工业硅酸浸去除金属杂质钙

Removal of calcium contained in industrial silicon with acid leaching method

研究了HF-HCl浸出剂体系中,HF含量、HCl含量、浸出时间和硅粉粒度等因素对除钙的影响。结果表明,HF含量是最主要的影响因素;在2%HF-3%HCl、室温20℃、5 h的最佳条件下,钙的去除率达到84.5%;在HF-HCl浸出剂体系中,CaF_2的形成降低了钙的去除率。电子显微镜和能谱分析发现,工业硅中存在含钙四元系金属间化合物Si_8Al_6Fe_4Ca,该化合物易被低浓度氢氟酸去除。

The influence of factors such as HF contents, HC1 contents, leaching time, silicon powder particle size on the calcium removal in the HF-HC1 leaching agent system was researched. And the research results showed that the HF contents was the main influential factors, the calcium removal rate could reach 84.5% under the optimal conditions of 2%HF-3%HCI, 20℃ and 5 hours, and the CaF2 could decrease the calcium removal rates in the HF-HC1 leaching agent system. Based on the electron microscopy and energy spectrum analysis, it is discovered that the SisA16Fe4Ca of calcium-containing quatermary intermetallics existed in the industrial silicon could be easily removed by low-concentration hydrofluoric acid.