Abstract

Nahcolite solution mining process comprising drilling at least one well into a Nahcolite bed, circulating hot barren aqueous liquor in a cavity in said Nahcolite bed for a time sufficient to produce a pregnant liquor having an increase in the concentration of NaHCO3 in the range of from about 3 to about 20% while maintaining Na2 CO3 concentration in the range of about 0.25-4%, preferably less than 2.5%, withdrawing said pregnant liquor, cooling said pregnant liquor to preferentially precipitate NaHCO3 therefrom and to produce a barren liquor, recovering said NaHCO3, and reheating and re-injecting said barren liquor in said well. The cavity temperature is maintained below about 250° F. and preferably below about 200° F. The barren liquor is injected at a pressure of below about 150 psig. The pregnant liquor is extracted at a temperature in the range of from about 85° F. to about 200° F., and the cystallization occurs at a temperature of about 25°-120° F. The NaCl concentration is maintained at below about 6% and preferably below about 1.0%. Crystalline sodium bicarbonate of high purity (98+% NaHCO.sub. 3) is produced in the as-crystallized form, and simple washing increases the purity.