Abstract
The purification of metallurgical grade silicon (MG-Si) by using a combination of solvent refining and super gravity separation was studied. MG-Si was first alloyed with aluminum and then solidified at different cooling rates in order to precipitate dendritic primary Si from the Al-Si alloy. Primary Si dendrites were separated under super gravity, resulting in the ejection of Al-Si eutectics from the solid Si-eutectics melt mixture. The effect of the gravity coefficient on the separation efficiency and then influence of the cooling rate and proportion of Si in the Al-Si alloy on the removal efficiency of Al entrainment were investigated. The results demonstrate that super gravity is an effective tool for the separation of primary Si dendrites from Al-Si alloy, with an optimum gravity coefficient of 280. When the proportion of Si was held constant, varying the cooling rate had almost no effect on the entrainment of Al in the separated Si. However, increasing the proportion of Si in the Al-Si alloy had the effect of reducing Al entrainment.
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References
Pizzini S (2010) Towards solar grade silicon: challenges and benefits for low cost photovoltaics. Sol Energy Mater and Sol Cells 94:1528–1533
Hofstetter J, Lelièvre JF, del Cañizo C, Luque A (2009) Acceptable contamination levels in solar grade silicon: From feedstock to solar cell. Mater Sci Eng: B 159-160:299–304
Luo DW, Liu N, Lu YP, Zhang GL, Li TJ (2011) Removal of boron from metallurgical grade silicon by electromagnetic induction slag melting. T Nonferr Metal Soc 21:1178–1184
Naomichi N, Hiroyuki B, Yasuhiko S, Yoshiei K (2004) Born removal in molten silicon by a steam-added plasma melting method. Mater Trans 45:858–864
Zheng SS, Chen WH, Cai J, Li JT, Chen C, Luo XT (2010) Mass Transfer of phosphorus in silicon melts under vacuum induction refining. Metall Mater Trans B 41:1268–1273
Lee W, Kim J, Jang B, Ahn Y, Lee H, Yoon W (2011) Metal impurities behaviors of silicon in the fractional melting process. Sol Energy Mater and Sol Cells 95:59–62
Mitrašinović AM, Utigard TA (2009) Refining silicon for solar cell application by copper alloying. Silicon 1:239–248
Hu L, Wang Z, Gong XZ, Guo ZC, Zhang H (2013) Impurities removal from metallurgical-grade silicon by combined Sn-Si and Al-Si refining processes. Metall Mater Trans B 44:828–836
Li JW, Guo ZC, Tang HQ, Wang Z, Sun ST (2012) Si purification by solidification of Al-Si melt with super gravity. T Nonferr Metal Soc 22:958–963
Yoshikawa T, Morita K (2005) Refing of silicon by the solidification of Si-Al melt with electromagnetic force. ISIJ Int 45:967–971
Gu X, Yu X, Yang DR (2011) Low-cost solar grade silicon purification process with Al–Si system using a powder metallurgy technique. Sep Purif Technol 77:33–39
Li JW, Guo ZC, Tang HQ, Li JC (2013) Removal of impurities from metallurgical grade silicon by liquation refining method. High Temp Mater Proc 32:503–510
Zhao LX, Wang Z, Guo ZC, Li CY (2011) Low-temperature purification process of metallurgical silicon. T Nonferr Metal Soc 21:1185–1192
Esfahani S, Barati M (2011) Purification of metallurgical silicon using iron as impurity getter, part II: extent of silicon purification. Met Mater Int 17:1009–1015
Morito H, Karahashi T, Uchikoshi M, Isshiki M, Yamane H (2012) Low-temperature purification of silicon by dissolution and solution growth in sodium solvent. Silicon 4:121–125
Shimpo T, Yoshikawa T, Morita K (2004) Thermodynamic study of the effect of calcium on removal of phosphorus from silicon by acid leaching treatment. Metall Mater Trans B 35:277–284
Esfahani S, Barati M (2011) Purification of metallurgical silicon using iron as an impurity getter part I: growth and separation of Si. Met Mater Int 17:823–829
Mitrašinović AM, Utigard TA (2011) Copper removal from hypereutectic Cu-Si alloys by heavy liquid media separation. Metall Mater Trans B 43:379–387
Li JW, Guo ZC, Tang HQ, Lin YH (2012) Thermodynamicevaluation of phosphorus removal within metallurgical grade silicon by fractional melting process. Int Conf Mater Renew Energy Environment 1:15–18
Morita K, Yoshikawa T (2011) Thermodynamic evaluation of new metallurgical refining processes for SOG-silicon production. T Nonferr Metal Soc 21:685–690
Sklyarchuk V, Plevachuk Y, Yakymovych A, Eckert S, Gerbeth G, Eigenfeld K (2009) Structure sensitive properties of liquid Al–Si alloys. Int J Thermophys 30:1400–1410
Wang QD, Ding WJ, Jin JZ (1999) Step growth of a primary silicon crystal observed by decantation during centrifugal casting. Mater Sci Technol 15:921–925
Kobayashi KF, Hogal MN (1985) The crystal growth of silicon in Al-Si alloys. J Mater Sci 20:1961–1975
Shamsuzzoha M, Hogan L M (1985) Twinning in fibrous eutectic silicon in modified Al-Si Alloys. J Cryst Growth 72:735–737
Yoshikawa T, Morita K (2003) Solid solubilities and thermodynamic properties of aluminum in solid silicon. J Electrochem Soc 150:465–468
Miller RC, Savage A (1956) Diffusion of aluminum in single crystal silicon. J Appl Phys 27:1430–1432
Trumbore FA (1960) Solid solubilities of impurity elements in germanium and silicon. Bell Sys Tech J:205–233
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Li, Jw., Guo, Zc., Li, Jc. et al. Super Gravity Separation of Purified Si from Solvent Refining with the Al-Si Alloy System for Solar Grade Silicon. Silicon 7, 239–246 (2015). https://doi.org/10.1007/s12633-014-9197-z
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DOI: https://doi.org/10.1007/s12633-014-9197-z