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US 7,708,972 B2Granted
Method for obtaining sodium carbonate crystals
AssigneeSolvay (SociétéAnonyme)
InventorsFrancis Coustry, Michel Hanse
Life of this patent
Estimating the term…
Abstract
Method for producing sodium carbonate, according to which an aqueous sodium chloride solution (5) is electrolyzed in a membrane-type cell (1) from which an aqueous sodium hydroxide solution (9) is collected, and carbonated by direct contact with carbon dioxide (15) to form a slurry of crystals of a sodium carbonate (16), and the slurry or its mother liquor is evaporated (3) to collect sodium carbonate (18).
Claims14
A method of producing sodium carbonate monohydrate, comprising:
- electrolyzing an aqueous sodium chloride solution in a cell with an ion permselective membrane in order to produce chlorine and an aqueous solution comprising at least 25% by weight of sodium hydroxide, and
- carbonating the aqueous solution comprising sodium hydroxide essentially free of bicarbonate and carbonate ions, wherein the carbonation is carried out by directly contacting carbon dioxide with the aqueous solution comprising sodium hydroxide under conditions that cause the initial conversion of the aqueous solution into an aqueous slurry of comprising sodium carbonate monohydrate crystals without evaporation.
Dependencies are inferred from the claim text.