The Bureau of Mines investigated methods of recovering potash values from process and waste brines. Laboratory pan evaporation of four chloride brines produced crude salts containing predominantly sylvite, halite, and carnallite. Six sulfate-chloride brines produced crude salts containing primarily schoenite, kainite, leonite, sylvite, carnallite, and halite. Potash grades ranged from 7.2% to 22.2% K20 and recoveries by crystallization ranged from 85% to 99%. Sylvite flotation from chloride evaporites with amine collector recovered 90% to 97% of the potash in a concentrate containing 54.3% to 60.3% K2o. Fatty acid flotation of the high sulfate evaporite recovered 78% of the sulfate minerals in a 28%-k2o concentrate. Flotation of the remaining chloride minerals with amine collector recovered 80% of the potash in a 59.7%-K2o concentrate. Solar evaporation of 10,000 gal of brine recovered 99% of the potash in a crude evaporite containing 24.5% Schoenite and 20% sylvite. Flotation in a 100-lb/h continuous flotation unit recovered over 95% of the potash in schoenite and sylvite concentrates containing 28% and 62.3% K2o, respectively.
Ch.12 Salts & Brines '85, Soc. Min. Eng. AIME, New York, 1985, PP. 119-133