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ArticleName Upgraded metallurgy grade silicon for photovoltaic needs
ArticleAuthor Turmagambetov T. S., Abdullin Kh. A., Mukashev B. N., Tamendarov M. F., Beketov B. A.

In this paper results on development of pure silicon production method by aluminothermic reduction of natural quartzite and following purification were present. The optimal composition of furnace charge for complete reaction of reduction is determined. Results are show that purity of raw material has weak impact on purity of silicon obtained, except for impurity of boron and phosphorus. Concentration of CaAl2Si2 and CaAl2Si1,5 phases has sharply decreased and the free silicon phases increased in result of carried out experiments on slag refining of melt. Cleaning of silicon by a chemical method carried out and influence of various processing modes on efficiency of cleaning are investigated. It is shown that total concentrations of impurity sharply decrease up to ~ 10 ppm after crystallization of silicon. Single crystals with concentration of impurity of boron and aluminium less than 2 ppm, phosphorus less than 7 ppm and resistivity of 1–1.5 Ohm · cm are grown by Czochralski method from silicon obtained by direct reduction of quartzite and following chemical treatment.

keywords Silicon, aluminothermy, quartzites, silicate slag, slag refining, acid cleaning, crystallization
Language of full-text russian
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