The effects of multielement basicity on niobium-bearing phase reconstruction in low grade niobium rougher concentrate

The beneficiation and recovery of ores with complex nature, low abundance have become the main direction for the development of niobium resources. The niobium resources with large reserves in Bayan Obo have not been effectively developed due to their fine particles, low grade, and complex nature. A new method for the phase reconstruction of minerals through a reconstruction process was proposed. The reconstruction of Bayan Obo niobium-bearing rougher concentrate was realized by a high-temperature melting-cooling crystallization process. The impacts of multielement basicity on the reconstruction of niobium-bearing minerals were investigated by adjusting the composition of the slag in this study. The loparite ((Ca,Ce,Na)(Nb,Ti)O₃) phase is formed in slag with a higher basicity. On the contrary, the calciobetafite (Ca₂(Nb,Ti)₂O₇) is generated in slag with a lower basicity. Besides, the combined mass fractions of valuable TiO₂, Nb₂O₅, and rare earth oxide (REO) in calciobetafite reaches 71.94% (only 56.83% in loparite). The formation mechanism of niobium-bearing phases under different basicities was also discussed. The results of this study can provide theoretical guidance for transforming the niobium-bearing phase and enriching valuable elements in the process of phase reconstruction.