Ecc America Inc.

Lev F Verbov

Weyman H Dunaway

A method for forming a hydrothermally aggregated kaolin clay pigment, comprising preparing an aqueous slurry of particulate kaolin clay and sodium aluminate, having a total solids concentration of from about 2 to 25% by weight, the weight ratio between kaolin and aluminate being greater than 1; and hydrothermally treating the slurry in a closed system to form aggregates of adherent kaolin platelets.

Method for forming aggregated kaolin pigment

Aggregation of kaolin particles by wet processing using a hydrothermal technique is described. Calcined clay is first digested in a solution containing NaOH and the obtained sodium silicate solution is separated. Aggregation of uncalcined clay particles by hydrothermal treatment is then carried out using the obtained solution. The method enables aggregation of low grade clays unsuitable for calcination. A two-stage hydrothermal process is also described. Bleaching with oxygen or bleaching compounds may be effected during hydrothermal treatment.

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Milledgeville, GA, United States of America

Lev F Verbov