South Ural State University (Chelyabinsk, Russia)

S. P. Salikhov, Cand. Eng., Associate Prof., e-mail: salikhovsp@susu.ru
A. V. Roshchin, Dr. Eng., Associate Prof., Senior Researcher
V. E. Roshchin, Dr. Eng., Prof.

An overview of the existing methods of processing and using of the Bakal sideroplesite ore is presented. Due to the high content of refractory magnesium oxide in the ore, this ore is used in a limited amount as an additive to traditional ore raw materials. To increase the use of ore, new scientific fundamentals of its pyrometallurgical processing are needed. The process of dissociation of ore carbonates is investigated, as well as the mechanism of solid-phase reduction of iron in the dissociation product. Calculated and experimental methods for studying the reduction process are presented. Based on the results of the thermodynamic calculation, it is established that the most fusible phase during metallization is metal because of carburization of iron and the formation of cast iron. Therefore, in order to realize solid-phase reduction without the formation of liquid phases, the temperature is selected to be no more than 1250 °C. It was revealed that the solid-phase reduction process is successfully realized inside the oxide phase in pieces measuring 20-30 mm. At the same time, metal contamination with harmful impurities of the reducing agent does not occur, as a result of which cheap energy coal can be used as the reducing agent. The composite metal-oxide material obtained as a result of solid-phase reduction of iron in sideroplesite contains direct reduce iron (up to 60-85 %) and magnesia (15-25 %), as well as in a small amount of silicon oxide and oxides of iron, manganese and aluminum. When analyzing the results of iron precipitate during metallization, we proceeded from the concept of an electronic mechanism for the reduction and separation in the space of the process of interaction of a reducing agent with anions of complex oxide and the precipitate of a metal phase in the volume of the oxide. Based on the obtained results, a pyrometallurgical processing scheme for lumpy sideroplesite ore in rotating furnaces is proposed to produce a composite metal oxide material that can be used as an additive to steelmaking units to increase the lining stability and reduce the concentration of non-ferrous metal impurities in the steel.

1. Dmitriev A., N., Shumakov N. S., Leontev L. I., Onorin O. P. Theory and technology of blast furnace melting: fundamentals. Yekaterinburg: UrO RAN, 2005. 545 p.
2. Panishev N. V., Rashnikov V. F., Dubrovsky B. A., Redin E. V. Metallization of Chelyabinsk region spar ironstones and titaniferous magnetites with production of granulated iron. Brief outline reports of participants of 8^th Industrial forum «Reconstruction of industrial plants — breakthrough technologies in metallurgy and machine building». Chelyabinsk: Chelyabgipromez, 2016. pp. 48–49.
3. Leontev L. I., Vatolin N. A., Shavrin S. V., Shumakov N. S. Pyroprocessing of complex ores. Moscow: Metallurgiya, 1997. 431 p.
4. Smirnov A. N., Savchenko I. A., Turchin M. Yu. Preparation of Bakalsk ore body high-magnesian siderites for metallurgical production by pyroand hydrometallurgy. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. Seriya «Metallurgiya». 2016. Vol. 16. No. 3. pp. 63–69.
5. Kolokoltsev V. M., Bigeev V. A., Klochkovsky S. P., Smirnov A. N., Bessmertnykh А. S. Application of pyro- and hydrometallurgy methods for processing of siderite ores with increased magnesium oxide content. Gornyi zhurnal. Chernye metally. Special issue. 2012. pp. 22–24.
6. Kolesnikov Yu. A., Bigeev V. A., Sergeev D. S., Dudchuk I. A. Possibility of usage of siderite ore for smelting of converter steel with increased cast iron share in metal charge. Chernye metally. 2017. No. 6. pp. 40–44.
7. Sheshukov O. Yu., Nekrasov I. V., Metelkin А. А. Siderite as coolant for converter melting of steel from high-carbon product. Stal. 2014. No. 3. pp. 22–24.
8. Bigeev V. A., Kolesnikov Yu. A. Prediction of converter steel melting technological parameters using siderite. Teoriya i tekhnologiya metallurgicheskogo proizvodstva. 2011. No. 11. pp. 30–36.
9. Rostovtsev S. T. Theory of metallurgical processes. Moscow: Metallurgizdat, 1956. 515 p.
10. Popel S. I., Sotnikov A. I., Boronenkov V. N. Theory of metallurgical processes. Moscow: Metallurgiya, 1986. 463 p.
11. Vignes A. Extractive Metallurgy 2. Metallurgical Reaction Processes. London: Ltd, 2011. 355 p.
12. Geld P. V. Mechanism of oxides reduction by solid carbon. Uspekhi khimii. 1957. Vol. XXVI. Issue. 9. pp. 1070–1086.
13. Chufarov G. I., Zhuravleva M. G., Balakirev V. F., Men A. I. The state of theory for oxide metals reduction. Collection: Mechanism and kinetics for metals reduction. Moscow: Nauka, 1970. pp. 7–15.
14. Chufarov G. I., Men A. I., Balakirev V. F. Thermodynamics of oxide metals reduction processes. Moscow: Metallurgiya, 1970. 399 p.
15. Rostovtsev S. T., Simonov V. K., Ashin A. K., Kostelov O. L. Mechanism of oxide metals carbothermic reduction. Collection: Mechanism and kinetics for metals reduction. Moscow: Nauka, 1970. pp. 24–31.
16. Kulikov I. S. Mechanism of iron, manganese, silicon and chrome oxide reduction. Collection: Mechanism and kinetics for metals reduction. Moscow: Nauka, 1970. pp. 19–24.
17. Elyutin V. P., Pavlov Yu. A., Polyakov V. P., Sheboldaev B. V. Interaction of metals oxides with carbon. Moscow: Metallurgiya, 1976. 359 p.
18. Ryabchikov I. V. Interaction of carbon with metals oxides. Khimiya tverdogo topliva. 1968. No. 5. pp. 89–99.
19. Ryabchikov I. V., Mizin V. G., Yarovoy K. I. Chemism of iron and chrome reduction from carbon oxides. Stal. 2013. No. 6. pp. 30–33.
20. Roshchin V. E., Salikhov S. P., Povolotsky A. D. Solid-phase preliminary reduction of iron - the basis of non-waste technologies for processing of complex ores and anthropogenic wastes. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. Seriya: Metallurgiya. 2016. Vol. 16. No. 4. pp. 78–86.
21. Salikhov S. P., Bryndin S. A. Separation of metal at solid-phase iron reduction from one-metal and complex ores. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. Seriya: Metallurgiya. 2012. No. 39 (298). pp. 118–121.
22. Alkac D., Atalay Ü. Kinetics of thermal decomposition of Hekimhan–Deveci siderite ore samples. International Journal of Mineral Processing. 2008. Vol. 87, No. 3–4. pp. 120–128.
23. Roshchin V. E. et al. Role of a silicate phase in the reduction of iron and chromium and their oxidation with carbide formation during the manufacture of carbon ferrochrome. Russian Metallurgy (Metally). 2016. Vol. 2016. No. 11. pp. 1092–1099.
24. Bryndin S. A., Salikhov S. P. Estimation of possibility for co-injection of magnesium oxide in slag and freshly reduced iron in liquid metal. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. Seriya: Metallurgiya. 2013. Vol. 13. No. 1. pp. 179–181.
25. Roshchin V. E., Bryndin S. A., Salikhov S. P., Roshchin A. V. Technology and equipment for direct complex processing of lump siderite ore at steel production. Problemy chernoy metallurgii i materialovedeniya. 2016. No. 1. pp. 22–27.
26. Roshchin V. E., Salikhov S. P., Roshchin A. V., Bryndin S. A. Production of iron-reach magnesia flux and first-born iron by metallization of lump siderite ore. Novye ogneupory. 2016. No. S3. pp. 24–25.