Thermodynamic and experimental study of high-temperature roasting of blast furnace gas ash for recovery of metallic zinc and iron
Zi-han Wang1, Jing Guo1, Han-jie Guo1, Bin Li2
1 School of Metallurgical Engineering, University of Science and Technology Beijing, Beijing 100083, China 2 School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi, China
Thermodynamic and experimental study of high-temperature roasting of blast furnace gas ash for recovery of metallic zinc and iron
Zi-han Wang1, Jing Guo1, Han-jie Guo1, Bin Li2
1 School of Metallurgical Engineering, University of Science and Technology Beijing, Beijing 100083, China 2 School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi, China
摘要 A high-temperature reduction roasting method was used to achieve metallic iron and zinc recovery from blast furnace gas ash (BFA). The reduction processes for Zn-containing and Fe-containing oxides were analyzed in detail by using thermodynamic equilibrium calculation and the principle of minimum free energy. The results showed that the main reaction in the system is the reduction of ZnFe2O4 and iron oxides. Over the full temperature range, iron oxides were more easily reduced than zinc oxides. Regardless of the amount of CO contained in the system, the reduction of ZnO to Zn was difficult to proceed below the boiling point (906 °C) of Zn. When the reduction temperature is below 906 °C, the reduction process of zinc ferrate was ZnFe2O4 → ZnO; when the reduction temperature is above 906 °C, its reduction process becomed ZnFe2O4 → ZnO → Zn(g). The metallization and dezincification rates of the BFA gradually increased with increasing reaction temperature. As the C/O ratio increased, the metallization and dezincification rates first increased and then decreased. The effect of reduction time on BFA reduction was similar to that of reaction temperature.
Abstract：A high-temperature reduction roasting method was used to achieve metallic iron and zinc recovery from blast furnace gas ash (BFA). The reduction processes for Zn-containing and Fe-containing oxides were analyzed in detail by using thermodynamic equilibrium calculation and the principle of minimum free energy. The results showed that the main reaction in the system is the reduction of ZnFe2O4 and iron oxides. Over the full temperature range, iron oxides were more easily reduced than zinc oxides. Regardless of the amount of CO contained in the system, the reduction of ZnO to Zn was difficult to proceed below the boiling point (906 °C) of Zn. When the reduction temperature is below 906 °C, the reduction process of zinc ferrate was ZnFe2O4 → ZnO; when the reduction temperature is above 906 °C, its reduction process becomed ZnFe2O4 → ZnO → Zn(g). The metallization and dezincification rates of the BFA gradually increased with increasing reaction temperature. As the C/O ratio increased, the metallization and dezincification rates first increased and then decreased. The effect of reduction time on BFA reduction was similar to that of reaction temperature.
Zi-han Wang,Jing Guo,Han-jie Guo1 Bin Li. Thermodynamic and experimental study of high-temperature roasting of blast furnace gas ash for recovery of metallic zinc and iron[J]. Journal of Iron and Steel Research International, 2024, 31(1): 108-120.
2024, Vol. 31 
