Systems for treating aqueous compositions comprising lithium sulfate and sulfuric acid

A system for treating an aqueous composition comprising lithium sulfate and sulfuric acid, said system comprising:

• an evaporative crystallizer for crystallizing the aqueous composition comprising lithium sulfate and sulfuric acid under conditions to obtain crystals of lithium sulfate monohydrate and a lithium sulfate-reduced solution, and to at least substantially prevent decomposition of said crystals of lithium sulfate monohydrate into anhydrous lithium sulfate, wherein said conditions comprise the aqueous composition comprising lithium sulfate and sulfuric acid comprises from about 1 wt % to about 35 wt % lithium sulfate, based on the total weight of the aqueous composition;
• a separator for separating the crystals of the lithium sulfate monohydrate from the lithium sulfate-reduced solution;
• and
• wherein the evaporative crystallizer is configured to evaporate further vapour in either a different effect, or in the same effect by either operating an additional effect at a different pressure, or compressing the vapour and recondensing in a steam chest in the same effect.