A novel process for Fe recovery and Zn, Pb removal from a low-grade pyrite cinder with high Zn and Pb contents

Comprehensive utilization of pyrite cinders is increasingly important because of their huge annual outputs and potential valuable metals recovery to cope with the gradual depletion of high-grade mineral resources. In this work, a new process, i.e., a high-temperature chlorination-magnetizing roasting-magnetic separation process, was proposed for recovering Fe and removing Zn, Pb from a low-grade pyrite cinder containing 49.90wt% Fe, 1.23wt% Zn, and 0.29wt% Pb. Various parameters, including the chlorinating conditions (dosage of CaCl₂, temperature, and time) and the magnetization roasting conditions (amount of coal, temperature, and time) were investigated. The results indicate that the proposed process is effective for Fe recovery and Zn, Pb removal from the pyrite cinder. Through this process, 97.06% Zn, 96.82% Pb, and approximately 90% S can be removed, and 89.74% Fe is recovered as magnetite into the final product under optimal conditions. A purified magnetite concentrate containing 63.07wt% Fe, 0.16wt% P, 0.26wt% S, and trace amounts of nonferrous metals (0.005wt% Cu, 0.013wt% Pb, and 0.051wt% Zn) was obtained. The concentrate can be potentially used as a high-quality feed material for producing oxidized pellets by blending with other high-grade iron ore concentrates.