论文

CaCl2-NaCl-CaO熔盐中电解精炼Si的研究

  • 王淑兰 ,
  • 陈晓云
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  • 东北大学理学院, 沈阳 110089
王淑兰, 女, 1959年生, 教授

收稿日期: 2011-08-30

  修回日期: 2011-11-20

  网络出版日期: 2012-02-11

基金资助

国家自然科学基金资助项目51154002

STUDY ON THE ELECTRO–REFINING SILICON IN MOLTEN SALT CaCl2–NaCl–CaO

  • YU Shu-Lan ,
  • CHEN Xiao-Yun
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  • School of Sciences, Northeastern University, Shenyang 110004

Received date: 2011-08-30

  Revised date: 2011-11-20

  Online published: 2012-02-11

Supported by

Supported by National Natural Science Foundation of China (No.51154002)

摘要

以冶金级Si和电解Cu为原料, 制备了Cu-31Si(摩尔分数, %)合金. 以Cu-31Si合金为阳极、Mo为阴极和参比电极, 采用循环伏安和计时电位方法研究了1173 K下熔盐 81CaCl2-8.0NaCl-8.5CaO-2.5Si(摩尔分数, %)的阴极行为, 讨论了熔盐中Si电解精炼过程的还原步骤. 用SEM, EDS和电感耦合等离子原子发射光谱仪(ICPAES)分析和表征了Si晶体的形貌和组成.电解精炼后得到了多晶Si, 与冶金Si原料相比, 主要杂质含量都显著降低,特别是对太阳能级Si危害较大的杂质B和P去除效果明显, 分别从42×10-6和25×10-6降至4.5×10-6和8.2×10-6.电解精炼过程的电流效率为84.4%.

关键词: 熔盐; 电解精炼; Si

本文引用格式

王淑兰 , 陈晓云 . CaCl2-NaCl-CaO熔盐中电解精炼Si的研究[J]. 金属学报, 2012 , 48(2) : 183 -186 . DOI: 10.3724/SP.J.1037.2011.00547

Abstract

Use Cu–31Si alloy (31mol% Si) prepared by inductive melting metallurgical grade silicon as anode and molybdenum as cathode and reference electrode, the cathodic behavior of molten salt 81CaCl2–8.0 NaCl–8.5CaO–2.5Si (Mole fraction, %) at 1173 K was studied by means of cyclic voltammetry and chronopotentiometry, and the reduction steps of silicon from the molten salt were discussed. The electro–refining of silicon was performed in the two electrode system under the voltage of −0.2 V. SEM, EDS and inductively coupled plasma atomic emission spectrometry (ICPAES) technologies were used to analyze and characterize the morphology and composition of the deposited silicon. Polycrystalline silicon was obtained after the electro–refining. Main impurity in the metallurgical grade silicon are greatly decreased. Especially boron and phosphorous which are very harmful to solar cell grade silicon were greatly removed. The contents of boron and phosphorous are decreased from 42×10−6 and 25×10−6 to 4.5×10−6 and 8.2×10−6, respectively. The current efficiency of the electro–refining process is 84.4%.

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