Estudo da influência do tratamento termomecânico nas propriedades do resíduo de ardósia

Study of the influence of thermo-mechanical treatment on the properties of slate waste

ABSTRACT

This paper studies the effect of thermomechanical treatment (calcination and grinding) of slate waste focusing on the activation of pozzolanic properties. The experimental program consisted in evaluating the physical, chemical, mineral and morphological properties of the residue. The material was comminuted for 1 hour and 45 minutes, sieved, and then samples passing through 45 μm were subjected to heat treatment, which were exposed at 1000 °C temperature, remaining constant for up to 5 hours and were ground again. Crystallographic analyzes demonstrated that the calcination process generated a reduction in crystallinity by reducing the peaks and forming a possible amorphization halo. The slate waste after thermal treatment, increased the average size due to the effect of agglomeration by the melting of the particles, which interfered in the pozzolanic activation effect, and a greater grinding ensured an excellent activation result, proving that the higher granulometry interferes in the material reactivity. It was evidenced that for the slate residue activation it is necessary to use grinding before the heating process (particles smaller than 45 μm) and after (particles smaller than 38 μm).

Keywords
Slate vaste; Mechanical activation; Thermal activation; Reuse of waste