THE INTERACTION MECHANISM OF AL-MG MMH SO LS WITH NA-MONTMORILLONITE SUSPENSIONS

The effects of inorganic salts (NaCl, KCl and CaCl2) and pH values on the interaction between Al-Mg MMH soi(aluminum magnesium mixed metal h ydroxides) and Na-montmorillonite (Na-Mt) suspensions have been studie d Ly the measurments of rheology, electrophoretic mobility and pH. The results show that the increase of MMH in Na-Mt suspensions produced a n increase in YP(yield point) at first and then a decrease after a max imum but a gradual decrease in pH, The results are interpreted as mean ing that the MMH sols can interact with Na-Mt suspensions through an i on exchange mechanism, In the presence of saturated NaCl, a much less change of YP and no YP maximum under the experimental concentrations o f MMH can be explained by DLVO theory, Due to tile effects of pH on io n exchange reaction the change of YP with pH of MMH/Na-Mt systems is i n terms oi parabolic curve, Inorganic salts lower YP and pH in the ord er of CaCl2 > KCl similar to NaCl, and the order is found to be consis tent with that for experimental estimates oi the number of unit layers in face-to-face association, This would imply that the metallic ions must. function as the exchangeable cations.