熔盐电解精炼制备太阳能级多晶硅

采用熔盐电解精炼技术在物质的量比为1∶1的NaF-KF混合共晶熔盐中对冶金硅进行精炼提纯制备太阳能级多晶硅.采用SEM和ICP-MS对熔盐电解精炼后产物硅进行表征.考察了熔盐电解精炼过程中电压、温度、时间对冶金硅中主要杂质去除率的影响.在2.0 V,1 073 K条件下,冶金硅阳极经电解精炼400min后,精炼产物形貌为线状,直径主要分布在50~150nm之间,长度达到几十微米.冶金硅中主要金属杂质的去除率在92%以上,B,P杂质的去除率分别为92.1%和97.6%,产物硅的纯度达到99.999%.

Preparation of Solar Grade Silicon by Electrorefining

Purification of metallurgical grade silicon (MG-Si) for solar grade silicon (SOG-Si) preparation with electrorefining in molten NaF-KF eutectic was studied. SEM and ICP-MS were used to examine and characterize the refining products. The effects of voltage, temperature and time on refining efficiency were analyzed and discussed. The results show that, under the refining conditions in 1073 K NaF-KF molten salt at 2.0 V for 400 min, the electrolyzed products are Si wires with length of several tens of micrometers and diameter of 50 nm to 150 nm. The removal efficiency of metal impurities from MG-Si can reach above 92%, with B and P removal efficiencies of 92.1% and 97.6% respectively. The purity of refined silicon product can reach up to 99.999%.