Ozone treatment of alkali metal compound solutions
An aqueous solution containing an alkali metal compound solute and organic compound contaminants may be treated with ozone to oxidize and/or dissolve the organic contaminants. Treating the aqueous solution with ozone may decrease color contaminants in the alkali metal compound and may also decrease foaming in subsequent crystallization of the alkali metal compound.
1. A method of treating an aqueous alkali metal compound solution, comprising:
forming an aqueous solution comprising an alkali metal compound derived from a natural ore source, and organic compound contaminants;
crystallizing the alkali metal compound from the aqueous solution; and
introducing ozone gas into the aqueous solution when crystallizing the alkali metal compound solute therefrom to reduce total organic carbon (TOC) and color in the aqueous solution.
2. The method of claim 1 , wherein the alkali metal compound is a carbonate or bicarbonate of an alkali metal.
3. The method of claim 2 , wherein the alkali metal is sodium.
4. The method of claim 3 , wherein introducing ozone gas into the aqueous solution comprises supplying a sufficient amount of the ozone gas to reduce foaming of the aqueous solution.
5. The method of claim 1 , wherein introducing ozone gas into the aqueous solution comprises introducing the ozone gas into the aqueous solution in conjunction with oxygen gas or ambient air.
6. The method of claim 5 , wherein introducing the ozone gas into the aqueous solution in conjunction with the oxygen gas or the ambient air comprises introducing oxygen and ozone at weight ratio within a range of from about 15.7:1 to about 5.25:1.
7. A method of treating an aqueous alkali metal compound solution, comprising:
forming an aqueous solution comprising an alkali metal compound derived from a natural ore source, and organic compound contaminants;
crystallizing the alkali metal compound from the aqueous solution in a crystallizer to form a crystal slurry stream and a purge steam;
treating the purge stream with ozone; and
recycling the ozone treated purge stream to the step of crystallizing the alkali metal compound.
8. The method of claim 7 , wherein treating the purge stream with ozone comprises:
filtering at least a portion of the purge stream; and
treating the filtered at least a portion of the purge stream with the ozone.
9. The method of claim 7 , wherein recycling the ozone treated purge stream to the step of crystallizing the alkali metal compound comprises sending the ozone treated purge stream into the crystallizer.
10. The method of claim 7 , wherein recycling the ozone treated purge stream to the step of crystallizing the alkali metal compound comprises sending the ozone treated purge stream into the aqueous solution before the aqueous solution enters the crystallizer.
11. The method of claim 10 , wherein sending the ozone treated purge stream into the aqueous solution before the aqueous solution enters the crystallizer comprises sending the ozone treated purge stream into the aqueous solution before the aqueous solution enters a filtration system upstream of the crystallizer.
12. A process of forming an alkali metal compound product, comprising:
introducing ozone into an alkali metal compound solution comprising an alkali metal compound and soluble organic colorant contaminants to reduce each of color, total organic carbon, and foaming in the alkali metal compound solution;
crystallizing the alkali metal compound from the alkali metal compound solution in a crystallizer to form a crystal slurry stream and a purge stream;
forming an alkali metal compound product from the crystal slurry stream, the alkali metal compound product exhibiting high bulk density and a white color; and
treating the purge stream with additional ozone.
13. The process of claim 12 , wherein the alkali metal compound comprises at least one of sodium carbonate and sodium bicarbonate.
14. The process of claim 12 , further comprising dissolving alkali metal compounds derived from a naturally occurring ore body in water to form the alkali metal compound solution.
15. The process of claim 12 , wherein introducing ozone into an alkali metal compound solution comprises introducing the ozone into the alkali metal compound solution in conjunction with oxygen gas.
16. The process of claim 15 , wherein introducing the ozone into the alkali metal compound solution in conjunction with oxygen gas comprises introducing the oxygen gas and the ozone at a weight ratio within a range of from about 15.7:1.0 to about 5.25:1.0.
17. The process of claim 12 , wherein introducing ozone into an alkali metal compound solution comprises introducing the ozone at a stoichiometric ratio of about 50% to about 500% of the soluble organic colorant contaminants.
18. The process of claim 12 , wherein introducing ozone into an alkali metal compound solution comprises introducing the ozone into the alkali metal compound solution before crystallizing the alkali metal compound from the alkali metal compound solution.
19. The method of claim 12 , further comprising recycling the purge stream treated with ozone to the crystallizer, another crystallizer, or a crystallizer feed tank.
20. The method of claim 12 , wherein introducing ozone into an alkali metal compound solution comprises introducing the ozone into the alkali metal compound solution while crystallizing the alkali metal compound from the alkali metal compound solution.