(昆明理工大學(xué) 冶金與能源工程學(xué)院，昆明 650093)
摘 要: 針對(duì)工業(yè)硅中雜質(zhì)深度去除困難的問(wèn)題，本文提出在傳統(tǒng)濕法除雜的基礎(chǔ)上，通過(guò)借助金屬輔助化學(xué)刻蝕技術(shù)在工業(yè)硅中引入多孔結(jié)構(gòu)，使工業(yè)硅內(nèi)部包裹的雜質(zhì)充分暴露給浸出劑以實(shí)現(xiàn)各主要雜質(zhì)深度去除目的。系統(tǒng)考查了不同工業(yè)硅粉粒度、刻蝕時(shí)間對(duì)主要金屬雜質(zhì)Fe、Al、Ca、Ti和V的去除影響，探究了工業(yè)硅中雜質(zhì)相及周邊硅相形貌的原位衍變過(guò)程及多孔硅形成原理。結(jié)果表明：隨著工業(yè)硅粉粒度的減小，多孔硅表面多孔形貌逐漸變得緊致，硅中雜質(zhì)的去除率升高；隨著刻蝕時(shí)間的延長(zhǎng)，多孔形貌變得更為疏松并有利于雜質(zhì)的去除；雜質(zhì)相的存在可促進(jìn)金屬輔助化學(xué)刻蝕反應(yīng)的進(jìn)行并有利于多孔形貌的引入。在較優(yōu)試驗(yàn)條件下，工業(yè)硅中各主要雜質(zhì)去除率為Fe 98.91%、Al 98.15%、Ca 95.41%、Ti 99.76%、V 100%。
關(guān)鍵字: 工業(yè)硅；金屬輔助化學(xué)刻蝕；多孔結(jié)構(gòu)；雜質(zhì)去除；濕法冶金
（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
