Using Na2CO3 as an additive to enhance the growth kinetics of iron grains during carbo-thermic reduction of ilmenite concentrate

Abstract

The deep reduction of ilmenite concentrates through carbothermic way with the addition of Na2CO3 to produce high-quality titanium slag and iron powder is a novel energy-efficient process to utilise the low-grade ilmenite concentrate effectively. The growth behaviour of iron grain in this process is of great significance for the subsequent separation between iron and slag. Thus, the growth behaviour and kinetics of iron grain in this process under different Na2CO3 concentrations were investigated. The results show that the increase of reduction temperature, time, and Na2CO3 addition promoted the growth of iron grains. Particularly, the influence of additives was more significant when the reduction temperature was over 1300 °C. The growth of iron grain gradually changed from being controlled by surface diffusion to being controlled by grain boundary diffusion with increasing Na2CO3 addition. Growth models of iron grain under different Na2CO3 concentrations were also established in this study.