Harmless Treatment and Valuable Metals Recovery of Tungsten Leaching Residues: A Thermodynamic and Experimental Study

Abstract

Tungsten leaching residues are industrial wastes that are largely generated during commercial tungsten production. The residues have been classified as hazardous solid wastes due to the presence of toxic elements. On the other hand, the residues contain valuable elements, such as W, Mn, and Fe which can be recovered for economic benefit. To utilize the residue, a carbothermic reduction process was studied to achieve the effective utilization of the residue and sustainable development of the tungsten industry. Fe-W-Mn alloys and nontoxic slags were obtained successfully at 1450°C, and can be used to produce wear-resisting iron materials and glass–ceramics, respectively. The more effective metal–slag separation was achieved by controlling the MnO concentration of the slag, which impacted the liquidus temperature and the viscosity of the slag. This study confirmed a method for utilizing the tungsten residues, which could be a step toward practical industrial-scale techniques.