative charge and finer texture associated 

with montmorillonite-type clays, a higl ?,r degree of 

dispersion is possible with them than with other types 

of clay.

Kaolinite-type clays. The predominant source of 

negative charge on kaolinite-type clay minerals is unsatisfied chemical bonds at the broken edges, or from 

dissociation of H+ from exposed OH+ groups or the 

octahedral (alumina) sheet. The negative charge may 

also be increased through the adsorption o* high valence 

negative ions to positive ions exposed at the broken 

edges. Since the anion exchange capacity of kaolinite 

particles is equivalent to the cation exchange capacity, 

it is logical that the dispersibility of kaolinite could 

readily be influenced by the valence cf the anions 

injected into the clay-water system.

Illite-type clays. The dispersion characteristics of 

illite-type clays should be intermediate between those 

of montmorillonite- and kaolinite-type clays. The negative charge on the surface of illite-type clays is the 

result of both isomorphous substitution r.nd anion adsorption at the broken edges. Illite clays are generally 

components of shales and are less likely to be monomineralic than are montmorillonite and kaolinite deposits, therefore, the characteristics of this type of 

material are more difficult to evaluate or predict.
DISPERSION CHARACTERISTICS, MONTMORILLONTTE, KAOUNITE, ILLITE CLAYS 255

MECHANISM OF DISPERSION CONTROL

Since a dispersed clay-water system may be more 

readily obtained with Na+ as the dominant cation in 

the system, most dispersion controls involve deactivation or removal of Ca++ and Mg++ from the clay-water 

system and replacement with Na+ ions.

Calcium and magnesium ions may be removed from 

a clay-water system by causing them to form insoluble 

precipitates and to settle out of the system. This may 

be accomplished by adding Na2CO3 to the system. For 

example, if calcium were in the system as CaSO4 and 

NaaCOs were added to the system, the salts would react 

according to the following equation:

H2O+CaSO4+Na2CO3 -»CaCO3 | +Na2SO4+H2O

4-

(insoluble precipitate)

Since calcium is precipitated, no equilibrium could be 

maintained and most of the calcium could be removed 

from solution. The settling of the precipitate thus 

formed to the canal bottom could hinder the penetration and sealing action of clay. To avoid this it is possible to cause the Ca++ and Mg++ ions to lose their 

entity as active cations by causing them to become 

part of a complex phosphate anion. This process is 

known as sequestration.

Through the mechanism of sequestration, Ca++ and 

Mg++ ions that can quite effectively neutralize the 

negative charge on clay particles and cause flocculation 3 in a clay, water, ionized salt system lose their 

identity as cations and subsequently lose their positive 

charge by becoming part of a complex anion.

Concurrent with the removal of calcium and magnesium from the solution as active ions, amounts of 

sodium from the sodium polyphosphates may be released into the clay, water, ionized salt system.

The amount of calcium that may be sequestered by 

a dehydrated sodium phosphate is related to the dissociation of Na+, and its replacement by Ca++ or Mg++.

The dehydrated sodium phosphates do not dissociate 

completely when dissolved in water as do salts such as 

sodium chloride. Sodium chloride dissociates as follows :

All of the Na+ ions in sodium chloride immediately 

ionize and are available for reactions. According to 

Daugherty (1948) sodium hexametaphosphate ionizes 

or dissociates in two steps as follows:

Na++[NaB_2 (P03)

* Bolt (1954) presented evidence that the binding force among particles within a 

floe may be the attraction of positive ions exposed at broken edges to the negative 

surfaces, but that these attractive forces are too small to be effective until most of the 

negative charge on the clay surface has been equalized by the introduction of sufficient quantities of cations into the system.

and possibly a secondary ionization as follows:

[NaB_2 (P03) B]-^2 Na++[NaB_4 (PO3) B]-

This dissociated sodium is available to react with the 

clay, water, ionized salt system. If Ca++ or Mg++ are 

present they replace the dissociated Na+ and tl ** equilibrium reverses to form Ca NaB_2 (PO3) B or 2 Ca 

NaB_4 (PO3 )n. Which complex salt is formed is a function of the concentration of Ca++ and Mg++ in the 

system. The other dehydrated sodium phosphates 

tested, dissociate and sequester in a similar iranner. 

The net result is a more dispersed system through the 

mechanisms previously described. This may not always 

hold true, for if the initial salt concentration in the 

system is such that even the less effective Na+ ions 

neutralize the negative charge close to the cHy surfaces, the clay-water system will remain flocculated; as 

occurred in the soft water used in the first year's study. 

Aside from the sequestration of Ca++ and Mg++ as 

a part of complex anions, these anions affect tl °> total 

negative charge on the clay particles in a clay, water, 

ionized salt system. As previously discussed, anions 

may be attracted to incompletely neutralized positive 

ions exposed at the broken edges of clay particles. If 

the absorbed negative ion is a long chain polyanion, it 

could be attracted to the clay particle by a fraction of 

its negative valency. The net result could be tl °> addition of a strong negative charge to the clay particle, thus 

increasing the dispersion potential of the system. This 

would increase the negative charge proportionately 

more for kaolinite than for montmorillonite.

TABLES OP DATA AND DISPERSION INDICTES

All of the base data obtained during this investigation are contained in tables 2 to 19. Each table includes the data for a specific combination of colloid and 

deflocculent. Soft water refers to a synthetic water 

having a content of calcium, magnesium, and soiium of 

3, 2, and 15.5 milliequivalents per liter, respectively. 

Hard water refers to a synthetic water having a content 

of calcium, magnesium, and sodium of 17, 8, and 17 

milliequivalents per liter, respectively.

Ion saturation, This column designates the ion saturation on the colloid prior to its introduction into the 

system.

Grams deflocculent. The total amount of d°-flocculating chemicals in the system is listed for each hydrometer test run.

Percent in suspension. In these columns ar°. listed 

the amounts of colloid remaining in suspensior at the 

given times following mixing as indicated by the hydrom-
256 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

eter reading corrected for the hydrometer reading in 

the check cylinder. These amounts are listed as percentages of the colloid originally introduced into the 

system. With montmorillonite, these percentages occasionally exceed 100 because of the anomalous behavior of this clay in dilute suspensions. The loose floe 

structure formed by some suspensions of montmorillonite seems to consolidate instead of settle as discrete 

particles. If the zone measured by the hydrometer is 

within the consolidated portion of a cylinder of this 

suspension it will measure a higher concentration of clay 

than the original freshly mixed sample contained. 

Percentage values in parentheses were obtained by extrapolation. Approximate grain size being measured at 

each time in a normal hydrometer grain size analysis is:

Time in minutes ________

Approximate grain size in

1

37

4

19

19

9

60

£

435

2

1,54;

]

These grain sizes have no literal significance in the current investigations and should be used onl;T as a guide 

in plotting the hydrometer data for comparison 

purposes.

The column headed "sum" is the sum of the percentages in suspension as listed in the preceding six 

columns. This sum was used in computin,: the dispersion indices.

Dispersion index. This column lists 8 percentage 

comparison between the given sample run and a standard. This is described and discussed in a previous 

section of this report.

TABLE 2. Hydrometer data: Montmorillonite and sodium tripolyphosphate

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sam Dispersion 

index

Distilled water

Sodium __ _____ _ ___

Do______. ________

Do_______________

Calcium- __ ______ __

Do_____._________

Do____.__________

Do___---________.

Do__ __________

Do__--_.________

Do__. ____________

0 0

 025

1

0

05

1

3

5

1 0

1 5

91

98

101

74

84

82

Of)

90

87

87

on

99

54

67

70

72

83

86

86

86

96

99

28

38

10

46

69

86

8Q

92

99

99

11

4

7

34

6Q

86

88

90

98

100

(4) o\

/o\

24

52

82

87

90

97

96

o\

(0)

(1)

(14)

41

73

82

5f9

5f4

5f4

173

105

173 27*)

404

409

519

100.

109.

111.

32.

36.

32.,

50.

75.

93.

97.

Soft water

Sodium _ __ _ _ __ __

Do__-___________

Do_______________

Calcium- _____________

Do _

Do_______________

Do_______________

Do_______________

Do__-_.__________

Do__-.-_________

0.0

.025

. 1

.0

.025

. 1

.5

1.0

1 e

2.0

102

QQ

74

81

82

83

Q6

97

91

102

98

54

65

66

71

92

07

Q1

106

1O9

101

34

44

47

68

91

Q7

Ql

100

102

102

8

15

7

54

88

OK

91

103

103

07

0

(5)

fO\ (*)

34

80

92

OQ

(100)

108

((ff\

(0) / ON

(1)

(14)

70

79 !86

613

612 5r<»

170

213

206

324

517

557

539

115.

115.1

110.'

32.1

40.1

38.

60. <

97.

104.

101.,

Hard water

Sodium_______ __ ____

Do_______________

Do_______________

Do_._____________

Do_-__-_________

Do____-____._____

Do___-.__________

Do_______________

Calcium. _ _ ______ _

Do_______________

Do__-___________

Do _ _

Do___.___________

Do_______________

Do_______________

Do_____-___._____

Do_______________

0.0

.05

. 1

.5

1.0

2.0

3.0

4.0

.0

.025

.05

. 1

.3

.5

1.0

2.0

3.0

82

88

84

OK

82

85

96

94

80

84

84

86

86

85

80

82

94

81

88

86

85

CO

OK

96

94

72

72

71

75

70

73

75

78

94

80

88

86

85

7Q

76

96

CM

1

1

1

2

1

13

64

70

04

86

89

84

86

82

76

96

94

0

(0)

(0)

(1)

(0)

(7)

24

74

94

85

(80)

(74)

(60)

(80)

83

85

89

(0)

(0)

(0)

(0)

(0)

(0)

12

55

92

4

C\Q\

(6)

?oS

fKN

(47)

(H)

52

(0)

(0)

(0)

(0)

(0)

(0)

(0)

37

78

418

451

420

403

410

452

480

517

153

157

156

164

157

178

2>5

405

516

78.6

84.8

78.9

75.8

77.1

85.0

90.2

97.2

28.8

29.5

29.3

30.8

29.5

33.5

47.9

76. 1

102.6

* At 4,320 minutes=71 percent; at 5,760 minutes=64 percent.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITB, ILUTE CLAYS 

TABLE 3. Hydrometer data: Montmorillonite and sodium hexametaphosphate

257

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

Sodium _ _____ _ _ _

Do__-___-.______,

Do_.__-_-________

Calcium______._ _____

Do__-__---__.____

Do_______________

Do___----________

Do______-._______

Do_______-_____._

Do_______________

0. 0

.025

. 1

. 0

.05

. 1

.3

.5

1.0

1.5

89

98

99

72

75

78

82

83

83

92

87

Qfi

Qfi

51

fiQ

RK

70

7C

81

83

8Q

QQ

07

26

49

48

60

68

81

QO

QQ

97

97

10

9fi

36

Cfl

62

78

QO

QO

07

99

(5) {ii\

C94.1

36*;9

77

84

86

95

96

(0)

(0)

(191

('94.1

43

62

77

530

582

584

164

225

262

322

383

462

516

99.

109.'

109. i

30. J

42 :

49

60.,

72. (

86. J

97. (

Soft water

Sodium___ ______ ___ _

Do_______________

Do_______________

Calcium____________ _

Do_______________

Do______-._______

Do__-__._________

Do.. __________

Do__.____________

Do_. _____________

0.0

. 025

. 1

.0

. 025

. 1

.5

1.0

1.5

2.0

98

no

91

78

81

84

86

Q4

99

89

Q7

no

QO

KQ

fifi

fiQ

76

QO

QQ

QQ

100

Qfi

QO

36

4A

48

67

78

00

on

no

Q7

QO

11

11

6

58

79

86

00

QQ

QK

(80)

2

(5)

(i\

8

58

73

82

(QO\

100

(75)

(1)

(1)

(0)

(4)

KO

61

172

585

574

519

187

209

210

299

445

506

509

110. (

107. <

97. (

35. 5

39. I

39. {

56. 5

83. 6

95. 1 95."

Hard water

Sodium________ ____

Do______________,

Do____._________

Do__-__-_____.___

Do__-___________,

Do-_____.________

Do_. _____________

Do_.-____-_______

Calcium. __ ________ _

Do_. _____________

Do___-__._______.

Do______-___-__._

Do_. _____________

Do___.___________

Do__-____-___.___

Do______________,

Do__-_-__.__.____

Do_______________

Do__.___. ________

0.0

.05

. 1

.5

1.0

2.0

3.0

4 o

.0

.025

.050

. 1

.3

.5

1.0

2.0

3.0

4.0

5.0

85

88

86

86

82

86

96

93

92

92

89

94

89

93

94

98

96

75

59

85

88

86

86

81

86

Qft

93

82

81

/7K\

74

70

70

84

QO

Qft

75

59

85

88

86

86

89

86

Qft

Qft

4

6

6

21

77

Q1

74

CO

85

74

83

8ft

8O

86

96

88

2

/ o\

(t)\

5

ci\

8

58

44

74

58

7Q

(70)

(80)

(80)

C7*i\

fon\

85

86

(1)

( 0\

(0)

(0) / o\

(0)

(4)

12

44

68

67

34

(25)

(30)

(40)

/ocS

(40)

(50)

85

(0)

(0)

(0)

(0)

(0)

(0)

(0)

(6)

18

8

65

453

433

451

464

425

464

519

541

185

189

172

174

173

172

211

341

418

374

366

85. 5

81.4

848

87. $

79. £

87. 5

97. C

101.7

348

35. £

32.4

32. 7

32. B

32. 2

39.7

64 1

78. e

70. 3

68.8

i At 4,320 minutes=61 percent; at 5,760 minutes=58 percent.
258 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

TABLE 4. Hydrometer data: Montmorillonite and sodium hexametaphosphate plus sodium carbonate

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for tne number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

DfBttlled water

Sodium. ______________

Do________----__-

Do________-._____

Calcium. __ __________

Do__.._. ._______.

Do__________--___

Do... ____________

Do_______________

Do.. _...._._..___

Do-_______.-_-___

0.0

.025

. 1

. 0

. 05

. 1

.3

. 5

1. 0

1.5

88

98

98

72

78

81

76

89

86

87

88

Q7

59

62

70

67

81

83

85

89

QQ

Q7

32

42

51

KO

69

81

86

88

98

98

16

26

35

41

59

76

85

88

98

98

(0\

(13)

( isS

28

49

68

82

89

96

96

(0)

(7)

(QS

(20)

37

58

76

530

584

f>R4

187

228

264

284

384

452

501

99.6

109.8

109.8

35. 2

42.9

49. 6

53. 4

72. 2

85.0

94. 2

Soft water

Sodium. ______________

Do.. _____________

Do_______________

Calcium. ____ ________

Do___. ___________

Do.. .._._. _______

Do________-_____-

Do_. _____________

Do___. ___________

Do_______________

0.0

.025

. 1

.0

.025

. 1

. 5

1. 0

1. 5

2. 0

102

98

100

76

79

77

85

86

95

90

102

98

99

57

59

62

70

78

95

88

103

102

104

33

40

38

54

68

91

88

102

104

104

12

7

3

27

61

88

86

104

101

103

0

(4) o\

0

25

76

83

(102)

108

105

(0)

(0)

(0)

(0)

2

60 >76

615

611

615

17?

18ft

183

236

320

505

511

115.6

114.8

115. 6

33.5

35.5

34. 2

44. 4

60. 2

94.9

96. 1

Hard water

Sodium_______ ______

Do_. ____..----_._

Do.-_--______-___

Do.. _____________

Do___--_-_--____-

Do_-___------_-__

Do_. _______-----_

Do_________-_-_-_

Calcium... __________

Do_______________

Do_______________

Do__.____________

Do__-_____-__--_-

Do_-_____________

Do________---____

Do_.______-__--__

Do _ -. -_

Do_-__-_______-_

Do.________-_____

0.0

.05

. 1

. 5

1.0

2.0

3. 0

4. 0

. 0

.025

. 05

. 1

. 3

. 5

1.0

2. 0

3.0

40

5.0

86

83

84

86

90

83

88

93

83

80

84

82

84

82

83

89

100

73

59

86

83

84

86

90

83

88

91

74

72

f70\

75

73

73

77

87

100

73

59

86

81

84

85

90

83

85

85

3

0

0

0

0

0

51

80

90

72

57

91

81

85

85

90

83

88

82

0

(0)

(0)

(0)

(0)

(0)

0

62

76

71

57

4

(7)

(12)

(20)

( Af\\

(60)

85

75

(0)

(0)

(0)

(0)

(0)

(0)

(0)

0

56

71

68

(2)

(2)

(6)

(4)

(8)

(12)

34

0

(0)

(0)

(0)

(0)

(0)

( °}

(0)

(0)

0

69

68

355

337

355

366

40f

404

468

42(3

160

152

157

157

157

155

211

318

422

429

368

66.7

63.3

66.7

68.8

76.7

75.9

8&0

80. 1

30. 1

28.6

29. 5

29. 5

29.5

29. 1

39.7

59.8

79.3

80.6

69.2

i At 4,320 minutes=58 percent; at 5,760 minutes=55 percent.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 

TABLE 5. Hydrometer data: Kaolinite and sodium tripolyphosphate

259

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for the number of minutes Indicated

1 4 19 60 435 1,545

Sum Dispersion 

^dex

Distilled water

Sodium. ______________

Do-______________

Do-___-__-.______

Calcium. _______ _____

Do____-__--____._

Do__-_-___.______

Do.______________

Do______.-_______

Do___.___________

Do.. _____________

0.0

.025

. 1

.0

.05

. 1

.3

. 5

1.0

1.5

90

92

99

68

80

83

75

85

90

88

88

92

07

17

64

34

30

74

88

91

86

QO

QC

0

14

9fi

64

83

86

80

85

86

0

8

21

55

73

73

58

66

68

(0) / o\

(4)

16

39

57

58

49

56

55

(0)

/O\

(t)\

(ID

29

45

46

451

481

500

85

168

139

179

346

436

442

99. 6

106.2

110. 4

18. 8

37. 1

30.7

39.5

76. 4

96. 2

97.6

Soft water

Sodium.. ____ ___ __ _

Do__. ____________

Do_-__-____-___._

Do_______________

Do__. ____________

Do__. ____________

Do_______-.______

Calcium. _________ ___

Do.. _____________

Do_______________

Do... ____________

Do__. ____________

Do____. __________

Do_-____. ._.....

0.0

.025

. 1

. 5

. 75

1.0

1.5

.0

. 025

. 1

. 5

1.0

1. 5

2.0

91

9507

97

94

97

96

66

79

70

80

96

QR

91

80

QO

Qfi

95

93

QC

96

37

58

Kfi

65

93

Q8

89

7

Of)

CO

88

86

87

88

8

10

19

55

84

07

89

7

6

10

78

75

77

75

5

5

4

39

71

81

82

(6) f<t\ (3)

58

54

58

57

0

(0) (<>}

54

62

62

(5)

(0)

(4)

16

44

45

45

(0)

(0)

(1)

(0)

49

52

»53

196

226

275

432

446

459

457

116

152

145

240

447

488

466

43. 3

49.9

60.7

95. 4

98.5

101. 3

100.9

25. 6

33. 6

32.0

53. 0

9&7

107.7

102.9

Hard water

Sodium. _ . _________

Do.-____________

Do___ ____________

Do... ____________

Do_______________

Do_.____-_. ______

Do_._____________

Do... ____________

Calcium. ________ ___

Do.. ._._.________

Do.. _____________

Do... ____________

Do_______________

Do_. _____________

Do____. ....______

Do.. _____________

Do-___. __________

0.0

.05

. 1-

. 5

1.0

2.0

3.0

4.0

.0

. 025

. 05

. 1

.3

. 5

1.0

2.0

3.0

70

87

83

85

82

85

96

96

89

93

97

99

99

99

97

97

94

27

44

50

70

71

85

91

89

37

48

63

61

69

78

8107

94

0

0

2

0

0

25

77

83

3

4

4

7

5

4

4

59

94

(0)

(0)

(0)

(0)

(0)

0

21

72

2

f 9^

o\

(4) / >\

o\

2

10

78

(0)

(0)

(0)

(0)

(0)

(0)

5

54

(0)

(0)

(0)

(0)

(0)

(0)

(1)

2

54

(0)

(0)

(0)

(0)

(0)

(0)

(3)

38

(0)

(0)

(0)

(0)

(0)

(0)

(0) (1)

41

97

131

135

155

157

195

293

432

131

147

166

171

176

183

185

266

455

21. 4

28.9

29.8

342

34 7

43. 0

647

95. 4

28.9

32. 4

36.6

37.7

3&8

40. 4

40.8

5&7

100. 4

i At 4,320 minutes=45 percent; at 5,760 minutes=40 percent.
260 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

TABLE 6. Hydrometer data: Kaolinite and sodium hexametaphosphate

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for tbe number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

Sodium_____ _ _____

Do___. ___________

Do. ________....__

Calcium. ____ __ _

Do______. __.___..

Do_________._____

Do-______________

Do... ____________

Do____. __________

Do... ____________

0.0

. 025

. 1

. 0

.05

. 1

. 3

. 5

1.0

1. 5

91

101

100

68

79

82

93

93

87

95

90

100

QQ

28

50

68

86

91

86

93

88

97

96

2

40

48

77

85

81

88

79

86

88

0

21

28

66

74

69

76

63

72

73

(0)

(10)

f 1 e\

46

55

55

52

55

60

60

(0)

(0)

(10)

(35)

40

42

41

4*J6

516

516

98

200

2)1

403

438

420

445

102. £

113. £

113. £

21. (

44 e*

55.4

89. (

96.7

92. 7

98.S

Soft water

Sodium.. _ ____________

Do... ___._...__._

Do.. __ _________

Do_..___. _____._.

Do.. ________._._.

Do._.___.________

Do__. ____________

Calcium_____ ___ ____

Do.. __._.___._.__

Do.____. _________

Do.. _._.___. _ __

Do.. _____________

Do____. __________

Do.______. _______

0. 0

.025

. 1

. 5

.75

1.0

1.5

. 0

. 025

. 1

. 5

1.0

1.5

2.0

91

94

95

93

92

91

92

50

62

58

67

91

99

88

82

92

93

91

91

QO

86

34

47

47

59

87

99

87

4

80

78

87

86

85

84.

12

15

11

51

83

86

85

3

7

13

78

76

73

73

7

6

6

39

70

78

76

(2)

( t\\

6

34

50

58

56

2

(3)

(4)

3

54

60

60

(1)

(4) (*\\

4

7

33

43

(1)

(2)

( 9\

(1)

35

49

»50

183

2f2

290

3?7

402

430

434

106

135

128

220

420

471

446

40. ;

62. 5

64. (

85.^ 88.'

94.1

95. {

23.'

29. i

28. 5

48. (

92. '

104 (

98. '

Hard water

Sodium. ____ _____

Do______________.

Do...... _________

Do__-_-_--.______

Do._--.__________

Do.. _____________

Do._______. .._.__

Do.. _____________

Calcium. _ ____ _ __

Do....... ________

Do...............

Do.___. _._...___.

Do___. ...________

Do...... _________

Do... ._____..___.

Do... .._..____.__

Do... .___..____._

Do_________....__

Do_______________

Do_____.________.

0.0

. 05

. 1

. 5

1.0

2.0

3.0

40

.0

.025

. 05

. 1

. 3

. 5

1. 0

2.0

3.0

40

5. 0

6. 0

82

85

82

86

82

86

96

90

92

99

98

95

98

98

100

99

96

75

57

45

33

39

40

48

50

72

96

83

33

61

/ £* 1 \ (61)

62

59

62

70

90

92

75

57

44

0

0

0

0

2

8

53

83

8

8

3

3

7

4

8

11

73

72

56

43

(0)

(0)

(0)

(0)

(0)

f e\

13

67

3

4

0}

(2)

6

/q\

8

11

17

30

56

43

(0)

(0)

(0)

(0)

(0)

(3)

8

10

(2)

(2)

(0)

(1)

(4)

(2)

(7)

12

14

8

13

40

(0)

(0)

(0)

(0)

(0)

(2)

(6)

5

(1)

(0)

(0)

(0)

(2)

(1)

(6)

(12)

17

10

12

6

115

124

122

134

134

176

272

338

139

174

164

163

176

170

199

235

309

270

2,o 1

221

25. ;

27.^

26. <

29. (

29. (

38. J

60. (

74 ( 30.'

38.;

36. 5

36. (

38. J

37.,

43. <

51. <

68. 5

59. (

55. ;

48. {

i At 4,320 minutes=40 percent; at 5,760 minutes =36 percent.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 

TABLE 7. Hydrometer data: Kaolinite and sodium hexametaphosphate plus sodium carbonate

261

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

Sodium. _______ ___

Do__-____________

Do__________..___

Calcium______ _ __

Do-__-_-_--._____

Do_____--_-___-._

Do___-----_-_____

Do.. _.________.._

Do___. _--..._____

Do___-_-_._______

0. 0

.025

. 1

. 0

. 05

. 1

. 3

. 5

1. 0

1. 5

89

Q7

97

68

77

82

85

94

88

90

88

07

96

26

57

66

72

89

86

89

QQ

QC

QO

4

35

47

c7

78

82

82

70

85

87o\

20

33

46

65

72

72

57

66

67

(0)

(10) oe>\

27

46

55

55

53

57

55

(0)

(0)

(11) / ic\

30

43

43

443

497

495

100

199

261

305

402

426

431

97.5

109.'

109.

22.

43. «

57.

67.J

88. '

94. (

95.

Soft water

Sodium. ______

Do--_----___-_-__

Do-._____________

Do_______________

Do___-___________

Do_______________

Do-__--________._

Calcium, __ __

Do________-____._

Do______-_______.

Do_______________

Do__________.____

Do_______________

Do____-___.______

0. 0

. 025

. 1

. 5

.75

1. 0

1. 5

. 0

. 025

. 1

. 5

1. 0

1. 5

2. 0

95

95

102

95

98

97

73

74

76

80

89

96

97

78

92

93

92

93

93

95

44

56

60

67

75

95

Q1

2

70

70

94

Q9

QO

QO

18

11

52

63

85

88

0

8

6

81

80

80

80

4

5

3

11

55

76

74

(0)

3

0

58

59

58

60

0

(0)

(0)

0

42

55

57

(0)

(0)

(0)

36

46

47

47

(0)

(0)

(0)

(0)

30

42

'47

176

276

272

463

465

466

469

130

153

150

210

354

449

454

38.8

60.9

60.0

102.2

102. 6

102.9

103. 5

28.7

33.8

33. 1

46. 4

78. 1

99. 1

100. 2

Hard water

Sodium. ______ ___

Do_______________

Do_-_____________

Do__________.____

Do______________.

Do

Do.______________

Do_______________

Calcium __ _ ___

Do_______________

Do_______________

Do_______________

Do__.____________

Do_______________

Do_______________

Do_______________

Do_______________

Do_______________

Do_______________

Do_______________

0. 0

. 05

. 1

. 5

1. 0

2. 0

3.0

4. 0

. 0

. 025

. 05

. 1

. 3

. 5

1. 0

2. 0-

3. 0

4. 0

5. 0

6. 0

60

78

80

84

83

81

88

91

93

90

91

90

89

90

89

95

100

74

61

42

28

40

46

68

69

79

80

90

35

52

/cox

69

78

80

87

95

100

74

61

42

0

0

0

0

1

34

64

82

6

3

3

5

5

4

23

55

95

70

57

42

(0)

(0)

(0)

(0)

(0)

(10)

53

72

4

o\

o\f}\

(0\

(2)

0

2

65

70

57

42

(0)

(0)

(0)

(0)

(0)

(0)

5

46(i\

(1)

(1)

(1)

(0)

(0)

(0)

0

6

46

50

41

(0)

(0)

(0)

(0)

(0)

(0)

(0)

16o\

(0)

(0)

(0)

(0)

(0)

(0)

(0)

0

30

36

38

88

118

126

152

153

204

290

397

143

148

149

168

175

176

199

247

366

364

322

247

19.4

26. 0

27.8

33. 6

33. 8

45. 0

64. 0

87. 6

31. 6

32.7

32.9

37. 1

38. 6

38. 8

43. 9

54. 5

80.8

80.4

71. 1

54. 5

i At 4,320 minutes=36 percent; at 5,760 minutes=30 percent.
262 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

TABLE 8. Hydrometer data: Illite and sodium tripolyphosphate

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

Sodium. _______ _____

Do_______._______

Do____-___.______

Calcium. ___ ___ _ _ _

Do____________.._

Do________. ______

Do_______________

Do_______________

Do_______________

Do_______________

0.0 

.025 

. 1 

.0 

.05 

. 1 

. 3 

. 5 

1. 0 

1. 5

94 

96 

104 

19 

26 

32 

28 

29 

28 

29

92 

95 

102 

14 

18 

24 

20 

21 

18 

22

84 

91 

96 

8 

12 

16 

14 

15 

14 

18

70 

78 

78 

0 

4 

12 

9 

11 

9 

11

38

46 

46 

(0) 

(2) 

(6) 

4 

6 

6 

8

25 

31 

29 

(0) 

(0) 

(4) 

(2) 

4 

0 

6

403

437 

455 

41 

62 

94 

77 

86 

75 

94

102.0 

110.6 

115.2 

10.4 

15.7 

23. 8 

19.5 

21. 8 

19.0 

23.8

Soft water

Sodium _ ___ ___ ___

Do_______________

Do__________.____

Do_______________

Do_______________

Do_____________ _

Do_____________ _

Calcium. ___ __ ___ _

Do_______________

Do_____________

Do_______________

Do_______________

Do______________

Do_______________

0.0

.025

. 1

. 5

.75

1.0

1. 5

. 0

. 025

. 1

. 5

1. 0

1. 5

2.0

Qfl

93

Q4

93

92

92

93

52

63

58

57

54

72

75

on

Q1

93

68

3007

no

34

44

_L9

23

12

C7

63

Of)

77

68

12

11

1Q

86

18

20

21

5

5

44

49

16

24

20

12

8

17

68

7

5

3

2

4

32

38

(5)

6

7

4

8

15

39

0

o\

o\

0

4

21

26

(t)\

(3)

(4)

(2)

6

10

23

(0)

(1)

(0)

(0)

8

19

124

2"4

274 2">6

191

155

190

402

111

135

126

87

87

245

275

66. i

74.<

72.'

48.'

39.!

48.

101. !

28. 34.:

31. (

22. (

22. (

62. (

69. <

Hard water

Sodium_ _ ________

Do____________,

Do_______________

Do_______________

Do____________, _

Do____________.

Do____________.

Do____________.__

Calcium. _ _ ___

Do_______________

Do____________.

Do_______________

Do_______-___.___

Do

Do_______-__.____

Do__________.__

Do_______________

0. 0

.05

. 1

. 5

1. 0

2.0

3. 0

4. 0

. 0

.025

. 05

. 1

. 3

. 5

1.0

2.0

3.0

81

85

78

83

80

85

88

83

43

46

45

46

48

47

44

48

52

74

67

66

64

65

37

80

83

39

36

41

41

43

40

38

45

47

26

33

36

2

1

0

32

80

Q

13

18

18

4

2

0

3

43

3

0

0

(0)

(0)

(0)

13

56

2

(6)

(Q\

(Q)

(2)

(1)

0

2

34

(2)

(0)

(0)

(0)

(0)

(0)

0

38

(1)

(3)

Ci\

(3)

(0)

(0)

(0)

0

23

(0)

(0)

(0)

(0)

(0)

(0)

(0)

27

(0)

(1)

(2)

(2)

(0)

(0)

(0)

(0)

20

186

185

180

149

146

122

213 3 "7

94

105

118

119

97

90

82

98

219

47.

46.5

45. < 37.'

37. (

30. <

53. (

92. <

23. !

26. <

29. <

30.

24. <

22. i

20. i

24. 5

55. '

1 At 4,320 minutes=21 percent; at 5,760 minutes=20 percent.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 

TABLE 9. Hydrometer data: Illite and sodium hexametaphosphate

263

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

Sodium. __ _ ________

Do________.______

Do_. _____________

Calcium. ______ _____

Do_______-.______

Do_____._________

Do_______________

Do_ ___-_______

Do_______________

Do_______________

0. 0

.025

. 1

. 0

.05

. 1

. 3

. 5

1.0

1. 5

qo

98

QR

31

26

31

27

28

23

28

90

Q6

98

21

18

23

20

22

15

22

83

Q1

QO

8

12

14

13

14

q

15

67

74

73

0

7

q

8

8

4

10

39

44

46

(0)

(4)

(5)

3

4

0

5

25

29

29

(0) (ft\

(1\

O\

1

2

1

394

432

434

60

69

85

73

77

53

81

99. 1

109.'

109. <

15. 5

17. £

21.!

18. !

19. i

13.'

20. !

Soft water

Sodium _ __________

Do_-____.________

Do_ ___________

Do_______________

Do__-___.________

Do_______________

Do_-___-_.______

Do_-_____________

Do____-------___-

Do_____---.______

Do_-______--_-__-

Do____-__._._-___

Do____.__________

0.0

. 025

. 1

. 5

.75

1. 0

1. 5

.0

.025

. 1

. 5

1.0

1. 5

2.0

Q4

94

93

Q4-

97

97

58

RC

65

64

6Q

77

74

Q1

90

90

Q4

92

96

95

37

46

45

44

51

60

59

64

82

84

QO

Q1

Q1

QO

18

1Q

16

23

31

41

44

12

42

52

73

71

73

74

8

6

4

13

20

29

34

(4)

1

5

37

38

36

43

0

(0)

(0)

0

11

22

26

o\

(0) (i\

16

23

24

27

(0)

(0)

(0)

(0)

13

1Q

» 24

267

309

327

406

409

417

426

121

136

130

144

195

248

261

67. (

78. i

82. i

102. i

103. I

105. (

107. i

30. (

34.^

32. <

36. <

49. i

62. {

66.

Hard water

Sodium____ _________ _

Do-___-___-._____

Do________. ______

Do_______________

Do______.________

Do___________.___

Do_-_-____-_.____

Do-__________-.__

Calcium. _ _ ____

Do_ ___________

Do____-______.___

Do_______________

Do_______________

Do___________.___

Do____________.__

Do____.__________

Do_______________

Do_.-____________

Do_-___-______-._

Do_______________

0.0

.05

. 1

. 5

1. 0

2. 0

3.0

4.0

.0

.025

.05

. 1

. 3

. 5

1. 0

2. 0

3.0

4.0

5.0

6.0

70

86

82

85

81

86

QQ

99

42

47

40

38

40

42

45

43

4Q

39

43

35

59

85

82

84

78

86

Qfi

96

39

39

(35)

33

34

40

40

37

43

35

35

31

17

43

40

42

16

33

fiQ

83

9

20

12

9

8

2

14

15

36

31

31

28

0

4

2

4

8

14

16

35

0

2

(4)

(5)

2

(1)

0

6

10

14

25

20

(0)

o\

(1)

(2)

(4)

(7)

11

10

(0) (1) fO\

(0) (1)

(0)

(0)

7

10

4

19

16

(0)

(0)

(0)

(0)

(0)

(4)

(Q}

12

(0)

(0)

o\

(0)

(0)

(0)

(0)

(6)

10

6

12

12

146

220

207

217

187

230

300

335

90

109

96

85

85

85

99

114

158

129

165

142

37.0

55. 7

52. 4

54. 9

47.3

58. 2

75. 9

84. 8

22. 8

27. 6

24. 3

21. 5

21. 5

21.5

25. 1

28. 9

40.0

32. 7

41. 8

35. 9

i At 4,320 minutes=22 percent; at 5,760 minutes=20 percent.
264 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

TABLE 10. Hydrometer data: Illite and sodium hexametaphosphate plus sodium carbonate

Ion saturation Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,645

Sum Dispersion 

index

Distilled water

Sodium-.______ ______

Do___.___________

Do__ __-______

Calcium _______ ___

Do-_.____________

Do_______________

Do__.____________

Do_______________

Do_______________

Do_-____________

0.0

. 025

. 1

. 0

. 05

. 1

.3

.5

1. 0

1.5

93

100

100

26

28

31

28

29

26

25

92

100

QQ

20

19

22

18

20

17

17

83

93

Q3

10

12

18

14

16

13

13

64

76

73

(5)

8

12

8

11

8

9

37

42

43

(3)

(5)

(8)

3

8

6

7

23

30

28

(0)

(1)

(6)

(9}

3

3

4

392

441

436

64

73

97

73

87

73

75

99.-

111. <

110. <

16.:

18.,

24. <

18. i

22. (

18. i

19. (

Soft water

Sodium _ _ _____ ___

Do_______________

Do__-___________

Do_________._____

Do. -_____-.___

Do ___ __. _____

Do__-___________

Calcium ________ ___

Do__--__--___.__

Do__--______-.___

Do ____________

Do ____________

Do ____--_._.__

Do_______________

0. 0

.025

. 1

.5

.75

1. 0

1.5

. 0

.025

. 1

.5

1. 0

1.5

2. 0

Q1

88

88

91

90

Q3

94

58

61

58

67

67

74

71

87

85

84

88

87

QO

92

37

38

38

46

47

52

48

65

78

80

85

85

85

84

16

15

12

20

24

31

29

9

28

51

66

67

66

68

7

4

2

8

16

22

19

(0

(0)

0

18

30

32

35

0

(0)

(0)

0

9

13

10

(0)

(0)

(0)

2

15

17

20

(0)

(0)

(0)

(0)

8

11

1 10

2-2

279

303

3^0

374 3°3

3^3

118

118

110

141

171 2-)3

187

63.J

70. (

76. '

88. ( 94.'

97. (

99.,

29. '

29.1

27. i 35.'

43. :

51.'

47.;

Hard water

Sodium__ ____ _ _____

Do ___________

Do_-____________

Do ____________

Do ____________

Do ____________

Do ____________

Do________. ______

Calcium ___ ________

Do ____________

Do ____________

Do _ __--_____.

Do___ ____________

Do ____________

Do_-____________

Do_-_ -_------_

Do ____________

Do ____________

Do ____________

Do ____________

0.0

.05

. 1

.5

1.0

2.0

3.0

4.0

.0

. 025

.05

. 1

.3

. 5

1.0

2.0

3.0

4.0

5.0

6. 0

76

80

78

83

87

83

88

88

36

34

35

35

34

37

37

41

50

46

49

32

70

78

74

83

77

75

80

85

33

30

/01 \

32

29

31

33

37

46

40

39

32

24

40

47

52

15

3

64

72

5

10

8

20

18

11

0

23

40

32

34

32

0

0

0

0

0

(0)

32

56

0

(0\

(2)

(10)

0

(1)

(0)

0

29

24

27

24

(0)

(0)

(0)

(0)

(0)

( 5°

22

(0)

(0)

(0)

(0)

(0)

(0)

(0)

(0)

17

14

20

15

(0)

(0)

(0)

(0)

(0)

(0)

(0)

3

(0)

(0)

(0)

(0)

(0)

(0)

(0)

(0)

5

7

10

5

170

198

199

218

179

161

2^9

326

74

76

76

97

81

80

70

101

187

163

179

140

43.

50.

50.

55.

45.

40.

68.

82.

18.

19.

19.

24.

20.

20.

17.

25.

47.

41.

45.

35.

At 3,420 minutes=5 percent; at 5,760 minutes=4 percent.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS

TABLE 11. Hydrometer data: Volclay and sodium tripolyphosphate 

[Ion saturation 78.8 percent sodium]

265

Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

0.0

. 025

.05

. 1

91

92

92

91

88

92

92

89

89

92

91

91

88

95

91

93

85

87

88

85

86

84

85

86

527

542

539

535

99. 1

101. 9

101. 3

100. 6

Synthetic Tri-County water

0.0

.05

. 1

. 2

. 3

. 5

.75

1. 0

1. 25

1. 5

1.75

2.0

98

95

98

93

97

96

92

93

94

97

97

94

98

92

98

90

94

94

89

90

92

95

96

92

100

91

94

91

92

89

88

90

91

94

92

92

90

88

87

90

91

86

90

88

91

92

88

92

(0)

(0)

46

76

77

74

(77)

84

90

90

88

87

(0)

(0)

3

23

59

74

68

74

80

84

84

85

386

366

426

463

510

513

504

519

538

552

545

542

72.6

68.8

80. 1

87.0

95.9

96.4

94.7

97.6

101. 1

103. 8

102. 4

101. 9

TABLE 12. Hydrometer data: Volclay and sodium hexametaphosphate 

[Ion saturation 78.8 percent sodium]

Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

0.0

. 025

.05

. 1

91

94

93

93

90

91

90

89

88

93

93

93

88

93

93

93

87

94

92

89

87

87

87

89

531

552

548

546

99.8

103. 8

103. 0

102. 6

Synthetic Tri-County water

0.0

.05

. 1

. 2

.3

. 5

.75

1.0

1. 25

1. 5

1.75

2.0

102

94

95

95

94

92

92

92

91

90

89

98

102

91

92

93

91

92

91

90

86

88

85

94

103

90

92

90

90

89

89

90

90

92

86

91

100

86

88

88

89

85

88

86

89

91

83

88

(0)

(0)

43

83

78

80

(84)

82

85

87

84

84

(0)

(0)

5

8

49

66

70

71

75

76

76

80

407

361

415

457

491

504

514

511

516

524

503

535

76. 5

67. 9

78. 0

85. 9

92. 3

94.7

96. 6

96.0

97.0

98. 5

94. 5

100. 6
266 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

TABLE 13. Hydrometer data: Volclay and tetrasodium pyrophosphate 

[Ion saturation 78.8 percent sodium]

Grams

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion

index

Distilled water

0. 0

. 025

. 075

. 1

91

95

93

93

91

93

93

92

90

93

94

94

88

93

93

92

87

94

93

89

90

86

88

90

537

554

554

550

100. 9

104. 1

104. 1

103. 4

Synthetic Tri-Connty water

0. 0

. 05

. 1

. 2

. 3

. 5

.75

1. 0

1. 25

1. 5

1.75

2.0

98

92

98

94

94

94

91

94

97

95

98

94

97

91

96

91

92

92

89

92

95

92

94

92

98

90

94

90

92

91

89

92

94

90

92

92

92

84

91

86

89

90

91

91

90

87

90

91

(0)

(0)

48

79

79

89

(83)

90

91

90

89

92

(0)

(0)

5

41

61

79

72

80

85

85

85

89

385

357

432

481

507

535

515

539

552

539

548

550

72.4

67. 1

81.2

90.4

95.3

100.6

96. 8

101.3

103. 8

101. 3

103.0

103.4

TABLE 14. Hydrometer data: Kaolinite and sodium tripolyphosphate

[Ion saturation 78.8 percent sodium]

Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

0. 0 

. 025 

. 05 

. 1

94 

96 

98 

97

93 

95 

96 

95

88 

94 

90 

93

79

84 

82 

83

58

59

64 

59

50 

48 

49 

50

462 

476 

479 

477

102.0 

105. 1 

105.7 

105.3

Synthetic Tri-County water

0.0

.05

. 1

. 2

.3

.5

.75

1.0

1. 25

1.5

1. 75

2.0

100

96

100

97

98

98

100

100

96

100

100

98

51

92

99

96

96

96

94

98

94

97

98

96

5

10

28

61

84

89

89

90

91

90

89

92

5

2

4

6

13

75

80

79

81

82

87

80

(0)

(0)

0

2

1

4

(42)

61

63

63

61

57

(0)

(0)

1

(0)

(0)

(0)

14

49

50

49

48

50

161

200

232

262

292

362

419

477

475

481

483

473

35.5

44.2

51.2

57.8

64.5

79.9

92.5

105.3

104.8

106.2

106.6

104.4
DISPERSION. CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 267

TABLE 15. Hydrometer data: Kaolinite and sodium hexametaphosphate 

[Ion saturation 78.8 percent sodium]

Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

in lex

Distilled water

0.0

.025

.05

. 1

91

95

93

92

90

93

91

91

84

91

91

89

80

82

81

80

56

64

63

60

50

49

51

50

451

474

470

462

99.6

104.6

103.8

102.0

Synthetic Tri-County water

0. 0

.05

. 1

. 2

.3

.5

.75

1.0

1. 25

1.5

1.75

2.0

100

95

100

99

97

96

95

94

94

94

96

92

64

92

96

98

94

92

93

90

91

92

90

91

6

11

21

69

86

87

90

86

87

88

84

78

4

2

6

8

16

76

76

74

76

78

72

69

(0)

(0)

0

3

1

24

(60)

59

62

62

58

56

(0)

(0)

(0

(0

(0

(6

48

47

50

49

47

46

174

200

223

277

294

381

462

450

460

463

447

432

38.4

44. 2

49. 2

61. 1

64.9

84. 1

102.0

99.3

101.5

102.2

98.7

95.4

TABLE 16. Hydrometer data: Kaolinite and tetrasodium pyrophosphate

[Ion saturation 78.8 percent sodium]

Grams 

deflocculent

Percentage in suspension after settling for the number of minntes indicated

1 4 19 60 435 1,545

Sum Dispersion 

in "lex

Distilled water

0.0

.025

.050

. 1

93

95

96

93

93

93

94

91

86

89

92

90

77

71

79

79

57

64

62

59

50

48

49

51

456

460

472

463

100.5

101.7

104,2

102. 7

Synthetic Tri-County water

0.0

.05

. 1

. 2

.3

.5

.75

1.0

1.25

1.5

1.75

2. 0

100

95

103

99

95

98

97

102

98

96

95

96

64

90

99

97

94

97

93

99

96

94

92

94

6

6

17

32

45

86

88

91

91

87

88

87

4

2

7

2

3

15

21

81

81

76

77

78

2

(0)

0

2

0

1

(ID

22

64

62

60

58

(0)

(0)

(0)

(0)

(0)

(0)

4

5

52

48

49

49

176

193

226

232

237

297

314

400

482

463

461

462

38.

42.

49.

51.

52.

65.

69.

88.

106.

102.

101.

102.
268 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

TABLE 17. Hydrometer data: Illite and sodium tripolyphosphate 

[Ion saturation 78.8 percent sodium]

Grams

deflocculent

Percentage in suspension after settling for tbe number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion

index

Distilled water

0. 0

.025

.05

. 1

94

95

97

95

90

94

93

92

81

86

83

87

64

70

67

71

38

38

40

40

28

27

25

28

395

410

405

413

100. 0

103. 8

102.5

104 6

Synthetic Tri-County water

0. 0

. 05

. 1

. 2

. 3

. 5

.75

1.0

1.25

1. 5

1.75

2. 00

2. 25

2. 50

2. 75

101

96

100

96

97

94

94

98

96

95

98

96

100

100

96

94

94

96

94

95

93

90

92

92

90

92

89

96

98

95

40

83

88

82

75

72

75

80

79

80

78

76

84

90

90

4

33

30

23

3

4

10

59

66

66

61

67

70

77

73

(0)

(3)

2

5

1

0

(5)

6

40

40

40

40

51

50

50

(0)

(0)

(0)

(0)

(0)

(0)

0

0

25

28

26

31

35

36

38

239

309

316

300

271

263

274

335

398

399

395

399

436

451

442

60.

78.

80.

75.

68.

66.

69.

84.

100.

101.

100.

101.

110.

114

111.

TABLE 18. Hydrometer data: Illite and sodium hexametaphosphate 

[Ion saturation 78.8 percent sodium]

Grams 

deflocculent

Percentage in suspension after settling for tbe number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion 

index

Distilled water

0. 0 

. 025 

. 05 

. 1

90 

95 

93 

92

90 

91 

90 

89

80 

85 

85 

83

66 

71 

67 

68

38 

42 

42 

39

28 

26 

27 

28

392 

410 

404 

399

99.2 

103.8 

102. 3 

101. 0

Synthetic Trl-County water

0. 0

. 05

. 1

. 2

. 3

. 5

.75

1. 0

1. 25

1. 5

1.75

2. 0

2. 25

2. 50

2. 75

102

95

98

99

97

94

95

94

96

98

94

98

95

100

95

97

92

94

88

94

91

92

90

95

93

89

92

93

98

93

43

80

65

76

44

47

72

69

83

82

76

81

82

90

83

4

15

6

6

2

4

4

6

48

64

60

68

65

76

71

(0)

(0)

1

3

2

0

3

4

5

6

34

37

47

47

48

(0)

(0)

(0)

(0)

(0)

(0)

1

3

3

4

5

7

11

11

37

246

282

264

272

239

236

267

266

330

347

358

383

393

422

427

62. I

71. <

66. J

68.1

60.! 59.'

67. (

67. ;

83. J

87. *

90. (

97. (

99. i.

106. f

108. ]
DISPERSION CHARACTERISTICS, MONTMORILLONTTE, KAOLINITE, ILLITE CLAYS

TABLE 19. Hydrometer data: Illite and tetrasodium pyrophosphate 

[Ion saturation 78.8 percent sodium]

269

Grams 

deflocculent

Percentage in suspension after settling for the number of minutes indicated

1 4 19 60 435 1,545

Sum Dispersion

bK'BX

Distilled water

0. 0

. 025

. 05

. 1

94

94

91

94

94

91

89

84

84

83

80

82

66

70

65

66

38

40

40

40

30

26

27

29

406

404

392

395

102. 8

102. 3

99.2

100.0

Synthetic Tri-County water

0.0

. 050

. 1

. 2

.3

. 5

.75

1. 0

1. 25

1. 5

1.75

2.0

2. 25

2. 50

2.75

97

96

101

86

97

96

93

99

101

98

99

99

96

102

97

91

93

100

93

91

90

71

34

88

91

93

65

86

102

97

33

83

81

51

21

2

0

8

50

60

66

56

78

94

89

4

24

11

0

0

0

-1

2

30

38

46

50

65

76

73

(0)

(6)

1

2

-2

0

_ o

-4

7

17

21

22

41

47

44

(0)

(0)

(0)

(0)

(0)

(0) -5

-6

3

8

10

14

25

30

32

225

302

294

232

207

188

155

133

279

312

335

306

391

451

432

57.

76.

74.

58.

52.

47.

39.

33.

70.

79.

84.

77.

99.

114.

109.

FILTER-LOSS TEST OF CLAY SUSPENSIONS

By I. S. McQuEEN

A series of exploratory tests was conducted during 

the second year of the investigation to determine if 

there were significant differences in the sealing capacity 

of various clays with different deflocculents.

A standard operating procedure in the oil-well 

drilling-mud industry known as the filter-loss test or 

"filtration" provides information on the ability of a 

slurry to retain water inside of a drill hole during 

drilling operations (American Petroleum Institute, 

1950, p. 7). The sediment lining in a canal is analogous 

to the filter cake in a drill hole.

The nature of the seal developed in a canal bottom 

by dispersed clays is not thoroughly understood. 

There are several possible mechanisms involved. 

Probably the seal easiest to develop is a surface seal 

or skin on the canal bottom. This type of seal, however, would be subject to erosion and would therefore 

be extremely temporary. The seal most permanent 

would be achieved by material that penetrates the soil 

mass and fills its interstices. The filling of cracks and 

other flow channels is an important factor in canalsealing. Probably all of the above mechanisms are 

involved in an effective seal. The filter-loss test 

procedure was designed to define differences in poresealing as well as the relative permeability of the filter 

cake.

In the drill-mud filtration test, a quantity of 500 to 

600 grams of mud is placed inside a cylinder on a disc 

of filter paper supported by a screen. The top of the 

cylinder is sealed and a pressure of 100 pounds per 

square inch is applied for 30 minutes. The character 

of the filter cake and the quantity of water extracted 

are measures of the effectiveness of the mud. The 

above procedure was modified for the current investigations because it was found that ordinary filter paper 

would not retain the dilute colloidal suspensions used.

Test procedure. To retain colloidal-size partic^s an 

attempt was made to develop a barrier of greater depth 

and smaller pore size than ordinary filter paper. This 

was done by using glass beads, which are available in 

uniform sizes as small as 28 microns in diameter. In 

the chosen mixture 80 percent of the beads were 

between 20 and 70 microns in diameter. Uniform 

filter beds of these beads were formed by depositing 

a known weight of them in water on a filter pape^ in a 

Buechner funnel and consolidating the mass by alternately jarring the funnel and withdrawing the excess 

water with a partial vacuum. A filter paper was p^ced 

over the bed of beads to protect the bed from being 

disturbed by the suspensions being filtered and also to 

provide a means of removing the filter cake for testing 

the sealing brought about by particles that penetrated 

into the voids.

Results of the filter-loss tests are shown in table 

20. The first four columns of table 20 describ?, the
270 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

TABLE 20. Results of fitter-loss tests

Sample

1

2

3

4

5

6

7

8

9

Colloid

Volclay_______

_....do.._..._.

_____do.____-_.

___._do-_______

_-.__do-___-_-_

_____do____.___

Illite_ ________

__-._do._______

_____do._______

Deflocculent

Sodium tripolyphosphate_____ _

Sodium hexametaphosphate ___

Sodium hexametaphosphate.

Sodium tripolyphosphate. ______

Water

Synthetic Tri-County with

NaHCO3 

_____do-_-------------------_-

Synthetic Tri-County with NaCL

_ _ _ _ _do_ _______-_---__-----___

Natural Tri-County __________

_____do_ ----------------------

Synthetic Tri-County with NaCL

-____do__----_--------- --. __

_____do____ ________________ _

Prerun 

cubic centimeters 

per hour

447

473

411

415

493

522

379

286

336

Cake development 

time in 

seconds

7,740

8,790

7,380

9, 780

7,500

8,760

2, 100

600

1, 680

After run 

cubic centimeters 

per hour

125

143

114

115

<100

356

293

suspension being tested. The next column shows the 

rate of movement of distilled water through the filter 

bed under a tension of 55 centimeters of water, prior 

to the application of the clay sample. The last column 

shows the rate of movement of distilled water through 

the filter bed under a tension of 55 centimeters of water, 

after application of the sample suspension and removal 

of the filter cake. This rate indicates the relative 

effectiveness of the suspension in sealing the soil 

matrix. The time required to develop the cake, by 

dewatering 100 cubic centimeters of the sample suspension with an applied tension of more than 800 

centimeters, indicates the relative effectiveness of the 

sample in forming an impermeable cake.

The following characteristics may be inferred from 

the limited data obtained.

1. The filter cake formed using Volclay with sodium 

hexametaphosphate was consistently less 

permeable than the cake formed with Volclay and 

sodium tripolyphosphate.

2. There was no difference between sodium hexametaphosphate and sodium tripolyphosphate with 

Volclay in their "pore-sealing" ability.

3. The Volclay penetrated the filter bed and reduced 

its permeability to about one-third of its pretreatment permeability. The effect of illite on 

the permeability of the filter bed was variable; 

ranging from an increase in permeability to a 

reduction to about one-fourth.

The filter-loss experiments were discontinued because 

no well-defined differences in the effectiveness of the 

dispersants were evident and time would not permit a 

complete development of the method.

Limitations on filter-loss tests. There are several 

serious limitations on the filter-loss test in its present 

stage of development. It is difficult to achieve consistently uniform filter beds. At present, the difference 

in permeability of two freshly prepared filter beds may 

be as great as the difference in the change in permeability imposed on the filter beds by two samples with 

different deflocculating agents. The filter beds were 

not stable. One or two of them broke down and changed 

their basic permeability during the course of the tests. 

Sample 8 (table 20) is an example of this. The permeability of the filter bed increased 25 percent with the 

addition of the colloid. In this sample, the original 

packing of the beads seemed to be completely disturbed. 

Time would not permit further work on this filter-loss 

test to eliminate these limitations so tH tests were 

discontinued.

SELECTED REFERENCES

American Petroleum Institute, 1950, Recommended practice for 

standard field procedure for testing drillm*1 fluids (tentative) : Am. Petroleum Inst. Research Paper ?9.

Bell, R. N. , 1947, Hydrolysis of dehydrated sodium phosphates: 

Indus, and Eng. Chemistry, v. 39, p. 136-140.

Chu, T. Y. and Davison, O.T., 1955, Deflocculating agents for 

mechanical analysis of soils: Highway Research Board Bull. 

95, Natl. Acad. Sci., Natl. Research Council, Pub. 343, 

p. 15-26.

Daugherty, T. H., 1948, Sequestration, dispersion, and dilitancylecture demonstrations: Jour. Chem. Education, v. 25, p. 

482-486.

Dirmeyer, R. D., Jr., 1955, Report of sediment lining investigations, fiscal years 1954-55: Colorado A & M College, Fort 

Collins, Colo., 150 p.

Grim, R. E., 1953, Clay mineralogy: New York, McGraw-Hill 

Book Co., 384 p.

Kelley, W. P., 1948, Cation exchange in soils: New York, Reinhold Pub. Corp., 144 p.

Krynine, D. P., 1941, Soil mechanics, its principles and structural 

applications: New York, McGraw-Hill Book Co., 511 p.

Marshall, C. E., 1949, The colloid chemistry of the silicate minerals: New York, Academic Press, 195 p.

Olphen, H. Van, 1950, Stabilization of montmonllonite sols by 

chemical treatment, part 2. Effect of polyr*etaphosphates, 

sodium metasilicate, oxalate, citrate and orthophosphate on 

Na and Ca montmorillonite sols: Recue1 ! des travaux 

chimiques des pays-bas, v. 69, no. 9-10, p. 1313-1322, 

September-October.

Puri, A. N., 1949, Soils: Their physics and chemistry: New 

York, Reinhold Pub. Corp., 550 p.
DISPERSION CHARACTERISTICS, MONTMORILLONITE, KAOLINITE, ILLITE CLAYS 271

Richards, L. A., and others, 1954, Diagnosis and improvement of

saline and alkali soils: U.S. Dept. Agriculture, Agriculture

Handbook no. 60, 160 p. 

Ruehrwein, R. A., 1953, The interactions of polyelectrolytes with

clay suspensions: Monsanto Chemical Co., Central

Research Dept., Dayton, Ohio, 6 p. 

Russell, Sir John E., 1950, Soil conditions and plant growth: 8th

ed., New York, Longmans, Green & Co., 635 p. 

Tchillingarian, G., 1952, Study of the dispersing agents: Jour.

Sed. Petrology, v. 22, p. 229-233.

Whitehouse, U. G. and Jeffrey, L. M., 1955, Peptization resistance of selected samples of kaolinitic, montmorillonitic, and 

illitic clay materials: Clays and clay minerals, Natl. Acad. 

Sci., Natl. Research Council Pub. 395, p. 260-281.

Wintermyer, A. M. and Kinter, E. B., 1955, Dispersing agents 

for particle-size analysis of soils: Highway Research Board 

Bull. 95, Natl. Acad. Sci., Natl. Research Council Pub. 343, 

p. 15-26.
INDEX

Page 

Anions, adsorption.___-_-_---_-_____--......_-. -_-_... 237,241,243,246,252,253

valence.--------------------._. ...__........_-.-...-___. 263

Bentonite, dispersion, in distilled water._--_.--- ____.___.....__.. 243

dispersion, in medium-hard water_. _..............._.........__. 243,246

exchange complex.----_.___..._____________.__._.. 233

occurrence, Kendrick project, Casper, Wyo.. .____................. 230

Canal, irrigation, lining..____.__________.____.__ 229,230,269

irrigation, lining, colloid size_--_-------__...._________ 230,252

lining, cost __~ ___ ____.______. __ ___________ 230

natural sedimentation. - _________.__ ___.______ 230

Cations, behavior in solution.-_--_.__ .__.._____.__.....____ 253

concentration-...------...---___........._._.___________ 253

eflect of clay particles-_.. _..___.__._________._ 237,246 

hydration..._ _____.__._________________ .__.__ 254 

mobility. . .. ..... . ........ 254

sources...-._... ------ .....__________________ 233

valence_.... ------------____..______._____._____ 253

Clay minerals, classification--__________________.______ 248 

ilhte, cation exchange capacity. -...._---_-----___..____.. 250

dispersion, general characteristics.-.-__.----..--....-._,_.... 254

in distilled water............................___........ 241,246,248

in hard water__.______.______..____.______ 241 

in medium-hard water...__.........._.........._._..-.. 248

in soft water_ _._.-._..._-__ __..._.......__ 241

structure....---__...____ ._-__.___________ 250

kaolinite, cation exchange capacity..._______.__________ 249,254 

dispersion, general characteristics.... ._ __..___...._... 254

in distilled water.....______._______________ 239,246

in hard water...-------_.. __.. _____________ 241

in medium-hard water.._____.______.______.__ 246 

in soft water___...._______.____.________ 239,241

particle size.-----------_ _ ---_-_...__..____..._. 249

structure.... .....__.... __________.__ 249

montinorillonite, cation exchange capacity.___. __ _ ___ _ _. _ 249,254

dispersion, general characteristics____ ________. ______. 254 

in dilute suspensions_. _____. ______. _________ 256 

in distilled water..--.--..-.----...-.........---........-..._ 235,237

in hard water....... ....__..._._______________ 237

in soft water______________.____________.__ 237 

occurrence ... - ---._..--....-._...____................ 249

particle size___...-_...___--.___..___...- _.-- 249 

structure.-.-____ _.__..___..______.___.__ 249

Page 

Clay, water, ionized salt system._____._....__..________ 230,231

factors controlling dispersion..._... -_----- -- 253,254,255

Clays, calcium-saturated...--- - - 231,233,235,237,23T 241,243

exchange complex.-__.._.-..- .--- .. 233

homoionic, preparation...-.___------_ .... -.-... 233

sodium-saturated...-- . . - . - 231,233,235,237,239,241.246,248 

Colorado State University.. . -_----- 230,231

Dispersionindex.-. -.-. .----- - . 233,237.241,246

computation . .. . __ 235,256-269

Osmotic pressure...__. .. ... - 254

Phosphatedeflocculents, effect on illite.-------------------------- 241,241,246,248

effect on kaolinite 239,241.246,248

montmorillonite....... -- -. 237,23*?, 239,243

Volclay - - - - 243,246

nomenclature. _. .. ... 231

uses.--.._____________-_--------_--..--.------. . 232

Stokes' law. See Tests, hydrometer.

Tests, conclusions---...-------.-- ------------ ----------------------- 248,270

filter-loss, limitations..--. 269,270

procedure.--.---.-- --- 269

results.----------...------------------------------------ --- 270

Volclay, as a filter cake.__._.. .. . . 270

hydrometer, advantages and disadvantages_.-... 251

grain-size measurement.. .. ------- 250

possible source of error - - ------- 251

Stokes' law used_..-.- ... ... - -....-- ... 250

results and discussion 234 

treatment with deflocculents, temperature and time effect.. . 234 

x-ray analysis__. _ _ - --___ -- -- - ----- - - --- 237

Volclay. See Tests, filter-loss.

Water, from Tri-County Canal, Nebr............... ... ... 233,243

hardness and softness determined ... - 231,255

sample prototype_ . 233,243

o

273