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During the smelting process of the high Al steels,the reaction between SiO_2 in molten slag and dissolved aluminum in liquid steel always takes place.This aluminathermic reduction reaction will lead to the substitution of 1mol SiO_2 for 2/3mol Al_2O_3.Therefore,the investigations about the influence of the ratio of Al_2O_3 to SiO_2on viscosity and structure changes of mould flux during this process are very necessary.The viscosity variation of CaO-SiO_2-Al_2O_3-CaFv2 melts was studied by changing compositions considering the aluminathermic reduction reaction.It was found that viscosity increased monotonously with gradually increasing the substitution extent.According to the Raman analysis,the substitution of Al_2O_3 for SiO_2 leads to the decrease of non-bridging oxygen but the increase of bridging oxygen.Therefore,degree of polymerization and viscosity increase as the substitution extent increases.By comparing the measured viscosities with the model calculated values,it was found that both the recently developed Zhang′s model and Roboud model could describe the viscosity variation behavior of CaO-SiO_2-Al_2O_3-CaF_2 melts very well.
The smelting process of the high Al steels, the reaction between SiO 2 in molten slag and dissolved aluminum in liquid steel always takes place. This aluminathermic reduction reaction will lead to the substitution of 1 mol SiO 2 for 2/3 mol Al 2 O 3. the influence of the ratio of Al_2O_3 to SiO_2on viscosity and structure changes of mold flux during this process are very necessary.The viscosity variation of CaO-SiO_2-Al_2O_3-CaFv2 melts was studied by changing compositions considering the aluminathermic reduction reaction. viscosity increased monotonously with gradually increasing the substitution extent. According to the Raman analysis, the substitution of Al 2 O 3 for SiO 2 leads to the decrease of non-bridging oxygen but the increase of bridging oxygen. wherefore, degree of polymerization and viscosity increase as the substitution extent increases.By comparing the measured viscosities with the model calculated values, it was found that both the recently developed Zhang’s model and Roboud model could describe the viscosity variation behavior of CaO-SiO_2-Al_2O_3-CaF_2 melts very well.