Effects of Transition Metal Oxides on Thermal Conductivity of Mould Fluxes

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• 作者：Xin QIU ; Bing XIE ; Xue-mei QING ; Jiang DIAO ; Qing-yun HUANG ; Shui-bo WANG
• 关键词：mould flux ; heat transfer ; transition metal oxide ; thermal conductivity
• 刊名：Journal of Iron and Steel Research, International
• 出版年：November, 2013
• 年：2013
• 卷：20
• 期：11
• 页码：27-32
• 全文大小：337 K

文摘

The thermal conductivity of the mould fluxes containing transition metal oxides was measured by hotline method at different temperatures. The relationship between the thermal conductivity of mold fluxes and the contents of transition metal oxides was discussed. The synthetic slags were composed of 30.0% 鈥?35.4% CaO, 34.7% 鈥?38.6% SiO₂, 6% Al₂O₃, 9% Na₂O, 14.4% CaF₂, 0-4% Cr₂O₃ and 0-8% MnO in mass percent. The results indicated that Cr₂O₃ and MnO had a negative effect on thermal conductivity of mold fluxes. The thermal conductivity of mold fluxes was about 0.25 鈥?0.55 W/(m K) when the temperature reached 1300 掳C, and it increased sharply to about 1.32-1.99 W/(m K) when the temperature reduced from 1300 to 1000 掳C. The thermal conductivity of mold fluxes containing Cr₂O₃ and MnO was 10%鈥?5% lower than those of original fluxes. The decrease in thermal conductivity was attributed to the change of molecular structure of mold fluxes. In addition, the poor integrity and regulation of polycrystal structure, complexity of crystal structure, and effects of impurities in the boundary and lattice distortion leaded to the reduction in the thermal conductivity. Na₂CrO₄, Mn₂SiO₄ and other minor phases were also found in the samples containing Cr₂O₃ and MnO, respectively.