Silicon production method

In the laboratory, magnesium powder can be used to reduce powdery silicon dioxide under red heat, and the magnesium oxide and magnesium powder generated are washed with dilute acid, and then the unused silicon dioxide is washed with hydrofluoric acid to obtain elemental silicon. All amorphous silicon obtained by this method is not pure enough, which is brown-black powder. Industrial production of silicon is the reduction of silica (SiO2 content greater than 99%) in an electric arc furnace. The reducing agents used are petroleum coke and charcoal. When using a DC electric arc furnace, the charcoal can be completely replaced by petroleum coke. The ash content of petroleum coke is low (0.3% to 0.8%), and high-quality silica (SiO2 greater than 99%) can be used to directly smelt high-quality silicon for manufacturing silicon steel sheets. High-purity semiconductor silicon can be prepared by reducing high-purity trichlorosilane SiHCl3 or SiCl4 with hydrogen on a hot silicon rod at 1200°C. Ultrapure monocrystalline silicon can be prepared by Czochralski or zone melting.

Amorphous silicon can be obtained by reducing silica with magnesium. Crystalline silicon can be obtained by reducing silicon dioxide with carbon in an electric furnace. High-purity silicon used in the electronics industry is prepared by reducing trichlorosilane or silicon tetrachloride with hydrogen.