Saint Petersburg Mining University (Saint Petersburg, Russia):

Piirainen V. Yu., Professor, Doctor of Engineering Sciences, piraynen@gmail.com
Mikhailov A. V., Professor, Doctor of Engineering Sciences, Mikhaylov_AV@pers.spmi.ru
Barinkov V. M., Graduate Student, barinkov1996@yandex.ru
Starovoitov V. N., Assistant, bob.star2016@yandex.ru

This paper covers the problem of alumina production waste recycling with the use of peat-based compounds as a carbon-containing reducing agent. The purpose of this study is to find a suitable technical solution to use red mud for the direct reduction of iron, as well as to develop and test a red mud-containing composite material to be used as a charge. The paper presents a method for carbothermic reduction of iron from a charge containing red mud. Certain test charge compounds and respective applicable heat treatment conditions were selected. In order to establish the iron oxide reduction mechanism and dynamics, the materials obtained were then tested and analyzed using X-ray diffraction, phase and chemical analysis methods. A spectral analysis of individual powder phases has demonstrated an iron content of up to 93 wt%, which indicates a high potential for subsequent direct metallurgical processing of the red mud-peat pellets. Since carbothermic reduction of iron generates magnetic materials even at low temperatures, this method may be regarded as one of the stages in magnetic separation of iron-containing raw materials. This paper successfully establishes and confirms the actual direct low-temperature carbothermic reduction of iron from a charge based on red mud and peat. According to the results of respective experimental studies, it has been preliminarily concluded that it is both technologically feasible and expedient to use red mud as a component in a respective red mud-peat charge for application as a raw material in the iron and steel industry.

1. Brichkin V. N., Vasilyev V. V., Nagornaya E. А., Gumenyuk A. M. Bauxite grade improvement through selective grinding. Obogashchenie Rud. 2017. No. 3. pp. 3–9. DOI: 10.17580/or.2017.03.01.
2. Zinoveev D., Petelin A., Grudinsky P., Zakunov A., Dyubanov V. Extraction of iron from Russian red mud by a carbothermic reduction and magnetic separation process. Materials Proceedings 3. 2021. No. 1. DOI: 10.3390/IEC2M-09247.
3. Vigneshwaran S., Uthayakumar M., Arumugaprabu V. Development and sustainability of industrial waste-based r edmud hybrid composites. Journal of Cleaner Production. 2019. Vol. 230. pp. 862–868.
4. Mukiza E., Zhang L., Liu X., Zhang N. Utilization of red mud in road base and subgrade materials: A review. Resources, Conservation and Recycling. 2019. Vol. 141. pp. 187–199.
5. Morgunov B. A., Bagin A. M., Kozeltsev M. L., Terentiev A. A. Problems of environmental safety of Russia in the light of the «green» growth concept. Ekologiya Cheloveka. 2017. Vol. 24, No. 4. pp. 3–11.
6. Lebedev A. B., Utkov V. A., Bazhin V. Y. Use of alumina production waste red mud during molten sulfur-containing slag granulation. Metallurgist. 2019. Vol. 63. pp. 727–732.
7. Cheremisina O. V., Cheremisina E. A., Ponomareva M. A., Fedorov А. Т. Sorption of rare earth coordination compounds. Zapiski Gornogo Instituta. 2020. Vol. 244. pp. 474–481.
8. Sizyakov V. M., Brichkin V. N. On the role of calcium bicarboaluminates in improving the technology of complex processing of nephelins. Zapiski Gornogo Instituta. 2018. Vol. 231. pp. 292–298.
9. Pyagay I. N. Experience of red mud processing with obtaining a number of valuable elements (Sc, Zr, Y) and iron-containing raw materials for the steel industry. Chernye Metally. 2019. No. 1. pp. 49–54.
10. Litvinenko V. S., Kozlov A. V., Stepanov V. A. Hydrocarbon potential of the Ural-African transcontinental oil and gas belt. Journal of Petroleum Exploration and Production Technology. 2017. Vol. 7. pp. 1–9.
11. Mashentseva I. A., Vlasova O. S. Analysis of the negative environmental impact of aluminum production enterprises. Inzhenernyi Vestnik Dona. 2017. No. 1. p. 83.
12. Sizyakov V. M., Bazhin V. Y., Sizyakova E. V. Feasibility study of the use of nepheline-limestone charges instead of bauxite. Metallurgist. 2016. Vol. 59. pp. 1135–1141.
13. Bazhin V. Yu., Brichkin V. N., Sizyakov V. M., Cherkasova M. V. Pyrometallurgical treatment of a nepheline charge using additives of natural and technogenic origin. Metallurgist. 2017. Vol. 1. pp. 147–154.
14. Largin I. F., Korchunov S. S., Malkov L. M. Reference book on peat. Moscow: Nedra, 1982. 760 p.
15. Bizhanov A., Kurunov I., Dalmia Y., Mishra B., Mishra S. Blast furnace operation with 100% extruded briquettes charge. ISIJ International. 2015. Vol. 55, No. 10. pp. 175–182.
16. Grudinsky P., Zinoveev D., Yurtaeva A., Kondratiev A., Dyubanov V., Petelin A. Iron recovery from red mud using carbothermic roasting with addition of alkaline salts. Journal of Sustainable Metallurgy. 2021. Vol. 7. pp. 858–873.
17. Trushko V. L., Utkov V. A., Bazhin V. Yu. Relevance and possibilities of complete processing of red mud of alumina production. Zapiski Gornogo Instituta. 2017. Vol. 227. pp. 547–553.
18. Khalifa A. E., Bazhin V. Y., Kuskova Y. V., Abdelrahim A. M., Yasser M. Z. Ahmed. Study the recycling of red mud in iron ore sintering process. Journal of Ecological Engineering. 2021. Vol. 22. pp. 191–201.
19. Chen R., Cai, G., Dong X., Mi D., Puppala A. J., Duan W. Mechanical properties and micro-mechanism of loess roadbed filling using by-product red mud as a partial alternative. Construction and Building Materials. 2019. Vol. 216. pp. 188–201.
20. Yoon K., Jung J. M., Cho D. W., Tsang D. C., Kwon E. E., Song H. Engineered biochar composite fabricated from red mud and lipid waste and synthesis of biodiesel using the composite. Journal of Hazardous Materials. 2019. Vol. 366. pp. 293–300.

21. Cherniak L., Varshavets P., Dorogan N. Development of a mineral binding material with elevated content of red mud. Technology Audit and Production Reserves. 2017. No. 3/3. pp. 22–28.
22. Fedorova E., Pupysheva E., Morgunov V. Modelling of red-mud particle-solid distribution in the feeder cup of a thickener using the combined CFD-DPM approach. Symmetry. 2022. Vol. 14, No. 11. DOI: 10.3390/sym14112314.
23. Vind J., Malfliet A., Blanpain B., Tsakiridis P. E., Tkacyk A. H., Vassiliadou V., Panias D. Rare earth element phases in bauxite residue. Minerals. 2018. Vol. 8, Iss. 2. DOI: 10.3390/min8020077.
24. Paramguru R., Rath P., Misra V. Trends in red mud utilization — A review. Mineral Processing and Extractive Metallurgy Review. 2005. Vol. 26, Iss. 1. pp. 1–29.
25. Piirainen V. Yu., Mikhaylov A. V., Barinkova A. A. The concept of modern ecosystem for the Ural Aluminium Smelter. Tsvetnye Metally. 2022. No. 7. pp. 39-45. DOI: 10.17580/tsm.2022.07.04.
26. Anameric B., Kawatra S. K. Properties and features of direct reduced iron. Mineral Processing and Extractive Metallurgy Review. 2007. Vol. 28, Iss. 1. pp. 59–116.
27. Sadangi J. K., Das S. P., Tripathy A., Biswal S. K. Investigation into recovery of iron values from red mud dumps. Separation Science and Technology. 2018. Vol. 53, Iss. 14. pp. 2186–2191.
28. Tripathy A., Bagchi S., Chaudhry S., Sadangi J. K., Das S. P., Biswal S. K. Red mud: avaluable source for iron recovery. Journal of Sustainable Planet. 2017. Vol. 8, Iss. 1. pp. 38–44.
29. Archambo M. S., Kawatra S. K. Red mud: fundamentals and new avenues for utilization. Mineral Processing and Extractive Metallurgy Review. 2020. Vol. 42. pp. 427–450.
30. Zinoveev D. V., Grudinskii P. I., Dyubanov V. G., Kovalenko L. V., Leont'ev L. I. Global recycling experience of red mud — A review. Part I: Pyrometallurgical methods. Izvestiya VUZov. Chernaya Metallurgiya. 2018. Vol. 61, No. 11. pp. 843–858.
31. Baake E., Shpenst V. A. Recent scientific research on electrothermal metallurgical processes. Zapiski Gornogo Instituta. 2019. Vol. 240. pp. 660–668.
32. Zhang R., Zheng S., Ma S., Zhang Y. Recovery of alumina and alkali in Bayer red mud by the formation of andradite-grossularhydrogarnet in hydrothermal process. Journal of Hazardous Materials. 2011. Vol. 189. pp. 827–835.
33. Wei D., Xia J., Peng Y., Shen S.-Y., Chen T. Iron extraction from red mud using roasting with sodium salt. Mineral Processing and Extractive Metallurgy Review. 2019. Vol. 42. pp. 153–161.
34. Utkov V. A., Sizyakov V. M. Modern questions of the metallurgical processing red mud. Zapiski Gornogo Instituta. 2013. Vol. 202. pp. 39–43.
35. Brichkin V. N., Kurtenkov R. V. Dealkylation of alumina production red mud on the basis of hydro chemical processing. Freiberg Online Geology. 2015. Vol. 40. pp. 189–194.
36. Pat. 2479648 Russian Federation.