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US 10,590,003 B1Granted
Method of brightening ground calcium carbonate
AssigneeMississippi Lime Company
InventorsSean Dingman, Kory Mueller
Life of this patent
Estimating the term…
Abstract
A chemical processing method to increase the brightness of a naturally sourced GCC. The process described herein employs a persulfate under certain heating and stirring conditions to effect a brightness change which can be on the order of about 8 points on the GE brightness scale and can move a GCC which is under a GE level of 80 to above a GE level of 80.
Claims12
A method of brightening calcium carbonate, the method comprising:
- providing an initial calcium carbonate solid with GE brightness of less than 80;
- mixing said calcium carbonate with a base and deionized water of about 1 to 3 by weight to produce a basic (pH>7) slurry;
- heating said basic slurry to a temperature of between 60° C. and about 85° C.;
- adding a persulfate to said slurry to form an intermediate slurry;
- agitating said intermediate slurry;
- filtering said intermediate slurry to collect an initial solid;
- diluting said initial solid with water and agitate to create a wash;
- filtering said wash and collect a final calcium carbonate solid;
- and
- drying said final calcium carbonate solid;
- wherein, said final calcium carbonate solid has a GE brightness of greater than 80.
8 more elements
Dependencies are inferred from the claim text.