Patent ID: 6609761
Filing Date: 2003-08-26
Classification: C01D,E21B

Abstract:
A process for the recovery of anhydrous sodium carbonate from geological formations containing deposits of lean oil shale as well as beds of essentially pure nahcolite, comprising:a. establishing a well; b. injecting hot aqueous solution via the well into a mining zone in the formation, so that the hot aqueous liquid has a temperature of at least 250Â° F. in the mining zone and is maintained at a sufficiently high pressure to prevent flashing of carbon dioxide and water vapor; c. dissolving nahcolite in the hot water to form a hot production solution comprising water and sodium bicarbonate; d. recovering the hot production solution from the well; e. decomposing the sodium bicarbonate portion of the hot production solution to form a hot aqueous solution comprising sodium carbonate; f. evaporating water from the hot aqueous solution comprising sodium carbonate to form a concentrated solution of sodium carbonate; g. producing sodium carbonate monohydrate from the concentrated solution of sodium carbonate by crystallization; and h. dewatering and calcining the sodium carbonate monohydrate to produce anhydrous sodium carbonate.