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US 5,397,754 AGranted
Method of brightening kaolin clay by thermal oxidative decarboxylation of organic contaminants
AssigneeImpex SA
InventorsJoseph Iannicelli, John T. Williamson
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Abstract
A method for brightening kaolin contaminated with organic matter by decarboxylation treatment of an aqueous kaolin slurry. The decarboxylation is carried out by contacting the clay slurry with selected oxidizing agent in a pressurized reaction vessel at a temperature of 175.degree.-500.degree. C. without dehydroxylation (calcination) of the kaolin. Oxidizing agents include oxygen, ozone, hydrogen peroxide, and hypochlorite.
Claims10
A method of improving the brightness of kaolin clay contaminated with organic material, comprising:
- a) mixing organically contaminated crude kaolin clay with water to produce an aqueous kaolin clay slurry;
- b) subjecting the slurry to thermal oxidative decarboxylation by heating the slurry in a pressurized reaction vessel in the presence of an oxidizing agent to a temperature of about 175.degree. C. for a period of time sufficient to decarboxylate the organic contaminates whereby said organic contaminants are substantially removed from the kaolin clay;
- c) cooling and depressurizing the slurry;
- and
- d) recovering kaolin clay having improved brightness from the slurry.
2 more elements
Dependencies are inferred from the claim text.