Production of sodium carbonate from solution mine brine

A method of producing sodium carbonate decahydrate from liquors containing sodium bicarbonate derived from the dissolution in situ of an underground carbonate ore deposit containing sodium bicarbonate values, comprising:

• a) contacting said ore deposit with an aqueous solution containing sodium carbonate to produce a sodium bicarbonate enriched feed brine in which the sodium bicarbonate and sodium carbonate content is such that cooling of such enriched feed brine to precipitate crystals in subsequent step b) will not result in the formation of sodium bicarbonate or sodium sesquicarbonate crystals instead of or in addition to sodium carbonate decahydrate crystals;
• b) cooling said sodium bicarbonate enriched feed brine stream of step a) to precipitate sodium carbonate decahydrate crystals, terminating the crystallization before significant sodium bicarbonate or sodium sequicarbonate precipitation occurs, and yielding a slurry of said crystals in a mother liquor;
• c) separating said sodium carbonate decahydrate crystals from said mother liquor;
• d) steam stripping said mother liquor to convert a portion of said sodium bicarbonate to sodium carbonate to yield a carbonate enriched, bicarbonate depleted aqueous solution;
• and
• e) recycling at least a portion of said carbonate enriched, bicarbonate depleted aqueous solution to form at least part of said aqueous solution which contacts said ore deposit.

A method of producing sodium carbonate decahydrate from liquors containing sodium bicarbonate derived from the dissolution in situ of an underground carbonate ore deposit containing sodium bicarbonate values, consisting essentially of:

• a) contacting said ore deposit with an aqueous solution containing sodium carbonate to produce a sodium bicarbonate enriched feed brine in which the sodium bicarbonate and sodium carbonate content is such that cooling of such sodium bicarbonate enriched feed brine to precipitate crystals in subsequent step c) would result in the formation of sodium bicarbonate or sodium sesquicarbonate crystals instead of or in addition to sodium carbonate decahydrate crystals;
• b) adjusting the concentration of sodium bicarbonate in said sodium bicarbonate enriched brine stream to form a brine stream of such a composition that it will not precipitate sodium sesquicarbonate or sodium bicarbonate upon cooling in the subsequent cooling sodium carbonate decahydrate crystallization of step c) and will precipitate essentially only sodium carbonate decahydrate in the subsequent cooling sodium carbonate decahydrate crystallization of step c);
• c) cooling said brine stream of step b) to precipitate sodium carbonate decahydrate crystals, terminating the crystallization before significant sodium bicarbonate or sodium sequicarbonate precipitation occurs, and yielding a slurry of said crystals in a mother liquor;
• d) separating said sodium carbonate decahydrate crystals from said mother liquor;
• e) steam stripping said mother liquor to convert a portion of said sodium bicarbonate to sodium carbonate to yield a sodium bicarbonate depleted aqueous solution;
• and
• f) recycling at least a portion of said sodium bicarbonate depleted aqueous solution to form at least part of said aqueous solution which contacts said ore deposit.

A method of producing sodium carbonate decahydrate from liquors containing sodium bicarbonate derived from the dissolution in situ of an underground carbonate ore deposit containing sodium bicarbonate values, consisting essentially of:

• a) contacting said ore deposit with an aqueous solution containing sodium carbonate to produce a sodium bicarbonate enriched feed brine in which the sodium bicarbonate and sodium carbonate content is such that cooling of such enriched feed brine to precipitate crystals in subsequent step b) will not result in the formation of sodium bicarbonate or sodium sesquicabonate crystals instead of or in addition to sodium carbonate decahydrate crystals;
• b) cooling said sodium bicarbonate enriched feed brine stream of step a) to precipitate sodium carbonate decahydrate crystals, terminating the crystallization before significant sodium bicarbonate or sodium sequicarbonate precipitation occurs, and yielding a slurry of said crystals in a mother liquor;
• c) separating said sodium carbonate decahydrate crystals from said mother liquor;
• d) steam stripping said mother liquor to convert a portion of said sodium bicarbonate to sodium carbonate to yield a carbonate enriched, bicarbonate depleted aqueous solution;
• and
• e) recycling at least a portion of said carbonate enriched, bicarbonate depleted aqueous solution to form at least part of said aqueous solution which contacts said ore deposit.