Method of purifying sols

Abstract

Abstract Electrolyte free colloidal sols having from 1 to 3 per cent colloidally dispersed acidic oxides are produced by removing the electrolyte therefrom by passing the sol in series through a cation-exchange material and an anion-exchange material. The sols may be produced by neutralizing an alkali metal salt of an acidic oxide, such as silica, tungstic oxide, molybdenum oxide or vanadium oxide, with an acid, such as hydrochloric or sulphuric acid, or other acidic substance. The cation-exchange material is preferably one which has been regenerated by an acid and the anion-exchange material is preferably a resinous type which has been regenerated by an alkali. Specification 20400/47, as open to inspection under Sect. 91, is referred to. The Specification as open to inspection under Sect. 91 describes also the preparation of electrolyte free sols of rubber latex, soaps, polyacrylic acid salts, albuminoids, polyvinyl alcohol, rubber, polystyrene, gums, resins, and degraded starches. This subject-matter does not appear in the Specification as accepted.ALSO:The Specification as open to inspection under Sect. 91 describes the preparation of electrolyte free colloidal sols of polyacrylic acid salts, polyvinyl alcohol and polystyrene by removal of electrolytes by passing the sols in series through cation and anion exchange materials, the former being preferably acid regenerated and the latter being preferably of a resinous type and alkali regenerated. This subject-matter does not appear in the Specification as accepted. Specification 20400/47, as open to inspection under Sect. 91, is referred to.ALSO:The Specification as open to inspection under Sect. 91 describes the preparation of electrolyte free colloidal sols of rubber, rubber latex and degraded starches by removal of electrolytes by passing the sols in series through cation and anion exchange materials, the former being preferably acid regenerated and the latter being preferably of a resinous type and alkali regenerated. This subject matter does not appear in the Specification as accepted. Specification 20400/47, as open to inspection under Sect. 91, is referred to.

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