摘要： 高Al钢连铸时，Al是强还原剂，它要还原保护渣中活泼性比它弱的氧化物，比如SiO2，MnO等，使得成分发生变化，理化性能也发生大波动，影响连铸稳定性及生产和质量问题。本研究围绕高Al钢连铸过程中Al还原SiO2反应中渣中SiO2的活度问题展开研究，采用化学平衡法实验测定渣中SiO2的活度系数γSiO2和活度aSiO2，及其与渣中SiO2浓度的关系。实验结果表明：在其他条件都不变的情况下，（1）γSiO2随着xSiO2的增加而线性增加，关系式：γSiO2 =1.132xSiO2 -0.136；（2）xSiO2越大，SiO2的活度就越大。50030

毕业论文关键词： 保护渣；SiO2；高铝钢；连铸

Study on the activity of SiO2 in the mold slag

Abstract: Al is a strong reducing agent for high Al steel continuous casting. It will restore the oxide in the mold slag which activity is weaker than it such as MnO, SiO2, etc. It will change the composition of mold slag, largely make the physical and chemical properties occurred, effect continuous casting stability and production and quality problems. This research focuses on the activity of SiO2 in the slag of Al reduction SiO2 reaction in high Al steel continuous casting process. The activity coefficient of SiO2 in slag was determined by chemical equilibrium method. The activity coefficient of γSiO2 and the activity of aSiO2 were determined the relationship between and the concentration of SiO2 in the slag. The experimental results show that: in the case of other conditions are unchanged, (1) lgγSiO2 increases linearly with the increase of xSiO2. Relationship: γSiO2 =1.132xSiO2 -0.136; (2) the greater the xSiO2, the greater the activity of SiO2.

Keywords: Mold slag; SiO2; High Al steel; Continuous casting

 目录

1  文献综述 1

1.1  高Al钢的研究现状 1

1.2  无氟保护渣 2

1.2.1  国外无氟保护渣的研究现状 2

1.2.2  无氟保护渣国内研究现状 4

1.3  活度的测量方法 6

1.3.1  化学平衡法 6

1.3.2  固体电解质法 6

1.3.3  蒸气压法 8

1.3.4  三元相图法 10

1.3.5  实验方法的选用 10

2 课题研究的意义及内容 11

2.1  课题研究的意义 11

2.2  课题研究的内容 11

3  实验研究方法 12

3.1  实验原理 12

3.2  实验用原材料 13

3.3  实验装置简图 14

3.4  实验设备 15

3.5  实验过程与步骤 18

3.6  实验的问题预测及解决方案 19

4 实验结果和分析讨论 20

4.1  渣金中的平衡浓度 20

4.2  渣中组分的摩尔分数 20

4.3  所研究反应的标准自由能变化