Abstract:Cyclic metallurgical process for separation and recovery of Cr from vanadium precipitated solution by precipitation with PbCO₃ and leaching with Na₂CO₃ was investigated. The concentration of Cr residue in the solution decreases from 2.360 to 0.001 g/L by adding PbCO₃ into vanadium precipitated solution according to Pb/Cr molar ratio of 2.5, adjusting the pH to 3.0 and stirring for 180 min at 30 °C. Then, the precipitates were leached with hot Na₂CO₃ solution to obtain leaching solution containing Na₂CrO₄ and leaching residue containing PbCO₃. The leaching efficiency of Cr reaches 96.43% by adding the precipitates into 0.5 mol/L Na₂CO₃ solution with the mass ratio of liquid to solid (L/S) of 10:1 mL/g and stirring for 60 min under pH 9.5 at 70 °C. After filtration, leaching residue is reused in Cr precipitation and leaching solution is used to circularly leach the Cr precipitates until Na₂CrO₄ approaches the saturation. Finally, the product of Na₂CrO₄·4H₂O is obtained by evaporation and crystallization of leaching solution.

Key words: vanadium precipitated solution; lead salt precipitating chromium; sodium carbonate leaching chromium; cyclic metallurgical process