State Marine Technical University of Saint-Petersburg (Saint-Petersburg, Russia):

Nifontov Yu. A., Head of Chair, Doctor of Engineering Sciences, Professor, nifontov@yandex.ru

This paper presents the results of studies of the structure formation mechanism for briquettes made from coal fines (sludge, coal dust, and fines), with the use of powdered technical lignosulfonate (100 % Na base) as the binder. It has been established that, when briquetting fine coal fines with active finely-dispersed binders in an air-dry state, the structure formation mechanism of the briquette does not fully align with any of the existing hypotheses. As a result of the research, a theoretical substantiation is proposed for the hypothesis of wet coal sludge briquetting with the use of active finelydispersed binders in an air-dry state. It has been shown that the walls of capillaries and pores in the central part of the briquette experience precipitation from the fluid systems, dissolved by internal moisture, and of coarse particles and a certain amount of the binder entrained in the fluid. Further, a lean fluid advances to the surface of the briquette, consisting mainly of moisture and an excess amount of the active binder, dissolved in it. In the near-surface compacted area of the briquette, the binder is adsorbed on coal particles and the moisture released in the process of thermal destruction and adsorption evaporates. The practical use of the concepts obtained allows controlling the structure formation processes to improve strength without increasing the binder content through layer-by-layer reinforcement of the briquette mass with a closed surface, which significantly improves the process results.

1. Tarazanov I. G., Gubanov D. A. Russia's coal industry performance for January–December, 2019. Ugol'. 2020. No. 3. pp. 54–69.
2. Nifontov Yu. A., Gerasimov A. M., Burtsev I. N., Karpunina V. P. The issue of processing low-grade coals and getting ash-free coal as a fuel for direct input into the gas turbine. Morskie Intellektualnye Tekhnologii. 2019. No. 3–2. pp. 142–150.
3. Gerasimov A. M., Grigoryev I. V., Ustinov I. D. Measurement of slope angles for granular materials. Obogashchenie Rud. 2020. No. 4. pp. 48–52. DOI: 10.17580/or.2020.04.08.
4. Blekhman I. I. Vibrational mechanics and vibrational rheology. Theory and applications. Moscow: Fizmatlit, 2018. 752 p.
5. Uriev B. N. Physicochemical dynamics of disperse systems and materials. Moscow: Intellekt, 2013. 232 p.
6. Vaisberg L. А., Demidov I. V., Ivanov K. S. Mechanics of granular media under vibration action: the methods of description and mathematical modeling. Obogashchenie Rud. 2015. No. 4. pp. 21–31. DOI: 10.17580/or.2015.04.05.
7. Carzo V. Granular gaseous flows. Badajos: Springer, 2019. 393 p.
8. Mollah M. M., Jackson W. R., Marshall M., Chaffee A. L. An attempt to produce blast furnace coke from Victorian brown coal. Fuel. 2015. Vol. 148. pp. 104–111.
9. Zhong Q., Yang Y., Li Q., Xu B., Jiang T. Coal tar pitch and molasses blended binder for production of formed coal briquettes from high volatile coal. Fuel Processing Technology. 2017. Vol. 157. pp. 12–19.
10. Adeleke A. A., Odusote J. K., Lasode O. A., Ikubanni P. P., Malathi M., Paswan D. Mild pyrolytic treatment of gmelina arborea for optimum energetic yields. Cogent Engineering. 2019. Vol. 6. Article 1593073. 13 p.
11. Fazylov S. D., Nurkenov O. A., Mukashev A. B., Satpaeva Zh. B., Arinova A. E., Muldachmetov M. Z., Dautova Z. S. Briquetting of coal-slurry mixed with wood sawdust pellets. Bulletin of the National Academy of Sciences of the Republic of Kazakhstan. 2017. Vol. 3, No. 367. pp. 94–99.
12. Kadin A. A., Lebedev E. B., Khitarov N. I. Water in magmatic melts. Moscow: Nauka, 1971. 267 p.
13. Naimark A. A. Evolution of geodynamic systems: chaos or order. Izvestiya Vysshikh Uchebnykh Zavedeniy. Geologiya i Razvedka. 1998. No. 1. pp. 11–17.
14. Mikhailov N. N., Popov S. N. Influence of non-linear effects on the compressibility properties of reservoir rocks. Geologiya, Geofizika i Razrabotka Neftyanykh i Gazovykh Mestorozhdeniy. 2016. No. 3. pp. 50–57.
15. Ostrovsky G. M. Applied mechanics of inhomogeneous media. St. Petersburg: Nauka, 2000. 359 p.
16. Prikhod'ko Yu. N., Nifontov Yu. A., Volkova I. B., Prokashev A. N. To the question of structure-forming briquetting processes. National Economy of the Komi Republic. Syktyvkar, 1995. pp. 284–287.
17. Makarov Yu. I. Mixing of bulk materials. Moscow: Khimiya, 1977. 272 p.
18. Sivrikaya O., Arol A. I. An investigation of the relationship between compressive strength and dust generation potential of magnetite pellets. International Journal of Mineral Processing. 2013. Vol. 123. pp. 158–164.
19. Petrov A. V. Technology of heat treatment and agglomeration of manganese concentrates. Krivoy Rog: R. Kozlov Publishing House, 2019. 517 p.