A simulative industrial processing, slag refining under open air atmosphere conditions, has been established to observe the removal efficiency of impurities from molten Si at 1823 K. The behavior of Ca and its compounds in Si are investigated. The results show that, CaSi₂ is a key compound on removing Fe, Al, Ca and P from Si. Ca in molten Si is produced from the reaction between CaO and Si at the melting stage of slag and Si, as well as at the beginning refining period of around 10 min, which is largely depends on the net content of single CaO phase. With the temperature going down to 1303 K gradually, most of Si is solidified and Ca percentage is increased, then species CaSi₂ phase is generated from the melt composed of 61.4 wt% Si, while Fe is precipitated at the boundary between phases CaSi₂ and Si. Furthermore, it is determined that, part of P in Si is oxidized to PO₄³⁻ not by SiO₂ but by CaO to form CaO·P₂O₅ slag phase, the other is more likely to be reduced to Ca_xSi_yP_z than to Ca₃P₂. Therefore, a slag rich in CaO will be much easier to produce Ca in Si and more efficient to remove impurities by acid leaching.

建立了模拟工业过程，在露天大气条件下精炼炉渣，以观察1823 K下从熔融硅中去除杂质的效率。研究了Ca及其化合物在Si中的行为。结果表明，CaSi ₂是去除Si中Fe，Al，Ca和P的关键化合物。熔融Si中的Ca是由CaO与Si在炉渣和Si的熔融阶段以及大约10分钟的开始精炼阶段之间的反应产生的，这在很大程度上取决于单个CaO相的净含量。随着温度逐渐降低到1303 K，大部分Si固化并且Ca百分比增加，然后形成CaSi ₂从由61.4 wt％的Si组成的熔体中产生相，而Fe在相CaSi ₂和Si之间的边界处析出。此外，可以确定的是，Si中的P的一部分不是被SiO ₂而是被CaO氧化为PO ₄ ^3-形成CaO·P ₂ O ₅渣相，而另一部分更可能被还原为Ca _x Si _y。 P _z大于Ca ₃ P ₂。因此，富含CaO的炉渣将更容易在Si中生成Ca，并且更有效地通过酸浸去除杂质。