A novel method of enhancing valuable element recovery for ultra-high-titanium magnetite

Abstract

The metallization reduction-magnetic separation process was adopted to carry out the experiments to promote the recovery ratio of valuable elements by adding diboron trioxide additive in this work. It is demonstrated that diboron trioxide has the function of destroying Si–O–Si bond for the reduction of ultra-high-titanium magnetite. The optimum experimental condition is found to be the reduction temperature of 1125 °C, the reduction time of 30min, and the diboron trioxide percent of 8 wt% for which the metallization ratio is 92%, and the recovery ratio of ferrum, vanadium, titanium is 90.9%, 78.5%, 76.1%, respectively. V and Ti are synchronously concentrated in non-magnetic materials. The phase composition transformation rule of the valuable components was Fe3O4 (FeTiO3) → FeO → Fe; FeTiO3 (→ FeTi2O5) → (Fe,Mg)Ti2O5; FeTiO3 → TiO2 → Ti3O5 → Ti2O3; (Fe3O4 + TiO2) → Fe3Ti3O10 → Fe. Increasing the temperature can promote the aggregation and growth of iron particles, but too high temperature is not conducive to the separation of Fe, V and Ti. It is evidently observed that when the temperature exceeds 1150 °C, the iron particles are closely connected with the gray titanium oxide, while at 1125 °C, the iron particles are relatively independent. Meanwhile, part of Ti is observed in silicate phase as solid-dissolved form because of high temperature and cause loss. Overall speaking, the metallization reduction-magnetic separation process with diboron trioxide as an additive has achieved the better separation of valuable components, with a higher degree of metallization, and large-scale lowered reaction temperature and time.