Empress Catherine II St. Petersburg Mining University (St. Petersburg, Russia):

I. N. Pyagay, Dr. Eng., Senior Researcher, Director of Scientific Center “The problems of processing of mineral and
technogenic resources”, e-mail: igor-pya@yandex.ru
A. B. Lebedev, Cand. Eng., Researcher, Scientific Center “The problems of processing of mineral and technogenic resources”, e-mail: 2799957@mail.ru

Laboratorial production of agglomerate with basicity CaO/SiO₂ = 1.3-1.5 is accompanied by its spontaneous friability, what leads to forming of visible cracks in agglomerate. When studying the influence of these sintering parameters on agglomerate strength, it is necessary to take into account content of not assimilated calcium oxides in sinter. Strength binding of agglomerate is formed on the base of calcium ferrites. Investigations were conducted on aluminium oxide of PA grade, Fe₂O₃, CaCO₃ of PA grade, aqueous silicic acid of P grade. Stability of sinters for above-mentioned systems was determined visually and using high-frequency method. In the first case the hightemperature Tamman furnace is used, where briquetted samples are put in a platinum cup and they are heated up to the temperature 1300 °C. Then, after 5 minutes holding for homogenization, the samples are cooled slowly together with the furnace to the temperature 500 °C. To determine the temperature of β→γ transition of dicalcium silicate, dielectric permeability is measured; it reacts on structural changes which cause variation of density. The boundary of sinters stability is situated along the line which is close to galenite. The part of aluminium oxide interacts with dicalcium ferrite and forms solid solutions together with complete Fe replacement by Al in dicalcium ferrite. Stable sinters are characterized by monotonous variation of dielectric losses and capacity in the conditions of complete dicalcium silicate binding by aluminium oxide. It was established that monocalcium ferrite does not form new compounds with aluminium oxide, which completely interacts with dicalcium silicate. The stable samples of the system CaFe₂O₄–Ca₂SiO₄–Al₂O₃ are characterized by increase of alumosilicate amount and decrease of dicalcium silicate amount. When Ca₂SiO₄ content decreases from 45 % to 28 %, the temperature reduces from 390–405 °C до 265–275 °C. Agglomerate containing 7 % of alumina practically does not contain free calcium oxide, what removes the cause of stresses appearing in the sinter. As a result of stabilization of ferrite-calcium sinter via replacement of silicon module by aluminium one, compression strength value increases up to 235 daN for a briquette.

1. Frolov Yu. A. Sintering. Technology. Heat engineering. Management. Ecology. Moscow : Metallurgizdat. 2016. 672 p.
2. Bersenev I. S., Petryshev A. Yu., Kolyasnikov A. Yu., Milokhin E. A., Semenov O. A., Isaenko G. E. Improving the Sinter at PAO NLMK. Steel in Translation. 2018. Vol. 48. No. 9. pp. 585–592.
3. Bersenev I. S., Gorbachev V. A., Klein V. I., Petryshev A. Yu., Yaroshenko Yu. G. To the problem of connection between ultimate stresses in agglomerate and its strength in rotating drum. Stal. 2013. No. 1. pp. 6-8.
4. Bobkov V. I., Dli M. I., Fedulov A. S. Imitating simulation of the drying process of sinters from wastes of apatite-nepheline ores. Izvestiya Sankt-Peterburgskogo gosudarstvennogo tekhnologicheskogo institute (tekhnicheskogo universiteta). 2020. No. 55. pp. 109-115.
5. Su Z., Li L., Liu Z., Huang C., Wang D., Wang T. Fabrication, microstructure, and hydration of nano β-Ca₂SiO₄ powder by coprecipitation method. Construction and Building Materials. 2021. Vol. 296. p. 123737. DOI: 10.1016/j.conbuildmat.2021.123737
6. Cheng S., Shevchenko M., Hayes P. C., Jak E. Experimental Phase Equilibria Studies in the FeO-Fe₂O₃-CaO-SiO₂ System in Air: Results for the Iron-Rich Region. Metallurgical and Materials Transactions B. 2020. Vol. 51. No. 4. pp. 1587–1602.
7. Malysheva T. Ya., Dolitskaya O. A. Petrography and mineralogy of iron ore raw materials. A manual for high schools. Moscow : MISiS. 2004. 424 p.
8. Puzanov V. P., Kobelev V. A. Introduction in the technologies of metallurgical structure forming. Ekaterinburg : UrO RAN. 2005. 501 p.
9. Nechkin G. A. Study of the influence of mineral structure forming on metallurgical properties of iron ore agglomerates. Dissertation … of a Candidate of Technical Sciences. Institute of Metallurgy of the Ural branch of RAS. Ekaterinburg. 2015. 141 p.
10. Efimenko G. G., Kovalev D. A. Management of the process of agglomerate structure forming for its strengthening. Izvestiya AN SSSR. Metally. 1966. No. 6. pp. 3-10.
11. Jin J , Liu X., Yuan S., Gao P., Li Y., Zhang H., Meng X. Innovative utilization of red mud through co-roasting with coal gangue for separation of iron and aluminum minerals. Journal of Industrial & Engineering Chemistry. 2021. Vol. 98. pp. 298–307. DOI: 10.1016/j.jiec.2021.03.038
12. Grudinskii P. I., Dyubanov V. G., Zinoveev D. V., Zheleznyi M. V. Solid-Phase Reduction and Iron Grain Growth in Red Mud in the Presence of Alkali Metal Salts. Russian Metallurgy (Metally). 2018. No. 11. pp. 1020–1026. DOI: 10.1134/S0036029518110071
13. Korzhaeva E. E., Voishchev A. E., Khoshafyan S. O., Bataeva F. A., Buntov V. V., Iskanderov R. D. Study of the effect of receipt parameters on forming a joint structure and properties of heavy concrete. Vestnik Evraziyskoy nauki. 2019. Vol. 11. No. 6. p. 9.
14. Kudinova A. A., Poltoratckaya M. E., Gabdulkhakov R. R., Litvinova T. E., Rudko V. A. Parameters influence establishment of the petroleum coke genesis on the structure and properties of a highly porous carbon material obtained by activation of KOH. Journal of Porous Materials. 2022. Vol. 11. No. 6. p. 9.
15. Mardashov D. V., Bondarenko A. V., Raupov I. R. Design procedure of technological parameters of non-Newtonian fluids injection into an oil well during workover operation. Journal of Mining Institute. 2022. DOI: 10.31897/PMI.2022.16.
16. Pavlovets V. M. Use of pore-forming additives of plant origination in manufacture of iron-containing agglomerated raw material. Vestnik Sibirskogo gosudarstvennogo industrialnogo universiteta. 2019. No. 3 (29). pp. 14-20.
17. Trushko V. L., Utkov V. A., Bazhin V. Y. Topicality and Possibilities for complete processing of red mud of aluminous production. Journal of Mining Institute. 2017. Vol. 227. pp. 41–47.
18. Polyakov A., Gorlanov E., Mushihin E. Analytical Modeling of Current and Potential Distribution over Carbon and Low-Consumable Anodes during Aluminum Reduction Process. Journal of The Electrochemical Society. 2022. Vol. 169. DOI: 10.1149/1945-7111/ac6a16
19. Zubkova O. S., Alexeev A. I., Sizyakov V. M., Polyanskiy A. S., Research of suxfuric acid salts influence on sedimentation process of a clay suspension. ChemChemTech. 2022. Vol. 65. No. 1. pp. 44–49. DOI: 10.6060/ivkkt.20226501.6447
20. Khalifa A., Bazhin V., Kuskova Y., Abdelrahim A., Ahmed Y. Study the Recycling of Red Mud in Iron Ore Sintering Process. Journal of Ecological Engineering. 2021. Vol. 22. No. 6. pp. 191–201. DOI: 10.12911/22998993/137966
21. Shao F., Zhuang Y., Ni J., Sheng J., Zhao H., Tao S., Yang K. Comparison of the microstructural characteristics and electrical properties of plasma sprayed Al₂O₃ and Al₂O₃–Ca₂SiO₄ coatings immersed in deionized water. Surface and Coatings Technology. 2021. Vol. 422. p. 127530. DOI: 10.1016/j.surfcoat.2021.127530
22. Karpova K. S., Karpov A. V. Solid phase reduction of iron oxides in laboratorial conditions. Sovremennye materialy, tekhnika i tekhnologii. 2018. No. 1 (16). pp. 27–32.
23. Krylova S. A., Sysoev V. I., Alekseev D. I., Sergeev D. S., Dudchuk I. A. Physical-chemical parameters of high-magnesial siderites. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta, Seriya: Metallurgiya. 2017. Vol. 17. No. 2. pp. 13-21.
24. Ortega J. M., Cabeza M., Tenza-Abril A. J., Real-Herraiz T., Climent M. Á., Sánchez I. Effects of Red Mud Addition in the Microstructure, Durability and Mechanical Performance of Cement Mortars. Applied Sciences. 2019. Vol. 9. No. 5. p. 984. DOI: 10.3390/app9050984
25. Boikov A. V., Savelev R. V., Payor V. A., Erokhina O. O. The control method concept of bulk material behaviour in the pelletizing drum for improving the results of DEM-modeling. CIS Iron and Steel Review. 2019. Vol. 17. pp. 10–13.
26. Omelchenko I. N., Kuznetsov A. A. New tendencies on the iron ore market. Gumanitarnyi vestnik. 2017. No. 8 (58). p. 7.
27. Maksimov L. I., Mironov V. V. Improvement of manufacturing technology for metallic iron powders from a sediment of deferrization station. Vestnik Tomskogo gosudarstvennogo arkhitekturnostroitelnogo universiteta. 2020. Vol. 22. No. 2. pp. 162–173.
28. Aydin S., Aydin M. E., Beduk F., Ulvi A. Removal of antibiotics from aqueous solution by using magnetic Fe₃O₄/red mudnanoparticles. Science of The Total Environment. 2019. Vol. 670. pp. 539–546. DOI: 10.1016/j.scitotenv.2019.03.205
29. Hoang M. D., Do Q. M., Le V. Q. Effect of curing regime on properties of red mud based alkali activated materials. Construction and Building Materials. 2020. Vol. 259. p. 119779. DOI: 10.1016/j.conbuildmat.2020.119779
30. Trushko V. L., Utkov V. A. Development of import subtituting technologies for increasing productivity of sintering machines and strength of agglomerates. Journal of Mining Institute. 2016. No. 221. p. 675. DOI: 10.18454/pmi.2016.5.675
31. Shiryaeva E. V., Podgorodetskiy G. S., Malysheva T. Ya., Detkova T. V., Gorbunov V. B. Influence of low-alkali red mud on composition and structure of agglomeration charge material made of iron ore concentrates with different genesis. Izvestiya vysshikh uchebnykh zavedeniy. Chernaya metallurgiya. 2015. Vol. 57. No. 9. pp. 13–17. DOI: 10.17073/0368-0797-2014-9-13-17
32. Sizyakov V. M., Brichkin V. N. On the role of calcium hydrocarboaluminates in improvement of the technology of complex processing of nephelines. Zapiski Gornogo instituta. 2018. Vol. 231. pp. 292–298. DOI: 10.25515/PMI.2018.3.292
33. Aleksandrov V. I., Vasilyeva M. A. Hydrotransport for condensed tailings of iron ore concentration at Kachkanarskiy GOK based on the results of pilot-industrial tests of hydraulic transport system. Zapiski Gornogo instituta. 2018. Vol. 233. pp. 471-479. DOI: 10.31897/PMI.2018.5.471
34. Sharikov Yu. V., Sharikov F. Yu., Titov O. V. Optimal control of annealing during the preparation of aluminum hydroxide and cement clinker in tubular rotary kilns. Theoretical Foundations of Chemical Engineering. 2017. Vol. 51. No. 4. pp. 503–507. DOI: 10.1134/S0040579517030125
35. Bazhin V. Y., Khalifa A. A., Shalabi M. E. K. Study of the kinetics of the process of producing pellets from red mud in a hydrogen flow. Journal of Mining Institute. 2022. Vol. 254. pp. 261-270. DOI: 10.31897/PMI.2022.18