| 摘要 |
1,146,926. Thixotropic thickeners. W. R. GRACE & CO. 3 July, 1967 [1 Aug., 1966], No. 30595/67. Heading C1A. [Also in Divisions C3 and C5] A binary composition of finely divided chrysotile asbestos in the form of fibres having cross-sections in the colloidal range 5 to 95% by weight and silica of particle size 2 to 10 microns 95 to 5% by weight for use in thicken- .ing liquids is produced by a process which forms a rotating body of particulate chrysotile asbestos and silica suspended in a gaseous medium in a grinding -zone at a temperature between ambient and 650‹ C., into which is continuously injected further gas in a plurality of high velocity streams directed inwardly into said body so as to cause extreme turbulence therein, withdrawing the gaseous medium and the composition and separating the composition from the gas. Suitable gaseous media are air and steam. The process may be carried out in a fluid energy mill of known type, and the operating pressure is from 7 to 35 preferably 7 to 21 kg/cm.<SP>2</SP> (gauge) and auxiliary gas may be fed in at 7 to 35 kg/cm.<SP>2</SP> preferably 10À5 to 35 kg/cm.<SP>2</SP> |
