Method of treating an aqueous suspension of kaolin

A method of treating a kaolin particulate material to improve one or more of its properties by removal of impurity particles therein which includes:

• (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) diluting the dispersed aqueous suspension by adding a diluent thereto;
• (c) adding a selective flocculation polymer to the diluted suspension;
• (d) allowing the suspension containing the polymer added in (c) to separate in a selective flocculation separator into layers comprising a flocculated product layer and a deflocculated impurity layer containing the separable impurity;
• and
• (e) extracting the separated layers from the separator to form a deflocculated impurity layer stream, and
• (f) recirculating at least a portion of the deflocculated impurity layer stream and adding into the dispersed aqueous suspension produced in step (a) without removing the impurities from the deflocculated impurity layer stream.