Fundamental Research on Selective Pre-enrichment of Low-Grade Niobium Concentrate from Bayan Obo Mine Via Super Gravity

Bayan Obo is the second largest niobium deposit in the world, and has been developed and utilized as iron ore for a long time because of its low niobium content and complex mineral composition. During the high-temperature reduction process, the recovery rate of niobium is low, and most niobium cannot be effectively recovered and utilized. Therefore, a new technology of slag iron separation via super gravity and preconcentration of niobium is proposed in this paper. Firstly, the reduction conditions of niobium concentrate at different temperatures, C/O, and reduction time have been studied to explore the optimal reduction conditions. The results show that the reduction effect was the best at 1200°C, C/O = 1.2 and a reduction time of 60 min. Secondly, under optimal reduction conditions, the super gravity realizes the low-temperature separation of slag and iron. We then studied the effect of C/O, gravity coefficient, and centrifugal time on the super gravity separation of niobium concentrate. The niobium content in slag increased from 4.05% to 15.7%, and the recovery of Nb₂O₅ reached 94.43%, which greatly improves the niobium grade and is beneficial to the deep processing of niobium concentrate.