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Indexed by:期刊论文

Date of Publication:2013-12-01

Journal:MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING

Included Journals:SCIE、EI

Volume:16

Issue:6

Page Number:1645-1649

ISSN No.:1369-8001

Key Words:Boron removal; Slag refining; Mass transfer coefficient; Optical basicity

Abstract:Solar energy is expected to be in great demand within the next few years. In relation to this, a global shortage in the solar-grade silicon (SoG-Si) used in the production of solar cells has motivated numerous studies on metallurgical-grade Si (MG-Si) refining. However, improvements in this material are limited by the difficulties involved in reducing boron (B) and phosphorus content. The present study investigated the removal of B using (CaF2)-Al2O3-CaO-SiO2 and Na2SiO3-CaO-SiO2 slag in an ambient air atmosphere in order to refine MG-Si. The mass transfer coefficients of B in molten Si (k(d[B])=1.19 x 10(-4) cm s(-1)) and BO1.5 in molten slag (k(d(B3+))=1.01 x 10(-5) cm s(-1)) were deduced through kinetic analysis. The mass transfer process of boron oxide limited slag refining; however, secondary slag treatment effectively improved the efficiency of B removal. L-B was determined by the combined effect of the oxygen partial pressure and the molten slag structure. (C) 2013 Elsevier Ltd. All rights reserved.