The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 01, 1994
Filed:
Mar. 30, 1993
William C Copenhafer, Yardley, PA (US);
David E Smith, Princeton, NJ (US);
Gerald F Niedringhaus, Rock Springs, WY (US);
FMC Corporation, Philadelphia, PA (US);
Abstract
A process for producing valuable sodium-based chemicals from a brine containing sodium carbonate and sodium bicarbonate, such as those containing from about 8% to about 20% total alkali obtained by contacting water with an underground trona formation by heating the brine at about 100.degree. C. to about 140.degree. C. to evaporate water, convert sodium bicarbonate to sodium carbonate and to drive off resulting carbon dioxide, reacting the brine with reduced sodium bicarbonate with an aqueous sodium hydroxide solution in amounts to convert essentially all of the remaining sodium bicarbonate in the brine to sodium carbonate, cooling to about 5.degree. C. to about 25.degree. C. to precipitate sodium carbonate decahydrate crystals, separating the crystals from their mother liquor, melting the separate crystals to form a sodium carbonate solution, heating the solution to from above about 60.degree. C. to below 110.degree. C. to evaporate water, precipitating sodium carbonate monohydrate crystals, separating the sodium carbonate monohydrate crystals from their mother liquor and calcining them to soda ash which is recovered as a product. The sodium hydroxide used in the above process is formed preferably by causticizing sodium carbonate values with calcium oxide or calcium hydroxide in a separate but parallel operating causticizing circuit.