Evaluation of ionic species contribution in critical metal extraction: A case study of high-purity vanadium production.

Critical metal sustainability is a worldwide issue whose extraction relies on hydrometallurgy mostly. The significance of metal ion species evolution in critical metal hydrometallurgy-extraction has got more and more attention. Here, the importance of the metal ion species during the whole vanadium recycling process has been evaluated quantitatively for the first time. Metal ion species as the key parameter was investigated through efficiency, material and energy accounting, and emission accounting to illustrate the effect of the metal ion species, which donated as ion species contribution (ISC). Specifically, 7 types of vanadium ion species were assessed in the process of V 2 O 5 production from leachate, including H 2 VO 4 −, HV 2 O 6 −, V 4 O 12 4−, H 2 V 5 O 14 −, V 10 O 28 6−, HVO 4 2− and VO2+. The results demonstrated that different vanadium ion species were closely related to recovery efficiency and purity, and they impact separation section, materials and energy consumption mostly in whole process. Consequently, V 4 O 12 4− occupied the highest ISC which was 1.11 times than V 10 O 28 6−, 1.37 times than VO2+ and 4.85 times than H 2 VO 4 −. Correspondingly, control of V 4 O 12 4− as dominant species appeared to be the most potential in the vanadium extraction process, which showed the feasibility of whole process optimization. With this research, ISC can help to point out dominant ion species in holistic critical metals supply chain, thus promote sustainability of critical metals in a new perspective. • Evaluating in detail the contribution of ion species to the whole V 2 O 5 production. • Covering comprehensive indicators related to ion species evolution. • An effective method for ion species regulation in critical metal resources recovery. [ABSTRACT FROM AUTHOR]