Mechanical properties and microstructure of cement mortars incorporating Cd-zeolitized fly ash

MONZÓN, J. D.; PEREYRA, A. M.; GONZALEZ, M. R.; ZERBINO, R. L.; BASALDELLA, ELENA I.

JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT

SPRINGER

Año: 2018 vol. 20 p. 2130 - 2139

1438-4957

A solid enriched with NaA zeolite was synthesized from a coal fly ash, and the so-obtained zeolitized material was usedas ion exchanger for purifying aqueous solution containing cadmium cations. Mechanical strengths and drying shrinkagemeasured on cement mortars containing not more than 10 wt% of the zeolitized product showed that the cement propertiesremained unaltered, being similar to those corresponding to mortars where non-zeolitized starting fly ash was used inthe mortar formulation. SEM analyses of fractured mortars show zeolitized fly ash particles strongly anchored inside themicrostructure, the particle surfaces being densely covered by hydration products. To analyze the viability of final disposalfor the cadmium sludge obtained after ion exchange, a leaching test was performed on cement pastes containing 10 wt% ofcadmium-exchanged zeolite (Cd-ZFA10) showing that the present methodology is an effective procedure for the immobilizationof the heavy metal