Aprovechamiento de un residuo del carbón para reducción del impacto ambiental de la minería del carbón en Colombia: estudio del potencial de uso en la industria del cemento

New materials capable of developing cementitious properties, especially industrial waste that allows reducing the clinker in cement, have been studied to reduce CO2 emissions in cement production, increase the use of waste and generate alternative raw materials with greater availability and potential for use.  Additionally, it is known that coal mining generates a large amount of waste, both in the exploitation and benefit of it. Therefore, this paper studies the mechanical performance (compression strength) and its effect on a cement matrix added with a thermally activated Colombian coal waste, generated from the coal washing process (washery rejects), with the purpose of using this waste as supplementary cementing material. The physical-chemical and mineralogical characterization of raw and calcined material was carried out by a hydrometer, XRF, XRD, TGA/TDA, and coal proximate analysis. The waste is composed mostly of SiO2, Al2O3, SO3, and Fe2O3, and its main minerals are mica, kaolinite, quartz, and illite. The compressive strength of mortars added with 20% of substitution was evaluated. Good results were obtained with this substitution, after both periods of 28 and 90 days of curing time.