Hydrometallurgical process development for the extraction, separation and recovery of vanadium from spent desulfurization catalyst bio-leach liquors

Abstract

Abstract The processes of vanadium extraction, separation and recovery from spent de-sulfurization catalyst bio-leach liquor solutions were studied. Spent catalyst processing has mainly two benefits: to protect the environment from the effects of waste and to create wealth from waste. Numerous experimental parameters are optimized. The first step evaluated possible suitable extractant systems, followed by the optimal pH conditions. Feasible extractant systems were screened in the first step. The commercial extractants of LIX 973N, Alamine 336, Alamine 308, Cyanex 272 and D2EHPA were examined. In this study, the initial pH varied from 0.0 to 2.5, and after extraction equilibrium, the measured pH was between 0.1 and 2.8. The developed process involves an examination of the phase ratio effect, the creation of a McCabe–Thiele diagram to extract the isotherm, and counter-current extraction (CCE), all of which were examined and optimized for vanadium. The McCabe–Thiele plots showed that quantitative extraction of the target metal was achievable in extraction stages. The CCE process further confirmed the maximum loading of the vanadium while minimizing interference from other metals. Other processes such as scrubbing and stripping were also established. Hydrochloric acid diluted with water was used as a scrubbing reagent, and its pH was 0.8 ± 0.1. Metal enrichment was achieved at a fivefold greater rate by a continuous counter-current extraction process and finally with ammonium hydroxide, with a vanadium amount as high as much as (2039 mg/L) recovered from a loaded organicphase (5180 mg/L).