SOME PROPERTIES OF ALUMINUM HYDROXIDE PRECIPITATED IN THE PRESENCE OF CLAYS

Abstract

With Arizona bentonite, Wyoming bentonite, Fithian illite, and Georgia kaolin it was found that the OH/Al ratio of the aluminum hydroxide precipitated was about 2.7, providing the initial OH/Al ratio was not greater than 2.7. When the initial OH/Al ratio was increased to 3.0 the OH/Al ratio of the precipitate also increased to 3.0. The decrease in cation exchange capacity of the clays per milliequivalent of Al in the precipitate was independent of the initial OH/Al ratio when the ratio was varied from 1.0 to 2.7. When this ratio was increased beyond 2.7, however, inactivation of the exchange sites decreased, until with an initial OH/Al ratio of 3.0 there was very little decrease in exchange capacity. It required less precipitated Al to decrease the exchange capacity of Arizona bentonite than it did for the other three clays.