Complexation separation for vanadium and chromium by dithiocarbamate and its application in treatment of chromium-vanadium-bearing slag
(1. Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
3. Pangang Group Co., Ltd., Panzhihua 617067, China)
2. School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
3. Pangang Group Co., Ltd., Panzhihua 617067, China)
Abstract: A novel method for the separation and reclamation of vanadium and chromium from acidic solution was proposed. The principle for the separation is based on selective complexation. In specific, V(V) can be complexated by dithiocarbamate to form VO(R1R2NCS2)3 precipitate, leaving Cr(III) remained in the acidic solution. Then the reclamation of V and Cr from VO(R1R2NCS2)3 precipitate and Cr(III)-bearing solution can be reached by decomplexation and neutralization, respectively. The kinetics of the complexation reaction was studied. In addition, the precipitation ratio of vanadium reached 97% and the loss of chromium was less than 4% after process optimization. The complexing agent could be regenerated with a high ratio of 99.5%. The method was successfully applied to treating chromium-vanadium-bearing slag produced in conventional vanadium production industry. Vanadium and chromium could be extracted from the slag in the form of calcium vanadate and Cr2O3 product with a purity of over 98%.
Key words: vanadium; chromium; separation; complexation; dithiocarbamate