Process for whitening kaolin
First Claim
1. A process for whitening kaolin contaminated with chlorite/biotite micas, the process comprising the steps of contacting the kaolin contaminated with chlorite/biotite micas with an aqueous acid solution at a pH of less than about 2 to convert the chlorite/biotite micas into kaolin and one or more dissolved metal salts, and separating the kaolin from the dissolved metal salts.
1 Assignment
0 Petitions
Accused Products
Abstract
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.
35 Citations
15 Claims
- 1. A process for whitening kaolin contaminated with chlorite/biotite micas, the process comprising the steps of contacting the kaolin contaminated with chlorite/biotite micas with an aqueous acid solution at a pH of less than about 2 to convert the chlorite/biotite micas into kaolin and one or more dissolved metal salts, and separating the kaolin from the dissolved metal salts.
- 8. In a process for whitening kaolin by removing impurities therein including one or more techniques for removing impurities comprising degritting, delaminating, centrifuge fractionation, magnetic separation or reduction leaching, the improvement comprising after removing the impurities, the step of contacting the kaolin with an aqueous acid solution to convert chlorite/biotite micas into kaolin.
-
12. A process for whitening kaolin contaminated with chlorite/biotite micas, the process comprising the steps of:
-
(a) blunging the kaolin contaminated with chlorite/biotite micas to a 20 to 70 percent solids slurry; (b) degritting the slurry; (c) delaminating the degritted slurry; (d) fractionating the degritted slurry; (e) subjecting the slurry to a magnetic field to remove iron or iron-titanium oxides; (f) reductive leaching the slurry with a hydrosulfite at pH of 3 to 4.5; (g) contacting the slurry with an aqueous acid solution to convert the chlorite/biotite micas into kaolin and one or more metal salts; and (h) separating the kaolin from the metal salts. - View Dependent Claims (13, 14, 15)
-
Specification