Recovery of vanadium and chromium from leaching solution of sodium roasting vanadium slag by stepwise separation using amide and EHEHPA

The recovery of vanadium and chromium in the leaching solution of sodium roasting vanadium slag has always been a difficult issue and received considerable interest. The present study was based on our previous research to recover vanadium from the raffinate where Cr(VI) had been removed with amide. Extraction of high concentration vanadium (V) from sulphate acid medium was explored and the extraction performances of D2EHPA, EHEHPA and Cyanex 272 were compared. The results demonstrated that EHEHPA was the most suitable extractant to extract vanadium from the raffinate and 99.91% vanadium could be recovered with three-stage countercurrent extraction. The V2O5 product with 99.97% purity was obtained when the V-loaded organic phase was scrubbed and stripped. The effects of different parameters on the stoichiometry of vanadium (V) extraction under equilibrium conditions were studied. The extraction mechanism was investigated using FT-IR and ESI-MS in depth, and the extraction of V(V) with three used extractants all followed an ion exchange mechanism. A feasible way was provided by the study for selective recovery of vanadium and chromium in the leaching solution of sodium roasting vanadium slag.