Pigmentos a base de xisto retortado impregnado com metais para aplicação em esmaltes cerâmicos

Abstract

Like most of the industries sectors, the ceramic sector also felt the need of developing. In this way, the ceramic industry has been seeking to create more and more pigments for the production of floors and coatings, aiming to meet the demand of ceramics for the decoration of domestic and commercial environments. In addition to that, there is a great interest in developing new materials that are in accordance with the environmental preservation that are also relatively low-cost. Retorted shale (RS) is a waste from the shale industry that may harm health and the environment if improperly stored. The aim of this study is to evaluate the viability of the materials, pure RS and metal-impregnated RS, to obtain pigments that are stable in several ceramic matrices, as well as to try to understand which parameters influence the pigmentation of the enamels. The RS-based pigments were prepared by wet impregnating of the metals and calcined at 700 and 900°C. After that, the materials were characterized by X-ray Fluorescence (XRF), Thermogravimetric analysis (Tg), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM /EDS), UV-Visible Spectroscopy and Colorimetry. The results confirm the feasibility of using RS as a ceramic pigment obtained by a simple method, low-cost and that reduces the environmental impacts caused by such waste. The pigments are light brown, red and shades of gray, according to the impregnation and calcination temperatures, which get darker at higher temperatures.