Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

Ying-yi Zhang^1,2，Wei Lü¹，Yuan-hong Qi²，Zong-shu Zou³

1. College of Materials Science and Engineering, Chongqing University2. State Key Laboratory of Advance Steel Processes and Products, Central Iron and Steel Research Institute3. School of Material and Metallurgy, Northeastern University

摘 要：A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w（CaO）/w（SiO₂） ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al₂O₃ grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100:16.17:59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recovery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca₂ SiO₄ and Ca₁₂Al₁₄O₃₃, with small amounts of Fe Al₂O₄, CaAl₂O₄, and Ca₂Al₂SiO₇.

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