METHOD OF EXTRACTING METALLIC SILICON FROM TECHNICAL GRADE SLAG Russian patent published in 2019 - IPC C22B7/04 C01B33/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to non-ferrous metallurgy and can be used in production of technical silicon and ferrosilicon. Method involves preparation of charge from slag produced during refining of silicon with introduction of slag-forming and solvent, melting of charge and maintenance, cooling of melt and separation of metal phase from slag. Slag-forming agents used are aluminum and calcium oxides, and the solvent used is iron in form of steel chips. Melting and maintenance are carried out at temperature not lower than 1,600 °C, wherein metal phase consisting of alloy of silicon and iron is obtained, and secondary slag is as follows, wt%: SiO₂ 46.4–52.2; Al₂O₃ 13.3–19.4; CaO 30.2–34.54.

EFFECT: separation of metallic phase from slag of technical silicon in form of alloy of silicon and iron.

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