Sulfidation Behaviour of Blast Furnace Dust at High Temperatures

Resumo

The sulfidation behaviour of blast furnace dust (BFD) with sulfur at high temperatures was investigated. The effects of the sulfur dosage, roasting temperature and time were studied on the basis of thermodynamic calculations. The results revealed that the Zn distribution ratio in ZnS increased from 13.28 to 92.01% after adopting the proposed process. The increase in the sulfur dosage, roasting temperature and time was conducive to the sulfidation of ZnO in the sample, but higher temperatures were not beneficial for sulfidation, which was ascribed to an accelerated volatilization rate of sulfur. The existence of carbon in the sample could decrease the O₂ partial pressure, which is advantageous for the generation of ZnS. In addition, it was found that the generated FeO was sulfurized and then proceeded to form iron sulfides. The produced iron sulfides were further dissolved into ZnS to form (Zn, Fe)S compounds. The growth of ZnS particles largely depended upon the roasting temperature, and the growth was significantly accelerated when the temperature increased to 850°C. It is feasible that the sphalerite was transformed into wurtzite at higher temperatures.