METHOD FOR EXTRACTION OF COBALT FROM CHLORIDE SOLUTIONS CONTAINING NICKEL AND IMPURITY METALS Russian patent published in 2007 - IPC C22B23/00 C22B3/28 

FIELD: hydrometallurgy of nonferrous metals.

SUBSTANCE: before extraction of cobalt method involves treatment of the parent chloride solution containing nickel and impurity metals with a reducing reagent as metallic nickel or its alloy and conversion of iron (III) and copper (II) to lower oxidation states. Then method involves correction of prepared chloride solution by the concentration of copper, cobalt and chlorine wherein this correction of the copper concentration is carried out by its extraction up to providing the concentration 1-20 mg/l and the concentration of cobalt and chlorine by mixing the parent solution with part of raffinate and evaporating the combined chloride solution up to providing the content of cobalt 30-70 g/l and that of chloride 280-355 g/l. Cobalt is extracted with organic mixture containing, vol.%: tertiary amine, 30-35; aliphatic (C₈-C₁₀)-alcohols and a diluting agent with the ignition point above 60°C, 50-60. Extraction can be carried out in a single or two-stage regimen. The cobalt extract is subjected for washing out with chloride solution with the concentration of chloride ions 120-300 g/l by countercurrent process on 3-6 steps in the ratio organic and aqueous phases O:A = (10-60):1 and conversion of nickel, manganese, lead and iron (II) impurity into chloride solution. Re-extraction of cobalt is carried out on 4-7 steps in the ratio organic and aqueous phases O:A = (5-12):1 up to providing its concentration 70 g/l, not less, and the following purification from microimpurities. For regeneration of organic phase the latter is purified from iron (III), copper and zinc impurities by aqueous re-extraction on 2-3 steps in the ratio O:A = 1:(0.5-2). Regenerated organic phase is used for extraction of cobalt, correction of chloride solution by copper and for purification of re-extract from microimpurities. The total content impurities of Fe, Ni, Cu, Mn and Zn in prepared cobalt chloride is 18-75 mg/l. Invention provides enhancing degree of extraction of cobalt to cobalt chloride up to 99.0-99.7% in simultaneous providing its concentration in solution 70-120 g/l. Method is safety and uses a limited number of reagents. Invention can be used in separating cobalt and nickel in chloride media formed in hydrochloride processing of natural and secondary cobalt-containing raw and for separation of cobalt from impurity components as nonferrous metals and iron.

EFFECT: improved method of extraction.

15 cl, 2 dwg, 4 ex