木质生物质直接还原硫酸渣中的赤铁矿

As a renewable zero-carbon fuel,biomass can replace coal-based reductants and has certain potential in terms of reducing iron oxides. In this paper,the effects of different temperatures and Na₂CO₃ addition on the evolution behavior of hematite in roasting sulfuric acid residues reduced by biomass,as well as the characteristics of gaseous and solid products were investigated. The experimental results showed that the reduction reaction path of hematite by biomass at different temperatures was hematite →magnetite+triiron carbide,and increasing the reduction temperature easily led to the formation of ferrosilicon aluminum alloy phase in the roasting products. The optimal reduction temperature was 700 ℃,and the corrected mass fraction of Fe₂O₃ in the reduced product was increased by about 20%. The addition of Na₂CO₃ can not only react with quartz to convert into sodium silicate,but also promote the formation of ferrous oxide and silicon carbide. After the reduction reaction,the average pore diameter of the biochar surface became smaller,while its specific surface area was larger. Compared to pyrolysis of pure biomass,the volume of combustible gases in the bio-gases was slightly changed for reduction reaction with sulfuric acid residues.