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Abstract
West Africa generates hundreds of millions of tonnes of crop residues each year that are largely under-utilised, openly burned, or dumped in waterways. This review examines the recycling of agro-waste ashes (AWA)—principally rice husk ash (RHA), cassava peel ash (CPA), cocoa pod husk ash (CPHA), palm-oil fuel ash (POFA) and maize-stalk ash (MSA)—as silica sources, fluxes and porogens in ceramic matrix composites. The silica-, alumina- and alkali-rich chemistry of these ashes allows them to substitute quartz, feldspar and lime in clay bricks, vitrified stoneware, refractories, glass-ceramics and wall tiles. Cocoa-pod, cassava-peel and rice-husk ashes accumulated between 2015 and 2025 are the most attractive ceramic feedstocks because of high amorphous silica (70–95% in selected RHA), substantial K₂O/CaO fluxes, and a demonstrated ability to lower sintering temperatures by 50–200 °C. Experimental West-African work shows that ≥15% CPA substitution can raise fired-clay flexural strength from 7.8 to 16.5 MPa, that 10% cocoa-cortex ash yields ISO 13006 stoneware (flexural strength 32 MPa; water absorption 2%), and that potash leached from cocoa pods produces stabilised bricks above the 4 MPa load-bearing threshold. AWA valorization is therefore a strategic route for the regional ceramics industry to cut raw-material imports, firing energy, and the environmental burden of agricultural residues.