Silicon purification through acid leaching and unidirectional solidification
1
조회
0
다운로드
5
인용
0
참고문헌
키워드
초록
Recently the shortage of silicon resources especially for poly-silicon of purity higher than 99.9999 % leads to search for the more cheap and quick synthesizing routes for silicon feedstock. In order to solve this situation, we investigated the purification process of metallurgical grade (MG) silicon of purity around 99 % by the acid leaching and following the unidirectional solidification. MG-Si lumps are pulverized with a planetary mill, and then leached with HCl/ HNO₃/HF acid solution. As a result, the concentration of metal impurities including Al, Fe, Ca, Mn, etc. decreased dramatically. This process led to silicon content higher than 99.99 %. The purified silicon powders were compacted and have been melted and uni-directionally solidified with heat exchange method (HEM) furnace. The properties of multicrystalline silicon ingots were specific resistance of 0.3 Ω·cm and minority carrier life time (MCLT) of 3.8 μ·sec.
Abstract
Recently the shortage of silicon resources especially for poly-silicon of purity higher than 99.9999 % leads to search for the more cheap and quick synthesizing routes for silicon feedstock. In order to solve this situation, we investigated the purification process of metallurgical grade (MG) silicon of purity around 99 % by the acid leaching and following the unidirectional solidification. MG-Si lumps are pulverized with a planetary mill, and then leached with HCl/ HNO₃/HF acid solution. As a result, the concentration of metal impurities including Al, Fe, Ca, Mn, etc. decreased dramatically. This process led to silicon content higher than 99.99 %. The purified silicon powders were compacted and have been melted and uni-directionally solidified with heat exchange method (HEM) furnace. The properties of multicrystalline silicon ingots were specific resistance of 0.3 Ω·cm and minority carrier life time (MCLT) of 3.8 μ·sec.
참고문헌 (8)
- P. Woditsch, "Solar grade silicon feed-stock supply for PV industry", Sol. En. Mater. Sol. Cells, 72, pp.11~ (2002)
- A.D. Little, "16th European Photovoltaic Solar Energy Conference", pp.9~ (2000), James & James
- D. Sarti, "Silicon feedstock for the multi-crystalline photovoltaic industry", Sol. En. Mater. Sol. Cells, 72, pp.27~ (2002)
- A. Müller, "Silicon for photovoltaic applications", Mater. Eng. B, 134, pp.257~ (2006)
- I.C. Santos, "Purification of metallurgical grade silicon by acid leaching", Hydrometallurgy, 23, pp.237~ (1990)
- K. Morita, "Thermodynamics of solargrade- silicon refining", Intermetallics, 11, pp.1111~ (2003)
- J.M. Kim, "Growth and characterization of 240kg multicrystalline silicon ingot grown by directional solidification", Sol. Energy Mater. Sol. Cells, 81, pp.217~ (2004)
- F.A Trumbore, "Solid solubilities of impurity elements in germanium and silicon", Bell Syst. Tech. J, 39, pp.205~ (1960)