Patent ID: 6615987
Filing Date: 2003-09-09
Classification: B01D,B03D,C01P,C09C

Abstract:
A method of treating a kaolin particulate material to improve one or more of its properties by removal of impurity particles therein which includes the steps of:(a) producing a dispersed aqueous suspension of a kaolin particulate material containing at least 0.1% by weight, based on the dry weight of the kaolin particulate material of separable particulate impurity; (b) conditioning the suspension prior to adding selective flocculation polymer thereto by allowing the suspension to age for a period of at least 30 minutes and optionally by adding one or more conditioning chemicals thereto; (c) adjusting the pH of the suspension to be at least about 9.5; (d) adding to the suspension at a pH of at least about 9.5 a selective flocculation polymer which facilitates separation of the separable impurity from the kaolin by flocculating the kaolin and allowing particles of the impurity to be or remain deflocculated; (e) allowing the suspension containing the polymer added in step(d) to separate in a selective flocculation separator into layers comprising a flocculated product layer and a deflocculated impurity layer containing the separable impurity; and (f) extracting the separated layers from the separator.