Reuse of coal fly ash in the manufacture of Portland cement

Abstract

The cement industry has an important role in global development, considering that cement is the fundamental material for the production of mortar and concrete. The search for the inclusion of materials considered to be waste from other production processes, as fly ash from burning coal for cement manufacturing, it has become a viable alternative both from an environmental and an economic point of view. The objective of the research was to evaluate the possibility of reusing the fly ash residues in the cement manufacturing process from the burning of mineral coal in the boilers of a thermoelectric plant located in São Luís - MA. It was necessary to develop a study with fly ash through physical-chemical characterization, using test methods specified. Cement mixtures with the addition of ash in 5%, 10%, 15%, 20% and 25%, were prepared. Physical, chemical and mechanical results obtained met all the requirements of the standard ABNT NBR 16697:2018, classifying the ash as a cementitious material, allowing its use as a raw material in the production of cement, enabling a more noble destination for the solid residues from coal, reduction of raw material costs in the cement production process and reduction in the amount of CO₂ emitted per ton of cement produced.