In this study, a novel process was established for extraction of Fe and Al from a complex high aluminum iron ore (33.43% Fe total and 19.09% Al 2 O 3 ). The main steps in the proposed process included pre-reducing high alumina iron ore and subsequent smelting to produce pig iron and rich-alumina slag, followed by alkaline leaching of the slag to obtain sodium aluminate solution and a clean slag. When smelting the pre-reduced high alumina iron ore pellets at 1625 • C for 30 min with a slag basicity of 0.40, the pig iron yielded 97.08% Fe and extracted 0.13% Al 2 O 3, together with an iron recovery of 94.54%. In addition, more than 68.93% Al 2 O 3 was recovered by leaching the slag, which was achieved by firstly roasted the slag at 900 • C for 2 h and then alkaline leaching at 95 • C for 2 h with a liquid-to-solid ratio of 10 mL/g. In addition, the alkaline leaching slag could potentially be used as raw material for construction purpose, which mainly consisted of SiO 2 and CaO.Metals 2020, 10, 57 2 of 17 remove aluminum from iron ore containing Fe total 52.94%, 9.95% Al 2 O 3 and 6.1% SiO 2 , and only 40% alumina was removed after 6 or 15 days of in situ leaching at 10% pulp density. Biological method could play a certain role in the separation of iron from alumina, but its effect may be poorer, especially the period is too lengthy compared to smelting processes.Smelting processes consist of coal-based direct reduction-magnetic separation, roasting-magnetic separation, and smelting separation [11][12][13]. It is effective to recover iron from low-grade refractory iron ore through coal-based direct reduction-magnetic separation. However, there is a problem that exists in this process, low reduction rate [14,15]. Zhou et al. [13] proposed a high temperature reduction followed by magnetic separation for high aluminum hematite-limonite ore treatment. Their findings indicated that approximately 90.25% of iron recovery was obtained, but the recovery of Al 2 O 3 was not considered. Sellaeg et al.[16] adopted a direct smelting reduction process to recover iron from red mud, and the result showed that only 70% of iron was recovered and an Al 2 O 3 -containing slag was obtained. He et al. [17] proposed a slag-iron bath smelting reduction process for the treatment of alumina-rich iron ore, and more than 90% iron was recovered using this method. It is worth noting that the smelting separation process can achieve the separation of iron and alumina. However, the slag could not be effectively used, resulting in a difficulty of extracting aluminum.Considering that the existing processes for HAIO treatment have highly energy consumption and are economically impractical, it is urgent to develop a more economical and valid process. In this work, a new process was developed through the pre-reduction of high alumina iron ore and subsequent smelting to produce pig iron and rich-alumina slag, followed by alkali leaching to extract aluminum and generate a clean slag for cement industry.
