China Nonferrous Metallurgy

The resource utilization of silica slag and lead slag has problems such as complex recovery process and low utilization rate of valuable resources. However, the market demand for ferrosilicon alloy is large, and the research on the preparation of ferrosilicon alloy by lead slag has not been reported. In this paper, based on the analysis of the composition and phase of silica slag and lead slag, the thermodynamic analysis of the possible reactions was carried out by Gibbs free energy function method and HSC Chemistry software, and the preparation of ferrosilicon alloy was carried out according to the analysis results, and the following main conclusions were obtained:. The reaction of silicon with iron oxide to produce iron, the reaction of silicon with iron to produce FeSi, FeSi₂, Fe₃Si, Fe₅Si₃, and the reaction of silicon carbide with iron to produce FeSi could be carried out spontaneously within 298~2400K, but the reaction limit decreased with the increase of temperature. The ease of ferrosilicon generation is Fe₃Si＞Fe₅Si₃＞FeSi＞FeSi₂. The reaction between C and SiO₂ and the reaction between SiC and SiO₂ could not be carried out in the forward directionwhen the temperature was lower than 1900K. Through the experimental process of mixing-melting-water crushing-ball milling-screening, ferrosilicon containing Fe₃Si, Fe₅Si₃ and other phases can be prepared, which proved that the synergistic preparation of ferrosilicon by silica slag and lead slag was completely feasible, which provided a new idea for the resource utilization of the two waste slags.