The Effect of Metal Oxide Content on Ash Fusion Temperature (AFT) and Determination of Coal Slagging and Fouling Indices
DOI:
https://doi.org/10.59141/jiss.v6i10.1910Keywords:
Metal oxides, Ash Fusion Temperature, Slagging, Fouling, CoalAbstract
One of the abundant natural resources on Earth is coal, and one of its main uses is as fuel. The utilization of coal as an industrial fuel produces waste in the form of coal ash. The oxide composition of coal ash significantly influences the fusion temperature of the sample, which, in turn, affects the formation of slagging and fouling. Therefore, it is necessary to investigate the oxide composition of coal ash and its effect on the ash fusion temperature (AFT), as well as to determine the slagging and fouling indices. In this study, coal ash was melted and subsequently analyzed for its oxide composition, tested for ash fusion temperature (AFT), and evaluated for slagging and fouling indices. The results showed that high SiO₂ content combined with low Al₂O₃, Fe₂O₃, CaO, and MgO contents tends to decrease the AFT value. However, when both SiO₂ and Al₂O₃ contents are high and Fe₂O₃, CaO, and MgO contents are low, the AFT tends to increase. Furthermore, if the Fe₂O₃, CaO, and MgO contents are slightly higher than those of SiO₂ and Al₂O₃, the AFT also tends to increase. The calculated slagging and fouling indices indicated that almost all samples fall within the high to very high categories. These findings provide practical guidance for coal-fired power plant operators in Indonesia to predict and mitigate ash-related operational challenges, particularly in boiler design optimization and fuel blending strategies to minimize slagging and fouling occurrences, thereby improving combustion efficiency and reducing maintenance costs.
References
Admi, R., Saleh, S., & Fitrianto, G. (2022). The analysis of coal competitiveness and the factors affecting Indonesia’s coal exports to main destination countries (a case of 8 destination countries). Journal of Developing Economies, 7(1), 15–28.
Afni, N. (2021). Analisis potensi pembentukan slagging pada tiga jenis batubara dengan menggunakan AFT di PT Geoservices. Politeknik AKA Makassar, Makassar.
Efendi, M. A. A., Ghazidin, H., & Suyatno, S. (2025). Product evaluation and analysis of slagging-fouling potential. Chemical Engineering, 9(3), 1–12. https://doi.org/10.1016/j.ce.2025.01.001
Ghazidin, H., Suyatno, S., & Darmawan, A. (2024). Slagging, fouling, and corrosion potential during the co-firing of Indonesian coal and solid recovered fuel. AIP Conference Proceedings, 3069(1), 020107. https://doi.org/10.1063/5.0092345
Ghazidin, H., Suyatno, S., & Ruhiyat, A. S. (2023). Slagging-fouling evaluation of empty fruit bunch and palm kernel shell co-firing in coal-fired power plants. Energy Reports, 9, 1–10. https://doi.org/10.1016/j.egyr.2023.01.001
Harrison, R. (2023). Geological processes and coal formation. Earth Science Journal, 58(3), 112–118.
Kuswa, F. M., Prabowo, & Darmawan, A. (2023). Investigation of slagging fouling aspect of palm fiber and palm leaves waste in drop tube furnace. In Proceedings of the 6th Mechanical Engineering, Science and Technology International Conference (MEST 2022) (pp. 15–23). Atlantis Press. https://doi.org/10.2991/978-94-6463-134-0_3
Lachman, J., Baláš, M., Lisý, M., Lisá, H., Milčák, P., & Elbl, P. (2021). An overview of slagging and fouling indicators and their applicability to biomass fuels. Fuel Processing Technology, 217, 106804. https://doi.org/10.1016/j.fuproc.2021.106804
Li, J., Chen, X., Wang, B., Zhang, W., Zhang, Y., Guo, J., Zhang, W., Ge, Z., & Sun, Q. (2021). Effects of sodium and potassium on fusion characteristics of petroleum coke ash with high vanadium and nickel. Fuel, 303, 122177. https://doi.org/10.1016/j.fuel.2021.122177
Li, X., Zhi, L., Shi, W., Kong, L., Bai, J., Yu, J., Reinmöller, M., Guhl, S., Meyer, B., & Li, W. (2020). Effect of K₂O/Na₂O on fusion behavior of coal ash with high silicon and aluminum level. Fuel, 265, 116964. https://doi.org/10.1016/j.fuel.2019.116964
Liu, M., Baisheng, S., Alharthi, M., Hassan, M. S., & Hanif, I. (2023). The role of natural resources, clean energy and technology in mitigating carbon emissions in top populated countries. Resources Policy, 83, 103705.
Liang, H., Yi, J., Yang, Y., Zhang, L., Ma, T., Chen, W., Liu, H., & Che, D. (2025). Study on the mechanism of multiple sodium salts co-loading on ash fusibility and mineral evolution behaviors. Fuel, 397, 135397. https://doi.org/10.1016/j.fuel.2025.135397
Listiyowati, L. N., Mubarok, M. Z., Sanwani, E., & Santoso, I. (2023). Study on the slagging behavior of bio-coal ash based on composition, ash fusion temperature, and calculated critical-viscosity-temperature. In 5th International Seminar on Metallurgy and Materials (ISMM2022) (AIP Conference Proceedings, Vol. 3003, 020060). AIP Publishing. https://doi.org/10.1063/5.0186089
Muliati, M., & Rosdiana, R. (2024). The Impact Of The Construction Of A Steam Power Plant (PLTU) In The Socio-Economic Life Of The Community In Lampoko Village, Balusu District, Barru Regency. Jurnal Ekonomi, 13(03), 1012–1024.
Monika, I., & Sulistyohadi, F. (2019). Ash deposit characteristics of blended coal in coal-fired power plants. Indonesian Mining Journal, 22(1), 49–60. https://doi.org/10.30556/imj.v22i1.675
Myson, M. (2025). Comparative Reaction of Substitution of Diesel-fueled Steam Power Plant and Coal-fueled Steam Power Plant. International Journal of Technology, Education and Social Humanities, 3(2), 71–78.
Nasir, S. (2022). Pemanfaatan Batubara. Unsri Press.
Ordonez, J. A., Jakob, M., Steckel, J. C., & Fünfgeld, A. (2022). Coal, power and coal-powered politics in Indonesia 1. In The Political Economy of Coal (pp. 281–299). Routledge.
Pang, L., Liu, L., Zhou, X., Hafeez, M., Ullah, S., & Sohail, M. T. (2024). How does natural resource depletion affect energy security risk? New insights from major energy-consuming countries. Energy Strategy Reviews, 54, 101460.
Prayoga, M. Z. E., Putra, H. P., Wargadalam, V. J., Surachman, H., Luktyansyah, I. M., Saudah, S., Darmawan, A., Aziz, M., Prabowo, P., Wang, Y., Vuthaluru, H. B., & Hariana, H. (2025). Thermal characteristics and slagging-fouling analysis in co-combustion of coal and oil palm waste mixtures. Energy, 319, 134908. https://doi.org/10.1016/j.energy.2025.134908
Putra, I. B. G. P. (2023). The role of coal resources in Indonesia's energy and economic sector. Journal of Energy and Environmental Sustainability, 14(3), 112–120. https://doi.org/10.1016/j.jees.2023.02.006
Prismantoko, A., Ghazidin, H., Solikhah, M. D., Sugiyono, A., Maulana, I., & Hariana. (2023). Potential for slagging, fouling, and abrasion during co-firing of Indonesian bituminous coal and hardwood waste pellet. International Journal of Application on Sciences, Technology and Engineering, 1(1), 210–216. https://doi.org/10.24912/ijaste.v1.i1.210-216
Santoso Ali, A. M., Syaiful, A. Z., & Gazali, A. (2022). Pengaruh senyawa alumina (Al₂O₃) dan silika (SiO₂) dalam kualitas batubara. SAINTIS, 3(1), 1–7.
Sembiring, H. (2022). Classification and quality of coal in Indonesia: A review. Journal of Coal Science, 28(4), 249–256. https://doi.org/10.1016/j.jcs.2022.08.004
Smith, T., & Johnson, P. (2023). The classification of coal grades and their geological significance. International Journal of Earth Sciences, 39(4), 289–295. https://doi.org/10.1016/j.ijes.2023.05.008
Suyatno, S., Ghazidin, H., Prabowo, P., Kuswa, F. M., Putra, H. P., Ruhiyat, A. S., Karuana, F., Soleh, M., Utomo, S. M., Prismantoko, A., Abimanyu, H., Darmawan, A., & Hariana, H. (2024). Investigation of slagging-fouling and mineral contents in low-rank coals for improved combustion performance. Combustion Science and Technology. Advance online publication. https://doi.org/10.1080/00102202.2024.xxxxxx
Syahril, F., Putra, I. M., & Nasution, A. H. (2023). Coal mining in Indonesia: Geography, reserves, and sustainability issues. Indonesian Journal of Geology and Energy, 17(2), 67–75. https://doi.org/10.1016/j.ijgeoe.2023.01.003
Wang, Y. (2020). Effect of sodium and calcium on the ash fusion temperatures of Zhundong coal. Journal of Thermal Analysis and Calorimetry. https://doi.org/10.1007/s10973-020-09469-2
Yang, L. I., Wei, Z., & Yi-tian, F. (2022). Modification of ash fusion behavior of high ash fusion temperature (AFT) coal by textile dyeing sludge addition and its mechanism. Journal of Fuel Chemistry and Technology, 50(6), 703–713.
Zhang, J., Liu, Z., Li, X., Wang, B., Teng, Z., & Han, K. (2023). Study on slagging characteristics of co-combustion of meager coal and spent cathode carbon block. Energies, 16(2), 736. https://doi.org/10.3390/en16020736
Zhang, L., Wang, J., Wei, J., Bai, Y., Song, X., Xu, G., Pan, Y., & Yu, G. (2021). Synergistic effects of CaO and MgO on ash fusion characteristics in entrained-flow gasifier. Energy & Fuels, 35(1), 425–432. https://doi.org/10.1021/acs.energyfuels.0c03358
Zhou, Q., Deng, W., Xu, Y., Ma, X., & Gao, N. (2023). Investigation on ash fusion characteristics during the co-gasification of coal and textile dyeing sludge. Journal of Thermal Analysis and Calorimetry, 148, 14011–14022. https://doi.org/10.1007/s10973-023-12687-z
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2025 Muhammad Fat’hul Rozaq
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution-ShareAlike 4.0 International. that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.
