Experimental study on the melting-separation of carbon composite pellets in Ti-Nb-bearing Fe concentrate

Effects of the melting-separation temperature, melting-separation time and slag basicity on the melting-separation behavior of carbon composite pellets in Ti-Nb-bearing Fe concentrate and the properties of slag were studied by preproduction-melting-separation experiment in order to realize efficient utilization of Ti-Nb-bearing Fe concentrate in Bayan Obo Area, Inner Mongolia, with Ti-Nb-bearing Fe concentrate being the raw material. Moreover, the microstructure and phase transformation of pellets were characterized by XRD and SEM during melting-separation process. Results showed that complete slag-metal separation of reduced pellets whose metallization rate was 86.31 % could be realized after the melting-separation lasted 12 min at 1 400 ℃. Besides, iron nuggets and Nb-enriched slag were also obtained. The melting point of slag increased and the fluidity index of slag decreased with the increase of basicity. The best melting-separation effect could be achieved when slag basicity was 1.0. With the increase of melting-separation time, Ca₂Ti₂O₆ transformed gradually to Ca(Ti_0.4Fe_0.3Nb_0.3)O₃ and the size of Ca(Ti_0.4Fe_0.3Nb_0.3)O₃ increased.