Recovery of Pentavalent Vanadium from Leaching Solution by Precipitation with Melamine

The imperative to recycle vanadium from nontraditional resources arose from its escalating global demand, the progressive depletion of conventional ore deposits, and significant environmental challenges linked to terrestrial extraction operations. In this study, we presented a precipitation method to recover pentavalent vanadium ions, V(V), from vanadium leaching solutions using a compound containing −NH 2 functional groups, specifically melamine. The results indicated that melamine effectively precipitated vanadium from the solution with a precipitation efficiency of over 99% of vanadium from the solution. Response surface methodology analysis confirmed that all parameters enhanced the precipitation process, with their relative impacts ordered as follows: reaction temperature > melamine dosage > reaction time. DFT analysis identified the molecular mechanism: −NH 2 and N atoms containing a lone pair of electrons on melamine were coordinated with the V atom, facilitating stable complex formation of melamine-vanadium precipitation. Melamine exhibited high precipitation efficiency because of its strong affinity for V(V) ions, resulting in a high-purity vanadium precipitate. This method not only reduced environmental impact but also improved resource recovery, providing a sustainable alternative to conventional mining practices. The process was straightforward, cost-effective, and scalable, making it appropriate for industrial applications.