Evaluation and characterization of geopolymer foams synthesized from blast furnace with sodium metasilicate
Flávio James Humberto Tommasini Vieira Ramos, Maria de Fátima Vieira Marques, Lucas Galhardo Pimenta Tienne, Vinícius de Oliveira Aguiar
Abstract
This study concerns the synthesis of geopolymeric foams from blast furnace slags, comparing the results of the produced materials using 8 M alkaline solutions of sodium metasilicate (Na2SiO3) or sodium hydroxide (NaOH) as geopolymerization agents with 1.4 and 1.6 g/L (solid/liquid) ratios of slags. Blast furnace slags (BFS) were added to each alkali-activated solution reaction, maintaining under constant stirring during periods of 4, 20, and 24 h. Posteriorly, hydrogen peroxide 50% was inserted as a foaming agent. This method used room temperature (25 °C) to the production of the foams. The influence of the mixture parameters on the resultant porosity was observed through the characterization by X-ray fluorescence (XRF), Fourier transformed infrared (FTIR), X-ray diffraction (XRD), thermogravimetry (TG/DTG) and scanning electron microscopy (FEG-SEM) analyses. Geopolymeric foams (GF) were obtained with different characteristics of porosity, thermal stability, crystallinity, and interconnection between porous. Dimensional stability was observed on the samples of geopolymer of blast furnace slags with metasilicate. According to characteristics of the developed samples, they can be investigated as CO2 and other gases absorber, or retainer of harmful metals.