Effect of Na2O on Dissolution Rate of Alumina in CaO-Al2O3-MgO-SiO2 Slag
The removal of inclusion in tundish has received intensive interests from engineers and researchers.As the last step of inclusion removal in tundish,the dissolution of Al2O3 in tundish slag is a very important issue and has received many studies by previous reseachers.Tundish slags are mainly based on CaO-Al2O3-MgO-SiO2 with high basicity(CaO/SiO2).In the present work,the effect of Na2O addition on dissolution of Al2O3 in CaO-Al2O3-MgO-SiO2 slag at 1823K was investigated by using rotating finger method.The interface between rod and molten slag was investigated using SEM-EDS technique.Following conclusions have been reached.The dissolution of Al2O3 in CaO-Al2O3-MgO-SiO2-Na2O system increases with increase of rotating speed and immersing time.A linear relationship between logarithm of dissolution rate and logarithm of periphery velocity was found with a slope of 0.53,which indicate that rate determining step for dissolution of Al2O3 is the mass transfer of solute in boundary layer of molten slag.The dissolution rate of alumina in CaO-Al2O3-MgO-SiO2-Na2O system increases with increase of Na2O content at the same rotating speed.The increase of dissolution rate with increasing Na2O content could be attributed to the kinetic and thermodynamic factor.The decrease of viscosity of molten slag with increasing Na2O content could lead to increased mass transfer in boundary layer of molten slag.On the other hand,the increase of Na2O would lead to increase of thermodynamic driving force of Al2O3 dissolution.Some intermediate compounds such as MgAl2O4 and CaO·2Al2O3 were found at interface between alumina rod and slag.The present results indicate that the addition of Na2O would be beneficial to dissolution of alumina in CaO-Al2O3-MgO-SiO2 system,and thereby help to removal of inclusion in tundish.
tundish slag dissolution Na2O CaO-Al2O3-MgO-SiO2
Qifeng SHU Xiang ZHAN Yanfei WANG Jiangling LI Kuochih CHOU
School of metallurgical and ecological engineering,University of Science and Technology Beijing,Beij School of metallurgical and ecological engineering,University of Science and Technology Beijing,Beij
国际会议
the 6th International Congress on the Science and Technology of Steelmaking,ICS2015(第六届国际炼钢科技大会)
北京
英文
606-609
2015-05-12（万方平台首次上网日期，不代表论文的发表时间）