Optimization of preparation process of high-strength pellets from Panzhihua ilmenite concentrate

The preparation of high-strength pellets from Panzhihua ilmenite concentrate is important for the hydrogen-rich smelting of titania slag and was investigated. The effects of the magnetite concentrate and heating procedure including the preheating temperature and period as well as roasting temperature and period on the compressive strength of the roasted pellets were investigated. High-strength ilmenite concentrate pellets (2000 N) were prepared by optimizing the roasting process. The addition of magnetite concentrate is beneficial for increasing the compressive strength of the Panzhihua ilmenite concentrate pellet by oxidizing hematite which filled the pseudobrookite particles, functioned as a bridge bond, and improved the interconnection between the grains. The compressive strength can reach up to 2900 N when the ilmenite concentrate pellet with 15% magnetite concentrate is pre-heated above 800 C for 20 min and then roasted at 1250 C for 20 min. In addition, there is an overall upward trend in the compressive strength with an increase in the pre-heating temperature and period as well as the roasting temperature and period. The micromorphology and strengthening consolidation mechanism of Panzhihua ilmenite concentrate pellets were also discussed.