Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag Refining
As a critical impurity in the production of solar-grade silicon, the concentration of phosphorus (P) significantly affects photoelectric conversion efficiency. To address the challenge of P removal in solar-grade silicon production, this study proposes a combined process of Si-Fe solvent refining an...
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2025-06-01
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| author | Yi Zhong Qing Zhao Juncheng Li |
| author_facet | Yi Zhong Qing Zhao Juncheng Li |
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| description | As a critical impurity in the production of solar-grade silicon, the concentration of phosphorus (P) significantly affects photoelectric conversion efficiency. To address the challenge of P removal in solar-grade silicon production, this study proposes a combined process of Si-Fe solvent refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> slag treatment. Under conditions utilizing collaborative refining with an alloy composition of Si-10 wt. %Fe and a slag composition of 32 wt. %SiO<sub>2</sub>-48 wt. %CaO-10 wt. %TiO<sub>2</sub>-10 wt. %CaF<sub>2</sub>, the removal rate of P in silicon can reach up to 96.8%. This paper investigates the effectiveness of combining solvent refining with slag making under fixed conditions of a Si-10 wt. %Fe alloy paired with various slag systems (no slag addition, binary slag SiO<sub>2</sub>-TiO<sub>2</sub>, ternary slag SiO<sub>2</sub>-CaO-TiO<sub>2</sub>, and quaternary slag SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub>). Based on the experimental results, the optimal TiO<sub>2</sub> content in the slag system for maximizing P removal was analyzed and determined. Finally, leveraging both theoretical analysis and experimental findings, the mechanism of P removal was elucidated as a dual process: P is oxidized into Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> within the slag phase, and residual P is captured by the Fe-Si-Ti ternary phase. |
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| institution | Kabale University |
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| spelling | doaj-art-7dd034d2368f4bd889f8b21d875293042025-08-20T03:27:37ZengMDPI AGMetals2075-47012025-06-0115666810.3390/met15060668Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag RefiningYi Zhong0Qing Zhao1Juncheng Li2School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, ChinaKey Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang 110819, ChinaCollege of Energy and Environment Science, Yunnan Normal University, Kunming 650500, ChinaAs a critical impurity in the production of solar-grade silicon, the concentration of phosphorus (P) significantly affects photoelectric conversion efficiency. To address the challenge of P removal in solar-grade silicon production, this study proposes a combined process of Si-Fe solvent refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> slag treatment. Under conditions utilizing collaborative refining with an alloy composition of Si-10 wt. %Fe and a slag composition of 32 wt. %SiO<sub>2</sub>-48 wt. %CaO-10 wt. %TiO<sub>2</sub>-10 wt. %CaF<sub>2</sub>, the removal rate of P in silicon can reach up to 96.8%. This paper investigates the effectiveness of combining solvent refining with slag making under fixed conditions of a Si-10 wt. %Fe alloy paired with various slag systems (no slag addition, binary slag SiO<sub>2</sub>-TiO<sub>2</sub>, ternary slag SiO<sub>2</sub>-CaO-TiO<sub>2</sub>, and quaternary slag SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub>). Based on the experimental results, the optimal TiO<sub>2</sub> content in the slag system for maximizing P removal was analyzed and determined. Finally, leveraging both theoretical analysis and experimental findings, the mechanism of P removal was elucidated as a dual process: P is oxidized into Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> within the slag phase, and residual P is captured by the Fe-Si-Ti ternary phase.https://www.mdpi.com/2075-4701/15/6/668metallurgical-grade siliconphosphorus removalsolvent refiningslag treatmentSi-Fe-Ti phaseCa<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> |
| spellingShingle | Yi Zhong Qing Zhao Juncheng Li Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag Refining Metals metallurgical-grade silicon phosphorus removal solvent refining slag treatment Si-Fe-Ti phase Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> |
| title | Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag Refining |
| title_full | Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag Refining |
| title_fullStr | Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag Refining |
| title_full_unstemmed | Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag Refining |
| title_short | Phosphorus Removal in Metallurgical-Grade Silicon via a Combined Approach of Si-Fe Solvent Refining and SiO<sub>2</sub>-TiO<sub>2</sub>-CaO-CaF<sub>2</sub> Slag Refining |
| title_sort | phosphorus removal in metallurgical grade silicon via a combined approach of si fe solvent refining and sio sub 2 sub tio sub 2 sub cao caf sub 2 sub slag refining |
| topic | metallurgical-grade silicon phosphorus removal solvent refining slag treatment Si-Fe-Ti phase Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> |
| url | https://www.mdpi.com/2075-4701/15/6/668 |
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