ALKALI-ACTIVATED BINDERS PRODUCED FROM PETROCHEMICAL FLUID CATALYTIC CRACKING CATALYST WASTE

Carla Costa, Cátia Ferreira, M. Filipa Ribeiro, Auguste Fernandes

Abstract: This paper describes research on the viability of producing alkali activated binders using the aluminosilicate catalyst waste - generated by the fluid catalytic cracking (wFCC) unit in the Portuguese oil refinery company - as precursor. For this purpose, alkali-activated wFCC catalyst based mortars and cement pastes were produced. Tests were carried out to evaluate the effect of initial solids composition (wFCC catalyst/Ca(OH)2 ratio) on mortars workability or mechanical strength. The mineralogy and microstructure of the hardened alkali activated wFCC catalyst pastes were studied by means of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results obtained at macroscale showed that the content of Ca(OH)2 incorporated in the binder has a significant effect on compressive strength of hardened mortars. At microscale, FTIR and XRD results confirmed the occurrence of alkali-activation of the wFCC catalyst which leads to the formation of distinctive amorphous and crystalline products. Moreover, the obtained results also suggest that initial solids composition influences the alkali-activation reaction kinetics and mechanism.

Keywords: Alkali-activated binders, waste FCC catalyst, Mechanical strength, FTIR, XRD

DOI: https://doi.org/10.15623/ijret.2014.0325019