Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation

zeolite a was synthesized using the coal ash from siderópolis/rs - brazil. the synthesis was based on a standard iza synthesis using coal ash as the si and al source. xrf analysis showed that the coal ash has a si/al ratio of 1.52, which is close to the si/al ratio required to produce zeolite a (1.0). the synthesized materials were analyzed by xrd, sem and n2 adsorption. more crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 k at the dissolution of naoh step. the product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours iza synthesis. the zeolites synthesized by this method had an adsorption capacity of 120 mg.g-1 for ca2+, half the capacity of commercial zeolite a (300 mg.g-1). it was not possible to obtain blue or green pigments using the synthesized zeolite a.