High-strength porous ceramics from fine fly ash microspheres
About authors
- 1 — Junior Researcher Institute of Geology FRC Komi SC UB RAS ▪ Orcid
- 2 — Ph.D., Dr.Sci. Chief Researcher Institute of Geology FRC Komi SC UB RAS ▪ Orcid
- 3 — Ph.D. Senior Researcher Institute of Geology FRC Komi SC UB RAS ▪ Orcid
Date submitted:
2026-04-08
Date accepted:
2026-07-22
Online publication date:
2026-10-27
Date published:
2026-10-30
Abstract
Fly ash can be considered a promising secondary raw material for the production of high-strength porous mullite ceramics, since the absence of a need to grind the initial batch materials makes it possible to significantly reduce energy consumption. In this study, promising ceramic samples were produced using fly ash and aluminum ore, specifically low-iron bauxite, as an Al2O3-adjusting component. Thermogravimetric and X-ray diffraction phase analyses were used to determine the sequence and temperature ranges of phase transformations in the system “fly ash – bauxite” and to establish the optimal thermal treatment regime. Several exothermic peaks were observed in the 1200-1300 °C temperature range, reflecting a sequence of phase transformations. Mullite forms through a reaction between quartz and cristobalite, which pass into a transient liquid phase, and γ-Al2O3, formed by the decomposition of boehmite. The total mullite phase content reaches 83-84 %, which is significantly higher than the values reported by other researchers, including those who used various additives to accelerate mullite formation. Scanning electron microscopy was used to trace the evolution of the microstructure of the obtained samples as a function of synthesis temperature. As the treatment temperature increases to 1300 °C, sintering gradually intensifies, resulting in the formation of larger pores. Acicular mullite crystals form around flake-like γ-Al2O3 crystals, some of which subsequently transform into corundum. Laboratory tests of the finished ceramic samples confirmed that their technical characteristics – density, porosity, and compressive strength – meet the requirements for refractory, thermal insulation, and chemically resistant materials. The study presents the technological principles for developing high-strength and porous mullite-based ceramics intended for use in construction and thermal insulation applications.
Область исследования:
Geotechnical Engineering and Engineering Geology
Funding:
This work was carried out within the framework of State assignment project N 122040600011-5 at the Institute of Geology Komi SC UB RAS, using the equipment of the CFC “Geoscience” and “Chemistry”.
References
- Taskin A.V., Fediuk R.S., Fedotov D.R. Complex processing of ash and slag waste from coal-fired power plants and coal enrichment waste. Bulletin of the Kuzbass State Technical University. 2025. N 1 (167), p. 28-36 (in Russian). DOI: 10.26730/1999-4125-2025-1-28-36
- Kalinkin A.M., Kalinkina E.V., Ivanova A.G., Kruglyak E.A. Geopolymers based on mechanically activated mixtures of coal-fired power plant fly ash with natural calcium and magnesium carbonates. Trudy Fersmanovskoi nauchnoi sessii GI KNT RAN. Apatity: Geologicheskii institut KNTs RAN, 2022. N 19, p. 144-148 (in Russian). DOI: 10.31241/FNS.2022.19.027
- Hasanuzzaman Md., Quddus Md.S., Saha M., Sharmin N. Transformation of waste into wealth: Thermochemical conversion of coal fly ash to extract Al2O3 via alkali desilication and soda – lime assisted sintering. Chemistry of Inorganic Materials. 2026. Vol. 8. N 100143. DOI: 10.1016/j.cinorg.2026.100143
- Mingfei Xing, Xiaofang Wu, Zixin Li et al. Rare earth element recovery and aluminum-rich residue production from high alumina fly ash by alkali pre-desilication enhance the mechanochemical extraction process. Process Safety and Environmental Protection. 2023. Vol. 175, p. 60-69. DOI: 10.1016/j.psep.2023.05.022
- Kumar A., Samadder S.R., Elumalai S.P. Recovery of Trace and Heavy Metals from Coal Combustion Residues for Reuse and Safe Disposal: A Review. JOM. 2016. Vol. 68. N 9, p. 2413-2417. DOI: 10.1007/s11837-016-1981-3
- Delitsyn L.M., Kulumbegov R.V., Popel O.S. et al. Processing of Ash and Slag Waste from Coal-Fired Thermal Power Plants and Extraction of Commercial Products from the Waste (Review). Thermal Engineering. 2025. Vol. 72. N 3, p. 203-220. DOI: 10.1134/S0040601524700836
- Krasnyi B.L., Ikonnikov K.I., Lemeshev D.O., Sizova A.S. Fly Ash as Technogenic Raw Material for Producing Refractory and Insulating Ceramic Materials (Review). Glass and Ceramics. 2021. Vol. 78. N 1-2, p. 48-56. DOI: 10.1007/s10717-021-00347-3
- Kotova O.B., Shabalin I.N., Shushkov D.A., Kocheva L.S. Hydrothermal synthesis of zeolites from coal fly ash. Advances in Applied Ceramics: Structural, Functional and Bioceramics. 2016. Vol. 115. Iss. 3, p. 152-157. DOI: 10.1179/1743676115Y.0000000063
- Yang Luo, Shuhua Ma, Shili Zheng et al. Mullite-based ceramic tiles produced solely from high-alumina fly ash: Preparation and sintering mechanism. Journal of Alloys and Compounds. 2018. Vol. 732, p. 828-837. DOI: 10.1016/j.jallcom.2017.09.179
- Guanghui Li, Qunzhen Bu, Hu Sun et al. Cost-Effective and Sustainable Preparation of Porous Mullite-Based Ceramics Combining MoO3 Recovery from Industrial Calcine. ACS Sustainable Chemistry & Engineering. 2020. Vol. 8. Iss. 19, p. 7290-7299. DOI: 10.1021/acssuschemeng.0c00079
- Vakalova T., Sergeev N., Tolegenov D., Tolegenova D. High-strength building ceramics based on fly ash – red mud mixtures. Magazine of Civil Engineering. 2023. Vol. 121. Iss. 5. N 12104. DOI: 10.34910/MCE.121.4
- Babashov V.G., Varrik N.M., Karaseva T.A. Porous ceramic for filtration of metal melts and hot gases (review). Proceedings of VIAM. 2020. N 8 (90), p. 54-63 (in Russian). DOI: 10.18577/2307-6046-2020-0-8-54-63
- Akimochkina G.V., Fomenko E.V., Fadeeva N.P. et al. High Strength Porous Ceramics Based on Disperse Microspheres of Fly Ash and Pearlite. Journal of Siberian Federal University. Chemistry. 2024. Vol. 17 (3), p. 339-349 (in Russian).
- Sassykova L.R., Gilmundinov Sh.A., Massenova A.T. et al. Catalysts on metal and ceramic carriers for neutralization of waste gases of industry and motor transport. News of the National Academy of Sciences of the Republic of Kazakhstan. Series of chemistry and technology. 2016. Vol. 3. N 417, p. 135-144 (in Russian).
- Noskov А.S The scientific and technical level of research and the prospects for import substitution in the field of industrial catalysts. Vestnik Rossiiskoi akademii nauk. 2022. Vol. 92. N 10, p. 940-949. DOI: 10.31857/S0869587322100085
- Mengdan Huo, Tong Yu, Yu Wang et al. In-situ Ti doping induces distortion of mullite whiskers in fly ash-based ceramic membranes for enhanced oil-water separation performance. Journal of Environmental Chemical Engineering. 2025. Vol. 13. Iss. 6. № 119281. DOI: 10.1016/j.jece.2025.119281
- Roy R., Das D., Rout P.K. Mullite Ceramics Derived from Fly Ash Powder by Using Albumin as an Organic Gelling Agent. Biointerface Research in Applied Chemistry. 2023. Vol. 13. Iss. 4. N 339. DOI: 10.33263/BRIAC134.339
- Beiyue Ma, Chang Su, Xinming Ren et al. Preparation and properties of porous mullite ceramics with high-closed porosity and high strength from fly ash via reaction synthesis process. Journal of Alloys and Compounds. 2019. Vol. 803, p. 981-991. DOI: 10.1016/j.jallcom.2019.06.272
- Zhengbo Li, Yuhao Peng, Hongda Ren et al. Co-sintering of bauxite tailings and fly ash for low-density ceramic proppants: Sintering mechanism and process optimization. Ceramics International. 2025. Vol. 51. Iss. 26. Part C, p. 51267-51277. DOI: 10.1016/j.ceramint.2025.08.353
- Yingchao Dong, Hui Wu, Fenglin Yang, Stephen Gray. Cost and efficiency perspectives of ceramic membranes for water treatment. Water Research. 2022. Vol. 220. N 118629. DOI: 10.1016/j.watres.2022.118629
- Wan Fan, Dong Zou, Jingrui Xu et al. Enhanced Performance of Fly Ash-Based Supports for Low-Cost Ceramic Membranes with the Addition of Bauxite. Membranes. 2021. Vol. 11. Iss. 9. N 711. DOI: 10.3390/membranes11090711
- Zou Xinwei, Hou Ruyuan, Hao Jianying et al. The low temperature preparation of ultra low-density ceramic proppants by adding fly ash. Ceramics-Silikáty. 2020. Vol. 64. Iss. 2, p. 107-114. DOI: 10.13168/cs.2019.0055
- Yarotskaya E.G., Fedorov P.P. Mullite and its isomorphic substitution. Overview. Condensed Matter and Interphases. 2018. Vol. 20. N 4, p. 537-544 (in Russian). DOI: 10.17308/kcmf.2018.20/626
- Grushko I.S. Ways of Formation and Features of Development of the Crystal Phase in Amorphous Material (A Review). Glass Physics and Chemistry. 2020. Vol. 46. N 6, p. 549-561. DOI: 10.1134/S1087659620060103
- Koshy P., Ho N., Zhong V. et al. Fly Ash Utilisation in Mullite Fabrication: Development of Novel Percolated Mullite. Minerals. 2021. Vol. 11. Iss. 1. N 84. DOI: 10.3390/min11010084
- Kotova O.B., Ustyugov V.A., Shiyong Sun, Ponaryadov A.V. Mullite production: phase transformations of kaolinite, thermodynamics of the process. Journal of Mining Institute. 2022. Vol. 254, p. 129-135. DOI: 10.31897/PMI.2022.43
- Wei Lian, Yan Liu, Wenjie Wang et al. Preparation of environmentally friendly low‐cost mullite porous Ceramics and the effect of Waste Glass Powder on structure and mechanical Properties. International Journal of Precision Engineering and Manufacturing-Green Technology. 2022. Vol. 9. Iss. 2, p. 577-585. DOI: 10.1007/s40684-021-00333-8
- Dey S., Ray D., Mondal A., Parya T.K. Effect of yttria on sintering and microstructural behavior of reaction sintered mullite based on bauxite, fly ash and precipitated silica. Ceramics International. 2018. Vol. 44. Iss. 9, p. 10087-10093. DOI: 10.1016/j.ceramint.2018.02.214
- Mao Fu, Jing Liu, Xinfa Dong et al. Waste recycling of coal fly ash for design of highly porous whisker-structured mullite ceramic membranes. Journal of the European Ceramic Society. 2019. Vol. 39. Iss. 16, p. 5320-5331. DOI: 10.1016/j.jeurceramsoc.2019.08.042
- Mahnicka-Goremikina L., Rundans M., Goremikins V. et al. Effect of Microsize and Nanosize TiO2 on Porous Mullite-Alumina Ceramic Prepared by Slip Casting. Materials. 2024. Vol. 17. Iss. 24. N 6171. DOI: 10.3390/ma17246171
- Olcoski T.A., Chinelatto A.L., Chinelatto A.S.A. Effect of MgO addition on the sinterability and mechanical properties of mullite ceramics. Cerâmica. 2021. Vol. 67 (383), p. 261-268. DOI: 10.1590/0366-69132021673833075
- Jian-bin Zhu, Hong Yan. Microstructure and properties of mullite-based porous ceramics produced from coal fly ash with added Al2O3. International Journal of Minerals, Metallurgy, and Materials. 2017. Vol. 24. Iss. 3, p. 309-315. DOI: 10.1007/s12613-017-1409-2
- Zhiwen Zhu, Zhaoling Wei, Wenping Sun et al. Cost-effective utilization of mineral-based raw materials for preparation of porous mullite ceramic membranes via in-situ reaction method. Applied Clay Science. 2016. Vol. 120, p. 135-141. DOI: 10.1016/j.clay.2015.11.020
- Zhentao Cui, Tianran Hao, Shuaifeng Yao, Hongliang Xu. Preparation of porous mullite ceramic supports from high alumina fly ash. Journal of Material Cycles and Waste Management. 2023. Vol. 25. Iss. 2, p. 1120-1129. DOI: 10.1007/s10163-023-01598-8
- Belyaev I.V., Stepnov A.A., Mogilnikov P.S., Kireev A.V. Effect of Heat Treatment Temperature on Dilatometric and Densimetric Characteristics of Plasma-Sprayed Al2O3 Ceramics. Inorganic Materials. 2022. Vol. 58. N 7, p. 744-750. DOI: 10.1134/S0020168522070044
Similar articles
Activation of bioremediation processes in oil-contaminated terrestrial ecosystems using a composition of organomineral ameliorants
2026 Natalya Yu. Antoninova, Albert I. Usmanov, Vladimir A. Antonov, Artem V. Sobenin
Effect of drilling sludge cleaning methods on proppant properties
2026 Elena A. Yatsenko, Sergei V. Trofimov, Boris M. Goltsman, Lyudmila V. Klimova
Production of calcium carbonate with tailored particle size characteristics as a factor in efficient recycling of gypsum-containing technogenic raw materials
2026 Denis V. Suchkov, Tatyana E. Litvinova, Andrei P. Lebedev
Rationale for the application parameters of unmodified iron-magnesium production waste as a nature-like ameliorant for cadmium immobilization
2026 Natalya Yu. Antoninova, Artem V. Sobyanin, Albert I. Usmanov, Yaroslava A. Kuznetsova