Study for the incorporation of fine coal waste into the mass of red ceramic

Abstract

Given the problems involving the generation and management of tailings from the coal processing, in both environmental and economic aspects, ways were studied to find uses for this material that is currently discarded by coal companies. In this sense, it was decided to investigate its behavior when mixed with the red ceramic body. For this, seven formulations were developed in the laboratory, adding different percentages of tailings to the red ceramic body, with 21 specimens made for each formulation, firing them under three temperature ranges: 750°C, 800°C, and 850°C. In addition to the formulations, pieces were prepared without any addition of tailings, preserving the original body used in the industry, with the objective of comparing the results of the formulations with the standard body. In order to understand the behavior between both materials and the phenomena that may occur in them, chemical analyses were performed using XRF testing, and mineralogical analyses were performed using XRD testing. For the validation of the study and the possible application of the tailings, standard ceramic tests were carried out, such as firing shrinkage, water absorption, and mechanical strength. As it involves coal tailings, environmental tests for corrosivity, reactivity, leaching, and solubilization were also performed. The results of the laboratory tests showed that it is possible to use fine coal tailings in a red ceramic body in some percentages, with the formulation containing 2.5% tailings showing the best performance, even superior to that of the standard sample. Regarding the environmental aspect, both the standard sample and the best formulation were classified as non-hazardous waste, class II-A (non-inert)