Sodic and Potassium Zeolites from Fly Ash Coming from Coal Combustion of Thermoelectric Termotasajero S.A.S

Abstract

The fly ash (CV) of Termotasajero S.A.S, is a residue of coal combustion with high environmental impact on air, water, soil and ecosystems. They have a high content of Si and Al, which makes them an optimal by-product for the production of zeolites. The CV were sieved and leached in order to produce high purity zeolites. The synthesis was carried out by the hydrogel method in activation with alkalis of NaOH-2M and KOH-5M, crystallization of 2h and 3h respectively, at 90° C and 560 rpm. The sodium and potassium zeolites presented a Si/Al molar ration of 1.19 and 1.00 respectively, which were classified as zeolites natrosilite and zeolite K-F, according to the ray-X diffraction pattern (DRX). In the zeolitic product, the main elements were identified as Si, Al, O, Na, K, Ca, Fe, and in smaller proportions Ti and Mg, with irregular morphology of microcrystals with particle sizes less than 12 micrometers (μm). The analysis of Cationic Exchange Capability (CIC) shows the ionic capability of the material, finding that the highest value (141 meq/100g) corresponds to the zeolites activated with NaOH.