CARBONATE SOLUTION PROCESSING METHOD Russian patent published in 2001 - IPC

FIELD: metallurgy and chemical engineering. SUBSTANCE: method involves evaporation of carbonate solutions to isolate alkali metal carbonates or their mixture with sulfates, separation of mother liquor, conversion-mediated preparation of potassium sulfate, mixing mother liquor with sulfuric acid and/or aluminum sulfate solution, separating aluminum hydroxide precipitate from sulfate solution, and using the latter to prepare potassium sulfate. Depending on cation composition of carbonate solutions obtained from aluminum-containing raw material, soda or successively soda and potash are isolated as alkali metal carbonates. Sulfuric acid and/or aluminum sulfate solution is mixed with mother liquor after isolation of soda or potash. To obtain potassium sulfate by conversion of sulfate-containing solutions, alkali metal sulfates, e.g. sodium sulfate, or their mixture with carbonates, or sulfuric acid can be utilized. Mother liquor is advantageously mixed with aluminum sulfate solution at 50 to 90 C to achieve pH value of mixture between 9.5 and 11.0. EFFECT: reduced aluminum impurity level in soda and potassium sulfate and produced additional amount of aluminum hydroxide, which can be isolated in the form of pseudoboehmite. 7 cl, 1 tbl, 4 ex