Experimental Investigation on Direct Reduction Followed by Magnetic Separation for Nb_2O_5-Bearing Ore

摘要

Recently a special attention is being paid on the ferroniobium production worldwide, especially in China. In present work, direct reduction followed by magnetic separation for Nb_2O_5-bearing ore is investigated. Reflected light microscope, scanning electron microscope with EDX, and high performance X-ray diffraction were used for fundamental analysis. The experimental results show that, (1) the optimum reduction parameters are 0.9 of C/O, 1 200℃ and 20 min. At these optimum parameters, the degree of metallization of ore-coal composite pellet is more than 90%. (2) In direct reduced pellets, metallic iron and slag have gathered respectively, and they can be magnetically separated. Nb and Ti are associated together and inserted in slag, and stay in slag phase after magnetic separation. (3) Based on the process of direct reduction followed by magnetic separation, 7.71% of Nb_2O_5-enriched slag is obtained, which is a good feed for producing ferroniobium or metallic niobium in electric furnace. The Nb_2O_5 content in Nb_2O_5-enriched slag is 1.8 times of the original ore, and the recovery of Nb is about 85%. These experimental results can give some theoretical references for industrial application in future.