Aproveitamento do rejeito de minério de ferro em compósitos para construção civil

Abstract

The generation of large amounts of waste, together with the restriction of places for the disposal of industrial waste, the scarcity of natural minerals, the high rates of greenhouse gas emissions and the large consumption of energy, encouraged researchers and professionals to reflect on sustainable alternatives, in order to minimize the impact on the environment and reduce the problems of waste management. This work aimed to develop composites based on iron ore tailings, aluminum anodizing sludge, concrete residues and residues from the production of lime, for the production of new materials to be used in civil construction with properties that meet the requirements of the Brazilian Standards. For this, changes in mechanical properties and morphological structures were investigated during the curing periods of: 3, 7, 14, 28, 60 and 90, 180, 360 and 720 days. The results of the tests of resistance to axial compression, water absorption, diametrical variation and apparent specific mass met the requirements of Brazilian standards. Among all the compositions, the composition with 40% of iron ore tailings, 10% of aluminum anodizing sludge, 30% of concrete residue, and 20% of waste from lime production stands out. This composition obtained compression resistance of 7.15MPa at 28 days of cure and 8.93MPa at 365 days of cure. Regarding the changes in the mineralogical arrangement in composition 10, a greater amount of mineral syntheses was observed, which is one of the explanations for the greater resistance of this material. Changes in the morphological structure of the composition were also observed and there was a greater interaction between the particles, in addition to some areas with a flat and dense surface.