Research of Bayan Obo tailings characteristics and recovery methods

Abstract

This paper presents a new method for the recovery of iron and rare earth elements (REEs) from Bayan Obo tailings, which are the waste materials from the extraction of iron and REEs from the Bayan Obo ore deposit in Inner Mongolia, China. The method is based on the combination of microwave-assisted carbothermal reduction and acid leaching. The microwave-assisted carbothermal reduction can effectively reduce the iron oxides and REE oxides in the tailings to metallic iron and REE metals, respectively, and separate them from the gangue minerals. The acid leaching can then dissolve the REE metals from the reduced product and obtain a high-purity REE solution. The effects of various parameters on the performance of the method were investigated and optimized, and the mechanisms and kinetics of the reactions were analyzed and modeled. The results showed that the method can achieve a high recovery rate of iron and REEs, a high selectivity of REEs, a low energy consumption, and a simple process. The economic and environmental benefits of the method are also significant, as it can utilize the Bayan Obo tailings and recover the valuable elements from them, and reduce the waste generation and greenhouse gas emission. The method provides a new and efficient technology for the utilization of Bayan Obo tailings and the recovery of iron and REEs, and contributes to the fundamental understanding of the microwave-assisted carbothermal reduction and acid leaching processes.