ABSTRACT

The carbothermic reduction of an ilmenite concentrate, followed by wet magnetic separation, was performed with varying additions of Na₂CO₃ to generate metallic iron and a titanium-rich slag. The size of the metallic iron particles correlated positively with increasing graphite addition up to a C/O (O bound to Fe) molar ratio of 1.4; further increases beyond this level decreased the particle size. The size of these metallic iron particles also increased with greater addition of Na₂CO₃. The addition of Na₂CO₃ to the ilmenite concentrate enhances the carbothermic reduction by promoting the gasification of C and fluxing the slag phase, lowering its melting point and increasing fluidity; a 5.97 wt% addition of Na₂CO₃ decreased the reduction onset temperature from 1020 to 900°C. This fluxing of the slag with Na₂CO₃ also allows for much lower concentrations of FeO than the 10–12% concentration typically required to ensure adequate fluidity in conventional EAF smelting operations. With the addition of Na₂CO₃, the recovery of Fe to the magnetic fraction, following magnetic separation, was over 97% and the non-magnetic fraction contained more than 74% TiO₂. Within the range of conditions considered in this study, the highest recovery of TiO₂ to the non-magnetic fraction (89%) was achieved for material reduced at 1450°C.

摘要

对钛铁矿精矿进行碳热还原，然后进行湿法磁选，同时添加不同的Na ₂ CO ₃以产生金属铁和富钛渣。金属铁颗粒的大小与石墨添加量的增加呈正相关，直到C / O（与Fe结合的O）摩尔比为1.4；进一步增加超过该水平则减小了粒径。随着Na ₂ CO _3的增加，这些金属铁颗粒的尺寸也增加。Na ₂ CO _3的添加钛铁矿精矿通过促进C的气化和熔渣相，降低其熔点和增加流动性来增强碳热还原作用; 加入5.97重量％的Na ₂ CO ₃将还原起始温度从1020降低至900℃。炉渣与Na ₂ CO ₃的通量还使得FeO的浓度比确保常规EAF熔炼操作中足够的流动性通常所需的10-12％的浓度低得多。通过添加Na ₂ CO ₃，磁性分离后，Fe在磁性部分中的回收率超过97％，非磁性部分中TiO _2的含量超过74％。在本研究中考虑的条件范围内，对于在1450°C下还原的材料，TiO ₂达到非磁性部分的最高回收率（89％）。