U.S. Borax, Inc.

Samuel M Pickering, Jr

Donald G Turner

J Elmo Bloodworth

The present invention provides a process for whitening kaolin contaminated with chlorite/biotite micas. The process comprises the steps of contacting the kaolin contaminated with chlorite/biotite micas with an aqueous acid solution to convert the chlorite/biotite micas into kaolin and one or more dissolved metal salts, and separating the kaolin from the dissolved metal salts. The present invention also provided an overall system for whitening kaolin contaminated with chlorite/biotite micas. The process comprises blunging the kaolin contaminated with chlorite/biotite micas to provide a 20 to 70 percent solid slurry, degritting the slurry, delaminating the degritted slurry, fractionating the degritted slurry, subjecting the slurry to a magnetic field to remove iron or iron-titanium oxides, reductive leaching the slurry, contacting the slurry with an aqueous acid solution to convert the chlorite/biotite micas into kaolin or a kaolin-like clay and one or more dissolved metal salts (e.g., iron, magnesium, and potassium salts), and separating the kaolin or kaolin-like clay from the dissolved metal salts.

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Macon, GA, United States of America

Samuel M Pickering, Jr