Oxidative ladle refining (OLR) is the most used refining method in industrial production of metallurgical grade silicon. OLR is performed by purging the liquid alloy with oxygen-enhanced air at 1823 K to 1873 K, reacting with silicon and the primary slag forming impurities to a SiO\(_{2}\)-CaO-Al\(_{2}\)O\(_{3}\) slag. To further increase our capability to control this process, it is paramount to understand how the slag nucleates and forms, and represent it such that it is useful for predicting and controlling the process behavior. This work aims to formulate a comprehensive theoretical description of slag nucleation and formation at nano/microscale using classical macroscale thermodynamics, bridging these spatial regimes. To achieve this, the work argues that silica’s liquid structure allows its nuclei to exhibit “well defined” surfaces. Furthermore, silica is predicted to be highly surface active, so if its concentration is high while the slag nucleus is small, the SiO\(_{2}\)-CaO-Al\(_{2}\)O\(_{3}\) slag should retain silica’s surface properties. An experiment confirmed the surface active nature of silica in the SiO\(_{2}\)-CaO-Al\(_{2}\)O\(_{3}\) system. It was also shown that increasing the slag’s calcia concentration has a greater effect on the interfacial tension between the molten slag and liquid alloy than alumina, confirming industrial observations of the coupling between refining rate and relative alloy/slag composition.

氧化钢包精炼（OLR）是冶金级硅工业生产中最常用的精炼方法。通过用1823 K至1873 K的氧气增强的空气吹扫液态合金，与硅和一次炉渣反应形成SiO \（_ {2} \）- CaO-Al \（_ {2}的杂质，来进行OLR \） O \（___ 3）\）矿渣。为了进一步提高我们控制该过程的能力，了解炉渣如何成核和形成并表现出来以便对预测和控制过程行为有用非常重要。这项工作的目的是使用经典的宏观热力学，在纳米/微米尺度上建立关于炉渣成核和形成的综合理论描述，以弥合这些空间状态。为了达到这个目的，这项工作认为二氧化硅的液体结构可以使其核展现出“轮廓分明”的表面。此外，预计二氧化硅具有很高的表面活性，因此，如果其浓度高而炉渣核小，则SiO \（_ {2} \）- CaO-Al \（_ {2} \） O \（_ {3} \）炉渣应保留二氧化硅的表面性能。实验证实了SiO \（_ {2} \）- CaO-Al \（_ {2} \） O \（_ {3} \）体系中二氧化硅的表面活性。还显示出增加炉渣的氧化钙浓度比氧化铝对熔融炉渣和液态合金之间的界面张力具有更大的影响，证实了工业观察精炼速率与相对合金/炉渣组成之间的耦合。