Valorização de resíduos na indústria da cerâmica vermelha: caracterização da plasticidade de tarugos com a adição de lodo esgoto através de ensaios de deformação e reologia

Abstract

Economic development and population growth generate many types of waste. Sewage sludge (SS), a non-hazardous waste classified as non-inert A-II (NBR), is produced in sewage treatment plants, after collection and treatment, and it’s normally disposed in landfills. As another alternative to final disposal, researchers have been studying the possibility of recycling SS in the production of red ceramics, a material widely consumed in the global market, which offers the opportunity to recycle low levels of waste while maintaining the production of high-quality elements. The main purpose of the present research is to evaluate, through the production of red clay bricks on a reduced scale, the effect of varying the SS content on the plasticity of green samples of clay mixtures and to verify the influence of the SS content in the conformation process of clays. The moisture of the systems was fixed in 30%, according to previous studies, and the dry SS content ranged between 0% and 10%. The physical properties of the extruded green billets, such as plasticity and density, were measured through green mixture tests. The increment of SS content reduces the elastic phase of the mixture when compared to the reference system (0SS), however, evaluating the increasement of SS substitution in the systems, it was observed the necessity of a greater deformation to reach a predominantly viscous phase, which shows that the SS increment generates an increase in the viscoelastic phase. Mechanical tests as uniaxial compression and amplitude sweep showed that systems with lower SS content had better performances in the conformation of red ceramic clays, as they enabled the production of high-quality bricks, with high mechanical strengths and a required a lower energy consumption in the execution of the extrusion process.