Effect of cooling rate on precipitation behavior of sulfur in KR desulfurization slag
JIANG Jia-jun1, LI Jian-li1,2, ZHU Ren-lin2, YU Yue2, ZHU Hang-yu2
1. Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China; 2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China
Abstract：KR desulfurization slag is mainly composed of high-quality slag-making raw materials (CaO) for converter smelting, which can be used in converter smelting after sulfur is removed from slag in oxidizing atmosphere. However, due to the effect of different slag cooling systems, the precipitation behavior and occurrence state of sulfur in slag will be changed, which affects the desulfurization rate. Therefore, the effect of cooling rate on the precipitation behavior of sulfur was investigated in the form of synthetic slag to clarify the relationship between the occurrence state and precipitation behavior of sulfur in KR desulfurization slag and cooling rate, and provide theoretical reference for effective removal of sulfur from KR desulfurization slag by oxidizing atmosphere, and realize the comprehensive utilization of KR desulfurization slag in converter smelting process. The equilibrium solidification process of slag was simulated by thermodynamic database FactSage8.1, and the slag samples which were taken to glass tube(rapid), crucible(moderate) and furnace(slow) cooling were analyzed and detected by SEM-EDS and XRD. The average grain size of CaS in the slag was counted by Image-ProPlus6.0. The experimental results showed that the synthetic slag contained dispersively distributed sulfur and sulfur in the form of CaS particles. The sulfur in the rapid cooling slag sample was mainly dispersed in the matrix phase of slag, and a small amount existed in the form of CaS phase. The sulfur of samples cooled in the crucible and furnace mainly existed in the form of CaS particles, and a small amount of sulfur was dispersed in the matrix. The sulfur content in the matrix phase gradually decreased, the precipitation of CaS phase in slag gradually increased, and the average area of CaS particles gradually increased with the decrease of cooling rate.
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2022, Vol. 32 
