工业硅造渣提纯中硅与渣的熔分研究

Separation of Slag From Molten Silicon Bath in Slagging Purification

为了实现工业硅造渣除杂过程中硅与渣料在炉内高温状态下的分开排放,选用特制除硼渣料及冶金级硅粉在高温电阻炉中进行了硅与渣的熔分研究。考察了熔化温度、保温时间、硅液出炉温度、炉内气氛以及内衬材料对硅与渣分离的影响。结果发现:在高于硅和渣熔点较多的温度下,两者可依靠密度差及不同的表面张力实现一定程度的分离;延长保温时间有利于硅液中杂质的去除及硅和渣的充分分离;出炉温度较低,有利于硅液在凝固过程中杂质的富集;炉内应处于还原或惰性气体状态以避免硅的氧化;炉内坩埚材料应为石英质,以防止坩埚与硅发生反应。

To realize the tapping of silicon and slag respectively from the induction furnace in silicon purification, a special slag and metallurgical-grade silicon powder were mixed and smelt in resistance furnace. The influences of smelting temperature, holding time, tapping temperature, furnace atmosphere and lining materials on the separation effect of slag from molten silicon were examined. The results show that the molten silicon and slag can be divided into two layers to a certain extent when the smelting temperatureis much higher than the melting point of slag for both the different density and the surface tension. Increasing the holding time can promote impurities removal and separation of slag from molten silicon. At lower tapping temperature, the impurities can be well enriched in the course of molten silicon solidification. The furnace atmosphere should be reductive or inert gas protection to avoid molten silicon oxidation. The quartz should be used as the crucible materials to prevent the reaction of the crucible and the molten silicon.