精炼渣的夹杂物容量的概念及其应用

Concept of inclusion capacity of slag and its application

分析了目前文献中使用夹杂物组分在渣中的饱和质量分数和当前质量分数的差值除以渣的黏度(ΔC/η)这一参数来评价夹杂物在渣中溶解能力的文献来源以及该参数的局限性,包括该参数有量纲且没有包含夹杂物尺寸的影响。与流体流动的自然对流传热中使用的格拉晓夫数进行类比,提出了渣的夹杂物容量的概念,即无量纲的Zh数,同时提出了无量纲溶解速度Ry的概念,得到了渣的夹杂物容量与夹杂物无量纲溶解速度之间的关系。夹杂物容量可以用来预测夹杂物在渣中的溶解速度和溶解时间,可以用来计算溶解过程化学反应系数和夹杂物组分在渣中的扩散系数,还可以用来计算夹杂物从钢液中的去除时间。随着夹杂物容量Zh数的增加和夹杂物尺寸的增大,夹杂物的溶解时间增大。随着夹杂物尺寸的增大,夹杂物的平均去除时间增加而最大去除时间降低。温度为1600℃时,针对Al_(2)O_(3)夹杂物在CaO-Al_(2)O_(3)-SiO_(2)渣中的溶解过程,计算得到的界面化学反应系数为5×10^(-6)~10×10^(-6)m/s,扩散系数为2.5×10^(-10)~4×10^(-10)m^(2)/s,其值依据渣成分的变化而变化。

The parameter of the difference between the original concentration and the saturation concentration of inclusions in the refining slag divided by slag viscosity(ΔC/η)was retrieved from literatures and the disadvantages of the parameter were discussed,including its dimensional feature and the ignorance of the size of inclusions.Similar to the dimensionless Grash of number used to the natural convection of the fluid flow,the inclusion capacity of the refining slag was proposed(the dimensionless number of Zh).The dimensionless dissolution rate of inclusions in the slag(Ry)was proposed.The expression between the inclusion capacity of the slag and the dimensionless dissolution rate was obtained.The inclusion capacity of the slag,the Zh number,can be used to predict the dissolution rate and dissolution time of inclusions in the refining slag,to calculate the rate constant of the dissolution reaction and the diffusion coefficient of inclusions in the slag,and to calculate the removal time of inclusions from the molten steel.With the increasing of the Zh number and the increasing of inclusion size,the dissolution time of inclusions became longer.With the increasing of inclusion size,the average removal time of less than 500μm inclusions increased while the maximum removal time decreased.At the temperature of 1600℃,for the dissolution of Al_(2)O_(3)in the CaO-Al_(2)O_(3)-SiO_(2)slag,the dissolution reaction rate constant was 5×10^(-6)-10×10^(-6)m/s and the diffusion coefficient of Al_(2)O_(3)in the CaO-Al_(2)O_(3)-SiO_(2)slag was 2.5×10^(-10)^(-4)×10^(-10)m~2/s,and the two parameters varied with the composition of the slag.