ABSTRACT
III. The Clay-Water System............................................. 534 A. Hydrates of 2:1 Clay Minerals............................ 534 B. Structure of the Hydrates................................... 535 C. Structure with Diffuse Ionic Layers .................. 538 D. Effect of Calcium Ions......................................... 540
IV. How Colloidal Clay Mineral Dispersions are Prepared ................................................................... 542 A. Purification of Clays......................................... 542 B. Fractionation of Clays ...................................... 544 C. Dispersions of Kaolin ....................................... 546 D. Dispersions of Smectites and Vermiculites ..... 548 E. Hþ-Saturated Smectites ................................... 551
V. Coagulation of Clay Mineral Dispersions ............... 552 A. Stability Against Salts ..................................... 552 B. Calculation of Interaction Energies................. 556 C. Coagulation of Dispersions
Containing Two Smectites................................ 559 VI. Flocculation and Stabilization of Clay
Dispersions by Macromolecules.............................. 565 A. Flocculation by Polyanions............................... 565 B. Flocculation by Polycations.............................. 567 C. Peptization (deflocculation) of
Clays by Macromolecule................................... 569 VII. Aggregation of Clay Mineral Particles
and Gelation............................................................. 571 A. Types of Aggregation........................................ 571 B. Sedimentation, Filtration................................. 576 C. Sol-Gel Transitions .......................................... 578 D. Hydrogels of Organoclays ................................ 582 E. Gelation in Organic Solvents ........................... 585
VIII. Applications.............................................................. 586 A. Common Clays and Kaolins ............................. 586 B. Bentonite Dispersions ...................................... 589
IX. Final Remarks.......................................................... 591 References............................................................................ 592
I. INTRODUCTION
Colloid scientists dream of colloidal dispersions to behave as demanded by theories. Probably the dreams can never be realized; neither the systems nor the theories are perfect.
