Aluminium thermal reduction process for preparing ferrosilicon and alumina from fly ash
Keywords:
Fly ash, Aluminum ash, Aluminum thermal reduction, Ferrosilicon alloy
Abstract
There has been a focus on environmental protection and the recycling of solid waste resources, particularly fly ash and aluminum dross. Efforts to utilize fly ash efficiently have increased. In this paper, a process is introduced for producing alumina-rich slag and ferrosilicon alloy through aluminothermic reduction of fly ash with aluminium dross. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirm the formation of spherical ferrosilicon alloy encased in a loose, porous alumina matrix during the aluminothermic reduction process. Thermodynamic calculations indicated that the reduction temperature of SiO2 and mullite decreases in the presence of Fe2O3. Under conditions of 1673 K, a specific aluminium dross to fly ash ratio (A/F), and a reduction time of 20 minutes, the magnetic fraction contains 85.89% ferrosilicon, while the non-magnetic fraction has an alumina content of 79.42%. This process offers a solution with potential environmental and economic benefits for the application of fly ash and aluminum ash.
References
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[3] T. Hemalatha, A. Ramaswamy. A review on fly ash characteristics e Towards promoting high volume utilization in developing sustainable concrete, Journal of Cleaner Production, 147 (2017) 546-559. http://dx.doi.org/10.1016/j.jclepro.2017.01.114
[4] L. Li, H. Yu, H. Ma, C. Wu, N. Zhang, N. Wang, Theoretical foundation, hydration mechanism, and concrete performance of basic magnesium sulfate, Journal of Building Engineering, 111 (2025) 113120. https://doi.org/10.1016/j.jobe.2025.113120
[5] Y. Guo, Y. Li, F. Cheng, M. Wang, X. Wang, Role of additives in improved thermal activation of coal fly ash for alumina extraction. Fuel processing technology, 110(2013) 114-121. https://doi.org/10.1016/j.fuproc.2012.12.003
[6] X. Zhuang, L. Chen, S. Komarneni, C. Zhou, D. Tong, H. Yang, W. Yu, H. Wang, Fly ash-based geopolymer: clean production, properties and Applications. Journal of Cleaner Production, 125(2016) 253-267. https://doi.org/10.1016/j.jclepro.2016.03.019
[7] A. Liu, Z. Shi, K. Xie, X. Hu, B. Gao, M. Korenko, Z. Wang. Extraction of Al–Si Master alloy and alumina from coal fly ash. Journal of Mining and Metallurgy, Section B: Metallurgy. 2017, 53 (2) B : 155 – 162. https://doi.org/10.2298/JMMB160616006L
[8] C. Liu, S. Zheng, S. Ma, Y. Luo, J. Ding, X. Wang, Y. Zhang, A novel process to enrich alumina and prepare silica nanoparticles from high-alumina fly ash. Fuel processing technology, 173(2018) 40-47. https://doi.org/10.1016/j.fuproc.2018.01.007
[9] Z. Jiang, H. Ma, J. Yang, X. Ma, J. Yuan, Thermal decomposition mechanism of desilication coal fly ash by low-lime sinter method for alumina extraction. Ferroelectrics, , 486(1) (2015) 143-155. https://doi.org/10.1080/00150193.2015.1100878
[10] C. Liu, S. Zheng, S. Ma, Y. Luo, J. Ding, X. Wang, Y. Zhang. A novel process to enrich alumina and prepare silica nanoparticles from high-alumina fly ash. Fuel processing technology, 2018, 173: 40-47. https://doi.org/10.1016/j.fuproc.2018.01.007
[11] Z. T. Yao, M. S. Xia, P. K. Sarker, T. Chen. A review of the alumina recovery from coal fly ash, with a focus in China. Fuel, 120(2014) 74-85. https://doi.org/10.1016/j.fuel.2013.12.003
[12] L. Yan, J. Shang, Y. Wang, J. Li, H. Liu, T. Qu, C. Zhang. Experimental parameter optimization study on the acid leaching of coal fly ash. Desalination and Water Treatment, , 57(23) (2016) 10894-10904. https://doi.org/10.1080/19443994.2015.1040463
[13] A. K. Tripathy, B. Behera, V. Aishvarya, A. R. Sheik, B. Dash, C. K. Sarangi, B. C. Tripathy, K. Sanjay, I.N. Bhattacharya. Sodium fluoride assisted acid leaching of coal fly ash for the extraction of alumina. Minerals Engineering, 131(2019) 140-145. https://doi.org/10.1016/j.mineng.2018.10.019
[14] N. Nayak, C. R. Panda, Aluminium extraction and leaching characteristics of Talcher Thermal Power Station fly ash with sulphuric acid. Fuel, 89(1) (2010) 53-58. https://doi.org/10.1016/j.fuel.2009.07.019
[15] A. Shemi, R.N. Mpana, S. Ndlovu, L.D. van Dyk, V. Sibanda, L. Seepe. Alternative techniques for extracting alumina from coal fly ash. Minerals Engineering, , 34(2012) 30-37. https://doi.org/10.1016/j.mineng.2012.04.007
[16] P. Wang, H. Liu, F. Zheng, Y. Liu, G. Kuang, R. Deng, H. Li, Extraction of aluminum from coal fly ash using pressurized sulfuric acid leaching with emphasis on optimization and mechanism, JOM, 73(9) (2021) 2643-2651. https://doi.org/10.1007/s11837-021-04801-z
[17] Zhang Z Y, Qiao X C, Yu J G. Aluminum release from microwave-assisted reaction of coal fly ash with calcium carbonate. Fuel Processing Technology, 2015, 134: 303-309.
[18] D. Xu, H. Li, W. Bao, C. Wang. A new process of extracting alumina from high-alumina coal fly ash in NH4HSO4+H2SO4 mixed solution, Hydrometallurgy, 165 (2016) 336–344. https://doi.org/10.1016/j.hydromet.2015.12.010
[19] G. Zhu, H. Li, R. Lin, S. Li, X. Hou, Q. Tang, Synthesis of superfine calcium carbonate during causticization in highly alkaline system for utilization of high-alumina fly ash, Hydrometallurgy, 165(2016) 282-289. https://doi.org/10.1016/j.hydromet.2016.01.022
[20] Q. Yu, Y. Deng, Y. Feng, Z. Li. Phase Transformation of Alumina, Silica and Iron Oxide during Carbothermic Reduction of Fly Ash. Metals, 11(8) (2021) 1165. https://doi.org/10.3390/met11081165
[21] Q. Yu, Y. Deng, S. Yin, Z. Li. Thermal process for magnesium production with Al-Si-Fe from coal fly ash: thermodynamics and experimental investigation. Journal of Mining and Metallurgy, Section B: Metallurgy, 57(3) (2021) 421-430. https://doi.org/10.2298/JMMB210118038Y
[22] Y. Xue, W. Yu, W. Jiang, L. Wen, Z. You, X. Lv. A novel process to extract alumina and prepare Fe-Si alloys from coal fly ash. Fuel processing technology, 185(2019) 151-157. https://doi.org/10.1016/j.fuproc.2018.12.013
[23] Y. Xue, W. Yu, J. Mei, W. Jiang, X. Lv. A clean process for alumina extraction and ferrosilicon alloy preparation from coal fly ash via vacuum thermal reduction. Journal of cleaner production, 240(2019) 118262. https://doi.org/10.1016/j.jclepro.2019.118262
[24]J. Nyarko-Appiah, W. Yu, P. Wei, W. Jiang, Z. Liang, S. Gong. The alumina enrichment and Fe-Si alloy recovery from coal fly ash with the assistance of Na2CO3. Fuel, 310(2022) 122434. https://doi.org/10.1016/j.fuel.2021.122434
[25] X. Fu, X. Li, X. Zhang, Y. Zhao, J. Liu. Theoretical research on aluminum silicon alloy production by electrothermal method, World Nonferrous Met, (1) (2013) 40-42. (In Chinese)
[26] F. Zhang, M. Li. Technology of producing aluminum silicon alloys (50% Al), Ferro-alloys, (4) (2003) 17-21. (In Chinese)
[27] T. Shinjo, Y. Nakamura, N. Shikazono. Magnetic Study of Fe3Si and Fe5Si3 by Mössbauer Effect. Journal of the Physical Society of Japan, 18(6) (1963) 797-801. https://doi.org/10.1143/JPSJ.18.797
[28] J. Tomeczek, H. Palugniok, Kinetics of mineral matter transformation during coal combustion. Fuel, 81(2002) 1251–1258. https://doi.org/10.1016/S0016-2361(02)00027-3
[29] Q. Qiu, V. Hlavacek, S. Prochazka, Carbonitridation of Fly Ash. I. Synthesis of SiAlON-Based Materials, Industrial & Engineering Chemistry Research, 44(2005) 2469–2476. https://doi.org /10.1021/ie0497036
[30] C. A. Pickles, Thermodynamic analysis of the selective carbothermic reduction of electric arc furnace dust. Journal of Hazardous Materials, 2008, 150, 265–278. https://doi.org/10.1016/j.jhazmat.2007.04.097
[31] J. Liu，C. Zhang. Research status of low-temperature synthesis and sintering of MgAl2O4 spinel. Nonferrous Metals Design, 45(2) (2018) 104-110(in Chinese)
[32] Tan, X.M.; Zhao, Z.; Chen, P.A.; Li, X.C.; Zhu, B.Q. Effect of nano metallic Fe on Al5O6N Synthesis in Al2O3-C refractories. Interceram - International Ceramic Review, 64(2015) 108–111. https://doi.org/10.1007/bf03401110
Published
2026/07/02
How to Cite
Su, Q., Yu, Q., Zhu, X., Xiao, T., & Ye, B. (2026). Aluminium thermal reduction process for preparing ferrosilicon and alumina from fly ash. Journal of Mining and Metallurgy, Section B: Metallurgy, 62(1), 1-12. Retrieved from https://aseestant.ceon.rs/index.php/jmm/article/view/60188
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