Saint-Petersburg Mining University, Saint-Petersburg, Russia:

B. A. Kozyrev, Lead Engineer, e-mail: kozirev-48@yandex.ru
V. M. Sizyakov, Professor, Doctor of Engineering Sciences

REC “Mekhanobr-Tekhnika”, Saint-Petersburg, Russia:
V. A. Arsentyev, Chief Researcher, Doctor of Engineering Sciences

Due to the known limitations of economic nature, the global production complex continues to focus on the most accessible technologies of alumina production, leading to the accumulation of solid waste (red mud), which has created the well-known problem of their processing, and its scale and importance continue to grow in connection with the steady increase in the world volume of aluminum production and consumption. The priority of rational use of natural resources allows us to speak about the preference of principles of deep and waste-free processing of mineral raw materials, which are fully applicable to the processing of red mud, as accumulated raw materials of technogenic origin. At the same time, the key point of this approach becomes the hierarchical division of components into groups of technological products, taking into account the processes that ensure this selective-group division. In this regard, the use of carboxylic acids is of notable interest, as they have a known selectivity to the main components of red mud, which allows to separate low-soluble components (iron and silicon compounds) from light and rare-earth metals with minimum consumption rates. An experimental study has shown that flow-through leaching of thermochemically prepared red mud using formic acid provides high and acceptable recoveries of sodium, calcium, scandium, and rare earth metals. This makes it affordable to use the cheapest method of apparatus-free leaching when implementing this approach on an industrial scale. Experimentally determined the differences in the sequence of elution of sodium, calcium, aluminum and rare-earth metals formates during flow leaching, which creates favorable conditions for concentrating components and separate processing of sampled solutions. The regime parameters of the process that provides complete precipitation of aluminum, scandium and rare earth metals during the neutralization of formate solution with milk of lime, resulting in the necessary prerequisites for further concentration of rare earth metals to obtain technologically significant product are determined.

The work was carried out with the financial support of the Russian Science Foundation under the Agreement No. 18-19-00577-П of April 28 2021 of grant for fundamental scientific research and exploratory scientific research.

1. Uryvaeva G. D. Cements from Sludge. Novosibirsk: Nauka. Sibirskoye otdeleniye, 1970. 154 p.
2. Complex Use of Low-Quality bauxite. Ed. by S. I. Kuznetsov, V. A. Drevyankin. Moscow: Metallurgy, 1972. 239 p.
3. Layner A. I., Eremin N. I., Layner Yu. A., Pevzner I. Z. Alumina Production. Moscow: Metallurgy, 1978. 344 p.
4. Shmorgunenko N. S., Korneev V. I. Complex Processing and Use of Dump Sludge of Alumina Production. Moscow: Metallurgy, 1982. 129 p.
5. Korneev V. I., Suss A. G., Tsekhovoy A. I. Red Mud. Properties, Warehousing, Application. Moscow: Metallurgy,
1991. 144 p.
6. Sabirzyanov N. A., Yatsenko S. P. Hydrochemical Methods of Complex Bauxite Processing. Ekaterinburg: IKhTT UrO RAN, 2006. 384 p.
7. 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. 547–553.
8. 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 Visshikh Uchebnykh Zavedenii. Chernaya Metallurgiya. 2018. Vol. 61, Iss. 11, pp. 843–858.

9. Brichkin V. N., Vasiliev V. V., Bormotov I. S., Maksimova R. I. Production and Recycling of Limes in Integrated Mineral Processing. Gornyi Zhurnal. 2021. No. 11. pp. 88–94. DOI: 10.17580/ gzh.2021.11.12
10. Zhao Qiuyue, Zhang Zimu, Zhu Xiaofeng, Liu Yan, Lu Guozhi, Zhang Ting’an, Wang Shuchan. Economic Analysis of Producing Alumina with Low-Grade Bauxite (Red Mud) by Calcification-Carbonization Method. In book: Light Metals. 2014. pp. 165–168.
11. Sizyakov V. M., Brichkin V. N., Kurtenkov R. V. Increasing all-Round Utilization of Nepheline Raw Materials Through Belite Sludge Soda Conversion. Obogashchenie Rud. 2016. No. 1. pp. 54–59. DOI: 10.17580/or.2016.01.09
12. Brichkin V. N., Vasilyev V. V., Nagornaya E. A., Gumenyuk А. М. Bauxite Grade Improvement Through Selective Grinding. Obogashchenie Rud. 2017. No. 3. pp. 3–9. DOI: 10.17580/or.2017.03.01
13. Kozhevnikov G. N., Vodopyanov A. G., Pankov V. A., Kuzmin B. K. Joint Complex Processing of Bauxites and Red Muds. Tsvetnye Metally. 2013. No. 12. pp. 36–38.
14. Budon S. V., Ibragimov A. T., Mikhailova O. I., Medvedev V. V. Hydrochemical Processing of Red Sludge «Aluminium of Kazakhstan» JSC. Journal of Mining Institute. 2013. Vol. 202. pp. 44–47.
15. Archambo M. S., Kawatra S. K. Red Mud: Fundamentals and New Avenues for Utilization. Mineral Processing and Extractive Metallurgy Review. 2020. No. 42. pp. 427–450.
16. Brichkin V. N., Dubovikov O. A., Nikolaeva N. V., Besedin A. A. Red Mud Dewatering and Basic Trends in Its Recycling. Obogashchenie rud. 2014. No. 1. pp. 44–48.
17. Besedin A. A., Utkov V. A., Brichkin V. N., Sizyakov V. M. Red Mud Sintering. Obogashchenie Rud. 2014. No. 2. pp. 28–31.
18. Khalifa A. A., Bazhin V. Y., Ustinova Y. V. 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.
19. Khalifa A. A., Utkov V. A., Brichkin V. N. Red Mud Effect on Dicalcium Silicate Polymorphism and Sinter Self-Destruction Prevention. Proceedings of Irkutsk State Technical University. 2020. Vol. 24, Iss. 1. pp. 231–240.
20. Khalifa A. 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, Iss. 6. pp. 191–201.
21. 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.
22. Tripathy A., Bagchi S., Chaudhry S., Sadangi J. K., Das S. P., Biswal S. K. Red Mud: a Valuable Source for Iron Recovery. Journal of Sustainable Planet. 2017. Vol. 8, Iss. 1. pp. 38–44.
23. Wei Dingyi, Xia Junhui, Peng Yang, Shen Si-Yue, Chen Tao. Iron Extraction from Red Mud using Roasting with Sodium Salt. Mineral Processing and Extractive Metallurgy Review. 2019. Vol. 42, Iss. 3. pp. 153–161.
24. Mohapatra A., Bose P., Pandit S. S., Kumar S., Alex T. C. Bulk Utilization of Red Mud in Geopolymer Based Products. Advances in Sciences and Engineering. 2020. Vol. 12, Iss. 2. pp. 86–91.
25. Vigneshwaran S., Uthayakumar M., Arumugaprabu V. Development and Sustainability of Industrial Waste-Based Red Mud Hybrid Composites. Journal of Cleaner Production. 2019. Vol. 230. pp. 862–868.
26. 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.
27. 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
28. Brichkin V. N., Kurtenkov R. V. Dealkylation of Alumina Production Red Mud on the Basis of Hydro Chemical Processing. Freiberg Online Geology. 2015. No. 40. pp. 189–194.
29. Pyagay I. N., Kremcheev E. A., Pasechnik L. A., Yatsenko S. P. Carbonization Processing of Bauxite Residue as an Alternative Rare Metal Recovery Process. Tsvetnye Metally. 2020. No. 10. pp. 56–63. DOI: 10.17580/tsm.2020.10.08
30. Lilio u A.-M., Saru M.-L., Veksha A., Lisak G., Giannis A. Selective Leaching of Scandium and Yttrium from Red Mud Induced by Hydrothermal Treatment. Journal of Chemical Technology & Biotechnology. 2021. Vol. 96, Iss. 9. pp. 2620–2629.
31. Akhmadieva N. K., Abdulvaliyev R. A., Ata Akchil, Gladyshev S. V., Kuldeev E. I. Red Mud of Alumina Production as Potential Raw Material for Rare Earth Elements Recovery. Review. Kompleksnoye Ispol’zovaniye Mineral’nogo Syr’ya. 2016. Vol. 299, Iss. 4. pp. 98–104.
32. Yatsenko S. P., Sabirzyanov N. A., Pasechnik L. A., Pyagay I. N., Skachkov V. M. Hydro Chemical Reprocessing of Alumina Industry Mud. Ecology and Industry of Russia. 2012. No. 11. pp. 10–13.
33. Pyagay I. N. The Block Processing of Red Mud of Alumina Production. Tsvetnye Metally. 2016. No. 7. pp. 43–51. DOI: 10.17580/tsm.2016.07.05
34. Pyagai 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. 49–54.
35. Brichkin V. N., Fedorov A. T. Thermodynamic Modelling of Ion Equilibria in the Na₂O – Al₂O₃ – H₂O System with Gibbsite. Tsvetnye Metally. 2022. No. 3. pp. 74–81. DOI: 10.17580/tsm.2022.03.083
36. Brichkin V. N., Fedorov A. T. Сalculation and Experimental Determination of Equilibrium Composition of Liquors in Certain Instances of the Na₂O – K₂O – Al₂O₃ – H₂O System. Tsvetnye Metally. 2022. No. 7. pp. 33–38. DOI: 10.17580/tsm.2022.07.03
37. Kozyrev B. A., Sizyakov V. M. Heap Leaching of Red Mud by the Formate Method. Obogashchenie Rud. 2021. No. 4. pp. 40–45. DOI: 10.17580/or.2021.04.07