Estudo da influência do tratamento termo-mecânico nas propriedades do resíduo de ardósia

Abstract

Mining represents an important sector within the Brazilian economy, with a direct influence on the country's development, however, it is responsible for major environmental impacts and the generation of environmental liabilities. In order to minimize these problems, the search for waste recovery solutions has become common. The aim of this study was to evaluate changes in slate residue properties after the thermo-mechanical treatment process (calcination and grinding) in an attempt to activate its pozzolanic properties. The experimental program consisted in evaluating the physical and mechanical properties of cementitious composites with the addition of slate residue under variations of activation temperatures (500º C to 1000º C) and in natura. Two forms of cooling were used, slow cooling and abrupt cooling. By means of tests and experiments the performance of the thermal treatment in slate residues, was made the evaluation of alteration in the physical characteristics, alterations in the microstructure, and the amorphization process, besides the pozzolanic activity. Results from the evaluation of pozzolanicity showed that pozzolanicity appeared when the material was subjected to a longer exposure time in the ball mill (1 hour after ball milling), that is, when the granulometry reached values below 38 m, in addition, it can be seen that the material underwent changes in its structure when passing through the beneficiation process. In general, the work showed that the slate can be worked as much as pozolana, because it presented a potential of pozzolanic activation, as filer, because according to the results of compression presented higher values.