State Enterprise “State Titanium Research and Design Institute”, Zaporozhe, Ukraine

D. V. Pruttskov, Leading Researcher, phone: (+38061) 218-41-66
N. P. Krivoruchko, Head of the Electrochemical Productions Laboratory

Results of laboratory and experimental-industrial study of development of process for recycling of fine silicon waste, formed in the process of direct synthesis of organochlorosilanes — waste contact mass (WCM) — has been presented. As the result of research optimal technology concepts for application of silicon waste in production of high-silicon ferrosilicon and silicon tetrachloride have been determined. In both cases preparation of waste includes heat treatment to remove the organic substances residues, and briquetting. It is suggested that briquetting should be carried out with application of complex binding agent based on lignosulphonate and coal-tar pitch. For mastering of technology for grade FS-90 high-silicon ferrosilicon melting briquettes, which contained only WCM and binder with elementary silicon mass fraction reaching 70%, were used. Briquettes were added to a standard charge material. It has been experimentally deduced that adding of briquettes in quantities corresponding to 7–8% of the charge weight has the most influence on increase of furnace production rate and reduction of electrical energy consumption. In this case furnace production rate increase of 35% and energy consumption reduction by 2.200 kW h/t have been observed. In studies of possibility of industrial silicon tetrachloride production alternatives of siliceous briquettes in a horizontal water-cooled furnace and in a shaft-type chlorinator have been tested. Application of a horizontal furnace has been found unacceptable due to carbonic layer formation on the briquette periphery, which caused process fading as a result of change of mechanism of chlorine feeding from outside diffusion to inside diffusion. With application of a shaft-type chlorinator heat balance and optimal temperature conditions inside the layer of chlorinated material have been obtained by means of siliceous sand adding to briquettes with the SiО₂ to WCM ratio of 1.2–1.5 to 1. It has been determined that in this case sand chlorination ratio reached 35–40%.

1. Andrianov K. A., Khananashvili L. M. Tekhnologiya elementoorganicheskikh monomerov i polimerov (Technology of hetero-organic monomers and polymers). Moscow : Khimiya, 1973. 400 p.
2. Ragulina R. I., Emlin B. I. Elektrotermiya kremniya i silumina (Electrothermy of silicon and silumin). Moscow : Metallurgiya, 1972. 240 p.
3. Pruttskov D. V., Lebedev V. N., Krivoruchko N. P. Tsvetnye Metally – Non-ferrous metals. 2008. No. 1. pp. 63–66.
4. Pruttskov D. V., Krivoruchko N. P. Tsvetnye Metally – Non-ferrous metals. 2010. No. 12. pp. 53–55.
5. Furman A. A. Neorganicheskie khloridy (Inorganic chlorides). Moscow : Khimiya, 1980. 416 p.
6. Frank-Kamenetskiy D. A. Diffuziya i teploperedacha v khimicheskoy kinetike (Diffusion and heat transmission in chemical kinetics). Moscow : Nauka, 1967. 491 p.
7. Garmata V. A., Petrunko A. N., Galitskiy N. V. et al. Titan (Titanium). Moscow : Metallurgiya, 1983. 559 p.
8. Zelikman A. N., Korshunov B. G. Metallurgiya redkikh metallov (Metallurgy of rare metals). Moscow : Metallurgiya, 1991. 432 p.
9. Myshlyaeva L. V., Krasnoshchekov V. V. Analiticheskaya khimiya kremniya (Analytical chemistry of silicon). Moscow : Nauka, 1972. 212 p.