Abstract
A novel electrically-enhanced metal purification using slag has been developed. This was achieved by applying DC potential between liquid metal and slag phases. The concept was demonstrated through small-scale experiments at temperatures of 1500–1600°C for the removal of boron from Si-B melt using CaO-SiO2-16wt%Al2O3. Silicon (containing B) and slag were reacted in an alumina crucible in a resistance tube furnace. A circuit was produced by immersing graphite rods into the silicon bath and the slag layer. Electrical potential differences of up to 3.5 V were applied during the reactions. The reaction rates, the open-circuit voltages and short-circuit currents (in the case when the potential was applied) were then measured and determined for various slag to silicon ratio. It has been shown from this study that both the apparent rate and the boron partition ratio were increased by a factor of approximately 1.6.
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References
N. Sen et al., “Desulphurisation of high sulphur cast iron using an electrochemical technique,” Scandinavian journal of metallurgy 28(6) (1999), 249–253.
U. Pal, T. Debroy, and G. Simkovich, “Electronic and ionic transport in liquid PbO-SiO2 systems,” Metallurgical Transactions B 16(1) (1985), 77–82.
X. Pan, “Electrochemical effects of direct current on the reduction of manganese oxide from molten MnO-SiO2-CaO-Al2O3 slag,” J of the South African Inst of Min Metall 95(5) (1995), 221–224.
G. G. Krishna Murthy, A. Hashem, and U.B Pal, “Reduction rates of FeO in CaO-SiO2-Al2O3-X slags by Fe-C droplets,” Ironmaking and Steelmaking 20(3) (1993), 191–200.
D. Woolley and U. Pal, “Experimental evidence for electrochemical nature of the reaction between iron oxide in calcia-silica-alumina slag and carbon in liquid iron,” Metall Mater Trans B 30(5) (1999), 877–889.
X. Ma et al., “Hydrometallurgical purification of metallurgical grade silicon,” Rare Metals 28(3) (2009), 221–225.
M.D. Johnston and M. Barati, “Distribution of impurity elements in slag-silicon equilibria for oxidative refining of metallurgical silicon for solar cell applications,” Solar Energy Materials and Solar Cells 94(12) (2010), 2085–2090.
N. Yuge et al., “Purification of metallurgical grade silicon up to solar grade,” Progress in Photovoltaics: Research and Applications 9(3) (2001), 203–209.
T. Yoshikawa and K. Morita, “Boron removal in the solidification refining of Si with Si-Al melt,” Sohn International Symposium on Advanced Processing Metals and Materials, 1 (2006), 673–684.
E. Olsen and S. Rolseth, “Three-Layer Electrorefining of Silicon,” Metallurgical and Materials Transactions B 41(2) (2010), 295–302.
K. Yasuda et al., “Direct electrolytic reduction of solid SiO2 in molten CaCl2 for the production of solar grade silicon,” Electrochimica Acta 53(1) (2007), 106–110.
K. Suzuki et al., “Thermodynamics for removal of boron from metallurgical silicon by flux treatment,” Journal of the Japan Institute of Metals 54(2) (1990), 168–172.
H. Fujiwara et al., “Reducing removal of phosphorous from calcium containing silicon alloys,” Materials Transactions, JIM 37(4) (1996), 923–926.
L. A. V. Teixeira et al., “Removal of Boron from Molten Silicon Using CaO-SiO2 Based Slag,” ISIJ international 49(6) (2009), 783–787.
L. A. V. Teixeira et al., “Behavior and state of boron in CaO-SiO2 slags during refining of solar grade silicon,” ISIJ international 49(6) (2009), 783–787.
D. W. Luo et al., “Removal of boron from metallurgical grade silicon by electromagnetic induction slag melting,” Transactions of Nonferrous Metals Society of China 21(5) (2011), 1178–1184.
E. Krystad, K. Tang and G. Tranell, “The Kinetics of Boron Transfer in Slag Refining of Silicon,” JOM Journal of the Minerals, Metals and Materials Society, (2012), 1–5.
H. Nishimoto, H. and K. Morita, “The Rate of Boron Elimination from Molten Silicon by Slag and Cl2 gas Treatment,” Supplemental Proceedings: Materials Processing and Energy Materials, Vol 1(2011), 701–708.
M.A. Rhamdhani, G.A. Brooks, and K.S. Coley, “Kinetics of metal/slag reactions during spontaneous emulsification,” Metallurgical and Materials Transactions B, 36 (B) (2005), 219–27.
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Islam, M.S., Rhamdhani, M.A., Brooks, G.A. (2014). Electrically Enhanced Metal Purification Using Slag. In: Mackey, P.J., Grimsey, E.J., Jones, R.T., Brooks, G.A. (eds) Celebrating the Megascale. Springer, Cham. https://doi.org/10.1007/978-3-319-48234-7_58
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DOI: https://doi.org/10.1007/978-3-319-48234-7_58
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