Study On Hydrometallurgical Purification And Simulation Of The Directional Growth Of Multicrystalline Silicon

With the rapid development of polycrystal silicon solar cells, it is the pursuit of the goal for the scientific researcher to further reduce the polysilicon production costs, some new technology and new method of preparation the sun of polysilicon has been a rapid development.The metallurgical method is one of the most effectively low production cost of polysilicon technical because of its short production cycle, the low cost, less pollution. The process of hydrometallurgy purification polycrystalline and the preparation of Polycrystalline silicon by directional solidification method is the two important process of metallurgy method fabricate SoG-Si, it has been a new hot spot for researchers.Based on the shape of the impurities and the distribution of the impurities in Metallurgical-Grade Silicon (MG-Si), hydrometallurgical purification of MG-Si was studied in this research. In the premise condition of the hydrochloric acid as leaching agent, we design a four factors and three levels of orthogonal test program to investigate the specific influence factors such as the mass fraction of leaching agent, the particle size of silicon, leaching temperature, leaching time. The results showed that in the premise condition of the hydrochloric acid as leaching agent, When MG-Si powder had been leached at appropriate conditions:the mass fraction of leaching agent6mol/L, the average size of silicon powder particle44μm, reaction temperature100℃, reaction time10h, It was found that79.7%of Fe impurity and65.9%of Al impurity in MG-Si powder were removed.And the finite element software COMSOL Multiphysics is employed to simulate the thermal field and flow field coupling simulation for the process of metallurgy method fabricate SoG-Si,we got the temperature field distribution of each polycrystalline silicon crystal growth stage and the temperature field distribution of the surface and central shaft of no crystal polycrystalline silicon melt, and simulated the solid-liquid interface distribution condition of polysilicon crystalline phase with the steady magnetic field,and comparison with the solid-liquid interface distribution condition of polysilicon crystalline phase without the steady magnetic field, it will provide an important theoretical basis for optimizing technological program and defects analyzing in the follow-up productive practice.