Study of the Decomposition Kinetics of Kaolinite in Alkaline and Aluminate Solutions.

An experimental study was made of the decomposition kinetics of kaolinite in caustic soda solutions and in mother liquor and circulating aluminate solutions. The extraction of SiO//2 into the reaction products is determined. The existence of three periods of interaction between kaolinite and the solutions, corresponding to the dissolution of kaolinite in the kinetic, mixed, and diffusion regimes, is indicated. The activation energy of this reaction and the reaction rate constants during the different periods are determined. The data obtained are used in developing optimal conditions of desiliconization of bauxites and aluminate solutions.