Abstract
The viscosity of Na-saturated montmorillonite, kaolinite, halloysite, allophane and imogolite in 10-4 to 10-2M NaCl was measured using a rotational viscosimeter. The measured viscosity-clay particle concentration relationships were deviated from that stated in the Einstein equation. They were interpreted using a modified Robinson equation (Part I), and the effects of particle shape and particle-water and particle-particle interactions on the viscosity were evaluated for each mineral at different NaCl concentrations. The effect of particle shape varied with the clay mineral species in a way which was predictable on the assumption that clay particles can be approximated by rigid ellipsoids or spheres. In addition to the particle shape, the particle-water interaction, which is probably related to the development of the electrical double layer, had an important effect in the suspensions of montmorillonite and allophane at 10-3 to 10-4M NaCl, whereas the particle-particle interaction predominated in the suspensions of montmorillonite, halloysite and allophane at higher NaCl concentrations and in those of kaolinite and imogolite irrespective of the concentration of NaCl.
