Leaching behavior of impurities in metallurgical grade silicon subjected to electromagnetic strengthening

• Published in: Journal of alloys and compounds Vol. 831; p. 154888
• Main Authors: Li, Sheng, Deng, Xiaocong, Zhang, Cong, Wen, Jianhua, Wu, Jijun, Wei, Kuixian, Ma, Wenhui
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05.08.2020; Elsevier BV
• Subjects: Acid etching; Chemical precipitation; Electromagnetic strengthening; Impurities; Inclusions; Leaching; Metallurgy; Microstructure; Morphology; Precipitates; Reagents; Silicon; Solidification; Strengthening; Microstructure; Acid etching; Leaching; Electromagnetic strengthening
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.154888

The distributions and morphologies of precipitates in metallurgical grade silicon (MG-Si) were investigated and effects to control solidification rate and electromagnetic strengthening were tested. Decreasing the solidification rate caused the inclusions to become larger, and electromagnetic strengthening enriched precipitates in the center of the melt. Additionally, acid etching of different samples using an HCl–HF mixed leaching agent revealed the evolution of the microstructure of inclusions in silicon. Corrosion results indicate that the HCl–HF mixture is an effective leaching agent that can be used to dissolve impurities in MG-Si. Using this reagent, the total impurity content of the source silicon was reduced from 6320 ppmw to 171.8 ppmw, and the impurity content after controlling the solidification rate or electromagnetic strengthening was reduced to 158.1 ppmw and 99 ppmw, respectively. •Microstructure of inclusions in MG-Si subjected to different conditions were studied.•The HCl–HF mixture has been proved to be an effective leaching agent by corrosion.•Removal of impurities in silicon enhanced by electromagnetic strengthening.