54
E. A. HAUSER AND D. 8. LE BgAU
(5) CAMPBELL, W. B.: Can. Forest Service Bull. 84 (1933). (6) CARMAN, P. C.: Trans. Inst. Chem. Engrs. (London) 16, 150-66 (1937). (7) CARMAN, P. C.: J. SOC.Chem. Ind. 67,225-34 (1938);68,1-7 (1939). (8) EMMETT, P.H., AND BRUNAUER, S.: J. Am. Chem. SOC.6B, 1553-64 (1937). (9) GRACE,K.H., AND MAASS,0.: J. Phys. Chem. 36, 3046-63 (1932). (10) HARRIS,C. A , , ANn PURVES,C. B.: Paper Trade J. 110 (6),63-7 (1940). (11) HOWELL, R., A N D JACKSON, A.: J. Chem. SOC.1937, 979-82. (12) KOZENY,J.: Sitzber. Akad. Wiss. Wien, Math. naturw. Klasse, Abt. IIa, 136, 271-306 (1927). (13) SHEPPARD, S. E.,AND XEWSOME, P. T.: Ind. Eng. Chem. 36, 285-90 (1934). (14) STAMM, A. J.: J. Phys. Chem. 33, 398-414 (1929). (15) STAMM, A. J.: U. S. Dept. Agr. Misc. Pub. 240 (1936). (16) STAMM, A. J., AND HANSEN, L. A.: J. Phys. Chem. 41, 1007-15 (1937). (17) STAMM, A. J., A N D HANSEN,L. A.: J . Phys. Chem. 49, 209-14 (1938). (18) STAMM, A. J., AND LOUGHBOROUGH, W. K.: J. Phys. Chem. 39, 121-32 (1934). (19) URQUHART,A. R., AND WILLIAMS,A. M.: J. Text. Inst. 16, T433-42 (1924). (20) WIGGINS,E. J., CAMPBELL, W. B., AND MAASS,0.: Can. J. Research 17B, 318-24 (1939).
STUDIES I N COLLOIDAL CLAYS. 11’ E. A. HAUSER
AND
D.
s. LE BEAU
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts Received July 3, 1940
Purified, well-defined, colloidal, monodisperse fractions of Wyoming bentonite were prepared by rational supercentrifugal separation by the method originally proposed by Hauser and Reed (8) and further developed by Hauser and Schachmann (10) and Hauser and Lynn (7). Particle size fractions containing particles of 20, 60, and 96 mp apparent diameter were selected, and sols of concentrations ranging between 0.2 and 0.8 weight per cent were prepared therefrom. The cataphoretic velocity, the viscosity, and the apparent specific gravity of these systems were determined. Yield values were noted if present. With these data at hand an attempt was made to evaluate the number of particles present in a unit volume of sol as well as the average distance separating them. The results of the measurements were also used to obtain a better insight into the type of water adsorption in or around the particles and into the question of gelation of systems of extremely low concentration. 1
Presented a t the Seventeenth Colloid Symposium, held a t Ann Arbor, Michigan,
J u ~ 6-8,1940.
STUDIES I N COLLOIDAL CLhYS.
55
I1
The bentonite used throughout this investigation was obtained from the Wyodak Chemical Company, Cleveland, Ohio, and sold under the trade name of “Wyodak 350”. Table 1 gives a representative analysis of the purified fractions used throughout this work. The preparation of the standayd sols from the fractionated gels has been described by the authors elsewhere ( 5 ) .
sos.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.9 per cent 59.72 per cent 2.12 per cent 26.90 per cent 0.87 per cent 3.06 per cent 2.51 per cent Il’one
Sorption capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
75.6
................................. ................................. FezOs.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Al2Os, MnlOs, Pros.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................................ ................................ ;“;azO/KzO as Ka20... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
”
TABLE 2 Ave; ve number and distance of particles per 100 cc. ‘sol CONCENTRATION
p~ cent dry weight
0.210 0.372 0.516 0.742 0.211 0.340 0.525 0.713 0.240
0.424 0.612 0.800
AYERAQEAPPARENT PARTICLE DIAMETER
NUMBER O F PARTICLEB PER 100 CC. OF DI(IPER8lON
AYERAQE DISTANCE OF PARTICLEB
m)r
mM
1,724x 3.032 X 4.010 X 5.745 x 6.683 x 1.033 X 1.519 X 2.079 X 2.210 x 3.711 X 5.288 X 6.706 X
96 96 96 96 60 60 60 60 20 20 20 20
1014 lOI4
lOI4 10“ 10x4
10l6 10l6 10’6
10’8 1OI8 10“
738 593 521 458 471 399 341 304 145 119 104 94
* EVALUATION O F T H E AVERAGE NUMBER AND DISTANCE O F PARTICLES P E R
100
CC. O F SOL
The results enumerated in table 2 must be considered only as first approximations, uniform distribution throughout the system being a necessary assumption. A further assumption which was made to facilitate calculation was to attribute a spherical shape to the dispersed particles.
56
E. A. HAUSER AND D. 6. LE BEAU CATAPHORETIC VELOCITT
Most of the cells used for the determination of the cataphoretic velocity of dispersed particles are unsatisfactory for work with clay suspensions of truly colloidal dimensions. Therefore i t was decided to study the cataphoretic velocity of the bentonite sols in a specially constructed cell, using for the purpose of illumination a standard slit ultramicroscope set-up. The construction of the cell is schematically shown in figure 1.
SlfflS IN MILLIMETERS
FIG.1. Cataphoresis cell
TABLE
3
Cataphoretic velocity of bentonite sols COWCENWTlON
CATAPEOXEllC VCLOCITI
I
r-POTENRAL
I
APPABEWC PABRmE DIbYrnTIDB
par d per om. par a=.
mq.
mr
0.210 0.372 0.616 0.742
6.1 6.1 5.5 4.3
84.2 84.2 75.6 59.6
96 96 96 96
COWCENTBARON
CATAPEOBETE VIDLOCXI
