Ceramics-Silikáty 57 (4) 305-312 (2013)

DURABILITY PERFORMANCE OF RFCC SPENT CATALYSTBLENDED PORTLAND CEMENT PASTE EXPOSED TO SEA WATER ATTACK

This paper discusses the performance of the paste of Portland cement blended with spent catalyst from Resid Fluidized Catalytic Cracking (RFCC) unit of petroleum refining processes in sea water. 28-day cured paste specimens prepared from binary cement mixes containing different amounts of spent catalyst were exposed to Persian Gulf sea water. Compressive strength, weight, and length changes of the specimens were monitored and considered for evaluating the extent of deterioration. Laboratory techniques of X-ray diffractometry, scanning electron microscopy, and Energy dispersive X-ray spectroscopy were also used to study the deteriorated specimens. The results confirm that at relatively high replacement levels, the pozzolanic property of the spent catalyst and the increased open pore volume of such blended cements may result in contradictory consequences. Specimens of relatively higher replacement levels exhibit higher rates of deterioration in spite of their superior mechanical strength behavior caused by pozzolanic reaction. The results obtained by X-ray diffractometry confirm the presence of higher amounts of chlorine-containing Friedel’s salt in specimens containing RFCC spent catalyst compared to plain reference specimens.

Keywords: Spent Catalyst, Catalytic cracking unit, Portland cement, Sea water