SiO_2-CaO中添加CaCl_2去除冶金级硅中杂质硼的工艺研究
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摘要
以硼含量为16.6×10~(-6)(质量比)的冶金级硅为原料,在高温电阻炉中,利用SiO_2-CaO-CaCl_2、SiO_2-CaCl_2和CaO-CaCl_2造渣剂进行渣硅比、精炼时间、精炼温度和CaCl_2不同配比的除硼精炼实验。研究发现,在熔渣精炼除硼过程中,随着温度的升高和精炼时间的增长,硅中硼含量越来越低,而渣中硼含量越来越高。当渣硅比为2∶1、精炼温度为1550℃、精炼时间为120 min时,硼的分配系数LB由0.93增大到2.85,杂质硼的去除效果最好。在SiO_2-CaO-CaCl_2三元体系中加入质量比为16.67%CaCl_2时,硼的分配系数最高达到3.71,精炼效果最好。本研究为进一步获得低硼含量的高纯硅产品提供了依据。
Here,we experimentally addressed the removal of boron( 16. 6 × 10~(-6)( wt)) from metallurgical grade silicon( 98. 5% Si) by adding CaCl_2 to the slag-forming agents,such as SiO_2-CaO-CaCl_2,SiO_2-CaCl_2 and CaO-CaCl_2,in high temperature resistance furnace. The influence of the refining conditions,including the slag / silicon ratio,CaCl_2-proportion,refining-time and temperature,on the B-removal was investigated. The results show that the refining-temperature and time,and adding CaCl_2 to SiO_2-CaO-CaCl_2 all strongly affect the B-removal. For example,as the refining-temperature and time increased,B-content in the refined silicon decreased,but B-content in the slag increased; refined at 1550℃ for 120 min with slag / silicon ratio of 2 ∶ 1,the distribution coefficient of boron( LB) increased from 0. 93 to 2. 85,indicating fairly high B-removal efficiency. An increase of CaCl_2 to 16. 67% in SiO_2-CaO-CaCl_2 slag forming-agent,the highest LBwas found to be 3. 71. We suggest that the results be of some technological interest in Si-refining.
Here,we experimentally addressed the removal of boron( 16. 6 × 10~(-6)( wt)) from metallurgical grade silicon( 98. 5% Si) by adding CaCl_2 to the slag-forming agents,such as SiO_2-CaO-CaCl_2,SiO_2-CaCl_2 and CaO-CaCl_2,in high temperature resistance furnace. The influence of the refining conditions,including the slag / silicon ratio,CaCl_2-proportion,refining-time and temperature,on the B-removal was investigated. The results show that the refining-temperature and time,and adding CaCl_2 to SiO_2-CaO-CaCl_2 all strongly affect the B-removal. For example,as the refining-temperature and time increased,B-content in the refined silicon decreased,but B-content in the slag increased; refined at 1550℃ for 120 min with slag / silicon ratio of 2 ∶ 1,the distribution coefficient of boron( LB) increased from 0. 93 to 2. 85,indicating fairly high B-removal efficiency. An increase of CaCl_2 to 16. 67% in SiO_2-CaO-CaCl_2 slag forming-agent,the highest LBwas found to be 3. 71. We suggest that the results be of some technological interest in Si-refining.
引文
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[14]贾斌杰.氯化物熔盐去除冶金级硅中杂质硼的研究[D].昆明:昆明理工大学,2013:34
[2]刘玉芬,郜小勇,刘绪伟,等.掺磷微晶硅薄膜的微结构及光学性质的研究[J].真空科学与技术学报,2008,28(4):365-369
[3]马文会,戴永年,杨斌,等.太阳能级硅制备新技术研究进展[J].新材料产业,2006,(10):12-16
[4]伍继君,马文会,杨斌,等.冶金级硅氧气精炼过程杂质元素的热力学行为[J].北京工业大学学报,2013,39(10):1566-1569
[5]Goodrich A,Hacke P,Wang Q,et al.A Wafer-Based Monocrystalline Silicon Photovoltaics Roamap:Utilizing Known Technology Improvement Opportunities for Further Reductions in Manufacturing Costs[J].Solar Energy Materials and Solar Cells,2013,114:110-135
[6]周京明,张济祥.高纯金属硅吹气造渣除硼工艺研究[J].能源研究与信息,2014,30(1):58-61
[7]Noguchi R,Suzuki K,Tsukihashi F,et al.Thermodynamics of Boron in a Silicon Melt[J].Metallurgical and Materials Transactions,1994,25:903-907
[8]Cai Jing,Li Jintang,Chen Wenhui,et al.Boron Removal from Metallurgical Silicon Using Ca O-Si O2-Ca F2Slags[J].Transactions of Nonferrous Metals Society of China,2011,21(6):1402-1406
[9]Wu Jijun,Dai Yongnian,Ma Wenhui,et al.Latest Progress in Purifying Metallurgical Grade Silicon into Solar Grade Silicon by Oxidation Refining[J].Journal of Vacuum Science and Technology,2010,30(1):43-47
[10]Wu Jijun,Ma Wenhui,Yang Bin,et al.Boron Removal from Metallurgical Grade Silicon by Oxidizing Refining[J].Transactions of Nonferrous Metals Society of China,2009,19:463-467
[11]Ding Zhao,Ma Wenhui,Wen Kuixian,et al.Boron Removal from Metallurgical-Grade Silicon Using Lithium Containing Slag[J].Journal of Non-Crystalline Solids,2012,358:18-19
[12]Luo Dawei,Liu Ning,Lu Yiping,et al.Removal of Boron from Metallurgical Grade Silicon by Electromagnetic Induction Slag Melting[J].Transactions of Nonferrous Metals Society of China,2011,21(5):1178-1184
[13]Wu Jijun,Li Yanlong,Ma Wenhui,et al.Boron Removal in Purifying Metallurgical Grade Silicon by Ca O-Si O2Slag Refining[J].Transactions of Nonferrous Metals Society of China,2014,24(4):1231-1236
[14]贾斌杰.氯化物熔盐去除冶金级硅中杂质硼的研究[D].昆明:昆明理工大学,2013:34