Rejeitos de minério de ferro na produção de geopolímeros one-part: utilização como filler e na produção de silicato de sódio alternativo

Abstract

The consequences associated to the current tailings disposal and lack of investments in research focused on the use of these mining tailings, unfortunately, are hard to forget. This work objects to contribute with the development of alternative uses of iron ore tailings, aiming to reduce the amount of these materials stored in dams, using the geopolymerisation technology. This work is composed by two papers. The first paper is related to the use of iron ore tailings as fillers in one-part geopolymers. For this research metakaolin-based geopolymer mortars were produced with three different iron ore tailings as fillers. The amount of incorporated tailings have varied, without loss mechanical resistance. It was observed that the element iron, originally from the tailings, have been incorporated into geopolymer in bonds with the original silicon tetrahedron. The second paper evaluated the use of iron ore tailings, as silica source, in the production of an alternative sodium silicate, through a mechano-thermo-chemical process, to be used as activator in one-part geopolymer binders. The geopolymers synthesised with the alternative activator have shown compressive strengths comparable to ordinary Portland cement binders.