Purification of metallurgical-grade silicon using zirconium as an impurity getter
Purification of metallurgical-grade silicon using zirconium as an impurity getter
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DOI：
10.1016/j.seppur.2016.09.051
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发表时间：
2017-02
影响因子：
8.6
通讯作者：
Lei Yun;Wenhui Ma;G. Lv;K. Wei;Shaoyuan Li;Kazuki Morita
中科院分区：
文献类型：
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作者：
Lei Yun;Wenhui Ma;G. Lv;K. Wei;Shaoyuan Li;Kazuki Morita
Zr 被用作杂质吸收剂，以增强 MG-Si 中杂质的去除，因为它对多种杂质具有很强的亲和力。采用不同的浸出剂，HCl + HF、HF 和王水，研究了添加和不添加 Zr 的 MG-Si 在 348 K 下浸出 2.5 小时的行为。通过扫描电子显微镜（SEM）和能量色散X射线光谱（EDS）对酸浸前后Si晶界的典型沉淀进行观察和分析。浸出结果表明，浸出剂的浸出效率从高到低依次为HCl+HF>HF>王水。 HCl + HF 是添加或不添加 Zr 的 MG-Si 纯化的最佳浸滤剂。 MG-Si 中 Zr 的存在可以显着提高杂质的提取效率，尤其是 P 和 Al，而使用传统的湿法冶金技术无法有效去除这些杂质。 HCl + HF 浸出后，去除的杂质（Fe、Al、Ca、B、P、Zr、Ti、V、Mn、Cu 和 Ni）的总分数从 94.2% 增加到 97.5%。此外，HCl+HF浸出后，99.9%的杂质Zr被去除，其浓度从50,000ppmw下降到49ppmw。精炼Si中残留的Zr由于其偏析系数极小，可以通过定向凝固提纯进一步去除。
Zr was employed as an impurity getter to enhance removal of impurities from MG-Si because of its strong affinity for a wide range of impurities. Different lixiviants, HCl + HF, HF and aqua regia, were employed to investigate the leaching behavior of MG-Si at 348 K for 2.5 h with and without Zr addition. Typical precipitates at Si grain boundaries before and after acid leaching were observed and analyzed via scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). The leaching results show that the order of efficiency of the lixiviants, from highest to lowest, is HCl + HF > HF > aqua regia. HCl + HF is the optimal lixiviant for purification of MG-Si with and without Zr addition. The presence of Zr in MG-Si can significantly enhance the efficient extraction of impurities, especially P and Al, which cannot be removed efficiently using conventional hydrometallurgical technologies. The total fraction of impurities removed (Fe, Al, Ca, B, P, Zr, Ti, V, Mn, Cu and Ni) increased from 94.2 to 97.5% after HCl + HF leaching. In addition, 99.9% of the impurity getter Zr was removed, with its concentration decreasing from 50,000 ppmw to49ppmw after HCl + HF leaching. The residual amount of Zr in the refined Si can be further removed by directional-solidification purification because of its extremely small segregation coefficient.