Incorporation of industrial wastes as raw materials in brick's formulation

This article presents a case study conducted as an experiment with the incorporation of different types of industrial waste in brick manufacturing process in laboratory scale. The main objective of this work is to incorporate large amounts of different types of waste as raw material in brick's formulation. Three types of wastes were mixed with clay: automotive industry waste sludge containing heavy metal concentrations; glass waste, from a galvanic plant, mainly consisting of glass microspheres; and wood ash, from the ceramic burning furnace. The formulation's materials were analyzed by X-ray diffraction, X-ray fluorescence and electronic microscopy. The dried samples were milled separately and then dry mixed. Water was added to the mixture in order to contribute to the compaction process. The samples were dried and then burned at temperatures similar to those used for brick firing furnace. The obtained ceramics were analyzed for their retraction and then submitted to flexural strength testing. Samples obtained value above 4 MPa were approved. Among the samples tested, the formulation that showed higher flexural strength was chosen. It was prepared sufficient sample to perform the solubilization and leaching tests. For tests, the samples were reduced to dust. The results of such analyzes did not identify the presence of elements described in the initial samples' formulation. Morphological analysis was performed using scanning electron microscopy. Tested sample showed glassy characteristic of material that has been sintered during the firing process. This effect is also a proof that the waste identified in initial sample's formulation were inerted. Obtained results characterizes that the tested formulation can be considered as an alternative for bricks manufacturing with incorporation of industrial waste and an activity non-hazardous to the environment.