Granted Patent B2

US 7,067,106 · App. 10/610,379 · Granted Jun 27, 2006

Abstract

Claims (16)

1. In a composition of matter which is aluminum hydroxide, produced using the Bayer Process, the improvement comprising producing an aluminum hydroxide wherein the Total Organic Carbon of the aluminum hydroxide is less than about 0.5 milligrams Total Organic Carbon/gram of aluminum hydroxide.

2. The composition of matter of claim 1 wherein the Total Organic Carbon of the aluminum hydroxide is less than about 0.3 milligrams Total Organic Carbon/gram of aluminum hydroxide.

3. The composition of matter of claim 1 wherein the Total Organic Carbon of the aluminum hydroxide is less than about 0.2 milligrams Total Organic Carbon/gram of aluminum hydroxide.

4. In the Bayer Process to produce aluminum hydroxide, the improvement comprising producing said aluminum hydroxide with a Total Organic Carbon of less than about 0.5 milligrams Total Organic Carbon/gram aluminum hydroxide; comprising the steps of:

a) dispersing the aluminum hydroxide in water, wherein the pH of the water is greater than about 10, to create a slurry of aluminum hydroxide in water, wherein said slurry comprises from about 50 to about 1000 grams of solids per liter of water, wherein the temperature of said slurry is from about 5° C. to about 95° C.;

b) maintaining the solids in suspension in the slurry using any appropriate agitation technique;

c) contacting said slurry with a mixture of ozone in oxygen wherein the concentration of ozone in oxygen is from about 1 weight percent to about 20 weight percent and the temperature of the ozone in oxygen mixture is from about 0° C. to about 30° C.; and

d) collecting the aluminum hydroxide from the slurry.

5. The process of claim 4 wherein the pH of the slurry is maintained above 10 by addition of a base to said slurry, wherein said base is selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, and their respective hydroxides.

6. The process of claim 5 in which said base is selected from the group consisting of calcium oxide, barium oxide and their respective hydroxides; and sodium hydroxide.

7. The process of claim 6 in which said base is calcium oxide.

8. The process of claim 6 in which said base is barium oxide.

9. The process of claim 4 , further comprising the steps of:

e) adding the collected aluminum hydroxide to a solution of sodium hydroxide in water and allowing the sodium hydroxide to digest the aluminum hydroxide;

f) adding solid aluminum hydroxide to said solution to begin seeded precipitation of aluminum hydroxide; and

g) collecting the precipitated aluminum hydroxide, wherein said precipitated aluminum hydroxide has a Total Organic Carbon of less than about 0.2 mg organic carbon/gram of aluminum hydroxide.

Assignments (10)