Abstract:The reduction rate of zinc under different conditions was investigated by thermodynamic analyses, small and pilot tests, wherein high magnesium ferrochrome dust was employed as the raw material. The results indicate that a low liquidus temperature and a suitable composition of the viscosity system can be achieved when the slag parameters are MgO mass fraction of 25% and binary alkalinity (mass ratio of CaO/SiO2) of 0.5, MgO mass fraction of 25% and binary alkalinity of 0.6, and MgO mass fraction of 20% and binary alkalinity of 0.8, respectively. The results of preliminary experiments conducted with the aforementioned thermodynamically optimal parameters indicate that an elevated melting temperature, extended holding time, and augmented carbon distribution ratio exert a promoting influence on zinc volatilization. Conversely, an elevated CO concentration exerts a mitigating influence on the volatilization effect of zinc, which is attributable to the slower rate of gas-solid reaction. The residual zinc content in the samples is below 0.005% under suitable process conditions. The optimum conditions include reaction temperature of 1 450 ℃, reaction time of two hours, MgO mass fraction of 25%, binary alkalinity of 0.5 and carbon black/material mass ratio of 0.04. The feasibility of the side-submerged combustion smelting process and the fuming furnace process for the treatment of ferrochrome dust was verified through pilot test. Under the condition of 1 400~1 450 ℃, effective melting of materials and recovery of zinc can be achieved. The mass fraction of zinc in tailing slag can be reduced to less than 0.1%, and the mass fraction of zinc in zinc-rich fume ash reaches 41%.