Method for beneficiating discolored kaolin to produce high brightness coating clay

A method for beneficiating a low brightness, fine particle size discolored kaolin crude to produce a high brightness coating clay having a brightness of a least 89, comprising the steps of:

• preparing a dispersed aqueous slurry from a fine particle size discolored crude kaolin having a solids content, a water washed G.E. brightness in the range of 75 to 85, a contaminant titania content of from 0.5 to 3.0%, a contaminant iron content of from 0 to 2%, expressed as Fe.sub.2 O.sub.3, and a P.S.D. such that at least 85% by weight of the particles are of less than 2 .mu.m E.S.D.;
• classifying said slurry to recover a kaolin fraction wherein at least 90% by weight of the particles are of less than 0.5 .mu.m E.S.D.;
• subjecting said recovered fraction as a slurry to a first oxidative bleaching to partially bleach organic discolorants, and to facilitate subsequent flocculation of the clay;
• selectively flocculating the solids of the slurry from said first oxidative bleaching step with a high molecular weight anionic polyacrylamide or a copolymer of polyacrylate and polyacrylamide, to form a supernatant phase which is concentrated with said contaminant titania, and a flocced clay phase having a reduced titania content, but which includes the remaining discolorant organics;
• treating the flocs in aqueous suspension with gaseous ozone to destroy the flocculent polymer thereby restoring the kaolin to a dispersed phase, while further oxidizing the discoloring organics;
• and
• recovering and further beneficiating the ozonized kaolin to provide said high brightness coating clay.