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Utilization of a Spent FCC Catalyst in Kaolin-Based Ceramics: Sintering Behavior and Phase Evolution
Authors:
Ganka Kolchakova1
, Yancho Hristov1
1Department of Materials Science, Burgas State University “Prof. Dr. Assen Zlatarov”, Bulgaria
Received: 16 April 2026
Revised: 19 June 2026
Accepted: 25 June 2026
Published: 29 June 2026
Abstract:
Spent fluid catalytic cracking (FCC) catalysts represent an environmental challenge. Due to their high Al₂O₃ and SiO₂ content, they have significant potential for reuse as raw materials and additives in ceramics. In this work, the sintering behaviour, phase evolution and densification of kaolin- based ceramics were studied. Compositions containing 30, 50, and 70 mass% spent FCC catalyst (designated as C30, C50, and C70) were developed. The pressed blends were fired at temperatures between 1250 and 1500°C. X‑ray diffraction results show that the C50 samples present the highest mullite content, while cristobalite dominates in the C70 composition. C30 composition achieved the best densification. At 1500°C, they reach an apparent density of 2.38 g/cm3, an apparent porosity of up to 5.4% and water absorption of 2.3%. The decrease in surface area of the C30 sample—from 58.9 m²/g in the raw state to 1.3 m²/g after firing at 1250°C—confirms effective sintering. These results show that the spent FCC catalyst is an effective additive in ceramic production.
Keywords:
Spent FCC catalyst, Kaolin, Ceramics, Sintering, Phase evolution, Mullite
References:
[1] M.S. Akhtar, S. Ali, W. Zaman, Recent Advancements in Catalysts for Petroleum Refining. Catalysts, 14(12), 2024: 841. https://doi.org/10.3390/catal14120841
[2] E.T.C. Vogt, B.M. Weckhuysen, Fluid catalytic cracking: recent developments on the grand old lady of zeolite catalysis. Chemical Society Reviews, 44(20), 2015: 7342–7370. https://doi.org/10.1039/c5cs00376h
[3] E. Aghaei, R. Karimzadeh, H.R. Godini, A. Gurlo, O. Gorke, Improving the physicochemical properties of Y zeolite for catalytic cracking of heavy oil via sequential steam-alkali-acid treatments. Microporous and Mesoporous Materials, 294, 2020: 109854. https://doi.org/10.1016/j.micromeso.2019.109854
[4] A. Gil, I. Sancho-Sanz, S.A. Korili, Progress and Perspectives in the Catalytic Hydrotreatment of Bio-Oils: Effect of the Nature of the Metal Catalyst. Industrial & Engineering Chemistry Research, 63(27), 2024: 11759–11775. https://doi.org/10.1021/acs.iecr.4c00747
[5] L. Wang, J. Guo, C. Li, R. Xiong, X. Chen, X. Zhang, Advancements and future prospects in in-situ catalytic technology for heavy oil reservoirs in China: A review. Fuel, 374, 2024: 132376.
https://doi.org/10.1016/j.fuel.2024.132376
[6] T. Gameiro, C. Costa, J. Labrincha, R.M. Novais, Reusing spent fluid catalytic cracking catalyst as an adsorbent in wastewater treatment applications. Materials Today Sustainability, 24, 2023: 100555. https://doi.org/10.1016/j.mtsust.2023.100555
[7] H. Al-Dhamri, K. Melghit, Use of alumina spent catalyst and RFCC wastes from petroleum refinery to substitute bauxite in the preparation of Portland clinker. Journal of Hazardous Materials, 179(1–3), 2010: 852–859. https://doi.org/10.1016/j.jhazmat.2010.03.083
[8] A. Pathak, M.S. Rana, M. Marafi, R. Kothari, P. Gupta, V. Tyagi, Waste petroleum fluid catalytic cracking catalysts as a raw material for synthesizing valuable zeolites: A critical overview on potential, applications, and challenges. Sustainable Materials and Technologies, 38, 2023: e00733.
https://doi.org/10.1016/j.susmat.2023.e00733
[9] C. Ren, R.K. Enneti, Latest Developments in Manufacturing and Recycling of Refractory Materials. JOM, 73, 2021: 3401–3402. https://doi.org/10.1007/s11837-021-04890-w
[10] C. Bories, L. Aouba, E. Vedrenne, G. Vilarem, Fired clay bricks using agricultural biomass wastes: Study and characterization. Construction and Building Materials, 91, 2015: 158–163.
https://doi.org/10.1016/j.conbuildmat.2015.05.006
[11] G. Han, S. Yang, W. Peng, Y. Huang, H. Wu, W. Chai, J. Liu, Enhanced recycling and utilization of mullite from coal fly ash with a flotation and metallurgy process. Journal of Cleaner Production, 178, 2018: 804–813. https://doi.org/10.1016/j.jclepro.2018.01.073
[12] B.C.A. Pinheiro, J.N.F. Holanda, Reuse of solid petroleum waste in the manufacture of porcelain stoneware tile. Journal of Environmental Management, 118, 2013: 205–210.
https://doi.org/10.1016/j.jenvman.2012.12.043
[13] A.M.E. Khalil, M. Egiza, M.R. Diab, E. Ali, D. Xie, S. Zhang, Recycling industrial waste into sustainable high-temperature ceramics: A review of materials, processing, and circular economy strategies. Results in Engineering, 30, 2026: 109933. https://doi.org/10.1016/j.rineng.2026.109933
[14] S.M. Emami, A. Ramezani, S. Nemat, Recycling of spent FCC catalyst for the production of synthetic mullite. Results in Engineering, 30, 2026: 110053. https://doi.org/10.1016/j.rineng.2026.110053
[15] M. Ishaq, A. Ali, A.A. Hussain, K. Kamran, A. Ghuffar, A. Anwar, Industrial waste as clay substitute in brick manufacturing. Construction and Building Materials, 477, 2025: 141359.
https://doi.org/10.1016/j.conbuildmat.2025.141359
[16] ISO 5017:2025. Dense shaped refractory products — Determination of bulk density, apparent porosity and true porosity. International Organization for Standardization, Geneva, Switzerland, 2025.
[17] ISO 5014:2025. Dense and insulating shaped refractory products — Determination of modulus of rupture at ambient temperature. International Organization for Standardization, Geneva, Switzerland, 2025.
[18] E. Restrepo, F. Vargas, E. López, C. Baudín, The potential of La-containing spent catalysts from fluid catalytic cracking as feedstock of mullite based refractories. Journal of the European Ceramic Society, 40(15), 2020: 6162–6170. https://doi.org/10.1016/j.jeurceramsoc.2020.04.051
[19] A. Ramezani, S.M. Emami, S. Nemat, Reuse of spent FCC catalyst, waste serpentine and kiln rollers waste for synthesis of cordierite and cordierite-mullite ceramics. Journal of Hazardous Materials, 338, 2017: 177–185. https://doi.org/10.1016/j.jhazmat.2017.05.029
[20] Z. Zhao, Z. Qiu, J. Yang, S. Lu, L. Cao, W. Zhang, Y. Xu, Recovery of rare earth elements from spent fluid catalytic cracking catalysts using leaching and solvent extraction techniques. Hydrometallurgy, 167, 2017: 183–188. https://doi.org/10.1016/j.hydromet.2016.11.013
[21] C. Buttersack, A. König, R. Gläser, Stability of a highly dealuminated Y-zeolite in liquid aqueous media. Microporous and Mesoporous Materials, 281, 2019: 148–160.
https://doi.org/10.1016/j.micromeso.2019.02.014
[22] B.A. Holmberg, H. Wang, Y. Yan, High silica zeolite Y nanocrystals by dealumination and direct synthesis. Microporous and Mesoporous Materials, 74(1–3), 2004: 189–198.
https://doi.org/10.1016/j.micromeso.2004.06.018
[23] E. Gasparini, S.C. Tarantino, P. Ghigna, M.P. Riccardi, E.I. Cedillo-González, C. Siligardi, M. Zema, Thermal dehydroxylation of kaolinite under isothermal conditions. Applied Clay Science, 80–81, 2013: 417–425. https://doi.org/10.1016/j.clay.2013.07.017
[24] P. Ptáček, F. Šoukal, T. Opravil, J. Havlica, J. Brandštetr, The kinetic analysis of the thermal decomposition of kaolinite by DTG technique. Powder Technology, 208(1), 2011: 20–25.
https://doi.org/10.1016/j.powtec.2010.11.035
[25] A.K. Chakraborty, DTA study of preheated kaolinite in the mullite formation region. Thermochimica Acta, 398(1–2), 2003: 203–209. https://doi.org/10.1016/S0040-6031(02)00367-2
[26] F. Chargui, M. Hamidouche, H. Belhouchet, Y. Jorand, R. Doufnoune, G. Fantozzi, Mullite Fabrication From Natural Kaolin and Aluminium Slag. Boletín de la Sociedad Española de Cerámica y Vidrio, 57(4), 2018: 169-177. https://doi.org/10.1016/j.bsecv.2018.01.001
[27] Z. An, Y. Gao, J. Chen, Combined effect of La2O3 and Fe2O3 on the crystallization behavior and microstructure of CaO-MgO-Al2O3-SiO2 glass-ceramics. Ceramics International, 51(15), 2025: 21008–21016. https://doi.org/10.1016/j.ceramint.2025.02.269
[28] Z. Liu, W. Lian, Y. Liu, J. Zhu, C. Xue, Z. Yang, X. Lin, Phase formation, microstructure development, and mechanical properties of kaolin‐based mullite ceramics added with Fe2O3. International Journal of Applied Ceramic Technology, 18(3), 2021: 1074–1081. https://doi.org/10.1111/ijac.13720
[29] M. Omerašević, M. Krsmanović, N. Adamović, C.-A. Wang, D. Bučevac, Effect of Fe2O3 on Compressive Strength and Microstructure of Porous Acicular Mullite. Ceramics, 8(3), 2025: 111.
https://doi.org/10.3390/ceramics8030111
[30] P.S. Behera, S. Bhattacharyya, Effect of different alumina sources on phase formation and densification of single-phase mullite ceramic – Reference clay alumina system. Materials Today Communications, 26, 2021: 101818. https://doi.org/10.1016/j.mtcomm.2020.101818
[31] A. Shvarzman, K. Kovler, G.S. Grader, G.E. Shter, The effect of dehydroxylation/amorphization degree on pozzolanic activity of kaolinite. Cement and Concrete Research, 33(3), 2003: 405–416.
https://doi.org/10.1016/s0008-8846(02)00975-4
© 2026 by the authors. This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0)
Volume 11
Number 2
June 2026
Last Edition
Volume 11
Number 1
March 2026
How to Cite
G. Kolchakova, Y. Hristov, Utilization of a Spent FCC Catalyst in Kaolin-Based Ceramics: Sintering Behavior and Phase Evolution. Applied Engineering Letters, 11(2), 2026: 96-105.
https://doi.org/10.46793/aeletters.2026.11.2.4