Mechanism of Recovering Iron and Zinc from BF Gas Slime by Self-reduction

The heating self-reduction process of blast furnace(BF) gas slime was studied by non-isothermal thermogravimetric(TG) analysis and isothermal heating in Muffle Furnace.The equilibrium compositions and metallization rate of iron and zinc oxides for BF gas slime in reduction process were calculated by HSC thermodynamic calculation software,and the mechanism for reduction of iron and zinc oxides was also discussed.The results show that the heating self-reduction process of BF gas slime may be divided into five stages:I(22.0~390.1℃),physical adsorption of carbon gasification reaction; II(437.7~758.9℃),reduction of iron oxide with increase in metallization rate; III(758.9~936.1℃),co-reduction of iron and zinc oxides with increase in metallization rate of iron and zinc; IV(936.1~1 031.7℃),iron and zinc oxides are reduced sufficiently,with maximum 70% and 99.7% of metallization rate for iron and zinc,respectively; V(1 031.7~1 255.3℃),iron and zinc oxides are reduced completely,and zinc gas may be oxidized.