Purification of metallurgical-grade silicon in fractional melting process

Woosoon Lee, Wooyoung Yoon, Choonghwan Park

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The fractional melting process involves heating an alloy within its liquid-solid region, while simultaneously ejecting liquid from the solid-liquid mixture (the cake). The extent of purification obtained is comparable to that obtained in multi-pass zone refining. A new fractional melting process, in which the centrifugal force is used for separating the liquid from the cake, was developed and applied to the purification of metallurgical grade Si (MG-Si). The major impurities in MG-Si such as Fe, Ti, Al, and Cu can significantly degrade the efficiency of solar cells. So it is important to remove these metal elements from MG-Si to obtain high-quality silicon. Since these elements have low segregation coefficients in silicon, high purification is possible through the fractional melting process. By applying the fractional melting method, a mean refining ratio of 93% with a wetness of 0.038 was achieved during the refining of 2N-Si. A further increase in the refining ratio can be realized by either controlling the processing parameters or reducing the solid fraction.

Original languageEnglish
Pages (from-to)146-148
Number of pages3
JournalJournal of Crystal Growth
Volume312
Issue number1
DOIs
Publication statusPublished - 2009 Dec 15

Keywords

  • A1. Fractional melting
  • A1. Purification
  • A1. Refining
  • A1. Wetness
  • B2. Metallurgical grade silicon

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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