Heating rate effect during sintering on the technological properties of Brazilian red ceramics

Unbalanced energy consumption in the production of ceramic artifacts is responsible for considerable undesirable impacts, such as increased emissions of polluting gases, excessive consumption of fuel materials, land degradation, and unpredictable financial costs. By contrast, the practice of optimizing the ceramic sintering, which in associated with firing of high temperature, can result in increased productivity and reduced production costs preserving an environmentally friendly production system. Moreover, it allows further improvements in the quality of the final product. This work compares the effect of different sintering cycles, with heating rates of 2, 15, and 30 °C/min, on the technological properties of a Brazilian industrial clay ceramic body. Initially the clay ceramic specimens were characterized in terms of mineralogical, chemical, and physical properties. Specimens were prepared by extrusion and fired at temperatures of 800, 900, and 1000 °C. The evaluated properties by standard tests were water absorption, post-firing linear shrinkage, and flexural strength. It was found that owing to sintering carried out at higher heating rates, red ceramic products with superior technological properties were obtained. This is an unprecedented conclusion for common clay ceramics produced in Brazil. Based on the promising obtained results, in a clear and detailed way, the benefits of rapid sintering cycle application for conventional brick production are evidenced.