Caracterização e estudo da atividade pozolânica do caulim e do metacaulim da cidade de Cocal de Telha PI

Abstract

Kaolin is a generic term used to name the rock that contains kaolinite, a clay mineral composed of hydrated aluminum and iron silicates, which may also contain varying amounts of cations of alkaline and alkaline-earth elements. Metakaolin is a pozzolanic material, derived from the calcination of kaolin. Both kaolin and its byproduct are widely used in the ceramic and cement industries. The objective of this work was to characterize and analyze the chemical and mechanical properties of kaolin from the Queimada Nova community, municipality of Cocal de Telha-PI, and of the metakaolin obtained after heat treatment. Metakaolin was obtained from kaolin after thermal treatment at temperatures of 400ºC, 500ºC, 600ºC and 700ºC. Kaolin and metakaolins were characterized by X-Ray Fluorescence (FRX), X-Ray Diffraction (XRD), Thermal Analysis - ATG and Spectroscopy - by FTIR. The evaluation of pozzolanic activity was determined through electrical conductivity, according to the method by Luxán et al. (1989) and by compressive strength, according to NBR 5752:2014 and NBR 12653:2014 standards. After the characterizations, it was possible to observe through the FRX, DRX and FTIR analyzes that the collected sample consists of kaolin and that after the heat treatment metakaolin was obtained. Studies of pozzolanic activity using the method by Luxán et al. (1989), show that the samples that the calcined samples, called MK-600 and MK-700, presented the best results, according to the compressive strength tests, all samples can be classified as material of good pozzolanic potential. Thus, the collected kaolin is an alternative raw material for obtaining metakaolin.