Process for preparing soda ash from solution mined bicarbonate brines

  • US 6,589,497 B2
  • Filed: 06/13/2001
  • Issued: 07/08/2003
  • Est. Priority Date: 06/13/2001
  • Status: Expired due to Term
First Claim
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1. A process to optimize the recovery of sodium carbonate monohydrate from a mine brine derived by in situ dissolution of an underground sodium bicarbonate ore body, the mine brine containing quantities of sodium bicarbonate comprising:

  • a. feeding the recovered mine brine to an evaporation-stripping step to concentrate sodium content in the mine brine and to convert at least a portion of sodium bicarbonate therein to sodium carbonate to form a concentrated brine;

    b. neutralizing at least a portion of remaining sodium bicarbonate in the concentrated brine to form additional sodium carbonate to form a crystallizable solution having concentrations of sodium carbonate from which monohydrate crystals of sodium carbonate will form upon evaporation of water from the crystallizable solution;

    c. feeding the crystallizable solution to a monohydrate crystallizing step in which water is evaporated to form a slurry comprising sodium carbonate monohydrate crystals and a first mother liquor containing dissolved sodium carbonate in a concentration suitable as feed to a sodium carbonate decahydrate crystallization step;

    d. separating the sodium carbonate monohydrate crystals from the first mother liquor to form a first mother liquor and to recover monohydrate crystals;

    e. feeding at least a portion of the first mother liquor to a sodium carbonate decahydrate crystallization step to crystallize sodium carbonate decahydrate crystals as a slurry in a second mother liquor;

    f. separating the sodium carbonate decahydrate crystals from the second mother liquor; and

    g. recycling the sodium carbonate decahydrate crystals to the monohydrate crystallization step.

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