Polishing performance of eco-friendly porcelain stoneware tiles reusing bricks and roof tiles wastes

Abstract The industrial production of bricks and roof tiles plays a significant role in the economy of the state of Rio Grande do Norte, in northeastern Brazil. In the last years, production has grown exponentially, and so has the production of the waste from the breakage of those materials. Consequently, the concern has also arisen over the final disposal and reuse of this waste. Several studies reported the incorporation of this waste in the ceramic tiles matrix for porcelain stoneware tile, but only focused on the evaluation of basic technological properties. The present work investigates the influence of this waste over the gloss-gaining curve of the final products. The polishing behavior of three different eco-friendly compositions, with 5, 10 and 15% of waste from the breakage of bricks and roof tiles incorporated, was evaluated in comparison with standard composition, waste-free. For this purpose, porcelain stoneware tile samples were prepared and their corresponding microstructures were characterized. The industrial polishing condition was reproduced on a laboratory scale, keeping the same abrasive agent, SiC, in an automatic metallographic polishing machine. The roughness and gloss performances through the abrasive sequence adopted were investigated. Additionally, the texture of the surfaces was also evaluated. The results show a positive influence of the microstructure caused by the waste on the polishing performance, reaching a maximum of 72.7 gloss units for the composition with 15% of waste incorporated, representing an improvement of 13.7 gloss units comparing to the waste-free composition. Furthermore, the investigation indicates the feasibility and the promising potential of the polishing process of formulations containing this waste as an alternative raw material.