Research On The Purification Of Industrial Silicon By Physical Metallurgical Method

Energy crisis and environmental pollution led to the dual pressures of worldwide exploration for new energy research. Solar energy is considered to the most clean energy, resources are widely distributed, since the 21st century more and more attention are paid, set off a world-wide use of solar energy in the climax. Governments have introduced policies to promote the development of photovoltaic industry. But the shortage of solar grade silicon material has hampered the development of photovoltaic industry.Siemens conventional chemical methods such as purification of silicon as serious pollution, high energy consumption, high cost, development is restricted. Recent development of metallurgical silicon purification technology is environmentally friendly, low energy consumption, lower cost, to meet the rapid development of photovoltaic industry. Boron and phosphorus content of solar-grade silicon is an important factor in product quality, by metallurgical methods such as plasma and electron beam technology can be better to remove particles of silicon in boron and phosphorous impurities, but the energy consumption is still high, do not meet the low-Carbon economy concept.In this paper, combined with the vacuum by blowing slag making, pickling of the process line, and use self-designed vacuum melting furnace and pickling equipment, remove the metal impurities in silicon, and boron and phosphorus, industrial silicon to achieve the purpose of purification. By inductively coupled plasma emission spectrometer to analyze the samples. Of different slag, slagging time, slagging oxide, acid and other parameters of boron, phosphorus, and removal of metallic impurities. Through the above study are the following main results:Slagging process can significantly remove boron impurities in silicon to increase the slagging time, can significantly reduce the number slagging of boron in silicon, but there exists a saturation value. With the increase in the number slagging, the best time to reduce the slagging;Slagging process, which leads to oxygen can effectively reduce the silicon content of boron and calcium, in addition to boron effect is more obvious, while increasing the partial pressure of oxygen can promote the boron in silicon and calcium impurities removed;With Li2O-SiO2 (-Al2O3) system Java agent, you can significantly reduce the slagging of phosphorus in silicon content; with pickling process, can greatly remove phosphorus in silicon, and acid washing can only remove the surface of silicon block Metal impurities, and the smaller the benefit of silicon block the removal of metallic impurities.The results of this study show the metallurgical silicon purification method in terms of vitality and bright prospects. Phosphorus in this article based on the study, and further optimize the composition and process slag forming agent, combined pickling and directional solidification process, after 2 to 3 cycles, the non-particle beam through the purification process is expected to by metallurgical route will be in Silicon Phosphorus reduced to meet the requirements of solar-grade silicon.