Cleanliness control is an eternal theme to improve the properties of steel products. With the increasing recycling rates of scrap steel, the removal and stabilization of residual elements have become a vital issue for improving the performance of steel products. Thermodynamic and mismatch calculations plus laboratory experiments were carried out to study the heterogeneous nucleation phenomena of inclusions when lanthanum was employed to remove arsenic from molten steel and stabilize arsenic in solid steel. The effect of heterogeneous nucleation on the mechanism of arsenic removal was discussed. A series of heterogeneous nucleation phenomena of inclusions in the La-O-S-As system were discovered, and the heterogeneous nucleation among the inclusions turned out to be selective. As the vital product of arsenic removal, La-S-As is most likely to generate with LaS as heterogeneous nucleation cores, and its possible chemical formula turned out to be 3LaS⸱LaAs. Sulfur plays an essential role in removing arsenic from molten steel by adding lanthanum. It needs to control the initial sulfur content in an appropriate range, because the high initial content causes too much loss of rare earth, and the low initial content cannot produce LaS and La-S-As.

中文翻译：

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非均相成核对添加稀土去除钢水中砷的影响

清洁度控制是提高钢材性能的永恒主题。随着废钢回收率的提高，残留元素的去除和稳定化已成为改善钢材性能的重要问题。进行了热力学和失配计算以及实验室实验，研究了使用镧去除钢水中的砷并稳定固态钢中的砷时夹杂物的异相形核现象。讨论了异相成核对除砷机理的影响。在La-OS-As系统中发现了一系列夹杂物的异质形核现象，结果表明夹杂物中的异质形核是选择性的。作为除砷的重要产品，La-S-As最有可能以LaS作为异质核核生成，其可能的化学分子式为3LaS⸱LaAs。硫在通过添加镧从钢水中去除砷中起着至关重要的作用。它需要将初始硫含量控制在适当的范围内，因为高的初始含量会导致过多的稀土损失，而低的初始含量不能产生LaS和La-S-As。