College of Materials Science and Engineering, Chongqing University, Chongqing, 400045, China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials, Chongqing University, Chongqing, 400044, China.
College of Materials Science and Engineering, Chongqing University, Chongqing, 400045, China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials, Chongqing University, Chongqing, 400044, China.
J Environ Manage. 2023 Jul 15;338:117829. doi: 10.1016/j.jenvman.2023.117829. Epub 2023 Apr 4.
With the strengthened awareness of environmental protection and the growing interests of wastes recycling, silicon recovery from polycrystalline silicon kerf loss (PSKL) has drawn extensive attentions all over the world. In this paper, an efficient and environmental friendly approach for oxygen removal and silicon recovery from PSKL by combining vacuum magnesium thermal reduction (VMTR) and hydrochloric acid leaching was proposed. The effects of temperature, duration and particle size on the reduction of PSKL were investigated thoroughly. It is proved that the amorphous SiO in PSKL can be reduced by magnesium vapor at 923 K to generate MgO, and then the produced MgO can be dissolved by hydrochloric acid to eliminate the impurity oxygen. The oxygen removal fraction and the silicon recovery efficiency attained 98.43% and 94.46%, respectively, under the optimal conditions, indicating that a high efficiency recovery of silicon from PSKL was achieved. Compared to the existing PSKL deoxidation technologies, e.g., the high temperature process and the hydrofluoric acid leaching method, this method requires a relatively lower temperature and the waste acid can be easily recovered. Additionally, by taking into accounts the fact that the MgCl in leaching liquor can be recycled for cyclic utilization with a molten salt electrolysis method, it should be suggested that an efficient and environmental friendly process for PSKL recycling was obtained, which shows good prospects for commercial application.
随着环境保护意识的增强和对废物回收利用兴趣的增长，从多晶硅硅片切割废料（PSKL）中回收硅已引起全球广泛关注。本文提出了一种从 PSKL 中通过真空镁热还原（VMTR）和盐酸浸出联合去除氧和回收硅的高效环保方法。详细研究了温度、时间和粒度对 PSKL 还原的影响。结果表明，PSKL 中的非晶态 SiO 可在 923 K 下被镁蒸气还原生成 MgO，然后生成的 MgO 可被盐酸溶解以除去杂质氧。在最佳条件下，氧去除分数和硅回收效率分别达到 98.43%和 94.46%，表明从 PSKL 中实现了硅的高效回收。与现有的 PSKL 脱氧技术（如高温工艺和氢氟酸浸出法）相比，该方法所需温度相对较低，废酸易于回收。此外，考虑到浸出液中的 MgCl 可以通过熔盐电解法回收循环利用，因此可以认为已经获得了一种从 PSKL 中回收硅的高效环保工艺，具有良好的商业应用前景。
