China Nonferrous Metallurgy

With the decreased amount of high-grade lead sulfide concentrate, the lead-based solid wastes such as lead paste and lead glass as significant secondary lead resources have increasingly been used as the raw material for lead smelting. Lead concentrate is co-smelted with lead paste and lead glass by oxygen blowing in this experiment. The effects of oxygen flow rate, smelting temperature and ω(Fe)/ω(SiO2) and ω(CaO)/ω(SiO2) on the desulfurization rate of co-smelting process were studied by single-factor experiments. The physical phase changes of smelting slag with different compositions were analyzed by XRD mapping. The results showed that the increase of oxygen flow rate and temperature could improve the desulfurization rate, and when the reaction temperature was 1200℃ and the ω(Fe)/ω(SiO2) was between 0.6 and 0.97, the desulfurization rate was above 95% after 25 minutes of reaction. When the ω(Fe)/ω(SiO2) was higher than 0.97, the spinel phase appeared in the slag, the viscosity of slag increased and the desulfurization rate decreased. The ω(CaO)/ω(SiO2) increased from 0.22 to 0.87, and the slag desulfurization rate increased first and then decreased. With the ω(CaO)/ω(SiO2) ratio of 0.49, the desulfurization effect was better, with the content of sulfur in the final slag reduced to 0.61%, and desulfurization rate reaching 96.99%. The study could provide reference for lead smelting and recovery.