The Paton Welding Journal, 2026, №04

2026 №04 (02)

DOI of Article 10.37434/tpwj2026.04.03

2026 №04 (04)

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The Paton Welding Journal, 2026, #4, 15-23 pages

Production and refining of metallurgical silicon to solar-grade silicon (Review)

G.G. Didikin

E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: didikin@paton-icebt.kievua

Abstract
Studies of refining MG-Si silicon by metallurgical methods show that each method is selective in removing one or a small group of impurity elements. Particular attention is paid to the purity of silicon by boron, the content of which should not exceed 0.3 ppmw. Evaporation of P or B is possible, but it is most often a slow process and can be accompanied by a loss of Si. Solvent refining has proven effective in removing impurities, with Al being a suitable alloying agent. In order to take advantage of the high throughput and low cost benefits of metallurgical processing methods, combinations of methods must be used, either sequentially or simultaneously, to produce a product that is consistent with solar-grade SoG‒Si. Impurities in MG‒Si are classified as segregable and insoluble. Single acid leaching removes only certain impurities. In practice, sequential or mixed acid leaching is used. Adding oxidizing agents to acidic leachers increases the efficiency of impurity removal. External fields (ultraviolet radiation, ultrasonic field, and oxygen pressure leaching) or the introduction of cracks/porous structures and thermal pretreatment can improve impurity removal. In the electron beam remelting of metallurgical silicon, purification occurs by evaporating impurity elements from the melt surface in a vacuum. Refining is based on the process in a high vacuum and the difference in vapor pressure of different impurity elements, whose vapor pressure is higher than that of silicon. The method of electron beam remelting of metallurgical silicon in conjunction with oxidative refining makes it possible to purify up to the level of 5‒6 N.
Keywords: metallurgical silicon, slag treatment, leaching, electron beam melting, vacuum degassing, solar-grade silicon, impurity elements, segregation

Received: 15.12.2025
Received in revised form: 08.02.2026
Accepted: 16.04.2026

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Suggested Citation

G.G. Didikin (2026) Production and refining of metallurgical silicon to solar-grade silicon (Review). The Paton Welding J., 04, 15-23. https://doi.org/10.37434/tpwj2026.04.03

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