Nosov Magnitogorsk State Technical University (Magnitogorsk, Russia):

R. R. Dema, Cand. Eng., Associate Prof., Dept. of Machines and Technologies for Metal Forming and Mechanical Engineering, E-mail: demarr78@mail.ru

National University of Science and Technology “MISiS”, Novotroitsk branch (Novotroitsk, Russia):
A. N. Shapovalov, Cand. Eng., Associate Prof., Head of Dept. of Metallurgical Technologies and Equipment, E-mail: alshapo@misis.ru

South Ural State University (Chelyabinsk, Russia):

S. N. Baskov, Associate Prof., Dept of Mechatronics and Automation, E-mail: sbaskov@mail.ru

The results of the analysis of production data on the operation of blast furnace No. 1 (useful volume 1007 m³) of Ural Steel JSC for the period from 2013 to 2018 are presented. During this period, pellets from the Mikhailovsky GOK were used with varying degrees of fluxing: pellets of natural basicity in the ratio of CaO/SiO₂ equal to 0.08 ± 0.02 units. (2013-2015) and partially fluxed pellets with a basicity of 0.52 ± 0.05 units. (from 2016 to the present). It has been established that the effectiveness of the use of pellets of various basicities is determined by their behavior in the blast furnace and depends on the proportion of pellets in the iron ore part of the charge. The gas-dynamic conditions of the smelting worsen with an increase in the proportion of pellets in the charge, which is accompanied by an increase in the specific pressure drop and forces the flow rate to be adjusted. There is an optimal level of specific pressure drop (53–55 Pa per 1 m³ of blast per minute) for the operating conditions of blast furnace No. 1 of Ural Steel, which ensures the optimum combination of the melting characteristics. Deviation from the optimal level of pressure drop leads to an increase in coke rate and a decrease in the degree of CO use, which is associated with gas distribution disturbance. Due to the increase in high-temperature properties, the replacement of non-fluxed pellets with off-fluxed pellets improves the gas-dynamic conditions in the lower part of the mine (in the cohesive zone). This leads to a decrease in the total pressure drop and specific pressure drop at a constant flow rate of the blast, and is a reserve for melting intensification. To minimize coke rate and maintain the high-performance operation of blast furnaces of Ural Steel JSC, it is necessary to work on 40–45 % of fluxed or 20–25 % acid pellets in a charge. An increase in pellet consumption while maintaining the efficiency of blast-furnace smelting is possible only if their high-temperature properties are improved. The improvement of these properties is possible as a result of optimizing the basicity and increasing the MgO content, which affects the structure and properties of the silicate bond.
This work is carried out within a framework of the government order (No. FZRU-2020-0011) of the Ministry of Science and Higher Education of the Russian Federation.

1. Kurunov I. F. Blast furnace process is there an alternative? Metallurg. 2012. No. 4. pp. 40–44.
2. Iron metallurgy: textbook for universities 3^rd edition revised and supplemented. Edited by Yusfin Yu. S. Moscow: IKTs "Akademkniga", 2004. 774 p.
3. Gao Q., Shen Y., Wei G., Jiang X., Shen F. Diffusion behavior and distribution regulation of MgO in MgO-bearing pellets. International Journal of Minerals, Metallurgy, and Materials. 2016. Vol. 23, Iss. 9. pp. 1011–1018.
4. Puzakov P. V., Kozub A. V., Ugarov A. A., Efendiev N. T., Lavrinenko A. A. et al. Technological parameters determining physical-chemical properties and required quality of green pellets at the roasting machine No. 3 of PJSC "Mikhailovsky GOK". CIS Iron and Steel Review. 2017. Vol. 14. pp. 4–8.
5. Lu L., Pan J., Zhu D. 16 – Quality requirements of iron ore for iron production. Iron Ore: Mineralogy, Processing and Environmental Sustainability. 2015. pp. 475–504.
6. Babich A., Senk D. 17 – Recent developments in blast furnace iron-making technology. Iron Ore: Mineralogy, Processing and Environmental Sustainability. 2015. pp. 505–547.
7. Korotich V. I., Frolov Yu. А., Bezdezhskiy G. N. Agglomeration of ore materials: Scientific edition. Ekaterinburg: UGTU-UPI, 2003. 400 p.
8. Dmitriev A. N., Vitkina G. Yu., Chesnokov Yu. A., Petukhov R. V. Iron Ore Materials and Coke Quality Characteristics and Quantitative Indicators of Blast Furnace Smelting. IFAC Proceedings. 2013. Vol. 46, Iss. 16. pp. 307–311.
9. Malysheva Т. Ya., Dolitskaya О. А. Petrography and mineralogy of iron ore raw materials: textbook for universities. Moscow: MISiS, 2004. 424 p.
10. Lu L., Ishiyama O. 14 – Iron ore sintering. Iron Ore: Mineralogy, Processing and Environmental Sustainability. 2015. pp. 395–433.
11. Gustafsson G., Häggblad H.-Å., Jonsén P., Marklund P. Determination of bulk properties and fracture data for iron ore pellets using instrumented confined compression experiments. Powder Technology. 2013. Vol. 241. pp. 19–27.
12. Mróz J. Non‐isothermal reduction as a method of determining the softening — melting temperature of iron‐ore pellets and sinters. Steel Research. 1998. Vol. 69, Iss. 12. pp. 465–468.
13. Sheng-li Wu, Xiao-qin Liu, Qi Zhou et al. Low Temperature Reduction Degradation Characteristics of Sinter, Pellet and Lump Ore. Journal of Iron and Steel Research, International. 2011. Vol. 18. Iss. 8. pp. 20–24.
14. Iljana M., Kemppainen A., Paananen T. et al. Effect of adding limestone on the metallurgical properties of iron ore pellets. International Journal of Mineral Processing. 2015. Vol. 141. pp. 34–43.
15. Dwarapudi S., Sekhar C., Paul I. et al. Effect of fluxing agents on reduction degradation behaviour of hematite pellets. Ironmaking & Steelmaking. 2015. Vol. 43, Iss. 3. pp. 180–191.
16. Pavlov A. V., Onorin O. P., Spirin N. A., Polinov А. А. Operation of blast furnaces of OJSC MMK with a high proportion of pellets in the charge. Part 1. Metallurg. 2016. No. 6. pp. 36–42.
17. Lingyun Yi, Zhucheng Huang, Tao Jiang et al. Iron ore pellet disintegration mechanism in simulated shaft furnace conditions. Powder Technology. 2017. Vol. 317. pp. 89–94.
18. Umadevi T., Kumar A., Karthik P. et al. Characterisation studies on swelling behaviour of iron ore pellets. Ironmaking & Steelmaking. 2018. Vol. 45. No. 2. pp. 157–165.
19. Yang J.-L., Tan S.-Q., Wang Z.-P. Increase pellet proportion to optimize burden composition of BF. Kang T’ieh / Iron and Steel (Peking). 2005. Vol. 40, Iss. 10. pp. 13–17.
20. Sibagatullin S. K., Mayorova T. V. Increase in the gas flow activity in the BF with an increase in the total pressure drop along the height. Vestnik Magnitogorskogo gosudarstvennogo tekhnicheskogo universiteta imeni G. I. Nosova. 2011. No. 1. pp. 14–16.
21. Ovchinnikova E. V., Shapovalov А. N. Influence of the blast mode parameters on the efficiency of blast-furnace smelting in the conditions of JSC Ural Steel. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. Seriya: Metallurgiya. 2013. Vol. 13. No. 1. pp. 61–67.
22. Zhaoyang Li, Shibo Kuang, Sida Liu et al. Numerical investigation of burden distribution in ironmaking blast furnace. Powder Technology. 2019. Vol. 353. pp. 385–397.
23. Gao Q., Shen F., Wei G. et al. Effects of MgO Containing Additive on Low-Temperature Metallurgical Properties of Oxidized Pellet. Journal of Iron and Steel Research International. 2013. Vol. 20, Iss. 7. pp. 25–28.
24. Shen F., Gao Q., Jiang X. et al. Effect of magnesia on the compressive strength of pellets. Int. Journal Miner. Metall. Mater. 2014. Vol. 21, Iss. 5. pp. 431–437.
25. Qing G. L., Wang C. D., Hou E. J. et al. Compressive strength and metallurgical property of low silicon magnesium pellet. Journal of Iron and Steel Research. 2014. Vol. 26, Iss. 4. pp. 7–12.
26. Pal J., Arunkumar C., Rajshekhar Y. Development on iron ore pelletization using calcined lime and MgO combinedflux replacing limestone and bentonite. ISIJ International. 2014. Vol. 54, Iss. 10. pp. 2169–2178.
27. Ovchinnikova Е. V., Gorbunov V. B., Shapovalov А. N. et. al. Experimental studies of magnesia agglomerates using a flux based on magnesium silicate. Stal. 2018. No. 1. pp. 2–5.
28. Shapovalov A. N., Ovchinnikova E. V., Gorbunov V. B. et al. The effect of the composition of magnesia flux on the sinter structure and properties. IOP Conf. Series: Materials Science and Engineering. 2019. Vol. 625. 012009.
29. Shapovalov A. N., Ovchinnikova E. V., Gorbunov V. B. The use of magnesia fluxes of the Khalilovo deposit in the sinter production. Izvestiya vysshikh uchebnykh zavedeniy. Chernaya Metallurgiya. 2019. Vol. 62. No. 7. pp. 548–556.
30. Wang R., Zhang J., Liu Z. et al. Interaction between iron ore and magnesium additives during induration process of pellets. Powder Technology. 2020. Vol. 36. pp. 894–902.