Kaolin products and their production

摘要

A method of producing a kaolin particulate material suitable for use as improved SC filler includes the steps of: (a) preparing an aqueous feed suspension of kaolin; (b) treating the kaolin of the feed suspension by attrition grinding in a grinding vessel using grinding media granules; (c) delivering an aqueous suspension of the kaolin ground in step (b) to a particle size classifier and separating the kaolin of the suspension into a coarse fraction and a fine fraction; (d) returning an aqueous suspension of the coarse fraction produced in step (c) to the grinding vessel to be further attrition ground; and (e) extracting an aqueous suspension of the fine fraction produced in step (c) as a product suspension; wherein the kaolin of the feed suspension in step (a) is such that not more than 30 % by weight has a particle size less than 2 žm and not more than 30 % by weight has a particle size greater than 10 žm and wherein the kaolin of the product suspension produced in step (e) is such that not more than 10 % by weight has a particle size greater than 10 žm and not more than 10 % by weight has a particle size less than 0.25 žm.