The facilitation of metallic impurities removal via acid leaching pretreatment plays a key role in silicon recovery from diamond wire saw silicon powder (DWSSP) waste. Disappointingly, the occurrence state and dissolution mechanism of the metallic impurities present in DWSSP have not yet been revealed. For this reason, in this study, three different kinds of raw DWSSP were used for acid leaching tests and leaching behavior verification to investigate the dissolution mechanism. After two-stage acid leaching with 4 M HCl and 2 M HCl + 2.5 M HF, the results indicate that the removal efficiency was superior to that of other previously reported leaching processes. Furthermore, two occurrence states of metallic impurities present in DWSSP were defined based on their different dissolution behaviors, and the intrinsic relationship between dissolution behavior and the thinning process of the amorphous SiO₂ shell was derived. The findings indicate that the first type of impurity was more easily dissolved in HCl solution; however, the second type of retained metallic impurity was restricted by the SiO₂ shell barrier and was removed by the added HF solution. For this reason, the disintegration dissolution of the amorphous SiO₂ shell was found to have a significant impact on the facilitation of the removal of impurities retained in DWSSP. The findings of this study are significant for the recovery of silicon from DWSSP with an effective acid leaching flow design.

中文翻译：

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金刚石线锯硅粉中金属杂质的赋存状态及溶解机理

通过酸浸预处理促进去除金属杂质在金刚石线锯硅粉（DWSSP）废料的硅回收中起着关键作用。令人失望的是，DWSSP中存在的金属杂质的发生状态和溶解机理尚未揭示。因此，在本研究中，使用了三种不同的原始DWSSP进行酸浸测试和浸出行为验证，以研究其溶解机理。用4 M HCl和2 M HCl + 2.5 M HF进行两步酸浸后，结果表明其去除效率优于其他先前报道的浸出工艺。此外，根据DWSSP中金属杂质的不同溶解行为，定义了它们的两种发生状态，₂壳派生了。研究结果表明，第一类杂质更容易溶解在HCl溶液中。然而，第二种保留的金属杂质被SiO ₂壳阻挡层限制，并被添加的HF溶液除去。因此，发现无定形SiO ₂壳的崩解溶解对促进DWSSP中保留的杂质的去除具有显着影响。这项研究的发现对于通过有效的酸浸流设计从DWSSP回收硅具有重要意义。