Efficiency enhancement of thermal utilization of low-grade carbon-containing raw materials by adding alkali metal carbonates

The study explores the potential of using carbon-containing wastes as fuel raw materials. The research samples were coal preparation waste (CPW) from the Kuznetsk Basin and ash and slag waste (ASW) from the boiler house of the mining enterprise’s heat and water supply department. To enhance the efficiency of their thermal utilization, the possibility of adding reagent-catalysts, potassium and sodium carbonates, has been evaluated. The experimental methods included thermogravimetric analysis, differential scanning calorimetry, specific surface area determination, and scanning electron microscopy. Based on laboratory studies, the combustion rates of coal enrichment wastes and ash and slag wastes were calculated depending on the type and amount of additives. The mechanism of their interaction was also determined. Thermogravimetric analysis provided data to establish the values of combustion parameters: temperature of maximum mass loss, ignition and burnout temperatures, average and maximum mass loss rates, combustion index and ignition index, as well as a comprehensive combustion characteristic index. Activation energies of the oxidation process were calculated using isoconversional method. Based on the obtained data, the conclusion was made about the promising use of alkaline additives in the thermal utilization of low-grade carbon-containing raw materials. K2CO3 additive in the amount of 10% mass demonstrates the highest efficiency.

Duka A. A., Pashkevich M. A., Sverchkov I. P. Efficiency enhancement of thermal utilization of low-grade carbon-containing raw materials by adding alkali metal carbonates. MIAB. Mining Inf. Anal. Bull. 2025;(11-1):113—130. [In Russ]. DOI: 10.25018/0236_1493_2025_111_0_113.

This investigation was financially supported by the Ministry of Science and Higher Education of the Russian Federation (FSRW-2024−0005).

Duka A. A.¹, researcher, http://orcid.org/0009-0009-6656-7660, 2, Russia, e-mail: duka_aa@pers.spmi.ru;
Pashkevich M. A.¹, Dr.Sci., professor, head of department of Geoecology, http://orcid.org/0000-0001-7020-8219, e-mail: mpash@spmi.ru;
Sverchkov Ivan Pavlovich — Ph.D., senior researcher, http://orcid.org/0000-0003-4725-0050, e-mail: sverchkov_ip@pers.spmi.ru;
¹ Empress Catherine II Saint Petersburg Mining University, 199106, Saint Petersburg, Vasilievsky Island, 21st Line.
Conflict of interest: The authors declare that there is no conflict of interest.

Duka Arina Alexandrovna, e-mail: duka_aa@pers.spmi.ru.

1. Kondratev S. А., Khamzina Т. А. Improvement of concentrate quality in flotation of low-rank coal. Journal of Mining Institute. 2024, vol. 265, pp. 65–77. [In Russ].
2. Ministry of Energy of the Russian Federation, available at: https://minenergo.gov.ru/industries/coal/main-indicators/coal-processing-and-enrichment (accessed 24.04.2024). [In Russ].
3. Lange I. Yu., Lebedeva Y. A., Kotiukov P. V. A study of water permeability of coal ash and slag to assess the possibility of their use as road pavement layers. International Journal of Engineering Research and Technology. 2020, vol. 13, no. 2, pp. 374–378. DOI: 10.37624/IJERT/13.2.2020.374−378.
4. Strizhenok A. V., Bykova M. V., Korotaeva A. E. Extractive Industries as a Source of Greenhouse Gas Emissions and the Possibility of its Natural Sequestration under the Climatic Conditions of Central and Northern Eurasia. Journal of Ecological Engineering. 2024, vol. 25, no. 5, pp. 43–69. DOI: 10.12911/22998993/185585.
5. Kutepova N. A., Moseykin V. V., Kondakova V. N., Pospehov G. B., Straupnik I. A. Specificity of properties of coal processing waste regarding their storage. MIAB. Mining Inf. Anal. Bull. 2022, vol. 12, pp. 77–93. [In Russ]. DOI: 10.25018/0236_1493_2022_12_0_77.
6. Kharko P. A., Danilov A. S. Evaluation of the effectiveness of neutralization and purification of acidic waters from metals with ash when using alternative fuels from municipal waste. Journal of Mining Institute. 2025, vol. 274, pp. 167–176. 
7. Wang Hetang, Cheng Sisi, Wang Haojie, He Jun, Fan Lan, Danilov A. S. Synthesis and properties of coal dust suppressant based on microalgae oil extraction. Fuel. 2023, vol. 338, article 127273. DOI: 10.1016/j.fuel.2022.127273.
8. Pashkevich M. A., Patokin D. A., Danilov A. S. Processing the Nitrocellulose-containing Waste from the Chemical Industry to Obtain Mineral Soil Additives. Ecology and Industry of Russia. 2024, vol. 28, pp. 10–17. [In Russ]. DOI: 10.18412/1816-0395-2024-6-10−17.
9. Li Hong Wei, Na Zhang, Tian Hua Yang. Effects of Alkaline Earth Metal on Combustion of Pulverized Coal. Advanced Materials Research. 2012, vol. 516–517, pp. 271–275.
10. Tsuyoshi Takuwa, Ichiro Naruse. Detailed kinetic and control of alkali metal compounds during coal combustion. Fuel Processing Technology. 2007, vol. 88, pp. 1029–1034. DOI: 10.1016/j.fuproc.2007.06.010.
11. Jingkuan Li, Yun Chen, Yuanyuan Zhang, Jiao Wu, Congxiu Guo, Yan Jin, Yanlin Wang. Effects of alkali and alkaline earth metals on co-combustion of sewage sludge and coal slime: Combustion characteristics, interactions, and kinetics. Journal of Environmental Management. 2024, vol. 356. DOI: 10.1016/j.jenvman.2024.120735.
12. Shi M., Zhang R., Zhang L., Shi B. Effects of alkali and alkaline earth metal species on the combustion characteristics and synergistic effects: sewage sludge and its blend with coal. Waste Management. 2022, vol. 146, pp. 119–129. DOI: 10.1016/j.wasman.2022.05.005.
13. Veraa M. J., Bell A. T. Effect of alkali metal catalysts on gasification of coal char. Fuel. 1978, vol. 57, no. 4, pp. 194–200. DOI: 10.1016/0016−2361(78)90116−3.
14. Mingzhe Shi, Rui Zhang, Lijuan Zhang, Bingquan Shi Effects of alkali and alkaline earth metal species on the combustion characteristics and synergistic effects: Sewage sludge and its blend with coal. Waste Management. 2022, vol. 146, pp. 119–129. DOI: 10.1016/j.wasman.2022.05.005.
15. Katherine Le Manquais, Colin Snape, Jim Barker, Ian McRobbie. TGA and Drop Tube Furnace Investigation of Alkali and Alkaline Earth Metal Compounds as Coal Combustion Additive. Energy & Fuels. 2012, vol. 26, pp. 1531–1539. DOI: 10.1021/ef201936g.
16. Zhu H., Liao Q., Hu L., Xie L., Qu B., Gao R. Effect of removal of alkali and alkaline earth metals in cornstalk on slagging/fouling and co-combustion characteristics of cornstalk/coal blends for biomass applications. Renew. Energy. 2023, vol. 207, pp. 275–285. DOI: 10.1016/j.renene.2023.03.022.
17. Qin Y., He Y., Ren W. Catalytic effect of alkali metal in biomass ash on the gasification of coal char in CO2. J Therm Anal Calorim. 2020, vol. 39, pp. 3079–3089. DOI: 10.1007/s10973-019-08719-2.
18. Yao X., Zhao Z., Li J., Zhang B., Zhou H., Xu K. Experimental investigation of physicochemical and slagging characteristics of inorganic constituents in ash residues from gasification of different herbaceous biomass. Energy. 2020, vol. 198, article 117367. DOI: 10.1016/j.energy.2020.117367.
19. Han-min Xiao, Xiao-qian Ma, Zhi-yi Lai. Isoconversional kinetic analysis of co-combustion of sewage sludge with straw and coal. Applied Energy. 2009, vol. 86, pp. 1741–1745. DOI: 10.1016/j.apenergy.2008.11.016.
20. Peng Ling, Dezhi Chen, Kai Xu, Jun Xu, Mohamed E. Mostafa, Long Jiang, Yi Wang, Sheng Su, Song Hu, Jun Xiang. Insight into the synergistic effect on thermal behavior in co-pyrolysis of coal slime and sewage sludge: Kinetics, thermodynamics, dendrite neural network modelling, and evolved char structure. Journal of Cleaner Production. 2024, vol. 450, article 141790. DOI: 10.1016/j.jclepro.2024.141790.
21. Feihong Guo, Zhaoping Zhong. Optimization of the co-combustion of coal and composite biomass pellets. Journal of Cleaner Production. 2018, vol. 185, pp. 399–407. DOI: 10.1016/j.jclepro.2018.03.064.
22. Chuncai Zhou, Guijian Liu, Xudong Wang, Cuicui Qi. Co-combustion of bituminous coal and biomass fuel blends: Thermochemical characterization, potential utilization and environmental advantage. Bioresource Technology. 2016, vol. 218, pp. 418–427. DOI: 10.1016/j.biortech.2016.06.134.
23. Alexandrova T. N., Kuskov V. B., Afanasova A. V., Kuznetsov V. V. Improvement of the fine coking coal flotation technology. Obogashchenie Rud. 2021, vol. 3, pp. 9–13. [In Russ]. DOI: 10.17580/or.2021.03.02.
24. Feihong Guo, Zhaoping Zhong. Experimental studies on combustion of composite biomass pellets in fluidized bed. Science of the Total Environment. 2017, vol. 599–600, pp. 926–933. DOI: 10.1016/j.scitotenv.2017.05.026.
25. Biao Fu, Guijian Liu, Md Manik Mian, Chuncai Zhou, Mei Sun, Dun Wu, Yuan Liu. Co-combustion of industrial coal slurry and sewage sludge: Thermochemical and emission behavior of heavy metals. Chemosphere. 2019, vol. 233, pp. 440–451. DOI: 10.1016/j.chemosphere.2019.05.256.
26. Rodionov V. A., Tursenev S. A., Skripnik I. L., Ksenofontov Y. G. Results of the study of kinetic parameters of spontaneous combustion of coal dust. Journal of Mining Institute. 2020, vol. 246, pp. 617–622. [In Russ]. DOI: 10.31897/PMI.2020.6.3.
27. Han-min Xiao, Xiao-qian Ma, Zhi-yi Lai. Isoconversional kinetic analysis of co-combustion of sewage sludge with straw and coal. Applied Energy. 2009, vol. 86, pp. 1741–1745. DOI: 10.1016/j.apenergy.2008.11.016.
28. Vyazovkin S., Wight C. A. Kinetics in solids. Annual Review of Physical Chemistry. 1997, vol. 48, no. 1, pp. 125–149. DOI: 10.1146/annurev.physchem.48.1.125.
29. Vyazovkin S., Wight C. A. Model-free and model-fitting approaches to kinetic analysis of isothermal and nonisothermal data. Thermochimica Acta. 1999, vol. 340–341, pp. 53–68. DOI: 10.1016/S0040−6031(99)00253−1.
30. Vyazovkin S., Burnham A. K., Criado J. M., Pérez-Maqueda L. A., Popescu C., Sbirrazzuoli N. ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data. Thermochimica Acta. 2011, vol. 520, pp. 1–19. DOI: 10.1016/j.tca.2011.03.034.
31. Petrova T. A., Epishina A. D. Anti-corrosion protection of pipelines at mining and processing enterprises. Obogashchenie Rud. 2023, vol. 6, pp. 52–58. [In Russ]. DOI: 10.17580/or.2023.06.09.
32. McKee D. W. Mechanisms of the alkali metal catalysed gasification of carbon. Fuel. 1983, vol. 62, no. 2, pp. 170–175. DOI: 10.1016/0016−2361(83)90192−834. 
33. Kasatkin N. S., Alenicheva A. A., Yurchenko Yu. Yu., Talovina I. V. Molybdenum–copper–porphyry mineralization in the Pavlovich ore field. Gornyi Zhurnal. 2024, vol. 9, pp. 84–90. [In Russ]. DOI: 10.17580/gzh.2024.09.13.
34. Kang Yin, Yu-Ming Zhou, Qing-Zhao Yao, Cheng Fang, Ze-Wu Zhang. Thermogravimetric analysis of the catalytic effect of metallic compounds on the combustion behaviors of coals. Reaction Kinetics, Mechanisms and Catalysis Reac Kinet Mech Cat. 2012, vol. 106, no. 2, pp. 369–377. DOI: 10.1007/s11144-012-0444-2.
35. Slovák V., Taraba B. Effect of experimental conditions on parameters derived from TG-DSC measurements of low-temperature oxidation of coal. J Therm Anal Calorim. 2010, vol. 101, pp. 641–646. DOI: 10.1007/s10973-010-0878-6.