冶金級矽之化學提純研究

Study on Chemical Up-grading of Metallurgical-grade Silicon

龍村倪(Tsuen-Ni Lung) ； 林昌銘(Chang-Ming Lin)

《鑛冶：中國鑛冶工程學會會刊》 29卷2期 (1985/06) Pp. 100-114

https://doi.org/10.30069/MM.198506_29(2).0009

摘要

冶金級矽為以潛弧電爐在高溫下以碳還原石英岩所得之冶金屬，其主要用途除供配製鋁合金等外，亦為生產高純度及半導體級矽材料之原料。冶金級矽所含主要雜質為Fe、Al、Ca、C等；所含微量雜質則有Mg、Cu、Ti、As、B、P等。經化學提純處理後，絕大部份金屬雜質均可去除；非金屬雜質亦有明顯降低。冶金級矽（＋98.0％）經連續二次混酸浸漬處理後，所得提纯冶金級矽之純度可達＋99.95％，此一純度已可供作太陽能級矽饋料之用。使用超音波及微波以促進化學反應之初步實驗結果顯示對提高反應速率有利，對部份雜質之去除效果亦稍有增進。

並列摘要

Two different kinds of commercially available metallurgical-grade silicon (+98% Si) were used as star ting material for the study on chemical up-grading. After crushing and grinding the size of the silicon was reduced to ＜ 150μm (90%). The ground silicon was first leached with HP + HC1 mixed acid at 80°C with mechanical agitatation under atmospheric pressure. The obtained purity of first leached product was better than 99.9 % Si. The silicon powder was automatically broken to finer size owing to acid attack on grain boundaries. The second leach was carried out in a closed system at 150°C with HF+HC1+H_2C_2O_4 acids. After two successive leachings the metallic impurities were significantly reduced to a ppm level and the nonmetallic impurity elements only partially removed. The achieved purity of up-graded metallurgical silicon was +99.95%. For ultimate refinement the physicochemical methods other than leaching should be applied for further purification. The preliminary results of applying ultrasonic and microwave for the purpose of enhancemnt of leaching reactions was encouraging too.