Recovery of gallium from yellow phosphorus flue dust by vacuum carbothermal reduction

Abstract

Yellow phosphorus flue dust (YPFD) is a kind of solid waste generated from yellow phosphorus production. Because it contains approximately 0.05% of gallium (Ga), the recovery of Ga from YPFD has attracted the interest of many researchers. To reduce environmental pollution and storage problems associated with YPFD, a new vacuum thermal reduction method to recover Ga from YPFD was proposed in this study. Thermodynamic calculations and thermogravimetric analysis were first used to determine the initial reaction temperature between Ga2O3 and C. High-purity Ga2O3 and activated carbon were evenly mixed and heated at 1273 K and 10 Pa for 2 h. Experimental results showed that metallic Ga could be obtained in the condensation zone by vacuum carbothermal reduction. Based on this result, we next attempted to recover Ga from YPFD by vacuum carbothermal reduction. YPFD containing 30 wt% carbon was heated at 1273 K and 10 Pa for 2 h, and the experimental results also yielded Ga enrichment in the condensation zone. Therefore, this study provides a new and potential useful technology for recovery of Ga from YPFD, as well as a certain practical approach to comprehensively utilizing such industrial waste.