冶金法提纯工业硅的研究

Research on purification of metallurgical grade silicon by metallurgical methods

以冶金级硅为原料进行了制备高纯多晶硅锭的研究,自行设计了真空感应熔炼与定向凝固设备、电子束熔炼设备。通过酸洗、真空感应熔炼与第一次定向凝固、电子束熔炼、真空感应熔炼与第二次定向凝固等组合步骤对工业硅进行提纯。利用电感耦合等离子体发射光谱仪(ICP-AES)进行成分分析,实验结果表明,定向凝固有效去除了金属杂质,电子束对蒸汽压高的元素,尤其是磷元素的去除作用明显。Al的浓度降低到了0.4×10-6,Fe、Ca、Ti、Mn、Cu、Zn等金属杂质的浓度降到了0.1×10-6以下,P含量降低到1.5×10-6。

Research on manufacturing high quality multi-crystalline silicon ingot is carried out with metallurgical grade silicon. Metallurgical grade silicon is purified through acid leaching, vacuum induction melting followed with first directional solidification, electron beam melting, vacuum induction melting followed with second direc- tional solidification. Component analysis is carried out by inductive coupled plasma-atomic emission spectroscopy （ICP-AES）. The experimental results indicate that metallic impurities are effectively removed by directional solidification,and electron beam melting has a significant removal effort to elements of high vapor pressure, especially to phosphorus. The concentrations of Fe, Ca, Ti, Mn, Cu, Zn decrease to below 0.1×10^-6 and Al, P below 0.4×10^-6 ,1.5×10^-6 respectively.