Caracterización de arcillas provenientes de la mina Murano del municipio el Zulia, Norte de Santander,Colombia.

Abstract

This work was focused on the characterization of clays from La Alejandra Township in the municipality of El Zulia - Colombia. For this purpose, we collected five samples from the mantles exposed on the mine. In order to determine the chemical and mineralogical composition, samples were analyzed using X-ray diffraction (XRD) and X-ray fluorescence (XRF). The characterization of the chemical functional groups of the minerals, was performed by infrared spectroscopy with Fourier´s transformed (FTIR). The thermal behavior was determined with thermogravimetric analysis (TGA) and differential thermal analysis (DTA). In addition, the main physical properties such as particle size distribution, Atterberg´s limits of plasticity, linear shrinkage under air drying and under firing, and water absorption were determined. The chemical analysis showed that the main components of the samples were SiO2, Al2O3 and Fe2O3. Moreover, the mineralogical analysis indicated that all samples contained anatase, quartz, kaolinite and hematite. Muscovite was found only in F2 and F5 samples. Infrared spectroscopy analyses of samples confirm the characteristics of kaolinite clay and the typical absorption bands of quartz. TGA analysis of samples, exhibited three lost weight changes: dehydration, decomposition of organic matter and dehydroxylation of kaolinite. In addition, the TGA curves revealed the presence of carbonates in all samples. The DTA analysis showed the peaks of the dehydroxylation of kaolinite (450°C -505°C), and endothermic and exothermic peaks of formation of mullite (935°C-990°C). The results of XRD, DTA and FTIR allow us to determine that the kaolinite was structurally ranked. Analyses of clays physical properties indicated that the samples have middle plasticity, except sample F3, which was highly plastic. In addition, the ability of clay, determined by the particle size analysis, indicates that clay can be used directly in the manufacture of lightweight blocks and tiles. Curves of glazing along with the analysis of structural order/disorder showed that the process of sintering of clay is not complete at temperatures less or equal to1200 ° C.