Alkali activation of low-alumina mine tailings for more sustainable raw material supply

Mining industry generates a significant amount of mine tailings (MTs), disposal of MTs has environmental impacts, such as air pollution and releasing of heavy metals to surface and underground waters. This research includes a development of alkali-activated materials (AAMs) from low-alumina MTs. A series of samples with varying compositional ratios was synthesised from a combination of different activators, MT powder and water. Curing temperature of 40°C led to the strengthening of the AAMs. The effects of alkali activator addition on the phase evolution and morphology of the reaction products were investigated by using the XRD and SEM/EDS techniques. The results demonstrate that an increase in the percentage of the activator solution led to an increase in compressive strength and change the morphology structure of the reaction products. It should be noted that the alkali activation of MTs creates a new material with potential environmental protection applications, such as low permeable covers and a sustainable material with using geopolymerisation technology.