Method for recovery of alkali values from trona using sequential crystallization
AssigneeSolvay Minerals, Inc.
InventorsDavid R. Delling, Vladimir M. Zolotoochin, Francis M. Coustry, Kevin L. Green
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Abstract
A process for recovery of alkali values from trona ore comprising (a) dissolving the trona ore, (b) separating the insoluble material to obtain an alkali containing feed liquor, (c) cooling the feed liquor and crystallizing sodium bicarbonate and separating the bicarbonate crystals from the resulting mother liquor, (d) cooling the mother liquor and crystallizing sodium carbonate decahydrate and separating the decahydrate crystals from a weak liquor, and (e) treating the sodium carbonate decahydrate crystals to recover the alkali values therein.
Claims41
A method of recovering alkali values from underground trona deposits which comprises:
- (a) dissolving an alkali-containing ore in a heated dissolving solution to form a dissolved alkali feed liquor having suspended therein insoluble particles;
- (b) removing the suspended insoluble particles from the feed liquor;
- (c) cooling the feed liquor and precipitating sodium bicarbonate crystals thereby forming a mother liquor;
- (d) separating sodium bicarbonate crystals from the mother liquor;
- (e) cooling the mother liquor and precipitating sodium carbonate decahydrate crystals thereby forming a weak liquor;
- (f) separating sodium carbonate decahydrate crystals from the weak liquor;
- and
- (g) heating the weak liquor and recirculating it as the dissolving solution in step (a);
- and
- (h) recovering alkali values from the sodium carbonate decahydrate crystals.
A method of recovering alkali values from an aqueous solution comprising sodium carbonate and sodium bicarbonate, the method comprising:
- (a) providing a first feed liquor containing sufficient sodium carbonate and sodium bicarbonate in solution such that sodium bicarbonate crystals will precipitate upon cooling of the feed liquor;
- (b) cooling the feed liquor, precipitating sodium bicarbonate crystals and collecting the sodium bicarbonate crystals from a resulting first mother liquor;
- (c) adjusting the concentration of sodium carbonate and sodium bicarbonate in the first mother liquor to obtain a second feed liquor containing sufficient sodium carbonate and sodium bicarbonate such that sodium carbonate decahydrate crystals will precipitate upon cooling of the second feed liquor;
- (d) cooling the second feed liquor, precipitating sodium carbonate decahydrate crystals and collecting the sodium carbonate decahydrate crystals from a resulting second mother liquor;
- and
- (e) recovering the alkali values from the sodium bicarbonate and sodium carbonate decahydrate crystals.
A method of recovering alkali values from trona ore, the method comprising:
- (a) dissolving trona ore in a heated dissolving solution at a temperature between about 70.degree. C. and about 90.degree. C., to form a pregnant feed liquor, having suspended therein insoluble particles;
- (b) removing the suspended insoluble particles from the feed liquor;
- (c) cooling the feed liquor to a temperature between about 17.degree. C. and about 23.degree. C. and precipitating sodium bicarbonate crystals thereby forming a mother liquor;
- (d) separating sodium bicarbonate crystals from the mother liquor;
- (e) diluting the mother liquor to reduce the sodium bicarbonate concentration;
- (f) cooling the mother liquor to a temperature between about 7.degree. C. and about 12.degree. C. and precipitating sodium carbonate decahydrate crystals thereby forming a weak liquor;
- (g) separating sodium carbonate decahydrate crystals from the weak liquor;
- (h) heating the weak liquor by indirectly exchanging heat with the feed liquor;
- (i)recycling the weak liquor to make up the dissolving solution;
- and
- (j) recovering alkali values from the sodium carbonate decahydrate crystals.
Dependencies are inferred from the claim text.