Preparation of sodium carbonate anhydride
Patent 4252781 Issued on February 24, 1981. Estimated Expiration Date: 
April 2, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 2, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 439330 2005868 2133455 2183324 3113834 3246962 3264057 3451767 InventorsAssigneeApplicationNo. 06/026449 filed on 04/02/1979US Classes:423/427, By reacting a bicarbonate423/195, Subjecting mixture to pressure, vacuum, or steam423/421Alkali metal containing (Li, Na, K, Rb, or Cs)ExaminersPrimary: Carter, Herbert T.Assistant: Straub, Gary P. Attorney, Agent or FirmInternational ClassesC01D 7/00 (20060101)C01D 7/12 (20060101) C01D 7/37 (20060101) Foreign Application Priority Data1976-09-03 JPAbstractA thick suspension of sodium carbonate anhydride is obtained by countercurrent contacting of a high pressure steam and a suspension of sodium bicarbonate or sodium sesquicarbonate in a concentrated solution of sodium carbonate. The decomposition reaction is promoted to near completion by maintaining the reaction temperature above 150° C. to realize a high HCO3- ion concentration in the solution. The sodium carbonate anhydride suspension is cooled to cause transition of the anhydride to the monohydrate, followed by the separation of the crystalline monohydrate from the mother liquor. Calcination of this monohydrate gives a dense soda ash featuring a high purity and a uniform particle size, while the mother liquor is recycled for the preparation of the sodium bicarbonate suspension.Other References
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