(昆明理工大学 冶金与能源工程学院，昆明 650093)
摘 要: 针对工业硅中杂质深度去除困难的问题，本文提出在传统湿法除杂的基础上，通过借助金属辅助化学刻蚀技术在工业硅中引入多孔结构，使工业硅内部包裹的杂质充分暴露给浸出剂以实现各主要杂质深度去除目的。系统考查了不同工业硅粉粒度、刻蚀时间对主要金属杂质Fe、Al、Ca、Ti和V的去除影响，探究了工业硅中杂质相及周边硅相形貌的原位衍变过程及多孔硅形成原理。结果表明：随着工业硅粉粒度的减小，多孔硅表面多孔形貌逐渐变得紧致，硅中杂质的去除率升高；随着刻蚀时间的延长，多孔形貌变得更为疏松并有利于杂质的去除；杂质相的存在可促进金属辅助化学刻蚀反应的进行并有利于多孔形貌的引入。在较优试验条件下，工业硅中各主要杂质去除率为Fe 98.91%、Al 98.15%、Ca 95.41%、Ti 99.76%、V 100%。
关键字: 工业硅；金属辅助化学刻蚀；多孔结构；杂质去除；湿法冶金
（Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:Based on difficult problems in depth removal of impurities from metallurgical grade silicon, the metal assisted chemical etching (MACE) was proposed and discussed in this study. With the metal assisted chemical etching treatment, the formation of pores would provide numerous micro-scale “channels” for a better contact between impurities and acid lixiviants during acid leaching process. It is useful for deeply removing impurities from metallurgical grade silicon powders. The principle of pores formation, microstructural evolution of precipitates phase and MG-Si, the effects of etching time and silicon particle size on the morphologies and the structures of porous silicon as well as the removal rate of main impurities Fe, Al, Ca, Ti, V were studied. The results show that the porous silicon surface compacted and the impurities content reduce with the size of the silicon powder decrease. As the etching time prolonging, the porous structure become fluffy and have an important influence on the impurities removal from metallurgical grade silicon. As the size of silicon powder decreasing, the porous silicon surface compacted and the impurities content reduce. The impurities precipitates on the Si grain and surface are beneficial for etching of silicon and forming micro-pores. Under the optimized experiment condition, the better impurity removal efficiencies are Fe 98.91%, Al 98.15%, Ca 95.41%, Ti 99.76%, V 100%.
Key words: metallurgical grade silicon; metal assisted chemical etching; porous structure; impurities removal; hydrometallurgy
