Green and Efficient Pre-concentration of Niobium From Low-Grade Niobite via Super Gravity

Bayan Obo ore, located in Baotou China, is the second largest niobium (Nb) deposit in the world. However, mining of niobium from this ore has not yet been established industrially due to its extremely low niobium content and complex mineral properties. In this study, an efficient pre-concentration technique of super gravity was proposed to increase the grade purity of Nb in the low-grade niobite to an acceptable metallurgical mineral grade. Firstly, the transformation behavior of iron-bearing phases and the present morphology of niobium during the selective reduction process were systematically investigated, and the optimum reduction conditions for the maximum enrichment of niobium into the slag were considered. Subsequently, complete separation of Nb-rich slag and metallic iron was achieved via super gravity at low temperature, the niobium slag with a grade of 4.05 wt pct was acquired at 1200 degrees C and G = 1000, which was four times higher than that in the initial ore, and the recovery ratios of MFe and Nb2O5 were high up to 94.29 and 97.62 pct, respectively. This research developed a green pre-concentration technology for upgrading low-grade Nb minerals and facilitating the subsequent employment of hydrometallurgical separation techniques.

Automated summary

Bayan Obo ore in Baotou China is the world's second largest niobium deposit. Due to its low niobium content and complex mineral properties, industrial mining of niobium from this ore has not been established. This study proposed an efficient pre-concentration technique of super gravity to increase the grade purity of niobium in the low-grade niobite. The research successfully achieved complete separation of niobium-rich slag and metallic iron through super gravity at low temperature, obtaining niobium slag with a grade four times higher than the initial ore and high recovery ratios of MFe and Nb2O5.