Perspectives for the application of bauxite wastes in the development of alternative building materials

Abstract

Tailings from bauxite extraction are worldwide of environmental concern, due to their open-air disposal in landfill dams. Although numerous studies have been dedicated to the application and reuse of wastes from bauxite processing tailings, there is still an important gap regarding the identification of properties that may, enable its application in the development of materials, especially as construction elements. The objective of this research is to characterize environmentally and microstructurally the bauxite waste from processing tailings produced in the state of Pará, Brazil, aiming at a combined characterization and discussion that evaluates its potential applications, as possible alternative to simple disposal in landfills. Chemical characterization analyzes were performed by X-ray fluorescence (XRF), mineralogical by X-ray diffraction (XRD), morphological by Scanning Electron Microcopy (SEM) and Transmission Electron Microscopy (TEM) combined with Energy Dispersive Spectroscopy (EDS). In addition, physical analyzes were performed by granulometry, surface area measurement (BET) and Luxán pozzolanicity. Environmental analyzes were carried out through solubilization and leaching. The results obtained by chemical and mineralogical analyzes indicate that the material is an aluminosilicate with a high content of amorphous components, which allows it to be used as a pozzolan in either cementitious materials or as a precursor in alkali activated materials or else as a plasticity reducer in red ceramics. The results were confirmed by thermal analysis and by pozzolanicity test. Thus, it is possible to conclude, based on the characterization of the bauxite waste, that the material has potential for use in alternative construction materials, contributing to the sustainable development of civil construction.