Microbubble reagentless hydrophobization of the coal surface
Yu.F. Patrakov, S.A. Semenova
Federal Research Center for Coal and Coal Chemistry of the Siberian Branch of the Russian Academy of Sciences, Kemerovo, Russian Federation
Russian Mining Industry №S2 / 2023 р. 53-58
Abstract: The paper describes methodological features of coal surface hydrophobization the using a microbubble gas-liquid medium to intensify the process of flotation concentration of coal. Air microbubbles were generated using decompression of liquid saturated under air pressure. The influence of water saturation pressure with gas on the size of the bubbles and their stability over time has been established. It is shown that addition of microbubbles leads to formation of an intermediate hydrophobic air layer on the surface of coal, which is the basis for catching bubbles of the flotation size. The results of coking coals flotation using a microbubble gas-liquid mixture are presented. By means of the method of differential particle size analysis, the preferred flotation of fine coal particles < 50 microns in size by micro-bubbles of air was established. It was found that for low-ash coals, the efficiency of reagentless microbubble flotation can be comparable with the results of concentration using traditional petrochemical reagents. In the reagent mode, the micro-bubbles are attached to the oil-hydrophobized surface of small particles with the formation of carbon-air complexes.
Keywords: coal, microbubble gas medium, surface wettability, surface hydrophobization, flotation
Acknowledgments: The work was performed within the framework of the state assignment of the Federal Research Center of Coal and Coal Chemistry of the Siberian Branch of the Russian Academy of Sciences, Project FWEZ-2021-0002 'Development of efficient technologies of coal mining by robotic mining complexes operating without permanent presence of personnel in mining zones, design of control systems and methods to assess their technical condition and operating life as well as justification of the mineral resource base reproduction' (Reg. No. АААА-А21-121012290021-1). The authors express their gratitude for assistance in performing physical and chemical tests to Lead Engineer T.A. Papina, Yu.A. Kharlampenkova (Coal Institute of the Federal Research Center for Coal and Coal Chemistry, Siberian Branch of the Russian Academy of Sciences), Candidate of Physical and Mathematical Sciences S.A. Sozinov (Coal Institute, Federal Research Center for Coal and Coal Chemistry of Siberian Branch of the Russian Academy of Sciences).
For citation: Patrakov Yu.F., Semenova S.A. Microbubble reagentless hydrophobization of the coal surface. Russian Mining Industry. 2023;(S2):53–58. https://doi.org/10.30686/1609-9192-2023-S2-53-58
Article info
Received: 21.07.2023
Revised: 14.08.2023
Accepted: 17.08.2023
Information about the authors
Yury F. Patrakov – Dr. Sci. (Chem.), Professor, Head of the Laboratory of Scientific Bases of Coal Preparation Technologies, Federal Research Center for Coal and Coal Chemistry of the Siberian Branch of the Russian Academy of Sciences, Kemerovo, Russian Federation; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Svetlana A. Semenova – Cand. Sci. (Chem.), Associate Professor, Leading Research Associate, Federal Research Center for Coal and Coal Chemistry of the Siberian Branch of the Russian Academy of Sciences, Kemerovo, Russian Federation; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Conflict of interest
The authors declare no conflict of interests. All the authors have read and approved the final version of this paper.
References
1. Klassen V.I. Coal flotation. Moscow: Gosudarstvennoe nauchno-tekhnicheskoe izdatelstvo po gornomu delu; 1963. 380 р. (In Russ.)
2. Laskowski J.S. Coal flotation and fine coal utilization. Amsterdam: Elsevier Science, 2001. 368 p.
3. Abramov A.A. Collected works, Vol. 4, Flotation methods of enrichment. Moscow: Gornaya kniga; 2017. 597 p. (In Russ.)
4. Etchepare R., Oliveira H., Nicknig M., Azevedo A., Rubio J. Nanobubbles: Generation using a multiphase pump, properties and features in flotation. Minerals Engineering. 2017;112:19–26. https://doi.org/10.1016/j.mineng.2017.06.020
5. Tao D.E. Role of bubble size in flotation of coarse and fine particles – A review. Separation Science and Technology. 2004;39(4):741–760. https://doi.org/10.1081/SS-120028444
6. Patrakov Yu.F., Semenova S.A. Intensification of coal flotation by means of air microbubbles. Coke and Chemistry. 2021;64(2):64–68. https://doi.org/10.3103/S1068364X21020046
7. Gao Ya. Dashliborun A.M., Zhou J.Z., Zhang X. Formation and stability of cavitation microbubbles in process water from the oilsands industry. Industrial & Engineering Chemistry Research. 2021;60(7):3198–3209. https://doi.org/10.1021/acs.iecr.0c04795
8. Liu J. Self-absorbing Microbubble Generator. CN2227985Y, 1996.
9. Li B., Tao D., Ou Z., Liu J. Cyclo-microbubble column flotation of fine coal. Separation Science and Technology. 2006;38(5):1125–1140. https://doi.org/10.1081/SS-120018127
10. Zhang R., Liu Sh., Zheng S. Characterization of nano-to-micron sized respirable coal dust: Particle surface alteration and the health impact. Journal of Hazardous Materials. 2021;413:125447. https://doi.org/10.1016/j.jhazmat.2021.125447
11. Patrakov Yu.F., Semenova S.A., Kharlampenkova Yu.A., Sozinov S.A. Determining the Wettability of Coal Surfaces. Coke and Chemistry. 2019;62(12):545–551. https://doi.org/10.3103/S1068364X19120081
12. Artemiev V.B., Eremin I.V., Gagarin S.G. Petrography of coals and their effective use. Moscow: Nedra; 2000, 334 p. (In Russ.)
