1 College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, Hebei, China 2 Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China 3 College of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, Guizhou, China 4 School of Materials and Architectural Engineering, Guizhou Normal University, Guiyang 550025, Guizhou, China 5 School of Metallurgy, Northeastern University, Shenyang 110819, Liaoning, China
摘要 Converter slag is a by-product of the steelmaking process and contains a large amount of Ca, Fe, P and other elements. If the phosphorus in the converter slag can be effectively extracted, the resulting phosphorus can be used as a phosphate fertilizer. Phosphorus in converter slag is mainly enriched in 2CaO-SiO2–3CaO-P2O5 (C2S–C3P) solid solution and is easily dissolved in water. Therefore, acid leaching method was used to dissolve the solid solution to extract phosphorus in converter slag, so as to realize the recycling of phosphorus resources in converter slag. The leaching behavior of three actual converter slags from different steelmills in acid leaching solutions composed of citric acid, sodium hydroxide, hydrochloric acid and deionized waterwas studied by X-ray diffraction, scanning electron microscopy combined with energy dispersive spectrometry, Fourier transform infrared spectroscopy andRaman spectroscopy to reveal the change in object image structure aswell as SiO4 and PO4 tetrahedron before and after acid leaching. The results show that only a small amount of phosphorus in converter slag with too low basicity is enriched in C2S–C3P solid solution, resulting in poor leaching effect. When the converter slag has a high basicity, the removal effect of phosphorus is 70.64%–81.88%. In addition, when the basicity of converter slag is roughly the same, the dephosphorization effect of slag with high FeO content is relatively poor.And acid leaching will cause depolymerization behavior of SiO4 and PO4 tetrahedron, so that themole fraction ofQ0(Si) (asymmetric stretching vibration of Si–Obond in SiO4 tetrahedronwith bridge oxygen number of 0) and NBO/Si (non-bridging oxygen in silicate tetrahedra) will increase. Phosphate-containing solids can be obtained from the solution after acid leaching through static precipitation, and the solids have the potential to make phosphate fertilizers.
Abstract:Converter slag is a by-product of the steelmaking process and contains a large amount of Ca, Fe, P and other elements. If the phosphorus in the converter slag can be effectively extracted, the resulting phosphorus can be used as a phosphate fertilizer. Phosphorus in converter slag is mainly enriched in 2CaO-SiO2–3CaO-P2O5 (C2S–C3P) solid solution and is easily dissolved in water. Therefore, acid leaching method was used to dissolve the solid solution to extract phosphorus in converter slag, so as to realize the recycling of phosphorus resources in converter slag. The leaching behavior of three actual converter slags from different steelmills in acid leaching solutions composed of citric acid, sodium hydroxide, hydrochloric acid and deionized waterwas studied by X-ray diffraction, scanning electron microscopy combined with energy dispersive spectrometry, Fourier transform infrared spectroscopy andRaman spectroscopy to reveal the change in object image structure aswell as SiO4 and PO4 tetrahedron before and after acid leaching. The results show that only a small amount of phosphorus in converter slag with too low basicity is enriched in C2S–C3P solid solution, resulting in poor leaching effect. When the converter slag has a high basicity, the removal effect of phosphorus is 70.64%–81.88%. In addition, when the basicity of converter slag is roughly the same, the dephosphorization effect of slag with high FeO content is relatively poor.And acid leaching will cause depolymerization behavior of SiO4 and PO4 tetrahedron, so that themole fraction ofQ0(Si) (asymmetric stretching vibration of Si–Obond in SiO4 tetrahedronwith bridge oxygen number of 0) and NBO/Si (non-bridging oxygen in silicate tetrahedra) will increase. Phosphate-containing solids can be obtained from the solution after acid leaching through static precipitation, and the solids have the potential to make phosphate fertilizers.
Chao-gang Zhou1,2,Jin-yue Li1, et al. Leaching behavior and microstructure of phosphorus in converter slag[J]. Journal of Iron and Steel Research International, 2024, 31(07): 1646-1660.