Electrometallurgical recovery of nickel and vanadium from spent desulphurization catalysts using an acidic leaching–electrolysis technique

Spent desulphurization catalysts are considered a major secondary source of valuable metals. The contents of nickel and vanadium present in these catalysts, accompanied by environmental rules, have attracted scientists to explore diverse options for their effective processing. The electrometallurgy recovery of Ni and V from the spent desulphurization Ni-Mo-V/Al₂O₃ catalyst is described in this study. Using flat plate graphite electrodes, the electrochemical deposition of Ni and V from spent catalyst in an acid solution (HNO₃/H₂SO₄) was investigated. By the central composite design of the response surface methodology, the effect of the operating factors was examined and optimized. At the ideal conditions of reaction temperatures of 84.0 and 42.0°C, electrolysis times of 5.6 and 4.4 h, liquid/solid ratios of 22.7 and 15.4 ml/g, and current densities of 229.0 and 255.6 A/m², respectively, the recovery efficiencies of Ni and V were 81.96% and 93.07%. The statistical analysis revealed that the expected data (R² = 0.9984 and R² = 0.9883) were in good agreement with the observed data (R² = 0.9984), with an average variation from experimental data of 0.78% and 0.65% for the optimum conditions of Ni and V recovery, respectively. It shows that the Ni and V nanoparticles deposited have a spherical form with purities of 84.39% and 90.76%, respectively. Because of its great efficiency and purity, the current study can provide a dependable procedure for extracting Ni and V from solid waste.