Characterizing nano-indentation and microstructural properties of mine tailings-based geopolymers

The mining industry's extraction processes produce vast amounts of waste, including mine tailings (MT), traditionally stored in large ponds, causing significant environmental harm due to a lack of effective recycling methods. This research explores the potential of converting MT into a resource i.e., precursors in geopolymer synthesis. By analyzing the physicochemical and mineralogical properties of MT, the study formulates four geopolymer composites, substituting up to 30 wt% MT for fly ash. The composites' mechanical and microstructural properties show a contribution of MT in the stability of the matrix. Compressive strength of 59 MPa when incorporating 30 wt% MT, along with water absorption, microstructural analysis, and environmental impact assessments, support the hypothesis that the matrix is improved. Nano-indentation techniques further evaluated the nanomechanical properties, such as Young's modulus and fracture toughness. The findings reveal that geopolymers with 30 wt% MT exhibits up to 130 % increased strength. This research highlights the potential for innovative, eco-friendly solutions in waste management and material production, contributing to sustainable mining practices and advancing the field of geopolymer technology.