(1. 北京科技大學(xué) 鋼鐵冶金新技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，北京 100083；
2. 中國(guó)科學(xué)院過(guò)程工程研究所 綠色過(guò)程與工程重點(diǎn)實(shí)驗(yàn)室 濕法冶金清潔生產(chǎn)技術(shù)國(guó)家工程實(shí)驗(yàn)室，北京 100190；
3. 寧夏銀星多晶硅有限公司，吳忠 751100)
摘 要: 采用Sn-Si熔析體系，利用工業(yè)規(guī)模多晶硅鑄錠爐通過(guò)控制溫度梯度和熱場(chǎng)上移速率進(jìn)行定向凝固處理，研究硅錠的形貌特征、組織結(jié)構(gòu)和提純效果。結(jié)果表明：在定向凝固過(guò)程中析出了連續(xù)密實(shí)的硅晶，且晶體硅與金屬熔析劑之間形成了平坦穩(wěn)定的相界面，實(shí)現(xiàn)晶體硅與金屬熔析劑的有效分離。晶體硅經(jīng)過(guò)混酸酸洗后，總金屬雜質(zhì)含量由58.3×10-6降低為7.6×10-6，去除率可以達(dá)到87%；非金屬P含量由50.12×10-6降低為8.48×10-6，去除率大于80%。因此，Si-Sn合金精煉與定向凝固過(guò)程復(fù)合，解決了硅與金屬熔析劑的有效分離問(wèn)題，同時(shí)也實(shí)現(xiàn)了雜質(zhì)的高效去除。
關(guān)鍵字: 硅；分離；提純；合金精煉；定向凝固；晶體生長(zhǎng)
（1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083 China;
2. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,
Key Laboratory of Green Process and Engineering, Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100190, China;
3. Ningxia Yingxin Polycrystalline Silicon Co. Ltd, Wuzhong 751100, China）
Abstract:The directional solidification of Si-Sn melt was carried out by controlling the temperature gradient and the moving velocity of thermal field in the ingot furnace. The morphology characteristics, structure and purification effect of the silicon ingot were studied. The results indicate that the growth of bulk Si is achieved from Si-Sn melt, and a flat and stable phase interface forms between the silicon and solvent by directional solidification, resulting in an effective separation. Meanwhile, purification of the refined Si by acid-leaching shows that metallic impurities decrease from 58.3×10-6 to 7.6×10-6, and the removal rate reaches 87%. Non-metallic P content decreases from 50.12×10-6 to 8.48×10-6, and the removal rate is over 80%. Therefore, not only the effective separation of silicon and solvent, but also the efficient removal of impurities is realized through Sn-Si alloy refining and directional solidification process.
Key words: silicon; separation; purification; alloy refining; directional solidification; crystal growth
