Hydrometallurgical Purification of Metallurgical Grade Silicon with Hydrogen Peroxide in Hydrofluoric Acid

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• 作者：Huixian Lai ; Liuqing Huang ; Huaping Xiong ; Chuanhai Gan ; Pengfei Xing ; Jintang Li ; Xuetao Luo
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：56
• 期：1
• 页码：311-318
• 全文大小：548K
• ISSN：1520-5045

文摘

The effect of adding hydrogen peroxide (H₂O₂) as an oxidizing agent on purifying metallurgical grade silicon (MG-Si) by leaching with hydrofluoric acid (HF) was studied as a function of leaching temperature, particle size, leaching duration, and concentration of leaching agents. It was found that the extraction capacity for metallic impurities could be significantly enhanced with introduction of H₂O₂ into HF lixiviant with little dependence on HF concentration. Upon leaching with 1 mol·L^–1 HF and 2 mol·L^–1 H₂O₂ for only 0.25 h at 55 °C, the MG-Si purity could be upgraded from 99.74% to 99.96%, to 99.99% with further prolonging of leaching duration. The sensitivity sequences of precipitates to each etchant were obtained through revealing the microstructural evolution of MG-Si before and after etching. With the help of Raman spectrometry and transmission electron microscopy, the chemical etching mechanism is discussed.