Estudo preliminar da viabilidade de produção de blocos cerâmicos com adição de casca de arroz in-natura e lodo de ETE

Abstract

Waste generation is one of the main factors causing environmental pollution. Sewage sludge (SS) is currently classified by NBR 10004/2004 as a class II-A solid waste, non-inert and non-dangerous, and is generally destined for sanitary landfills. Rice husk (RH) has uses in both energy generation as a biofuel and in agriculture as a fertilizer. A viable destination for these wastes is the use in the manufacture of red ceramics, where the addition of small amounts does not affect quality and performance. The objective of this study is to evaluate, through mechanical strength, shrinkage, and water absorption tests, the production of ceramic blocks and cylinders on a reduced scale with different substitution levels of sewage sludge and rice husk. The ceramics were produced with SS substitution of 0%, 2% by weight and the addition of 0%, 2.5% and 5% by volume of RH. Due to the reduced scale of the tests (1:5), materials that were representative of the scale of the experiments were necessary, so the ImageJ software was used to characterize the rice husk, determining its dimensions. In addition, an automation of the process was proposed to facilitate and speed up the process and thus make research viable through image analysis. The image analyses had satisfactory results, achieving the goal of the scale and the automation of its process. The addition of sludge and husk influenced both the manufacturing process, requiring a higher water content for its extrusion, and the final performance of the blocks, increasing linear shrinkage, water absorption and decreasing the reliability of the Weibull module. The cylindrical samples were more reliable than the blocks, making the study of additions in ceramics clearer. Finally, from the analysis of the results, it can be concluded that it is possible to produce ceramics with sludge and husk together at low substitution levels, as long as there is control of the production process, from mixing the materials to its firing. It was also possible to conclude that the use of software for dimensional characterization is effective although there are characterization errors that can be overcome with automation.