A Novel Process for Preparing High-Strength Pellets of Ilmenite Concentrate

In the present study, a novel process to prepare high-strength pellets of high-calcium, high-magnesium ilmenite concentrate was investigated. Magnetite concentrate and bentonite were selected as the additive and binder of the pellet, respectively. The effects of the magnetite concentrate content, bentonite content, and roasting temperature on the compressive strength, phase transformations, and morphology were systematically investigated. The addition of magnetite concentrate is an effective way to improve the compressive strength of high-calcium, high-magnesium ilmenite concentrate pellets. A pellet with a compressive strength of more than 1800 N can be obtained through the addition of 15% magnetite concentrate and 1.5% bentonite, followed by roasting at 1100 degrees C. The pseudobrookite solid solution formed during the high-temperature roasting process can form crystal bridges, which contribute to the consolidation of ilmenite concentrate pellets. The hematite formed by the oxidation of magnetite concentrate, which recrystallizes during the roasting process, strengthens pellet consolidation. A long roasting time is required to form and recrystallize a large amount of hematite to prepare high-compressive-strength pellets for low roasting temperature ilmenite concentrate pellet, while the addition of magnetite concentrate to the pellet can accelerate this process. [GRAPHICS] .