Abstract: It is shown in this paper that KCl and AlCl₃ affect the colloidal properties of the mixed suspension consisting of montmorillonite(Mt)particles(possessing permanent negative charges)and aluminum magnesium hydroxide(possessing permanent positive charges)/glycerol particles by measuring electrophoretic mobilities(U), rheological parameters and middle pressure fluid loss(FL). With increase of KCl concentration, Uin absolute value, apparent viscosity(AV)and Bingham yield point(YP)of the mixed suspension increase first, then decrease, showing a maximum value at KCl content about 10%, and change no longer at KCl content above 4.0%. With increase of AlCl₃ concentration, U decreases in absolute value, and AV and YP decrease first and then increase and then decrease again. The FLincreases with the increase of KCl and AlCl₃ contents, indicating that aggregation in the mixed suspension is aggravated.

Key words: KCl, AlCl₃, montmorillonite, aluminum magnesium hydroxide, suspension, colloidal property