Scientific and Industrial Company “Etalon”, Magnitogorsk, Russia:
I. R. Manashev, Cand. Eng., Deputy Director for Development of Production of Composite Materials, e-mail: mir@ntpf-etalon.ru

Nosov Magnitogorsk State Technical University, Magnitogorsk, Russia:
T. O. Gavrilova, Postgraduate student, e-mail: gavrilova_to@mail.ru

The effective processing of cyclone dust and screenings of ferroalloys, which are formed in significant quantities during the grinding and fractionation of ingots, remains an urgent problem for domestic ferroalloy plants. This paper shows the possibility of recycling finely dispersed ferroalloys by the method of self-propagating high-temperature synthesis (SHS) using the example of the production of nitrided ferrochromium during the processing of screenings of low-carbon ferrochromium. The possibility of SН-synthesis of commercial ferrochromium nitride of two grades: FeCrN 10 (sintered) and FeCrN 4PL (melted) is shown by nitriding in the combustion mode of FeCr powders with a particle size of 150-400 μm. It has been determined that a prerequisite for the successful nitriding of such powders in the combustion mode is their preheating to a temperature of 300-600 °C. In the case of preliminary heating of the initial material to a temperature of 300-350 °C, the product contains the maximum concentration of nitrogen (10.0-10.5 % N) and has a sintered structure, the main components of which are CrN and Cr2N nitrides (with a predominance of mononitride) and iron with dissolved chromium and nitrogen. With an increase in the heating temperature of the source material to 400-450 °C, the structure of the product becomes inhomogeneous, with the presence of sintered and melted areas, while the total nitrogen content decreases, and its local concentration in various parts of the briquette can vary significantly. With an increase of the heating temperature of the initial alloy to 500-600 °C, nitriding passes into a liquid-phase mode, such a product has a cast high-density structure consisting of chromium semi-nitride, iron and chromium-iron semi-nitride. The nitrogen content in this case is evenly distributed over the volume of the ingot and is in the range of 3.5-4.5 %. As a result of industrial tests of the synthesized ferrochromium nitride, the expediency of its use for alloying stainless nitrogen-containing steel has been shown.

1. Pavlov А. V., Ostrovskiy D. Ya., Aksenova V. V., Bishenov S. А. Current state of ferroalloy production in Russia and CIS countries. Izvestiya vuzov. Chernaya Metallurgiya. 2020. Vol. 63. No. 8. pp. 600–605.
2. Zhuchkov V. I., Romanova О. А., Zayakin О. V., Sirotin D. V. Technogenic resources of the ferroalloy industry. Fundamental research and applied development of the processes of processing and disposal of technogenic formations: proceedings of the V Congress with international participation and the Conference of young scientists "TECHNOGEN-2021". Ekaterinburg: UrO RAN, 2021. pp. 36–40. DOI: 10.34923/technogen-ural.2021.20.31.001.
3. Pavlov S. V., Snitko Yu. P., Plyukhin S. B. Waste and emissions from ferrosilicon production. Elektrometallurgiya. 2001. No. 4. pp. 22–28.
4. Teslev S. А., Tesleva Е. P. Method for processing small fractions of ferrosilicon. Innovative technologies and economics in mechanical engineering: Proceedings of the V International Scientific and Practical Conference in 2 volumes. Yurga Institute of Technology. Tomsk: Izdatelstvo Tomskogo politekhnicheskogo universiteta. 2014. Vol. 1. pp. 407–409.
5. Nabil Ghali S., Eissa M., El-Faramawy H., Ahmed A., Mattar T., Mishreky M. Production and application of advanced high nitrogen steel. International Conference on Science and Technology of Ironmaking and Steelmaking. Jamshedpur, India. 2013. Vol. 1.
6. Lei Wang, Yichen Li, Jialiang Ding, Qiang Xie et al. Problems in welding of high nitrogen steel: a review. Metals. 2022. Vol. 12, Iss. 8. 1273. DOI: 10.3390/met12081273.
7. Kaputkina L. M., Svyazhin A. G. High nitrogen steels with special functional properties. CIS Iron and Steel Review. 2014. Vol. 9. pp. 19–25.
8. Gasik М. I., Lyakishev N. P., Emlin B. I. Theory and technology of ferroalloys production. Moscow: Metallurgiya. 1988. 784 p.
9. Zhuravlev V. М., Pandurskiy М. V., Umarov К. et al. Improvement of the technology for the production of nitrided ferrochromium. Stal. 1976. No. 3. pp. 232–234.
10. Patent CN, No. 105238989A. Production method for micro-carbon nitrogen containing ferrochromium. Huang Quinui, Jiang Rongkui, Hu Zi; Applied: 10.10.2015. Published: 13.01.2016.
11. Qingqing Hu, Donglai Ma, Yongjie Liu, Qingyun Huangetal. Preparation of ferrochromium nitride via reduction and nitridation of chromite spinel with ammonia gas. Powder Technology. 2021. Vol. 386. pp. 449–456.
12. Merzhanov А. G., Mukasyan А. S. Solid flame combustion. Moscow: TORUS PRESS, 2007. 336 p.
13. Ziatdinov М. Kh., Shatokhin I. М. Self-propagating high-temperature synthesis of nitrided ferrochromium. Stal. 2009. No. 9. pp. 48–53.
14. Shatokhin I. M., Ziatdinov M. Kh., Manashev I. R., Shiryaev O. P., Kartunov A. D. Self-propogating high-temperature synthesis (SHS) of composite ferroalloys. CIS Iron and Steel Review. 2019. Vol. 18. pp. 52–57. DOI: 10.17580/cisisr.2019.02.11.
15. Manashev I. R., Gavrilova T. O., Shatokhin I. M., Ziatdinov M. Kh. Technology for the production of nitrided ferroalloys by the method of self-propagating high-temperature synthesis. Teoriya i tekhnologiya metallurgicheskogo proizvodstva. 2019. No. 4 (31). pp. 4–11.
16. Veryatin U. D., Mashirev B. P., Ryabtsev I. G. Thermodynamic properties of inorganic substances. Moscow: Atomizdat, 1965. 460 p.
17. GOST 4757–91. Ferrochromium. Specification and conditions for delivery. Introduced: 01.01.1993.
18. Aldushin А. P. Theory of filtration combustion. Dissertation … of Doctor of Physical and Mathematical Sciences. Chernogolovka, 1982. 363 p.
19. Ziatdinov M. Kh. Combustion of chromium in a concurrent flow of nitrogen. Physics of combustion and explosion. 2016. Vol. 52. No. 4. pp. 51–60.
20. GOST 5632–2014. Stainless steels and corrosion resisting, heat-resisting and creep resisting alloys. Grades. Introduced: 01.01.2015.