Transforming Mining Waste to Wealth: A Novel Process for the Sustainable Recovery and Utilization of Iron Tailings through HCl Leaching and MOFs Absorption

Abstract

Rapid economic development and increased demand for mineral products in China have led to extensive extraction of various ores, resulting in significant environmental challenges associated with the generation of industrial solid waste, particularly iron tailings. Despite being a major mining nation, China faces issues of wasteful practices, with substantial amounts of valuable elements lost during the processing of iron ore. This study addresses the urgent need for sustainable solutions by proposing an innovative approach for the recovery of valuable elements from iron tailings. The proposed process involves a sequential application of acid leaching, chemical precipitation, and Metal-Organic Frameworks (MOFs) ion adsorption. The pre-treated iron tailings were leached in HCl solution with pH 1.5 at 70 °C for 2 h, and the co-leaching efficiency of 98.1% V, 98.2% Mo, 99.3% Fe, and 98.7% Mg was obtained. Chemical precipitation is then employed to isolate Fe, Mg V, and Mo and promote the formation of targeted compounds, ensuring concentration and purity. The integration of MOF ion adsorption, known for its high surface area and tunable pore structures, provides an efficient platform for selectively capturing and recovering target ions. 97.7% V and 96.3% Mo were selectively extracted from Zirconium 1,4-carboxybenzene metal-organic framework (UiO-66) adsorption system with pH 5.0 at 30 °C for 6 h, and 91.7% V and 90.3% Mo were selectively extracted from 2-methylimidazole zinc salt metal-organic framework (ZIF-8) adsorption system with pH 5 at 30 °C for 6.0 h. This three-stage process offers an efficient method for the recovery of valuable elements from iron tailings.