Simultaneous Recovery of Red Mud and Diamond Wire Saw Silicon Waste for Si–Fe Alloy Preparation

Red mud (RM) and diamond wire saw silicon waste (DWSSW) are two kinds of hazardous waste produced in industry, and it is urgent to treat it to recycle valuable resources and protect the environment. In this study, a process is proposed to treat both wastes simultaneously, where the Fe₂O₃ in the RM is reduced by Si in the DWSSW to prepare the Si–Fe alloy. The feasibility of reduction of RM by DWSW was identified through thermodynamic analysis. The effects of the proportion of DWSSW and holding time on the recovery rate of Fe was systematically studied. The recovery rate of Fe reached 94.37 pct under optimal conditions. The recovery process mechanism has been investigated by analyzing the SiO₂ layer removal and micromorphology. The alloy was purified by electromagnetic directional solidification, which further improved its application value. This process is environmentally friendly and simple and converts DWSSW and RM into valuable alloys and harmless slag, which provides a novel approach for the simultaneous utilization of the two kinds of wastes.