Caracterização de cinzas de carvão mineral e sua aplicação como barreira impermeabilizante

Abstract

Modern engineering in line with contemporary society should productive process to the correct destination of the waste generated by its activities. THE socio-environmental responsibility makes it mandatory to draw up management plans for waste, so that they are given the correct destinations and these do not cause damage to the environment and human health. In the generation of electric power, Thermoelectric generators (UTE's) generate huge amounts of coal-fired waste (light ash, coarse ash, slag and desulphurisation residues). A part of these waste is used in the cement industry, however, there are considerable volumes that are not used. This fact stimulated the development of several studies with the aim of technical, economical and environmentally viable alternatives for the use of coal ash. In this context, the companies Energia Pecém and ENEVA in partnership with the Federal University of Ceará developed a research project that sought to alternatives for the reuse of the ashes generated by Porto Pecém I and II UTEs. the present study starts from this project. In this work, the mineralogical characterization was carried out, morphological, physical-chemical and geotechnical characteristics of coal ash, so that, from their appropriate disposal. The objective of the study was to evaluate use of coal as geotechnical material, specifically as waterproofing of waste landfills (liners), checking that they meet necessary conditions for such application. Based on the analyzes carried out, it was observed that collected in a storage basin of Energia Pecém heterogeneous, presenting significant variability for several parameters. This motivated the proposition of a composite material consisting of the mixture of all ash samples composite ashes, which were more representative of and presented values ​​close to the mean of the individual samples. However, it was observed that the composite ashes did not have the necessary hydraulic conductivity for their application as liners (in the order of 10-7 cm / s), which led to the need to evaluate mixtures of a soil of the region with ashes in different proportions. Three mixtures, of which the S70C30 blend (70% soil mass and 30% mass ash) was to meet the minimum requirements for use of the material as a liner, coefficient of saturation of 4.26x10-7 cm / s, which together with other geotechnical characteristics, was adequate for the proposed use.