Síntese de zeólita LTA utilizando resíduos de cinzas leves de carvão

Abstract

Mineral coal is a solid fossil fuel that in the burning process generates large volumes of waste. As it is a waste that contains heavy metals, its disposal in inappropriate places causes great environmental impacts. In order to minimize waste management problems, this material was used in the synthesis process of zeolites, which are porous crystalline materials based on aluminosilicates. The residue used as a study was supplied by SATC Florianópolis - SC and has 24.09% Al2O3 and 54.25% SiO2 in its chemical composition. Synthesis studies using light coal ash with the objective of obtaining LTA zeolite were carried out, through conventional hydrothermal, alkaline fusion followed by conventional hydrothermal route and through a synthesis route applying sonochemical process through ultrasonification. In the studies applied to the methodologies, parameters such as: crystallization time, Na / T and OH / T ratio varied from 1.6 to 2.0 and 1.25 to 1.66 respectively, where T is Si + Al, pre treatment of the residue through ultrasound, temperature of agitation of the gel from 25 ° C to 80 ° C and alkaline melting temperature of the residue in the ranges of 200 ° C, 300 ° C and 500 ° C. Through the obtained studies it was verified that the methodology in two stages presented better results regarding the formation of the zeolitic product obtaining a percentage of crystallinity above 70% in 2h of crystallization. The synthesis results were characterized by X-ray diffraction techniques (XRD) and scanning electron microscopy (SEM-FEG).