Dephosphorization behavior of CaO-SiO2-FeO-10%MgO slag in BOF melting process
ZHAO Dong-wei1,LI Hai-bo1,SUN Liang2,ZHANG Yong2
(1. Strip Technology Department, Shougang Research Institute of Technology, Beijing 100043, China 2. Qian’an Iron and Steel Company, Shougang Co., Ltd., Qian’an 064404, Hebei,China)
Abstract:An expression among phosphorus partition ratio, slag composition, carbon content in steel and temperature is regressed based on thermodynamic analysis of the dephosphorization behavior of CaO-SiO2-FeO-10%MgO slag system at the slag-steel interface, and the iso-phosphate partition ratio graph of the CaO-SiO2-FeO-10%MgO slag system is depicted by regression expression, and the effect of FeO content, basicity of slag and temperature in the endpoint of BOF smelting process on the phosphorus partition ratio is analyzed. The results show that phosphorus partition ratio is a function of temperature, carbon content and slag composition, which has been proved based on actual production data. According to the above equation, with the increasing of FeO content of slag, the distribution ratio[LP]of phosphorus between slag and steel first increases then decreases and reaches a maximum when FeO content is about 18%. With the increasing of basicity of slag, the distribution ratio[LP]of phosphorus between slag and steel increases and the increase amount is not obvious when the basicity of slag is over 4.0.
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