Compósito geopolimérico adicionado de vermiculita in natura para revestimento de instalações rurais.

Abstract

The mining sector has a high importance in Brazil's economic growth. However, this segment is considered as one of the most aggressive for the environment. In Paraíba this market stands out with the exploration of vermiculite, which when submitted to a thermal process expands and is used in various sectors such as agriculture, water treatment and civil construction. However, in its granulometric processing, this mineral generates a high amount of residue that so far has no application. Thus, the present work aims to use the residue in geopolymeric composite to produce coating plates with thermal insulating properties for use in rural installations. A geopolymeric composite was elaborated with metakaolin, sodium silicate, sodium hydroxide and additions of vermiculite residue ranging from 20% to 100% were made. In the characterization of this composite, mechanical strength tests (simple compression and bending), water absorption by immersion, loss of mass by immersion and erosion, thermal conductivity by the K30 conductimeter method, thermal behavior by the mini wall method were performed. For chemical analysis, x-ray diffraction, X-ray fluorescence, infrared spectroscopy, thermogravimetry, nuclear magnetic resonance and finally scanning electron microscopy were performed. The composites with the addition of 20% and 40% of vermiculite residue had compressive strength of 13.2 and 19.9 MPa and bending resistance of 3.6 and 6.9 MPa, respectively. Water absorption by immersion, loss of mass by immersion and loss of mass by erosion within those established by standardization. As for thermal conductivity, the composites with 20% and 40% of residue registered 0.156 W/m.K and 0.155 W/m.K, which is lower than the conductivity of the plaster. In the XRD it was possible to observe the formation of an amorphous profile that characterizes the generation of N-A-S-H gel, but each composite had untinted mineralogical creation. With these results, the composite is promising to produce elements (plates) for coating that guarantees thermal comfort to rural installations.