Effect of H 3 PO 4 coordination on vanadium extraction and iron separation in a H 2 SO 4 leaching system

• Published in: RSC advances 2024-11, Vol.14 (50), p.37404-37418
• Main Authors: Zhao, Xuxia, Zhang, Yimin, Xue, Nannan, Hu, Pengcheng, Zheng, Qiushi
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/D4RA06632D

The selectivity of the full wet leaching process for vanadium extraction using H SO is low, resulting in a high impurity content in vanadium extracted from vanadium-bearing shale. This study focused on vanadium extraction and iron separation from vanadium-bearing shale, involving the coordination of H PO in an H SO leaching system. The effects of the ratio and quantity of H SO -H PO , leaching time, leaching temperature, and liquid-to-solid ratio on vanadium-bearing shale leaching were investigated. The dissolution processes of various minerals and the mechanism of iron coordination precipitation were analyzed. Results showed that vanadium leaching efficiency was 91.07% and iron leaching efficiency decreased from 84% to 23.86% under optimal leaching conditions-H SO -to-H PO ratio of 2 : 1, H content of 8 mol kg , liquid-to-solid ratio of 0.8 L kg , and leaching time of 12 h at 95 °C. Leaching kinetics showed that the leaching process of vanadium shale was a mixed-control process in the H PO -H SO leaching system; additionally, the leaching process was mainly controlled by a chemical reaction with an activation energy of 67 kJ mol . The preferential dissolution order of minerals in the vanadium-bearing shale was calcite, apatite, magnetite, muscovite, and pyrite. Under the H SO -H PO leaching system, the iron content was reduced by inhibiting the dissolution of pyrite and coordination precipitation of Fe with PO , thus separating iron and vanadium from the source. This provides guidance for vanadium extraction and impurity separation from vanadium-bearing shale using an all-wet method.