Abstract: A process for obtaining monochlorated lithium sulfate from natural brines by mixing two brines: one saturated or nearly saturated with silvite (KCl), carnallite (KCl, MgCl2.6H2O), and lithium sulfate (Li2SO4.H2O), with a magnesium content of 4.7-6%, 0.8-1.2% lithium, and 1.2-4.2% total sulfate; and the other brine is saturated with bischofite (MgCl.6H2O), monohydrated lithium sulfate (Li2SO4.H2O), and carnallite (KCl, MgCl2.6H2O), and with a lithium content of 2.5-6%, below 6% magnesium, and less than 0.2% total sulfate, such that the resulting brine achieves a lithium sulfate content that exceeds its solubility in the brine, hereby it precipitates as monohydrated lithium sulfate. Crystallization can be accomplished in three stages in order to separate the carnallite from the lithium sulfate by filtering and washing it so as to enhance its purity and then drying the product if the goal is to retain anhydrous lithium sulfate.

Abstract: A subterranean salt deposit is solution mined, and the resulting calcium- and sulfate-contaminated brine is treated, e.g., by soda ash, to precipitate insoluble calcium compounds. The resulting slurry is settled, and the effluent clear brine is evaporated in a series of solar ponds to produce high-grade sodium chloride.The brine becomes progressively more concentrated with respect to sodium sulfate as it moves through the solar ponds. The sulfate-enriched brine may be recycled to the solution mine, evaporated to form a sulfate-contaminated sodium chloride crystal crop, or it may be subjected to winter cooling to remove sulfate values as Glauber's salt, the residual brine being recycled to the solar ponds or the solution mine.

Abstract: Smelts produced in spent pulping liquor recovery operations and containing sodium chloride are treated to remove sodium chloride therefrom in pure form while the loss of usable components is avoided. A solid mixture of sodium chloride, sodium carbonate and sodium sulphate is provided as such in a soda mill, or first is separated from sodium sulphide, by fractionating the smelt where sodium sulphide is present, as in the Kraft mill. The solid mixture is leached at a high temperature to remove all the sodium chloride values therefrom, along with part of the sodium carbonate and sodium sulphate. Pure sodium chloride is deposited by cooling the leach liquor and the mother liquor is recycled to the leaching step.

Abstract: Smelts produced in Kraft mill and soda mill spent pulping liquor recovery operations and containing sodium chloride are treated to remove sodium chloride therefrom in pure form while the removal of usable components is avoided. A solid mixture of sodium chloride, sodium carbonate and sodium sulphate is provided in the case of the soda mill, or first is separated from the sodium sulphide in the case of the Kraft mill. Thereafter, the solid mixture is leached to remove the sodium carbonate and sodium sulphate while leaving the sodium chloride in a substantially pure form, the resulting leach liquor being refrigerated to deposit sodium carbonate and sodium sulphate. The mother liquor, after removal of the deposited salts is recycled to the solid mixture leaching step.