Compósitos poliméricos reforçados com resíduos de siderurgia e fibra de piaçava

Abstract

Abstract: The natural sources used in the basic productive sectors of the economy, which are extracted in significant volumes, show signs of exhaustion around the world, which leads to the need to develop materials that can perform properties similar to conventional ones and also provide adequate destination for the waste generated. In this way, the use of steelmaking residues, such as electric arc furnace – EAF – dust, as well as the use of leftovers from the production of non-wood forest products such as piassava shavings, are possible alternatives for different sectors of the economy, such as civil construction and agriculture, in the form of co-products for the production of wall coverings in internal and external areas. This thesis aims to analyze the technical and economic feasibility of using these residues, performing the tests of X-Ray Diffratometry, Fourier Transform InfraRed spectroscopy, Scanning Electronic Microscopy, granulometry, bulk density, Dynamic Thermal Analysis, Thermogravimetric Analysis and X-Ray Fluorescence in the residues. For the characterization of the composites, the residues were incorporated in a polymeric matrix of epoxy resin and the Shore hardness

tests, Izod impact, 3 point flexion, traction, compression, abrasion, moisture absorption, post- aging test, Ashby‟s analysis method and TEVS – Technical-Economic Viability Study. The

results obtained indicate an excellent interface promoted between the residues and the resin, guaranteeing excellent wettability and mouldability of the composite in volumes of complex geometry, but which requires specific conditions to guarantee a lower percentage of pores and, consequently, better material distribution. It is observed that the ideal grain size for working with the resin is less than 200 MESH, so that the stress concentrations in the material can be distributed in a more isotropic way. The percentage of heavy metals in the EAF dust stands out, indicating that its use requires care in the mixing procedure so as not to generate contamination to the user, but that it brings socioenvironmental benefits by removing a class I slag from the environment and applying it in a high-level added value industrial process. The results indicate that the use of fiber particles and EAF dust generate isotropic stress distribution, making it possible to have a considerable energy absorption capacity over the occupied surface area. It was also observed a good resistance to the flammability of the EAF dust when submitted to temperatures above 1000 oC, allowing indicating the material as flame retardant. Another relevant factor is the mechanical properties of hybrid composites, whose mixture of components promoted gains in resistance to abrasion compared to the benchmarks. About the analyzed compositions, each one presented mechanical for the production and commercialization process and the one that had the set with more optimized properties was the 15% piassava reinforced – resistance to abrasion, 3-point push-up, post-aging and compression resistance, whose properties frame them as composites of polymeric type. EAF dust composites also performed well in traction resistance, hardness, impact and water absorption. Economic feasibility analysis was carried out and products for wall and ceiling cladding have been proposed. Detach the production cost, where its cost is close R$ 18.99/piece for simulated planning with 90% efficiency production and safety sale price at R$ 25.70/piece, which leads to a degree of economic sustainability in approximately 19 months, making it a viable product in the technical, environmental and economic aspects.