Extraction and separation of chromium from the solution after hydrolysis precipitation of vanadium

ABSTRACT

The qualified chromium oxide product was prepared successfully using acidic chromium solution after hydrolysis precipitation of vanadium based on sodium salt roasting-water leaching process in high chromium vanadium slag. The reduction conditions of sodium thiosulfate were provided. The influences of various factors on the filtration performance of chromium hydroxide were discussed, including precipitation agents, precipitation modes and precipitation temperature. The effects of chromium hydroxide calcination conditions and washing mode on the quality of chromium oxide were investigated. The results indicated that Na₂S₂O₃ can completely reduce the acidic chromium solution, the reduction pH was less than 4.0, and the mass ratio of Na₂S₂O₃ to Cr(VI) in the solution was 3.1. When the temperature was higher than 60°C, chromium hydroxide obtained by parallel flow precipitation using sodium carbonate as precipitant performed much better in filtration. The washed chromium hydroxide was calcined at 1200°C for 2 h. The final product of Cr₂O₃ with a purity of 98.76% was obtained after grinding and washing appropriately.

KEYWORDS:

• Solution after vanadium precipitation
• parallel flow precipitation
• chromium hydroxide
• Cr₂O₃ preparation

Acknowledgements

This work was financially supported by National Science and Technology Support Program of China(Grant No. 2015BAB19B02).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by National Science and Technology Support Program of China(grant no. 2015BAB19B02).