火法提纯冶金级硅制备太阳能级硅的最新研究进展

雷云; 马晓东; 王烨; 陈志远; 任永生; 马文会; Kazuki Morita

doi:10.1007/s12613-022-2418-3

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文章导航 > 矿物冶金与材料学报（英文） > 2022 > 29(4): 767-782

Yun Lei, Xiaodong Ma, Ye Wang, Zhiyuan Chen, Yongsheng Ren, Wenhui Ma, and Kazuki Morita, Recent progress in upgrading metallurgical-grade silicon to solar-grade silicon via pyrometallurgical routes, Int. J. Miner. Metall. Mater., 29(2022), No. 4, pp. 767-782. https://doi.org/10.1007/s12613-022-2418-3

Cite this article as:

Yun Lei, Xiaodong Ma, Ye Wang, Zhiyuan Chen, Yongsheng Ren, Wenhui Ma, and Kazuki Morita, Recent progress in upgrading metallurgical-grade silicon to solar-grade silicon via pyrometallurgical routes, Int. J. Miner. Metall. Mater., 29(2022), No. 4, pp. 767-782. https://doi.org/10.1007/s12613-022-2418-3

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特约综述

火法提纯冶金级硅制备太阳能级硅的最新研究进展

1)
昆明理工大学冶金与能源工程学院，昆明 650093，中国
2)
Sustainable Minerals Institute, The University of Queensland, St Lucia 4072, QLD, Australia
3)
四川大学化学工程学院, 成都 610065, 中国
4)
Separation and Conversion Technology, Flemish Institute for Technological Research, Mol 2400, Belgium
5)
Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan

* 共同第一作者

通讯作者:
Kazuki Morita E-mail: kzmorita@material.t.u-kyo.ac.jp

文章亮点

(1) 回顾了采用火法冶金技术提纯冶金级硅的研究进展。

(2) 对各种火法冶金提纯硅技术进行了总结和评价。

(3) 提出了一种提纯冶金级硅或回收硅废料的新方法。

中文摘要

硅基光伏太阳能作为一种可再生的绿色能源发展迅速。硅基太阳能电池的广泛使用需要使用大量的太阳能级硅(99.9999%)来制造硅基太阳电池硅片。多晶太阳能级硅的制备主要采用化学法，以改良西门子法为代表;然而，传统的化学法涉及一系列复杂的化学反应，制备过程具有腐蚀性并使用各种危险的化学试剂。另一方面，随着硅基太阳能电池的普及，将产生大量复杂难处理的失效太阳能电池和硅切割废料；然而，利用现在的化学法很难回收这些光伏废料，需要提出新的方法来制备太阳能级硅和回收硅基光伏废料。冶金法提纯硅技术具有一定的应用前景，但如何去除冶金级硅中的B和P的杂质是急需解决的关键问题。针对这一问题，研究者们提出了各种火法冶金方法以提高冶金级硅中B和P杂质的去除率。本文对目前现有的造渣法、氯化法、真空挥发法和溶剂精炼法进行了回顾，并对这四种方法的基本原理以及近年来有代表性的研究工作进行了总结和讨论。结果表明，溶剂精制法是目前最有希望、最环保的低成本太阳能级硅制备方法，也是目前冶金法提纯硅的研究热点。最后，本文提出了一种采用溶剂精炼、造渣或真空定向凝固相结合的新方法进行冶金级硅的提纯和硅废料的回收，以实现绿色低成本制备太阳能级硅和回收光伏硅废料。

关键词:

Invited Review

Recent progress in upgrading metallurgical-grade silicon to solar-grade silicon via pyrometallurgical routes

+ Author Affiliations

1)
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China
2)
Sustainable Minerals Institute, The University of Queensland, St Lucia 4072, QLD, Australia
3)
School of Chemical Engineering, Sichuan University, Chengdu 610065, China
4)
Separation and Conversion Technology, Flemish Institute for Technological Research, Mol 2400, Belgium
5)
Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan

*These authors contributed equally to this work.

Corresponding author:
Kazuki Morita E-mail: kzmorita@material.t.u-kyo.ac.jp
Received: 7 October 2021; Revised: 17 December 2021; Accepted: 17 January 2022; Available online: 18 January 2022

Abstract

Abstract

Si-based photovoltaic solar power has been rapidly developed as a renewable and green energy source. The widespread use of Si-based solar cells requires large amounts of solar-grade Si (SoG-Si) to manufacture Si wafers. Chemical routes, mainly the modified Siemens process, have dominated the preparation of polycrystalline SoG-Si; however, traditional chemical techniques employ a series of complex chemical reactions involving various corrosive and hazardous reagents. In addition, large amounts of complex waste solar cells and Si kerf slurry waste gradually accumulate and are difficult to recycle using these approaches. New methods are required to meet the demand for SoG-Si preparation and Si waste recycling. The metallurgical route shows promise but is hindered by the problem of eliminating B and P from metallurgical-grade Si (MG-Si). Various pyrometallurgical treatments have been proposed to enhance the removal of B and P from MG-Si. This article reviews Si refining with slag treatment, chlorination, vacuum evaporation, and solvent refining, and summarizes and discusses the basic principles and recent representative studies of the four methods. Among these, solvent refining is the most promising and environmentally friendly approach for obtaining low-cost SoG-Si and is a popular research topic. Finally, a simple and green approach, i.e., a combination of solvent refining, slag treatment, or vacuum directional solidification, is proposed for low-cost SoG-Si preparation using MG-Si or Si wastes as raw materials.
- silicon refining;
- solar-grade silicon;
- solvent refining;
- vacuum evaporation;
- slag treatment;
- Si kerf slurry waste

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References

[1]	S. Philipps, F. Ise, and W. Warmuth, Photovoltaics Report, Fraunhofer Institiute for Solar Energy Systems [2021-07-27]. https://www.ise.fraunhofer.de/en/publications/studies/photovoltaics-report.html
[2]	J. Hofstetter, J.F. Lelièvre, C.D. Cañizo, and A. Luque, Acceptable contamination levels in solar grade silicon: From feedstock to solar cell, Mater. Sci. Eng. B, 159-160(2009), p. 299. doi: 10.1016/j.mseb.2008.05.021
[3]	B. G. Gribov and K. V. Zinov’ev, Preparation of high-purity silicon for solar cells, Inorg. Mater., 39(2003), No. 7, p. 653. doi: 10.1023/A:1024553420534
[4]	J.R. Davis, A. Rohatgi, R.H. Hopkins, P.D. Blais, P. Rai-Choudhury, J.R. McCormick, and H.C. Mollenkopf, Impurities in silicon solar cells, IEEE Trans. Electron Devices, 27(1980), No. 4, p. 677. doi: 10.1109/T-ED.1980.19922
[5]	L. Hu, Z. Wang, X.Z. Gong, Z.C. Guo, and H. Zhang, Impurities removal from metallurgical-grade silicon by combined Sn–Si and Al–Si refining processes, Metall. Mater. Trans. B, 44(2013), No. 4, p. 828. doi: 10.1007/s11663-013-9850-8
[6]	H.X. Lai, L.Q. Huang, C.H. Lu, M. Fang, W.H. Ma, P.F. Xing, J.T. Li, and X.T. Luo, Leaching behavior of impurities in Ca-alloyed metallurgical grade silicon, Hydrometallurgy, 156(2015), p. 173. doi: 10.1016/j.hydromet.2015.06.012
[7]	Y.V. Meteleva-Fischer, Y. Yang, R. Boom, B. Kraaijveld, and H. Kuntzel, Microstructure of metallurgical grade silicon during alloying refining with calcium, Intermetallics, 25(2012), p. 9. doi: 10.1016/j.intermet.2012.02.009
[8]	S.K. Sahu and E. Asselin, Effect of oxidizing agents on the hydrometallurgical purification of metallurgical grade silicon, Hydrometallurgy, 121-124(2012), p. 120. doi: 10.1016/j.hydromet.2012.03.007
[9]	Y. Lei, W.H. Ma, X.D. Ma, J.J. Wu, K.X. Wei, S.Y. Li, and K. Morita, Leaching behaviors of impurities in metallurgical-grade silicon with hafnium addition, Hydrometallurgy, 169(2017), p. 433. doi: 10.1016/j.hydromet.2017.03.004
[10]	F.S. Xi, S.Y. Li, W.H. Ma, Z.J. Chen, K.X. Wei, and J.J. Wu, A review of hydrometallurgy techniques for the removal of impurities from metallurgical-grade silicon, Hydrometallurgy, 201(2021), art. No. 105553. doi: 10.1016/j.hydromet.2021.105553
[11]	H. Chen, K. Morita, X.D. Ma, Z.Y. Chen, and Y. Wang, Boron removal for solar-grade silicon production by metallurgical route: A review, Sol. Energy Mater. Sol. Cells, 203(2019), art. No. 110169. doi: 10.1016/j.solmat.2019.110169
[12]	J. Kline, M. Tangstad, and G. Tranell, A Raman spectroscopic study of the structural modifications associated with the addition of calcium oxide and boron oxide to silica, Metall. Mater. Trans. B, 46(2015), No. 1, p. 62. doi: 10.1007/s11663-014-0194-9
[13]	Y. Wang and K. Morita, Measurement of CaO–SiO₂–SaCl₂ slag density by an improved Archimedean method, J. Min. Metall. Sect. B, 51(2015), No. 2, p. 113. doi: 10.2298/JMMB140905016W
[14]	E. Krystad, L.K. Jakobsson, K. Tang, and G. Tranell, Thermodynamic behavior and mass transfer kinetics of boron between ferrosilicon and CaO–SiO₂ slag, Metall. Mater. Trans. B, 48(2017), No. 5, p. 2574. doi: 10.1007/s11663-017-1015-8
[15]	H.M. Liaw and F.S. d’Aragona, Purification of metallurgical-grade silicon by slagging and impurity redistribution, Sol. Cells, 10(1983), No. 2, p. 109. doi: 10.1016/0379-6787(83)90012-1
[16]	L.A.V. Teixeira, Y. Tokuda, T. Yoko, and K. Morita, Behavior and state of boron in CaO–SiO₂ slags during refining of solar grade silicon, ISIJ Int., 49(2009), No. 6, p. 777. doi: 10.2355/isijinternational.49.777
[17]	K.X. Wei, H.F. Lu, W.H. Ma, Y.L. Li, Z. Ding, J.J. Wu, and Y.N. Dai, Boron removal from metallurgical-grade silicon by CaO–SiO₂ slag refining, Rare Met., 34(2015), No. 7, p. 522. doi: 10.1007/s12598-015-0496-3
[18]	J.J. Wu, Y.L. Li, W.H. Ma, K.X. Wei, B. Yang, and Y.N. Dai, Boron removal in purifying metallurgical grade silicon by CaO−SiO₂ slag refining, Trans. Nonferrous Met. Soc. China, 24(2014), No. 4, p. 1231. doi: 10.1016/S1003-6326(14)63183-6
[19]	M. Fang, C.H. Lu, L.Q. Huang, H.X. Lai, J. Chen, X.B. Yang, J.T. Li, W.H. Ma, P.F. Xing, and X.T. Luo, Multiple slag operation on boron removal from metallurgical-grade silicon using Na₂O–SiO₂ slags, Ind. Eng. Chem. Res., 53(2014), No. 30, p. 12054. doi: 10.1021/ie404427c
[20]	H.X. Lai, L.Q. Huang, C.H. Lu, M. Fang, W.H. Ma, P.F. Xing, J.T. Li, and X.T. Luo, Reaction mechanism and kinetics of boron removal from metallurgical-grade silicon based on Li₂O–SiO₂ slags, JOM, 68(2016), No. 9, p. 2371. doi: 10.1007/s11837-015-1656-5
[21]	R. Noguchi, K. Suzuki, F. Tsukihashi, and N. Sano, Thermodynamics of boron in a silicon melt, Metall. Mater. Trans. B, 25(1994), No. 6, p. 903. doi: 10.1007/BF02662772
[22]	D.W. Luo, N. Liu, Y.P. Lu, G.L. Zhang, and T.J. Li, Removal of boron from metallurgical grade silicon by electromagnetic induction slag melting, Trans. Nonferrous Met. Soc. China, 21(2011), No. 5, p. 1178. doi: 10.1016/S1003-6326(11)60840-6
[23]	E.J. Jung, B.M. Moon, S.H. Seok, and D.J. Min, The mechanism of boron removal in the CaO−SiO₂–Al₂O₃ slag system for SoG-Si, Energy, 66(2014), p. 35. doi: 10.1016/j.energy.2013.08.010
[24]	J. Safarian, G. Tranell, and M. Tangstad, Boron removal from silicon by CaO–Na₂O–SiO₂ ternary slag, Metall. Mater. Trans. E, 2(2015), No. 2, p. 109.
[25]	L. Zhang, Y. Tan, F.M. Xu, J.Y. Li, H.Y. Wang, and Z. Gu, Removal of boron from molten silicon using Na₂O–CaO–SiO₂ slags, Sep. Sci. Technol., 48(2013), No. 7, p. 1140. doi: 10.1080/01496395.2012.714438
[26]	J.J. Wu, F.M. Wang, W.H. Ma, Y. Lei, and B. Yang, Thermodynamics and kinetics of boron removal from metallurgical grade silicon by addition of high basic potassium carbonate to calcium silicate slag, Metall. Mater. Trans. B, 47(2016), No. 3, p. 1796. doi: 10.1007/s11663-016-0615-z
[27]	Y. Hou, Y.D. Wu, G.H. Zhang, and K.C. Chou, Removal of boron from metallurgical grade silicon by CaO–SiO₂ based slags, Metall. Res. Technol., 116(2019), No. 4, art. No. 413. doi: 10.1051/metal/2019001
[28]	M.Y. Zhu, G.X. Wu, A. Azarov, E. Monakhov, K. Tang, M. Müller, and J. Safarian, Effects of La₂O₃ addition into CaO–SiO₂ slag: Structural evolution and impurity separation from Si–Sn alloy, Metall. Mater. Trans. B, 52(2021), No. 5, p. 3045. doi: 10.1007/s11663-021-02232-4
[29]	F.M. Wang, J.J. Wu, W.H. Ma, M. Xu, Y. Lei, and B. Yang, Removal of impurities from metallurgical grade silicon by addition of ZnO to calcium silicate slag, Sep. Purif. Technol., 170(2016), p. 248. doi: 10.1016/j.seppur.2016.06.060
[30]	J.J. Wu, W.H. Ma, B.J. Jia, B. Yang, D.C. Liu, and Y.N. Dai, Boron removal from metallurgical grade silicon using a CaO–Li₂O–SiO₂ molten slag refining technique, J. Non Cryst. Solids, 358(2012), No. 23, p. 3079. doi: 10.1016/j.jnoncrysol.2012.09.004
[31]	Z. Ding, W.H. Ma, K.X. Wei, J.J. Wu, Y. Zhou, and K.Q. Xie, Boron removal from metallurgical-grade silicon using lithium containing slag, J. Non Cryst. Solids, 358(2012), No. 18-19, p. 2708. doi: 10.1016/j.jnoncrysol.2012.06.031
[32]	Y. Wang, X.D. Ma, and K. Morita, Evaporation removal of boron from metallurgical-grade silicon using CaO–CaCl₂–SiO₂ slag, Metall. Mater. Trans. B, 45(2014), p. 334. doi: 10.1007/s11663-014-0031-1
[33]	L.K. Jakobsson and M. Tangstad, Erratum to: Distribution of boron between silicon and CaO-MgO–Al₂O₃–SiO₂ slags, Metall. Mater. Trans. B, 45(2014), No. 6, p. 2516. doi: 10.1007/s11663-014-0224-7
[34]	C.H. Yin, B.F. Hu, and X.M. Huang, Boron removal from molten silicon using sodium-based slags, J. Semicond., 32(2011), No. 9, art. No. 092003. doi: 10.1088/1674-4926/32/9/092003
[35]	J.Y. Li, L. Zhang, Y. Tan, D.C. Jiang, D.K. Wang, and Y.Q. Li, Research of boron removal from polysilicon using CaO–Al₂O₃–SiO₂–CaF₂ slags, Vacuum, 103(2014), p. 33. doi: 10.1016/j.vacuum.2013.12.002
[36]	M.D. Johnston and M. Barati, Distribution of impurity elements in slag–silicon equilibria for oxidative refining of metallurgical silicon for solar cell applications, Sol. Energy Mater. Sol. Cells, 94(2010), No. 12, p. 2085. doi: 10.1016/j.solmat.2010.06.025
[37]	H. Nishimoto, Y. Kang, T. Yoshikawa, and K. Morita, The rate of boron removal from molten silicon by CaO–SiO₂ slag and Cl₂ treatment, High Temp. Mater. Process., 31(2012), No. 4-5, p. 471. doi: 10.1515/htmp-2012-0083
[38]	Z.F. Xia, J.J. Wu, W.H. Ma, Y. Lei, K.X. Wei, and Y.N. Dai, Separation of boron from metallurgical grade silicon by a synthetic CaO–CaCl₂ slag treatment and Ar–H₂O–O₂ gas blowing refining technique, Sep. Purif. Technol., 187(2017), p. 25. doi: 10.1016/j.seppur.2017.06.037
[39]	J.Y. Li, P.P. Cao, P. Ni, Y.Q. Li, and Y. Tan, Enhanced boron removal from metallurgical grade silicon by the slag refining method with the addition of tin, Sep. Sci. Technol., 51(2016), No. 9, p. 1598.
[40]	X.D. Ma, T. Yoshikawa, and K. Morita, Purification of metallurgical grade Si combining Si–Sn solvent refining with slag treatment, Sep. Purif. Technol., 125(2014), p. 264. doi: 10.1016/j.seppur.2014.02.003
[41]	X.D. Ma, T. Yoshikawa, and K. Morita, Removal of boron from silicon–tin solvent by slag treatment, Metall. Mater. Trans. B, 44(2013), No. 3, p. 528. doi: 10.1007/s11663-013-9812-1
[42]	M. Xu, Y.Y. Zhu, J.J. Wu, Z.F. Xia, K.X. Wei, and W.H. Ma, Mechanism of boron removal using calcium silicate slag containing CaCl₂ under O₂ atmosphere, Metall. Mater. Trans. B, 52(2021), No. 4, p. 2573. doi: 10.1007/s11663-021-02175-w
[43]	H. Chen, X.Z. Yuan, K. Morita, Y.J. Zhong, X.D. Ma, Z.Y. Chen, and Y. Wang, Reaction mechanism and kinetics of boron removal from molten silicon via CaO–SiO₂–CaCl₂ slag treatment and ammonia injection, Metall. Mater. Trans. B, 50(2019), No. 5, p. 2088. doi: 10.1007/s11663-019-01639-4
[44]	Q.L. Wang, J.J. Wu, S.F. Qian, H.Z. Gu, Z.F. Xia, K.X. Wei, and W.H. Ma, Effects of slag treatment conditions on boron removal from metallurgical silicon by united gas–slag refining technology, Silicon, 2021. DOI: 10.1007/s12633-021-01175-4
[45]	R. Al-Khazraji, Y.Q. Li, and L.F. Zhang, Comparison between slag refining processes for B removal with metallurgical grade silicon and Si–Sn alloy, Metall. Res. Technol., 115(2018), No. 3, art. No. 312. doi: 10.1051/metal/2018047
[46]	M. Li, T. Utigard, and M. Barati, Removal of boron and phosphorus from silicon using CaO–SiO₂–Na₂O–Al₂O₃ flux, Metall. Mater. Trans. B, 45(2014), No. 1, p. 221. doi: 10.1007/s11663-013-0011-x
[47]	G.Y. Qian, Y.W. Sun, Z. Wang, K.X. Wei, and W.H. Ma, Novel application of electroslag remelting refining in the removal of boron and phosphorus from silicon alloy for silicon recovery, ACS Sustain. Chem. Eng., 9(2021), No. 7, p. 2962. doi: 10.1021/acssuschemeng.0c07150
[48]	J. Safarian, G. Tranell, and M. Tangstad, Thermodynamic and kinetic behavior of B and Na through the contact of B-doped silicon with Na₂O–SiO₂ slags, Metall. Mater. Trans. B, 44(2013), No. 3, p. 571. doi: 10.1007/s11663-013-9823-y
[49]	M. Tanahashi, T. Fujisawa, and C. Yamauchi, Oxidative removal of boron from molten silicon by CaO-based flux treatment with oxygen gas injection, Metall. Mater. Trans. B, 45(2014), No. 2, p. 629. doi: 10.1007/s11663-013-9966-x
[50]	R. Al-khazraji, Y.Q. Li, and L.F. Zhang, Boron separation from Si–Sn alloy by slag treatment, Int. J. Miner. Metall. Mater., 25(2018), No. 12, p. 1439. doi: 10.1007/s12613-018-1698-0
[51]	E.F. Nordstrand and M. Tangstad, Removal of boron from silicon by moist hydrogen gas, Metall. Mater. Trans. B, 43(2012), No. 4, p. 814. doi: 10.1007/s11663-012-9671-1
[52]	Ø.S. Sortland and M. Tangstad, Boron removal from silicon melts by H₂O/H₂ gas blowing: Mass transfer in gas and melt, Metall. Mater. Trans. E, 1(2014), p. 211. doi: 10.1007/s40553-014-0021-x
[53]	J.J. Wu, Y.L. Li, W.H. Ma, K. Liu, K.X. Wei, K.Q. Xie, B. Yang, and Y.N. Dai, Impurities removal from metallurgical grade silicon using gas blowing refining techniques, Silicon, 6(2014), No. 1, p. 79. doi: 10.1007/s12633-013-9158-y
[54]	Z.Y. Chen and K. Morita, Iron-catalyzed boron removal from molten silicon in ammonia, Metall. Mater. Trans. E, 3(2016), p. 228. doi: 10.1007/s40553-016-0078-9
[55]	Z.Y. Chen and K. Morita, Removal of boron from molten Si and Si–Cu using ammonia containing gas, Silicon, 10(2018), No. 5, p. 1809. doi: 10.1007/s12633-017-9681-3
[56]	H. Chen, Y. Wang, W.J. Zheng, Q.C. Li, X.Z. Yuan, and K. Morita, Model implementation of boron removal using CaCl₂–CaO–SiO₂ slag system for solar-grade silicon, Metall. Mater. Trans. B, 48(2017), No. 6, p. 3219. doi: 10.1007/s11663-017-1105-7
[57]	C.H. Lu, L.Q. Huang, H.X. Lai, M. Fang, W.H. Ma, P.F. Xing, L. Zhang, J.T. Li, and X.T. Luo, Effects of slag refining on boron removal from metallurgical-grade silicon using recycled slag with active component, Sep. Sci. Technol., 50(2015), No. 17, p. 2759. doi: 10.1080/01496395.2015.1062028
[58]	C.H. Lu, T.Y. Tang, Z.L. Sheng, P.F. Xing, and X.T. Luo, Improved removal of boron from metallurgical-grade Si by CaO–SiO₂–CaCl₂ slag refining with intermittent CaCl₂ addition, Vacuum, 143(2017), p. 7. doi: 10.1016/j.vacuum.2017.05.025
[59]	Y. Wang and K. Morita, Measurement of the phase diagram of the SiO₂–CaCl₂ system and liquid area study of the SiO₂–CaO–CaCl₂ system, Metall. Mater. Trans. B, 47(2016), No. 3, p. 1542. doi: 10.1007/s11663-016-0641-x
[60]	L.Q. Huang, H.X. Lai, C.H. Gan, H.P. Xiong, P.F. Xing, and X.T. Luo, Separation of boron and phosphorus from Cu-alloyed metallurgical grade silicon by CaO–SiO₂–CaCl₂ slag treatment, Sep. Purif. Technol., 170(2016), p. 408. doi: 10.1016/j.seppur.2016.07.004
[61]	Z.Y. Chen, Y.L. You, and K. Morita, Sustainable simultaneous synthesis of titanium-bearing materials from silicon waste and TiO₂-bearing slag, ACS Sustainable Chem. Eng., 6(2018), No. 8, p. 10742. doi: 10.1021/acssuschemeng.8b02058
[62]	Y. Wang and K. Morita, Reaction mechanism and kinetics of boron removal from molten silicon by CaO–SiO₂–CaCl₂ slag treatment, J. Sustain. Metall., 1(2015), No. 2, p. 126. doi: 10.1007/s40831-015-0015-7
[63]	R. Al-Khazraji, Boron removal from metallurgical grade silicon and Si-Sn alloy through slag refining with gas blowing, Funct. Mater., 25(2018), No. 3, p. 625. doi: 10.15407/fm25.03.625
[64]	J.J. Wu, Y.Q. Zhou, W.H. Ma, M. Xu, and B. Yang, Synergistic separation behavior of boron in metallurgical grade silicon using a combined slagging and gas blowing refining technique, Metall. Mater. Trans. B, 48(2017), No. 1, p. 22. doi: 10.1007/s11663-016-0860-1
[65]	Y.Q. Li, W. Chen, J. Lu, X.H. Lei, and L.F. Zhang, Boron removal from metallurgical-grade silicon by slag refining and gas blowing techniques: Experiments and simulations, J. Electron. Mater., 50(2021), No. 3, p. 1386. doi: 10.1007/s11664-020-08651-4
[66]	J. Safarian and M. Tangstad, Vacuum refining of molten silicon, Metall. Mater. Trans. B, 43(2012), No. 6, p. 1427. doi: 10.1007/s11663-012-9728-1
[67]	D.C. Jiang, S.Q. Ren, S. Shi, W. Dong, J.S. Qiu, Y. Tan, and J.Y. Li, Phosphorus removal from silicon by vacuum refining and directional solidification, J. Electron. Mater., 43(2014), No. 2, p. 314. doi: 10.1007/s11664-013-2811-9
[68]	S.S. Zheng, T.A. Engh, M. Tangstad, and X.T. Luo, Numerical simulation of phosphorus removal from silicon by induction vacuum refining, Metall. Mater. Trans. A, 42(2011), No. 8, p. 2214. doi: 10.1007/s11661-011-0621-3
[69]	A. Hoseinpur, S. Andersson, K. Tang, and J. Safarian, Selective vacuum evaporation by the control of the chemistry of gas phase in vacuum refining of Si, Langmuir, 37(2021), No. 24, p. 7473. doi: 10.1021/acs.langmuir.1c00876
[70]	A. Hoseinpur and J. Safarian, Vacuum refining of silicon at ultra-high temperatures, Vacuum, 184(2021), art. No. 109924. doi: 10.1016/j.vacuum.2020.109924
[71]	K.X. Wei, D.M. Zheng, W.H. Ma, B. Yang, and Y.N. Dai, Study on Al removal from MG-Si by vacuum refining, Silicon, 7(2015), No. 3, p. 269. doi: 10.1007/s12633-014-9228-9
[72]	Y. Tan, S.Q. Ren, S. Shi, S.T. Wen, D.C. Jiang, W. Dong, M. Ji, and S.H. Sun, Removal of aluminum and calcium in multicrystalline silicon by vacuum induction melting and directional solidification, Vacuum, 99(2014), p. 272. doi: 10.1016/j.vacuum.2013.06.015
[73]	S.Q. Ren, P.T. Li, D.C. Jiang, S. Shi, J.Y. Li, S.T. Wen, and Y. Tan, Removal of Cu, Mn and Na in multicrystalline silicon by directional solidification under low vacuum condition, Vacuum, 115(2015), p. 108. doi: 10.1016/j.vacuum.2015.02.006
[74]	J.L. Murray and A.J. McAlister, The Al–Si (aluminum–silicon) system, Bull. Alloy Phase Diagr., 5(1984), No. 1, p. 74. doi: 10.1007/BF02868729
[75]	R.H. Hopkins and A. Rohatgi, Impurity effects in silicon for high efficiency solar cells, J. Cryst. Growth, 75(1986), No. 1, p. 67. doi: 10.1016/0022-0248(86)90226-5
[76]	Y. Lei, W.H. Ma, L.E. Sun, J.J. Wu, Y.N. Dai, and K. Morita, Removal of B from Si by Hf addition during Al–Si solvent refining process, Sci. Technol. Adv. Mater., 17(2016), No. 1, p. 12. doi: 10.1080/14686996.2016.1140303
[77]	K. Tang, E.J. Øvrelid, G. Tranell, and M. Tangstad, Thermochemical and kinetic databases for the solar cell silicon materials, [in] Crystal Growth of Si for Solar Cells, Springer, Berlin, Heidelberg, 2009, p. 219.
[78]	Takeshi Yoshikawa, Physic–Chemistry on Silicon Refining at Low-Temperature Using Si–Al Solvent [Dissertation], The University of Tokyo, Tokyo, 2005.
[79]	T. Yoshikawa and K. Morita, Continuous solidification of Si from Si–Al melt under the induction heating, ISIJ Int., 47(2007), No. 4, p. 582. doi: 10.2355/isijinternational.47.582
[80]	Q.C. Zou, H. Tian, Z.X. Zhang, C.Z. Sun, J.C. Jie, N. Han, and X.Z. An, Controlling segregation behavior of primary Si in hypereutectic Al–Si alloy by electromagnetic stirring, Metals, 10(2020), No. 9, art. No. 1129. doi: 10.3390/met10091129
[81]	G.Q. Lv, Y. Bao, Y.F. Zhang, Y.F. He, W.H. Ma, and Y. Lei, Effects of electromagnetic directional solidification conditions on the separation of primary silicon from Al–Si alloy with high Si content, Mater. Sci. Semicond. Process., 81(2018), p. 139. doi: 10.1016/j.mssp.2018.03.006
[82]	W.Y. Jiang, W.Z. Yu, J. Li, Z.X. You, C.M. Li, and X.W. Lv, Segregation and morphological evolution of Si phase during electromagnetic directional solidification of hypereutectic Al–Si alloys, Mater., 12(2018), No. 1, art. No. 10. doi: 10.3390/ma12010010
[83]	J.W. Li, Z.C. Guo, J.C. Li, and L.Z. Yu, Super gravity separation of purified Si from solvent refining with the Al–Si alloy system for solar grade silicon, Silicon, 7(2015), No. 3, p. 239. doi: 10.1007/s12633-014-9197-z
[84]	Y. Nishi, Y. Kang, and K. Morita, Control of Si crystal growth during solidification of Si–Al melt, Mater. Trans., 51(2010), No. 7, p. 1227. doi: 10.2320/matertrans.M2010001
[85]	J.W. Li, J.C. Li, Y.H. Lin, J. Shi, B.Y. Ban, G.C. Liu, W. Yang, and J. Chen, Separation and recovery of refined Si from Al–Si melt by modified czochralski method, Materials, 13(2020), No. 4, art. No. 996. doi: 10.3390/ma13040996
[86]	T. Yoshikawa, K. Arimura, and K. Morita, Boron removal by titanium addition in solidification refining of silicon with Si–Al melt, Metall. Mater. Trans. B, 36(2005), No. 6, p. 837. doi: 10.1007/s11663-005-0085-1
[87]	X.L. Bai, B.Y. Ban, J.W. Li, Z.Q. Fu, Z.J. Peng, C.B. Wang, and J. Chen, Effect of Ti addition on B removal during silicon refining in Al–30%Si alloy directional solidification, Sep. Purif. Technol., 174(2017), p. 345. doi: 10.1016/j.seppur.2016.11.002
[88]	B.Y. Ban, J.W. Li, X.L. Bai, Q.X. He, J. Chen, and S.Y. Dai, Mechanism of B removal by solvent refining of silicon in Al–Si melt with Ti addition, J. Alloys Compd., 672(2016), p. 489. doi: 10.1016/j.jallcom.2016.02.198
[89]	Y. Lei, W.H. Ma, L.E. Sun, J.J. Wu, and K. Morita, Effects of small amounts of transition metals on boron removal during electromagnetic solidification purification of silicon with Al–Si solvent, Sep. Purif. Technol., 162(2016), p. 20. doi: 10.1016/j.seppur.2016.02.014
[90]	Y. Lei, P. Qiu, K. Chen, X.H. Chen, W.H. Ma, J.J. Wu, K.X. Wei, S.Y. Li, G.Q. Lv, and J.J. Qiu, Mechanism of ZrB₂ formation in Al–Si alloy and application in Si purification, ACS Sustainable Chem. Eng., 7(2019), No. 15, p. 12990. doi: 10.1021/acssuschemeng.9b02065
[91]	T. Yoshikawa and K. Morita, Removal of B from Si by solidification refining with Si–Al melts, Metall. Mater. Trans. B, 36(2005), p. 731. doi: 10.1007/s11663-005-0076-2
[92]	Y. Lei, W.H. Ma, J.J. Wu, K.X. Wei, S.Y. Li, and K. Morita, Impurity phases and their removal in Si purification with Al–Si alloy using transition metals as additives, J. Alloys Compd., 734(2018), p. 250. doi: 10.1016/j.jallcom.2017.10.292
[93]	K. Chen, X.H. Chen, Y. Lei, W.H. Ma, J.X. Han, and Z.H. Yang, Mechanism of enhancing B removal from Si with V addition using Al–Si as the refining solvent, Sep. Purif. Technol., 203(2018), p. 168. doi: 10.1016/j.seppur.2018.03.067
[94]	W.Z. Yu, Y. Xue, J. Mei, X.Z. Zhou, M.L. Xiong, and S.F. Zhang, Segregation and removal of transition metal impurities during the directional solidification refining of silicon with Al–Si solvent, J. Alloys Compd., 805(2019), p. 198. doi: 10.1016/j.jallcom.2019.07.089
[95]	C. Chen, B.Y. Ban, J.F. Sun, J.W. Li, X.S. Jiang, J. Shi, J. Chen, J.B. Jia, H. Sakiani, and S.H. Tabaian, Mechanism of boron removal of primary Si phases and morphology evolution of impurity phases during slow cooling solidification refining of Al–30wt.%Si alloy with Zr additions, J. Alloys Compd., 860(2021), art. No. 158517. doi: 10.1016/j.jallcom.2020.158517
[96]	C. Chen, J.W. Li, X.S. Jiang, W.F. Song, J. Shi, B.Y. Ban, and J. Chen, Effect of impurity phase migration on Al–30wt.%Si solvent refining with Zr additions during directional solidification, Sep. Purif. Technol., 278(2021), art. No. 119572. doi: 10.1016/j.seppur.2021.119572
[97]	Y.L. Li, L.D. Liu, and J. Chen, Effect of mechanical stirring on silicon purification during Al–Si solvent refining, J. Cryst. Growth, 553(2021), art. No. 125943. doi: 10.1016/j.jcrysgro.2020.125943
[98]	Q.C. Zou, N. Han, Z.F. Shen, J.C. Jie, and T.J. Li, Effects of AlB₂/AlP phase and electromagnetic stirring on impurity B/P removal in the solidification process of Al–30Si alloy, Sep. Purif. Technol., 207(2018), p. 151. doi: 10.1016/j.seppur.2018.06.052
[99]	Y.F. He, X. Yang, Y. Bao, S.Y. Li, Z.J. Chen, W.H. Ma, and G.Q. Lv, Effects of silicon content on the separation and purification of primary silicon from hypereutectic aluminum–silicon alloy by alternating electromagnetic directional solidification, Sep. Purif. Technol., 219(2019), p. 25. doi: 10.1016/j.seppur.2018.10.033
[100]	T. Xiao, G.Q. Lv, Y. Bao, W.C. Duo, L. Xu, and W.H. Ma, Electromagnetic separation of coarse Al–Si melts: The migration behavior of iron-rich phase and continuous growth of primary silicon, J. Alloys Compd., 819(2020), art. No. 153006. doi: 10.1016/j.jallcom.2019.153006
[101]	G.Y. Qian, L.Y. Sun, H. Chen, Z. Wang, K.X. Wei, and W.H. Ma, Enhancing impurities removal from Si by controlling crystal growth in directional solidification refining with Al–Si alloy, J. Alloys Compd., 820(2020), art. No. 153300. doi: 10.1016/j.jallcom.2019.153300
[102]	B.Y. Ban, T.T. Zhang, J.W. Li, X.L. Bai, X. Pan, J. Chen, and S. Hadi Tabaian, Solidification refining of MG-Si by Al–Si alloy under rotating electromagnetic field with varying frequencies, Sep. Purif. Technol., 202(2018), p. 266. doi: 10.1016/j.seppur.2018.03.069
[103]	R.W. Olesinski and G.J. Abbaschian, The Si−Sn (silicon−tin) system, Bull. Alloy Phase Diagr., 5(1984), No. 3, p. 273. doi: 10.1007/BF02868552
[104]	L.X. Zhao, Z. Wang, Z.C. Guo, and C.Y. Li, Low-temperature purification process of metallurgical silicon, Trans. Nonferrous Met. Soc. China, 21(2011), No. 5, p. 1185. doi: 10.1016/S1003-6326(11)60841-8
[105]	X.D. Ma, T. Yoshikawa, and K. Morita, Phase relations and thermodynamic property of boron in the silicon–tin melt at 1673 K, J. Alloys Compd., 529(2012), p. 12. doi: 10.1016/j.jallcom.2012.03.057
[106]	T. Yoshikawa and K. Morita, Thermodynamic property of B in molten Si and phase relations in the Si–Al–B system, Mater. Trans., 46(2005), No. 6, p. 1335. doi: 10.2320/matertrans.46.1335
[107]	A. Hosseinpour and L. Tafaghodi Khajavi, Slag refining of silicon and silicon alloys: A review, Miner. Process. Extr. Metall. Rev., 39(2018), No. 5, p. 308. doi: 10.1080/08827508.2018.1459616
[108]	S. Thomas, M. Barati, and K. Morita, A review of slag refining of silicon alloys, JOM, 73(2021), No. 1, p. 282. doi: 10.1007/s11837-020-04474-0
[109]	Y. Lei, W.H. Ma, J.J. Wu, K.X. Wei, G.Q. Lv, S.Y. Li, and K. Morita, Purification of metallurgical-grade silicon using Si–Sn alloy in presence of Hf, Zr, or Ti, Mater. Sci. Semicond. Process., 88(2018), p. 97. doi: 10.1016/j.mssp.2018.07.039
[110]	Y.S. Ren, H.P. Wang, and K. Morita, Effect of Zr addition on B-removal behaviour during solidification purification of Si with Si–Sn solvent, Vacuum, 167(2019), p. 319. doi: 10.1016/j.vacuum.2019.06.029
[111]	L. Hu, Z. Wang, X.Z. Gong, Z.C. Guo, and H. Zhang, Purification of metallurgical-grade silicon by Sn–Si refining system with calcium addition, Sep. Purif. Technol., 118(2013), p. 699. doi: 10.1016/j.seppur.2013.08.013
[112]	X.D. Ma, T. Yoshikawa, and K. Morita, Si growth by directional solidification of Si–Sn alloys to produce solar-grade Si, J. Cryst. Growth, 377(2013), p. 192. doi: 10.1016/j.jcrysgro.2013.05.024
[113]	X.D. Ma, T. Yoshikawa, and K. Morita, Elemental properties of Si: Si–Sn solid solution and diffusion coefficient in the Si–Sn melt, Sci. Adv. Mater., 6(2014), No. 8, p. 1697. doi: 10.1166/sam.2014.1915
[114]	L.F. Zhang, Y.S. Ma, and Y.Q. Li, Preparing crystalline silicon from Si-Sn solvent by zone melting directional solidification method, Mater. Sci. Semicond. Process., 71(2017), p. 12. doi: 10.1016/j.mssp.2017.06.044
[115]	Y.S. Ren, H.P. Wang, and K. Morita, Growth control and enrichment of Si crystals from Si-Sn melt by directional solidification, Vacuum, 158(2018), p. 86. doi: 10.1016/j.vacuum.2018.09.044
[116]	X.D. Ma, Y. Lei, T. Yoshikawa, B.J. Zhao, and K. Morita, Effect of solidification conditions on the silicon growth and refining using Si–Sn melt, J. Cryst. Growth, 430(2015), p. 98. doi: 10.1016/j.jcrysgro.2015.08.001
[117]	F. Huang, L. Zhao, L. Liu, Z.L. Hu, R.R. Chen, and Z.L. Dong, Separation and purification of Si from Sn–30Si alloy by electromagnetic semi-continuous directional solidification, Mater. Sci. Semicond. Process., 99(2019), p. 54. doi: 10.1016/j.mssp.2019.04.015
[118]	T.Y. Li, L. Guo, Z. Wang, and Z.C. Guo, Purification of metallurgical-grade silicon combining Sn–Si solvent refining with gas pressure filtration, RSC Adv., 10(2020), No. 19, p. 11435. doi: 10.1039/C9RA09077K
[119]	L.T. Khajavi, K. Morita, T. Yoshikawa, and M. Barati, Removal of boron from silicon by solvent refining using ferrosilicon alloys, Metall. Mater. Trans. B, 46(2015), No. 2, p. 615. doi: 10.1007/s11663-014-0236-3
[120]	L.T. Khajavi, K. Morita, T. Yoshikawa, and M. Barati, Thermodynamics of boron distribution in solvent refining of silicon using ferrosilicon alloys, J. Alloys Compd., 619(2015), p. 634. doi: 10.1016/j.jallcom.2014.09.062
[121]	L.T. Khajavi and M. Barati, Thermodynamics of phosphorus removal from silicon in solvent refining of silicon, High Temp. Mater. Process., 31(2012), No. 4-5, p. 627. doi: 10.1515/htmp-2012-0100
[122]	L.T. Khajavi and M. Barati, Thermodynamics of phosphorus in solvent refining of silicon using ferrosilicon alloys, Metall. Mater. Trans. B, 48(2017), No. 1, p. 268. doi: 10.1007/s11663-016-0804-9
[123]	W. Yan, Y.D. Yang, W.Q. Chen, M. Barati, and A. McLean, Thermodynamic assessment of Si–P and Si–Fe–P alloys for solar grade silicon refining via vacuum levitation, Vacuum, 135(2017), p. 101. doi: 10.1016/j.vacuum.2016.10.028
[124]	H. Sakiani, S.H. Tabaian, J. Chen, J.W. Li, and B.Y. Ban, Investigating boron and phosphorus removal from silicon by Si–Ti and Si–Ti–Fe alloying systems, Sep. Purif. Technol., 250(2020), art. No. 117227. doi: 10.1016/j.seppur.2020.117227
[125]	X.C. Deng, S. Li, J.H. Wen, K.X. Wei, M.Y. Zhang, X. Yang, and W.H. Ma, Mechanism of enhancing phosphorus removal from metallurgical grade silicon by Si–Fe–Ti phase reconstruction, Metall. Mater. Trans. B, 52(2021), No. 2, p. 625. doi: 10.1007/s11663-020-02028-y
[126]	A. Hosseinpour and L. Tafaghodi Khajavi, Thermodynamics of boron removal in slag refining of Fe–Si alloy, J. Alloys Compd., 768(2018), p. 545. doi: 10.1016/j.jallcom.2018.07.246
[127]	A. Hosseinpour and L. Tafaghodi Khajavi, Phosphorus removal from Si–Fe alloy using SiO₂–Al₂O₃–CaO slag, Metall. Mater. Trans. B, 50(2019), No. 4, p. 1773. doi: 10.1007/s11663-019-01586-0
[128]	G.I.A. Taposhe and L.T. Khajavi, Removal of phosphorus from Si–Fe alloy by CaO–Al₂O₃–SiO₂–Na₂O slag refining, JOM, 73(2021), No. 2, p. 729. doi: 10.1007/s11837-020-04496-8
[129]	S. Esfahani and M. Barati, Purification of metallurgical silicon using iron as impurity getter part I: Growth and separation of Si, Met. Mater. Int., 17(2011), No. 5, p. 823. doi: 10.1007/s12540-011-1021-3
[130]	S. Esfahani and M. Barati, Purification of metallurgical silicon using iron as impurity getter, part II: Extent of silicon purification, Met. Mater. Int., 17(2011), No. 6, p. 1009. doi: 10.1007/s12540-011-6020-x
[131]	Y.Q. Li, C.C. Liu, X.H. Lei, L.F. Zhang, and T.H. Tsai, Bulk Si production from Si-Fe melts under temperature gradients, part I: Growth and characterization, J. Mater. Res. Technol., 9(2020), No. 6, p. 12595. doi: 10.1016/j.jmrt.2020.08.078
[132]	Y.Q. Li, X.H. Lei, C.C. Liu, and L.F. Zhang, Bulk Si production from Si–Fe melts by directional-solidification, part II: Element distribution, Mater. Sci. Semicond. Process., 128(2021), art. No. 105754. doi: 10.1016/j.mssp.2021.105754
[133]	R.W. Olesinski and G.J. Abbaschian, The Cu−Si (copper–silicon) system, Bull. Alloy Phase Diagr., 7(1986), No. 2, p. 170. doi: 10.1007/BF02881559
[134]	A.M. Mitrašinović and T.A. Utigard, Refining silicon for solar cell application by copper alloying, Silicon, 1(2009), No. 4, p. 239. doi: 10.1007/s12633-009-9025-z
[135]	L.Q. Huang, H.X. Lai, C.H. Lu, M. Fang, W.H. Ma, P.F. Xing, J.T. Li, and X.T. Luo, Enhancement in extraction of boron and phosphorus from metallurgical grade silicon by copper alloying and aqua regia leaching, Hydrometallurgy, 161(2016), p. 14. doi: 10.1016/j.hydromet.2016.01.013
[136]	L.Q. Huang, J. Chen, A. Danaei, S. Thomas, L.Y. Huang, X.T. Luo, and M. Barati, Effect of Ti addition to Cu–Si alloy on the boron distribution in various phases, J. Alloys Compd., 734(2018), p. 235. doi: 10.1016/j.jallcom.2017.10.279
[137]	L.Q. Huang, A. Danaei, S. Thomas, P.F. Xing, J.T. Li, X.T. Luo, and M. Barati, Solvent extraction of phosphorus from Si–Cu refining system with calcium addition, Sep. Purif. Technol., 204(2018), p. 205. doi: 10.1016/j.seppur.2018.04.087
[138]	M. Fang, C.H. Lu, H.X. Lai, L.Q. Huang, J. Chen, W.H. Ma, Z.L. Sheng, J.N. Shen, J.T. Li, and X.T. Luo, Effect of solidification rate on representative impurities distribution in Si–Cu alloy, Mater. Sci. Technol., 29(2013), No. 7, p. 861. doi: 10.1179/1743284713Y.0000000212
[139]	Y.S. Ren, S. Ueda, and K. Morita, Formation mechanism of ZrB₂ in a Si–Cu melt and its potential application for refining Si and recycling Si waste, ACS Sustainable Chem. Eng., 7(2019), No. 24, p. 20107. doi: 10.1021/acssuschemeng.9b05986
[140]	Y.S. Ren and K. Morita, Low-temperature process for the fabrication of low-boron content bulk Si from Si–Cu solution with Zr addition, ACS Sustainable Chem. Eng., 8(2020), No. 17, p. 6853. doi: 10.1021/acssuschemeng.0c01785
[141]	H. Morito, M. Uchikoshi, and H. Yamane, Boron removal by dissolution and recrystallization of silicon in a sodium-silicon solution, Sep. Purif. Technol., 118(2013), p. 723. doi: 10.1016/j.seppur.2013.08.022
[142]	H. Morito, T. Karahashi, M. Uchikoshi, M. Isshiki, and H. Yamane, Low-temperature purification of silicon by dissolution and solution growth in sodium solvent, Silicon, 4(2012), No. 2, p. 121. doi: 10.1007/s12633-011-9105-8
[143]	J.W. Li, B.Y. Ban, Y.L. Li, X.L. Bai, T.T. Zhang, and J. Chen, Removal of impurities from metallurgical grade silicon during Ga–Si solvent refining, Silicon, 9(2017), No. 1, p. 77. doi: 10.1007/s12633-014-9269-0
[144]	C.T. Zhang, H.X. Lai, Y.H. Zhang, Z.L. Sheng, J.T. Li, P.F. Xing, and X.T. Luo, Extraction of phosphorus from metallurgical grade silicon using a combined process of Si–Al–Ca solvent refining and CaO–CaF₂ slag treatment, Sep. Purif. Technol., 232(2020), art. No. 115954. doi: 10.1016/j.seppur.2019.115954
[145]	Y.Q. Li, Y. Tan, J.Y. Li, and K. Morita, Si purity control and separation from Si–Al alloy melt with Zn addition, J. Alloys Compd., 611(2014), p. 267. doi: 10.1016/j.jallcom.2014.05.138
[146]	J.Y. Li, Y. Liu, Y. Tan, Y.Q. Li, L. Zhang, S.R. Wu, and P.J. Jia, Effect of tin addition on primary silicon recovery in Si–Al melt during solidification refining of silicon, J. Cryst. Growth, 371(2013), p. 1. doi: 10.1016/j.jcrysgro.2012.12.098
[147]	Y.Q. Li, Y. Tan, J.Y. Li, Q. Xu, and Y. Liu, Effect of Sn content on microstructure and boron distribution in Si–Al alloy, J. Alloys Compd., 583(2014), p. 85. doi: 10.1016/j.jallcom.2013.08.145
[148]	M.D. Johnston and M. Barati, Calcium and titanium as impurity getter metals in purification of silicon, Sep. Purif. Technol., 107(2013), p. 129. doi: 10.1016/j.seppur.2013.01.028
[149]	Y. Lei, W.H. Ma, G.Q. Lv, K.X. Wei, S.Y. Li, and K. Morita, Purification of metallurgical-grade silicon using zirconium as an impurity getter, Sep. Purif. Technol., 173(2017), p. 364. doi: 10.1016/j.seppur.2016.09.051
[150]	C.T. Zhang, W. Sheng, L.Q. Huang, S. Zhang, Y.H. Zhang, H.X. Cai, J.S. Meng, and X.T. Luo, Vanadium as an impurity trapper for purification of metallurgical-grade silicon, Sep. Purif. Technol., 260(2021), art. No. 118199. doi: 10.1016/j.seppur.2020.118199
[151]	Y.S. Ren, H. Chen, T. Mizutani, W.H. Ma, Y. Zeng, and K. Morita, Efficient separation of bulk Si and enhanced B removal by Si–Sn–Cu ternary solvent refining with Zr addition, Sep. Purif. Technol., 275(2021), art. No. 119242. doi: 10.1016/j.seppur.2021.119242
[152]	H. Chen, Y.S. Ren, W.H. Ma, and Y. Zeng, Distribution behaviour of boron between ZrTiHfCuNi high entropy alloy and silicon, Sep. Purif. Technol., 271(2021), art. No. 118863. doi: 10.1016/j.seppur.2021.118863
[153]	J. Mei, W.Z. Yu, P. Hou, Y. Xue, Y.T. Xin, and K. Yan, Purification of metallurgical grade silicon via the Mg–Si alloy refining and acid leaching process, Silicon, 13(2021), No. 2, p. 341. doi: 10.1007/s12633-020-00439-9
[154]	M.Y. Zhu, D. Wan, K. Tang, and J. Safarian, Impurity removal from Si by Si–Ca–Mg ternary alloying-leaching system, Mater. Des., 198(2021), art. No. 109348. doi: 10.1016/j.matdes.2020.109348
[155]	M.Y. Zhu, S.Y. Yue, K. Tang, and J. Safarian, New insights into silicon purification by alloying–leaching refining: A comparative study of Mg–Si, Ca–Si, and Ca–Mg–Si systems, ACS Sustainable Chem. Eng., 8(2020), No. 42, p. 15953. doi: 10.1021/acssuschemeng.0c05564
[156]	C. Wang, Y. Lei, W.H. Ma, and P. Qiu, An approach for simultaneous treatments of diamond wire saw silicon kerf and Ti-bearing blast furnace slag, J. Hazard. Mater., 401(2021), art. No. 123446. doi: 10.1016/j.jhazmat.2020.123446
[157]	Y.H. Zhang, W. Sheng, L.Q. Huang, S. Zhang, G.Y. Chen, C.T. Zhang, H.X. Cai, J.S. Meng, and X.T. Luo, Preparation of low-boron silicon from diamond wire sawing waste by pressure-less sintering and CaO–SiO₂ slag treatment, ACS Sustainable Chem. Eng., 8(2020), No. 31, p. 11755. doi: 10.1021/acssuschemeng.0c03875
[158]	S.C. Yang, X.H. Wan, K.X. Wei, W.H. Ma, and Z. Wang, Investigation of Na₂CO₃–CaO–NaCl (or Na₃AlF₆) additives for the remanufacturing of silicon from diamond wire saw silicon powder waste, J. Clean. Prod., 286(2021), art. No. 125525. doi: 10.1016/j.jclepro.2020.125525