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More is currently studying solar grade polysilicon Metallurgical Method domestic and international companies and research institutes , the process route is different, but the basic principle is the use of physical and chemical properties between silicon and silicon impurities , solidified in addition to complex, high-temperature vacuum evaporation impurity oxide impurity , acid dip impurity , slagging impurity , electrolytic reduction of one or several organic combination together to form a process route , to purification and preparation of solar grade silicon purposes. The research process routes : a self-designed medium frequency induction furnace heated to the pre-treated carbon and silica as a raw material in the self-designed high-purity graphite crucible carbothermal reduction reaction to obtain a high-purity silica gas , and under certain temperature conditions so that a silicon oxide gas disproportionation reaction to obtain a high-purity silicon and high-purity silica , separation of the silica and then subjected to vacuum directional solidification Earn polysilicon . Using the X -ray diffraction analyzer ( XRD ) , Raman Spectroscopy Instrument scanning electron microscope ( SEM ) , the inductor coupling such as ion emission spectral analyzer (ICP) and other equipment , to study the microscopic structure of the disproportionation product , the mechanism of formation , phase composition , the product the purity and purification mechanism . Through research to obtain the following results : ( 1 ) Since the disproportionation product from the experiment of a few hundred nanometers in diameter of the nanowires and nanospheres , nanowires and nanoparticles inside the silicon surface adhered SiO2 on the these disproportionation matter after milling , using acid leaching separating the disproportionation product of the silica , to obtain high purity silicon ; ( 2 ) HF sour dip disproportionation product of silica and B impurity element can be totally eliminated , but lower purity removal of P , Fe , Al impurity element is not analyzed the mechanism of B have been removed ; ( 3 ) by the carbothermal reduction the disproportionation Preparation of high purity silicon , the ICP detection results show that B impurity elements undetectable removal efficiency close to 100% B impurity elements , P , Fe , Al impurity element content and raw materials , reduced by one to two orders of magnitude , and the higher the purity of raw materials , the higher the purity of product .
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