Scholarlink

<p>The reaction characteristics of metallic impurities in metallurgical grade silicon (MG-Si) significantly influence the efficiency of trichlorosilane (TCS) synthesis, a key process for the photovoltaic industry. This study elucidates the migration and evolution of these impurities using multi-scale characterization and thermodynamic calculations. We reveal that the primary impurities (Fe, Al, Ca, Ti) exist not as elements but as intermetallic compounds, including FeSi<sub>2</sub>, Si<sub>7</sub>Al<sub>8</sub>Fe<sub>5</sub>, Si<sub>8</sub>Al<sub>6</sub>Fe<sub>4</sub>Ca, and TiFeSi<sub>2</sub>. During synthesis, the migration of these elements is governed by the boiling points of their respective chlorides. Consequently, low-boiling-point chlorides (Al<sub>2</sub>Cl<sub>6</sub> and TiCl<sub>4</sub>) volatilize with the gaseous TCS, while high-boiling-point chlorides (FeCl<sub>2</sub> and CaCl<sub>2</sub>) cause Ca and Fe to be retained in the solid spent contact mass. The transformation follows a multi-step pathway: Intermetallic Compound → FeSi Intermediate Phase → Metal Chlorides, with unreacted FeSi also remaining in the solid residue. Furthermore, the retained FeCl<sub>2</sub> readily oxidizes to high-valence oxides upon air exposure after collection. This work establishes a new mechanistic framework for impurity behavior, focusing on the evolution of intermetallic.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Mechanism of the Evolution of Intermetallic Compounds in Metallurgical Grade Silicon During Trichlorosilane Synthesis via Hydrochlorination

  • 期刊论文

  • 发表日期：

    2026年5月22日

查看全文
  • Mo Yang,
  • Xiaocong Deng,
  • Kuixian Wei,
  • Wenhui Ma,
  • Qingyun Jiang

摘要

The reaction characteristics of metallic impurities in metallurgical grade silicon (MG-Si) significantly influence the efficiency of trichlorosilane (TCS) synthesis, a key process for the photovoltaic industry. This study elucidates the migration and evolution of these impurities using multi-scale characterization and thermodynamic calculations. We reveal that the primary impurities (Fe, Al, Ca, Ti) exist not as elements but as intermetallic compounds, including FeSi2, Si7Al8Fe5, Si8Al6Fe4Ca, and TiFeSi2. During synthesis, the migration of these elements is governed by the boiling points of their respective chlorides. Consequently, low-boiling-point chlorides (Al2Cl6 and TiCl4) volatilize with the gaseous TCS, while high-boiling-point chlorides (FeCl2 and CaCl2) cause Ca and Fe to be retained in the solid spent contact mass. The transformation follows a multi-step pathway: Intermetallic Compound → FeSi Intermediate Phase → Metal Chlorides, with unreacted FeSi also remaining in the solid residue. Furthermore, the retained FeCl2 readily oxidizes to high-valence oxides upon air exposure after collection. This work establishes a new mechanistic framework for impurity behavior, focusing on the evolution of intermetallic.