VOD精炼渣对Al_2O_3的溶解

Dissolution of Al_2O_3 in VOD Refining Slag

通过测定旋转的Al2O3棒在CaO-SiO2-Al2O3-MgO-CaF2五元VOD精炼渣中的溶解速率模拟研究精炼渣吸收Al2O3夹杂物的速率,考察了各因素对其溶解速率的影响.结果表明,该溶解过程的限制性环节为Al2O3向精炼渣基体的传质,Al2O3溶解速率随着旋转角速度的提高而增大,1600℃下,精炼渣碱度为4,Al2O3含量25%时,随着Al2O3棒的旋转角速度由100r/min增大到200r/min,其溶解速率由19.2×10-3g/(cm2.min)增大到29.2×10-3g/(cm2.min).1600℃时,当精炼渣碱度由3增加到5,Al2O3溶解速率由30.7×10-3g/(cm2.min)下降到9.4×10-3g/(cm2.min).升高温度、降低精炼渣碱度,有利于提高精炼渣吸收Al2O3的能力.1600℃下精炼渣碱度为4时,Al2O3含量从15%增加到35%,Al2O3溶解速率从36×10-3g/(cm2.min)下降到25.8×10-3g/(cm2.min).实验得出Al2O3溶解过程的表观活化能,精炼渣中Al2O3含量越高,Al2O3溶解过程的表观活化能越大.

The absorption rate of Al2O3 in CaO-SiO2-Al2O3-MgO-CaF2 VOD refining slag is simulated by the dissolution rate of rotating Al2O3 rod in the slag. The effects of various factors on its dissolution rate were examined. The results show that the limiting step of Al2O3 dissolution is its mass transfer to molten slag. The rate increases with increasing of the rotating angular velocity of Al2O3 rod. The dissolution rate in the slag with the basicity of 4 and Al2O3 content 25% increases from 19.2×10^-3 to 29.2×10^-3 g/（cm^2·min） with increasing of the rod rotation angular velocity from 100 to 200 r/min at 1600 ℃. Increasing the basicity of refining slag reduces the saturation solubility of Al2O3 in the slag. When the basicity of refining slag increases from 3 to 5, the dissolution rate of Al2O3 decreases from 30.7×10^-3 to 9.4×10^-3 g/（cm^2·min） at 1600℃. When the basicity of refining slag is 4, with the initial Al2O3 content in slag increasing from 15% to 35%, the dissolution rate from 36×10^-3 down to 25.8×10^-3 g/（cm^2·min） at 1600 ℃. Increasing the temperature and decreasing the basicity of slag are beneficial to increase of the Al2O3 absorbability. The dissolution activation energy of Al2O3 in dissolving process is obtained, which increases with the initial Al2O3 content in the refining slag.