Preparation and characterization of metal mine tailings based backfiling material through geopolymerization

The main objective of this study was to investigate the potential of using metal mine tailings (MT) as raw material for backfilling material preparation through geopolymerization. Due to the low reactivity of this aluminosilicate material in alkali solution, MT was pretreated through alkali fusion with various amounts of NaOH at 550°C for 30min. XRD, FTIR and ICP-OCE testing results showed that the reactivity of MT was improved by alkali fusion pretreatment. Different paste backfilling material (BFM) samples were prepared by adding water to the fused mine tailings (FMT). Compressive strength testing of BFM samples showed that, adding 20% NaOH during alkali fusion could satisfy the requirement of backing filling. As a result, by enhancing the reactivity of MT through alkali fusion pretreatment, MT can be recycled as an alternative raw material to be used as the replacement of Portland cement for mine filling.