Estudo da adição de terra diatomácea em matrizes cimentícias para captura de CO2

Abstract

One of the residues generated at beverage industries is diatomaceous paste resulted of the filtration and clarification stage. After many filtration campaigns occurs the pores' saturation with organic matter, decreasing filtration's efficiency and invalidating its reuse. Even if the organic matter is treated, restrictive policy of the industries avoids its reuse, so it is disposed in nature. However, without organic matter, recovered diatomaceous can be used in construction material's production based on Portland cement, due to high porosity and SiO2. Recently, literature showed that materials based on Portland cement can capture CO2 of atmosphere through accelerated carbonation. Considering diatomaceous porosity, the proposal of this study was to study the possibility of using recovered diatomaceous in matrix based on Portland cement to increase the absorption capacity of CO2. Cement pastes were chose using recovered diatomaceous as partial substitute of Portland cement, in levels of 10, 20 and 30% contemplating relations of water/cement material which would take to the same consistence rate. These pastes were treated in an environment with accelerated carbonation for 1h, after the initial and take times. To characterize the pastes it was performed isomeric calorimetry tests, water absorption by capillarity, mechanical resistance to simple compression, thermogravimetric analysis and electronic microscopy of scan. The results demonstrated that until level 20% of substitution of cement for recovered diatomaceous, occurs an increase of CO2 absorption capacity in proof bodies, however in pastes with 30% of diatomaceous substitution occurred a decrease of this efficiency.