National Mineral Resources University, Saint Petersburg, Russia:

I. I. Beloglazov, Assistant
A. P. Suslov, Pro-rector

“LENNIIGIPROKhIM” LLC, Saint Petersburg, Russia:
A. A. Pedro, Professor, Head of Laboratory of High-Temperature Processes and Apparatuses, e-mail: pedro1938@mail.ru

There is noted that a constant component, substantiated by valve effect of electric AC arc, exists in phase voltage of ore-smelting furnace for production of zirconium corundum. Presence of such component is caused by different density of thermionic current in neighboring half-cycles. In this process, DC, caused by valve effect of electric AC arc, is directed from electrode to melt, and its magnitude varies within 0–4 V and depends on arc combustion conditions. There is shown the connection between magnitude of the constant component of phase voltage and nature and indicators of zirconium corundum melting process in ore-smelting furnace. First of all, this corresponds to specific energy consumption, connected with electric arc, which development value should be optimal. Presence of connection between extent of electric arc development and constant component magnitude makes possible to select the optimal parameters of technological process (including voltage and electrode current) by latter adjusting. In the considered case, the optimum value of constant component should be in the range of 2–3 V. Reducing the magnitude of the constant component below the recommended value leads to deterioration of quality of obtained product due to reduction of iron, aluminum and zirconium oxides. Exceeding of the constant component value above 3 V is accompanied by increasing in specific electricity consumption.

1. Elektrotermicheskie protsessy khimicheskoy tekhnologii : uchebnoe posobie dlya vuzov (Electrochemical processes of chemical technology : tutorial for universities). Under the editorship of V. A. Ershov. Leningrad : Khimiya, 1984. 464 p.
2. Polubelova A. S., Krylov V. N., Karlin V. V., Efimova I. S. Proizvodstvo abrazivnykh materialov (Production of abrasive materials). Leningrad : Mashinostroenie, 1968. 180 p.
3. Pedro A. A. Elektrotekhnika — Russian Electrical Engineering. 1993. No. 9. pp. 48–50.
4. Elektricheskie promyshlennye pechi. Dugovye pechi i ustanovki spetsialnogo nagreva : uchebnik dlya vuzov (Electrical industrial furnaces. Arc furnaces and special heating installations : tutorial for universities). Under the editorship of A. D. Svenchanskiy. Moscow : Energoizdat, 1981. 296 p.
5. Markov N. A., Barannik O. V. Ekspluatatsionnyy kontrol elektricheskikh parametrov dugovykh elektropechey (Exploitation control of electric parameters of arc furnaces). Moscow : Energiya, 1973. 104 p.
6. Nikolskiy V. I. Elektrichestvo — Electrical Technology Russia. 1951. No. 3. pp. 33–38.
7. Lapshin I. V. Avtomatizatsiya dugovykh pechey (Automation of arc furnaces). Moscow : Publishing House of Moscow State University, 2004. 166 p.
8. Pedro A. A. Izvestiya vuzov. Tsvetnaya metallurgiya — Russian Journal of Non-ferrous Metals. 1992. No. 11. pp. 21–24.
9. Pedro A. A., Suslov A. P. Tsvetnye Metally — Non-ferrous metals. 2012. No. 12. pp. 91–95.
10. Pedro A. A., Starkova L. E., Suslov A. P. Priroda i kharakter postoyannoy sostavlyayushchey faznogo napryazheniya v rudnotermicheskoy pechi (Nature of steady component of phase stress in ore-thermal furnace). Vologda : Vologda State Technical University, 2013. 123 p.