Kaolin acid treated

Frequently kaolin clay is used for a raw material. In one of the older processes kaolin is treated with sulfuric acid at elevated temperature and subsequently washed to remove Hberated alumina and alkaUes. Kaolin can also serve as a raw material for preparing a number of synthetic zeofltes (21). 

Suzuki and Suga reported the use of clays as solid acids to support and activate metallocene catalysts for olefin polymerization. They were able to use much less alkylaluminmn cocatalyst relative to solution polymerization conditions. The clays were slurried with AlMeg in toluene, then treated with a solution containing zirconocene dichloride, II, and AIMeg. The metallocenium cation was presumed formed via abstraction of chloride and/or methyl ligands by acidic sites on the surface of the clay, and the low basicity of the clay smface was proposed to stabilize the coordinatively unsaturated cation. Propylene was copolymerized with 250 psi ethylene at 70°C. For acid-treated KIO montmorillonite, an activity of 3300 X 10 kg polymer/(g Zr h) was obtained. Catalysts based on vermiculite, kaolin, and synthetic hectorite all showed lower but still appreciable activities. In this brief report, the Al/Zr ratio was not specified, and the clay dispersion was not reported. 

Both kaolin and calcined clays are available with surface treatments. Many treatments may be applied but few have any commercial importance. Kaolins are available treated with surfactants and pH adjusters, which produce kaolins that may be dispersed directly into water, (e.g., rubber latices), or with amines to enhance cure performance. Stearic acid treated products may provide ease of dispersion. The most important treatments, technically, are the organo-silanes. 

Matrix Kaolin Kaolin Alumina (major), sili-ca/alumina, cerium-pillared clays, acid treated meta kaolin. 

Derivation (1) By treating pure kaolin or aluminum hydroxide or bauxite with sulfuric acid. The insoluble silicic acid is removed by filtration, and the sulfate is obtained by crystallization. (2) Similarly, from waste coal-mining shale and sulfuric acid. 

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