METHOD FOR PROCESSING SOLUTION CONTAINING SULFURIC ACID AND IMPURITY ELEMENTS Russian patent published in 2003 - IPC

FIELD: hydrometallurgy, chemical technology. SUBSTANCE: the parent sulfuric acid solution obtained by mixing regenerable solution and raffinate taken in the amount up to 80% of total raffinate volume is concentrated by evaporation up to content of sulfuric acid 850 kg/m³, not above, followed by cooling to temperature 17-45 C, filtration, precipitate separation, mixing with organic solvent as aliphatic alcohols and extraction of sulfuric acid is carried out. Alcohols with carbon atom number C₇-C₁₂ is used as aliphatic alcohol being preferably 2-ethylhexanol, octanol-1, octanol-2 or their mixtures. Extraction is carried out in 3-6 steps in volume ration of organic and aqueous phases 5:1, not above, up to concentration of sulfuric acid in raffinate 280-360 kg/m³. Re-extraction is carried out in 2-5 steps using purified water as re- extractant, condensate from evaporation of the parent solution or purified sulfuric acid solution up to the content of sulfuric acid in re-extract 500 kg/m³. The parent sulfuric acid solution can contain 50 kg/m³ and above of sulfuric acid in the total content of impurity element sulfates up to 150 kg/m³. After extraction washing out extract can be carried out using purified water, condensate from evaporation of the parent solution or purified sulfuric acid solution in volume ratio of organic and aqueous phases = (20-10):1 and with feeding washed out extract to re-extraction and washing out solution to stage of concentrating. Invention allows to enhance sulfuric acid extraction degree in average by 1.5-fold and to enhance its concentration up to 500 kg/m³ and to provide minimal content of impurity elements. Invention can be used in regeneration of industrial solutions containing sulfuric acid, in part, in preparing pigment titanium dioxide in manufacture of electrolyte copper, in preparing sulfuric acid by contact method and so on. Regenerated sulfuric acid in broad range of concentrations can be used both in the basic production and in other technologies. EFFECT: improved processing method, enhanced effectiveness. 7 cl, 3 dwg