CaO-SiO_(2)-Al_(2)O_(3)-MgO-FeO渣对Al_(2)O_(3)的溶解

Al_(2)O_(3)dissolution into molten CaO-SiO_(2)-Al_(2)O_(3)-MgO-FeO slags

为了控制低碳铝镇静钢中Al_(2)O_(3)夹杂物,并提升渣系对Al_(2)O_(3)夹杂物吸附能力,采用FactSage 8.1模拟计算CaO-SiO_(2)-Al_(2)O_(3)-5%MgO-5%FeO渣系的等黏度图和等ΔC/η(ΔC=C_(Al_(2)O_(3))^(s)-C_(Al_(2)O_(3))^(b),η为渣的黏度)值线图。根据模拟计算图选取合适的五元精炼渣做Al_(2)O_(3)的吸附试验,试验研究了Al_(2)O_(3)在CaO-SiO_(2)-Al_(2)O_(3)-5%MgO-5%FeO渣系中的溶解速率,讨论了Al_(2)O_(3)棒浸入深度、直径、转速、渣成分以及温度对Al_(2)O_(3)溶解速率的影响,求解了Al_(2)O_(3)在溶解过程中的活化能。最后,采用场发射扫描电子显微镜(Apreo S HiVac)对氧化铝棒与熔渣接触的界面处进行微区线元素的定性分析。研究结果表明,Al_(2)O_(3)在渣中的溶解速率受诸多因素的影响;溶解速率随氧化铝棒的旋转速度、棒直径、浸入深度和温度的增加而增加;溶解速率也会随着CaO含量的增加而增加,Al_(2)O_(3)和SiO_(2)含量的增加而降低。溶解速率高度依赖于熔渣的黏度,渣的黏度对Al_(2)O_(3)的溶解速率呈负相关,Al_(2)O_(3)的溶解速率与浓度驱动力呈正相关。氧化铝棒溶解于渣系前,会先生成中间相CaO·2Al_(2)O_(3)和CaO·6Al_(2)O_(3),中间相溶解在熔渣中,溶解于渣A中的表观活化能为410.9 kJ/mol。结合溶解速率图与等ΔC/η值线图进行对比,验证了Al_(2)O_(3)在渣中的溶解速率受渣物性的影响。

In order to control the Al_(2)O_(3)inclusions in low-carbon Al-killed steel and improve the adsorption capacity of the slag system to Al_(2)O_(3)inclusions,the isoviscosity diagram of CaO-SiO_(2)-Al_(2)O_(3)-5%MgO-5%FeO slag system and the contour map ofΔC/η(ΔC=C_(Al_(2)O_(3))^(s)-C_(Al_(2)O_(3))^(b),ηis the viscosity of slag)were simulated by FactSage 8.1.The dissolution rate of Al_(2)O_(3)in CaO-SiO_(2)-Al_(2)O_(3)-5%MgO-5%FeO slag system was studied.The effects of Al_(2)O_(3)rod immersion depth,diameter,rotation speed,slag composition and temperature on the dissolution rate of Al_(2)O_(3)were discussed.The activation energy of Al_(2)O_(3)in the dissolution process was solved.Finally,the qualitative analysis of the micro-line elements at the interface between the alumina rod and the slag was carried out by field emission scanning electron microscopy(Apreo S HiVac).The results show that the dissolution rate of Al_(2)O_(3)in slag is affected by many factors.The dissolution rate increases with the increase of rotation speed,rod diameter,immersion depth and temperature of alumina rod.The dissolution rate also increases with the increase of CaO content,and decreases with the increase of Al_(2)O_(3)and SiO_(2)content.The dissolution rate is highly dependent on the viscosity of the slag.The viscosity of the slag is negatively correlated with the dissolution rate of Al_(2)O_(3),and the dissolution rate of Al_(2)O_(3)is positively correlated with the concentration driving force.Before the alumina rod is dissolved in the slag system,it will be transformed into intermediate phases CaO·2Al_(2)O_(3)and CaO·6Al_(2)O_(3),and the intermediate phase is dissolved in the slag.The apparent activation energy of dissolution in slag A is 410.9 kJ/mol.The dissolution rate of Al_(2)O_(3)in slag was verified by comparing the dissolution rate diagram with the contour diagram ofΔC/η.