Chemical activation of pozzolanic reaction of fluid catalytic cracking catalyst residue (FC3R) in lime pastes: thermal analysis

Abstract

In this paper, the role and reactivity of fluid catalytic cracking catalyst residue (FC3R) as a pozzolanic mineral admixture are studied. For that purpose, thermogravimetric (TG) studies of several FC3R/lime pastes, activated by using different chemical compounds (NaOH, gypsum, CaCl2 and Na2SO4), were performed. First, lime fixation and the nature of the hydration products were characterised from TG curves. Second, sodium sulphate was considered as the best chemical activator in the lime fixation process, yielding a 100% of fixed lime for short curing periods. In addition, hydrated gehlenite crystals incorporating sulphate ions were identified, mainly in cured pastes. From these experimental studies, it can be concluded that FC3R is a very good pozzolanic material for inclusion in lime pastes and mortars, and the addition of a small amount of Na2SO4 and CaCl2 enhanced the reactive ability of FC3R with hydrated lime.