Iron ore tailing-based geopolymer containing glass wool residue: A study of mechanical and microstructural properties

Abstract

This work presents an evaluation of the application of iron ore tailing as primary precursor material to geopolymer production. Glass wool residue from the iron ore industry was also included as a blend material. Four mixtures of geopolymers were produced: one mixture using only iron ore tailing; three mixtures where the iron ore tailing was replaced by the glass wool residue, with a substitution ratio of 10%, 20% and 30% (in mass). Furthermore, three different grinding times and three NaOH solution concentration were applied. Compressive strength and flexural strength tests were performed in prismatic specimens at 7-days, and the microstructural analysis of the fragments was obtained by SEM analysis. QXRD analysis based on the Rietveld’s refinement method and TG/DTA analysis was applied for all specimens. The results showed the synthesis of a zeolite phase in all specimens, and the SEM micrographs showed a transformation process of the glass wool residue. Finally, high mechanical performances were found to the iron ore tailing-based geopolymer, reaching values higher than 100 MPa for compressive strength and 20 MPa for flexural strength. The obtained values are related to the grain packing improvements, geopolymerization products, and the glass wool residue working as a supplementary precursor material to the geopolymerization reaction. The result points to the potential of iron ore tailing and glass wool residue to geopolymers studies and application.