合金熔剂精炼法制备太阳能级硅的研究进展

Research Development on Preparation of Solar Grade Silicon by Alloy Solvent Refining

冶金法作为制备太阳能级硅的低成本技术,受到了光伏行业的广泛关注。其工艺主要包括酸洗、造渣、定向凝固、真空精炼、熔剂精炼等。其中,熔剂精炼由于操作温度低、杂质去除效率高,被视为最有可能实现大规模产业应用的低成本冶金技术之一。近年来,熔剂精炼法提纯太阳能级硅的研究发展迅速,科研工作者已经较系统地研究了Si-Al、Si-Sn、Si-Cu、Si-Fe、Si-Ca等不同合金熔剂体系杂质从硅中去除的行为和规律。综述了国内外学者利用不同合金体系去除冶金级硅中杂质的研究结果,特别关注了硅中杂质B、P的去除,同时也对熔剂精炼过程中熔剂金属与初晶硅的分离进行了概述。最后,指出了熔剂精炼提纯冶金级硅有待进一步深入研究的方向。

Metallurgical method has been widely concerned by the photovoltaic industry,because of its low-cost technology for the purification of solar grade silicon.The metallurgical route contains acid leaching,slag refining,directional solidification,vacuum refining,and solvent refining,etc.Due to the advantages of low-melting temperature and high-efficiency removal of impurities,solvent refining has been regarded as one of the most possible technologies to realize large-scale industrial applications.In recent years,research on the purification of solar grade silicon by solvent refining has been developed rapidly,and the removal behaviors of impurities from Si in various solvent refining systems such as Si-Al,Si-Sn,Si-Cu,Si-Fe and Si-Ca,etc.have been studied by researchers too.The results of the research on the removal of impurity in metallurgical grade silicon by different solvent refining systems are summarized,especially for the impurity B and P.Additionally,the separation methods of primary silicon during the refining process are discussed.Finally,it is pointed out that the possible development trend of solvent refining technology in the future.