Thiele Kaolin Company

Lee Ann Arrington-Webb

Prakash B Malla

Chris B Maxwell

Amy C Semratedu

Cesar I Basilio

Robert A Lowe

A improved process for beneficiating kaolin clays to remove discoloring impurities is disclosed. The beneficiation of kaolin clay is improved by fractionating a kaolin clay starting material into a lower brightness first fraction having a majority of the discoloring impurities and a higher brightness second fraction with less impurities. The first fraction is then beneficiated (such as by flotation, selection flocculation, high intensity magnetic separation and/or leaching) to produce a kaolin clay product with improved optical properties. The first and second fractions may be combined to produce a product with improved optical properties.

Process for beneficiating kaolin clays

Fine-grained kaolin clays having improved brightness can be produced by (a) using centrifugation to fractionate the clay starting material into finer and coarser fractions, (b) subjecting the coarser fraction to flotation to remove discoloring impurities and (c) combining the finer and floated coarser fractions to produce fine-grained kaolin clays having improved brightness.

Process for improving the brightness of fine-grained kaolin clays

An opacifying kaolin clay pigment with improved rheological properties and good opacifying characteristics is manufactured by a process which comprises reacting a mixture of water, kaolin clay and calcium carbonate with a hydroxide component at a temperature of at least 60.degree. C.

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Sandersville, GA, United States of America

Lee Ann Arrington-Webb