{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,13]],"date-time":"2026-03-13T06:21:26Z","timestamp":1773382886081,"version":"3.50.1"},"reference-count":66,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,8,1]],"date-time":"2025-08-01T00:00:00Z","timestamp":1754006400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Recycling"],"abstract":"<jats:p>The objective of this work is to evaluate how spent catalyst from fluid catalytic cracking (SCFCC) affects the physical, mechanical and durability properties of fly ash (FA) and blast furnace slag (BFS)-based alkali-activated materials (AAMs). Recycling of SCFCC by integrating it in a AAM matrix offers several advantages: valorization of the material, reducing its disposal in landfills and the landfill cost, and minimizing the environmental impact. Mineralogical, physical and mechanical characterization were carried out. The durability of the specimens was studied by performing acid attack and thermal stability tests. Mass variation, compressive strength and porosity parameters were determined to assess the durability. BFS- and FA-based AAMs have a different chemical composition, which contribute to variations in microstructure and physical and mechanical properties. Acid neutralization capacity was also determined to analyse the acid attack results. Porosity, including the pore size distribution, and the acid neutralization capacity are crucial in explaining the resistance of the AAMs to sulfuric acid attack and thermal degradation. Herein, a novel route was explored, the use of SCFCC to enhance the durability of AAMs under harsh operating conditions since results show that the compositions containing SCFCC showed lower strength decay due to the lower macroporosity proportions in these compositions.<\/jats:p>","DOI":"10.3390\/recycling10040149","type":"journal-article","created":{"date-parts":[[2025,8,1]],"date-time":"2025-08-01T06:37:47Z","timestamp":1754030267000},"page":"149","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Evaluation of Spent Catalyst from Fluid Catalytic Cracking in Fly Ash and Blast Furnace Slag Based Alkali Activated Materials"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0117-8316","authenticated-orcid":false,"given":"Yolanda","family":"Luna-Galiano","sequence":"first","affiliation":[{"name":"Chemical and Environmental Engineering Department, Technical and Higher School of Engineering, University of Seville, 41092 Seville, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-6756-0922","authenticated-orcid":false,"given":"Domingo","family":"Cabrera-Gallardo","sequence":"additional","affiliation":[{"name":"Chemical and Environmental Engineering Department, Technical and Higher School of Engineering, University of Seville, 41092 Seville, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6157-2633","authenticated-orcid":false,"given":"M\u00f3nica","family":"Rodr\u00edguez-Gal\u00e1n","sequence":"additional","affiliation":[{"name":"Chemical and Environmental Engineering Department, Technical and Higher School of Engineering, University of Seville, 41092 Seville, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5698-9135","authenticated-orcid":false,"given":"Rui","family":"Novais","sequence":"additional","affiliation":[{"name":"Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4782-1685","authenticated-orcid":false,"given":"Jo\u00e3o","family":"Labrincha","sequence":"additional","affiliation":[{"name":"Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7967-8102","authenticated-orcid":false,"given":"Carlos","family":"Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Chemical and Environmental Engineering Department, Technical and Higher School of Engineering, University of Seville, 41092 Seville, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.wasman.2020.04.046","article-title":"Sustainable management of spent fluid catalytic cracking catalyst from a circular economy approach","volume":"110","author":"Arenas","year":"2020","journal-title":"Waste Manag."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/j.apcata.2007.01.013","article-title":"Hydroprocessing catalysts regeneration and recycling","volume":"322","author":"Dufresne","year":"2007","journal-title":"Appl. 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