Intensified extraction of vanadium from vanadium-bearing titanomagnetite (VTM) concentrate via one-stage leaching and solvent extraction using acidic organophosphorus extractant

Abstract

Vanadium-bearing titanomagnetite (VTM) is a crucial source for vanadium production. Conventional methods for recovering vanadium from VTM involving combined pyro- and hydrometallurgy (production of vanadium-rich slag, followed by leaching) or direct leaching encounter significant challenges, such as vanadium losses and complexities in metal separation stage. This study proposes an innovative approach for vanadium extraction from VTM through one-stage leaching and solvent extraction (SX), utilizing an acidic organophosphorus extractant, di(2-ethylhexyl)phosphoric acid/D2EHPA, as the lixiviant. Initial assessment demonstrated the viability of D2EHPA for treating vanadium oxide (V₂O₅) and iron oxides (only Fe²⁺-containing oxides like Fe₃O₄ and FeO). Notably, the addition of a small amount of water had a significant impact on iron extraction. The study investigated the effects of parameters, including the amount of added water, stirring speed, D2EHPA concentration, temperature, time, and pulp density on the vanadium and iron extraction from VTM. The optimal conditions were applied to treat roasted/oxidized VTM. The findings were corroborated through analysis of the resultant loaded D2EHPA using appropriate techniques such as FTIR and UV–Vis spectroscopy. The practicability of the proposed method for treating VTM concentrate on a larger scale was demonstrated by conducting up-scaled tests. Additionally, the separation of vanadium from iron the loaded D2EHPA was explored using selective stripping with H₂SO₄ solution. The recyclability of D2EHPA, a critical factor for sustainability, was investigated through five cycles of extraction-stripping.