Showing papers in "Journal of the Clay Science Society of Japan in 1985"

Synthesis of Kaolinite

Abstract: Studies on the synthesis of kaolinite are reviewed. They were grouped into four categories: 1) studies on the phase diagrams or activity diagrams including kaolinite , 2) studies on procedures to synthesize kaolinite at room temperature, 3) studies on mechanisms of transformation from rock forming minerals or volcanic glasses to kaolinite, and 4) studies on partial equilibrium reaction or reaction kinetics of kaoli nite precipitation. Recent results on the synthesis of a large quantity of kaolinite are introduced, and the morphology of the synthesized kaolinite and its reaction kinetics are discussed.

Synthesis of Molecular Sieve Zeolites

Abstract: Basic researchs for the properties and uses of molecular sieve zeolites are being done extensively in every field of zeolite science, and the properties such as adsorption, molecular sieving, ion exchange and catalysis,which cannot be found in other minerals and inorganic compounds, make possible a variety of industrial applications. These are fundamentally related to the results of synthesis study of zeolites because the zeolite syntheses bring about the exploitation of new type zeolite and play a role as driving force in the discovery of new application. In this paper, the syntheses of molecular sieve zeolites under low temperature conditions are described, and the syntheses of high silica zeolites and non-aluminosilicate compounds with zeolite structures are briefly described.

Synthesis of Allophane and Imogolite

Abstract: Studies on synthesis of allophane and imogolite are briefly reviewed. Imogolite is synthesized by heating partially neutralized and slightly re-acidified solutions containing monomeric silicic acid and aluminum salts. The optimum Si/Al molar ratio is slightly greater than 0.5. Allophane is synthesized by heating neutralized solutions which have Si/Al molar ratio of 0.5 to 4. In the light of recent studies on the reactions between monomeric silicic acid and aluminumions, imogolite is considered to from by the growth of ionic \"proto-imogolite\" Allophane is considered to form by reorganization of the structure of precipitated noncrystalline aluminum silic ates. The structure and properties of synthetic allophane and imogolite are considered to be essentially the same as those of natural counterparts except that the diameter of the tubular structural unit of the synthetic imogolite is greater than that of natural imogolite.