Influence of Shea Shell Waste as a Biomass Additive on Thermal Transformations, Gas Emissions, and the Properties of Sustainable Building Ceramics

The study investigated and quantified the feasibility of using waste derived from shea tree fruit shells ( Vitellaria paradoxa ) as an organic multifunctional additive for building ceramic bodies, focusing on its influence on thermal behavior, pore formation, and mechanical performance. The scope of the research included sieve analysis, chemical analysis (WDXRF), phase composition analysis (XRD), thermal analysis coupled with evolved gas analysis (DTA–TG–EGA), and the evaluation of the physical and mechanical properties of the obtained ceramic materials. The analyses demonstrated that the shea waste was characterized by a high content of organic matter, a loss in ignition of 93.84%, and a calorific value of 19.421 kJ/g. The incorporation of biomass resulted in increased porosity and reduced apparent density of the ceramic materials. The relative porosity increased from 27.00% for the reference sample to 34.98% for the sample containing 30% shea waste. Simultaneously, the compressive strength decreased from 23.67 MPa to 10.10 MPa, while the flexural strength decreased from 8.96 MPa to 4.76 MPa. Partial replacement of conventional mineral additives and, in particular, partial substitution of fossil-derived kiln fuel demand with high-calorific biomass enabled a reduction in overall CO 2 emissions associated with ceramic production. This includes both process-related emissions from raw material decomposition and fuel-related emissions generated in the tunnel kiln. In addition, a reduced contribution of carbon originating from inorganic mineral sources (including carbonates) to total emissions covered by emission trading systems (ETSs) was observed. Despite the reduction in mechanical parameters, samples containing up to 20% shea waste retained properties suitable for application in the production of ceramic building materials.