Pozzolanic activity of a spent fluid catalytic cracking catalyst residue

The reaction between a spent fluid cracking catalyst (FC3R) residue and portlandite was monitored over 56 days using several material characterisation techniques. The results showed that the residue was heterogeneous and composed of reactive and non-reactive fractions and that both fractions contained silicon and aluminium. After 56 days, the development of C–S–H gel was evident; part of the catalyst residue was pozzolanic. The CH combination could be monitored by thermogravimetry or X-ray diffraction, by measuring the signal corresponding to CH. However, due to the low crystallinity of cementing products and their complex stoichiometry, the above-mentioned techniques were less able to characterise C–A–S–H. However, nuclear magnetic resonance techniques allowed the evolution of the pozzolanic reaction to be evaluated and the hydrate products to be characterised.