Date of Award

Spring 2012

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Materials Science and Engineering

Supervisor

Antony Petric

Co-Supervisor

Kenneth Coley

Language

English

Committee Member

Gordon A. Irons

Abstract

A supply shortage of solar-grade silicon in recent years resulted from a rapid expansion of the solar cell industry. Therefore, many efforts have been done to obtain reliable metallurgical methods for production of SoG silicon from metallurgical grade silicon.

In this research, refining of metallurgical grade silicon by chlorination treatment with the emphasis on Al removal was investigated. Thermodynamic calculations through Factsage confirmed the feasibility of Al removal in repeated steps of chlorination. Therefore, an Ar+SiCl4 gas mixture with different flow rates was applied to the silicon melt by blowing and injection methods at different temperatures and the ICP-OES was used for analysis of the impurities in silicon.

Results revealed that Al removal from silicon by chlorination treatment under the conditions employed in this study is first order reaction with respect to Al. By increasing the temperature in the chlorination process, the rate constant increases which is related to an increase in the liquid mass transfer rate. Also the observed higher rates of Al removal under injection conditions appear to be the result of improved stirring in the melt rather than an increase in the interfacial area.

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