Synthesis of a Geopolymer Binders Using Spent Fluid Catalytic Cracking (FCC) Catalyst

A synthesis of a geopolymer binder using spent fluid catalytic cracking (FCC) catalyst is evaluated in this research. Spent FCC catalyst is a solid waste product from the oil refining industry worldwide. It is composed mainly by aluminium and silicon oxides. The silica modulus (Ms), NaOH molar concentration, and liquid/solid (AS/FCC) weight ratio were studied as key factors of the mixture composition for the evaluation of the compressive strength and bulk density of geopolymers. Additional total ratios of SiO₂/Al₂O₃, Na₂O/SiO₂, and H₂O/total solids, which consider chemical composition of the final mixture, were studied. Results indicate that there is an optimum value for each Ms, NaOH molar concentration and AS/FCC that produces the maximum compressive strength. These values also match with the optimized total ratios of SiO₂/Al₂O₃, N₂O/SiO₂ and H₂O/total solids in the mixture, which can be considered as alternative control parameters for the formulation process. The bulk density is more related to AS/FCC value. A geopolymer binder with a compressive strength of 24.7 MPa after curing for one day at 65°C and six days at room temperature was produced using this spent FCC waste.