| 摘要 |
1,191,761. Treatment of filteraids. GREFCO Inc. 26 Jan., 1968 [13 Feb., 1967], No. 4331/68. Heading C1A. The flow ratio characteristics of diatomaceous earth and perlite filteraids are improved by treatment with a solution of a tri- or tetravalent metal salt which has a pH less than 4À0. The solution wets the filteraid uniformly and then the filteraid is heated to remove the solvent, but below the fusion temperature of the filteraid. The metal salt may be aluminium chloride, aluminium sulphate, ferric chloride, ferric sulphate (or) stannic chloride, Ce(HSO 4 ) 4 , Ce(SO 4 ) 2 or ZrOCl 2 . The solution may be in aqueous media or in alcohols, ketones or ethers and is so made as to contain an amount of metal salt equal to 0À25-10% by weight of the amount of filteraid treated. In the examples, the perlite is prepared for treatment according to Specification 791,993. The solution may be mixed with the filteraid by simply adding to the filteraid whilst stirring, by fluidizing the particles and spraying the solution on to the particles, or by picking the particles up in a high velocity air stream and injecting the solution into the air suspension. The heating temp. may be 500- 1000‹ F. The product may be agitated to break up the filteraid. |
