Synthesis of a Paste Backfill Geopolymer Using Pure Acidic Gold Mine Tailings

A comparison between fly ash- and basic oxygen furnace slag-modified gold mine tailings geopolymers

“…Disposal of mine tailings has been shown to create environmental pollution and as such their stabilisation is of paramount importance [5,6]. Mine tailings have been shown to be rich in aluminium and silicon and hence can be used as precursors for the synthesis of geopolymers [7,8].…”

“…Most mine tailings have been shown to be crystalline materials [8,9] and hence require some form of modification or activation to enhance their activity. Metallurgical slags and fly ash are some of the incorporations that have been added to mine tailings to enhance their activity and increase the strength of synthesised geopolymers [7].…”

“…South African gold mine tailings (GMT) have been successfully used to synthesise geopolymers but a number of disadvantages have been picked up [8]. The curing at elevated temperatures for 5 days have been shown to be energy intensive and not practicable for large uses of GMT.…”

“…There are a few studies available on the geopolymerisation of gold mine tailings [3,8]. The energy intensive process of GMT geopolymerisation necessitates the need of incorporating additives which can help in the energy demand reduction.…”

“…The mixture of GMT with other activators like granulated ground blast furnace slag (GGBFS) [3] has shown that geopolymerisation can take place at ambient temperature accompanied with a 400% increase in unconfined compressive strength. The geopolymerisation of GMT alone has shown to produce a monolith with a low strength (less than 7 MPa) [8,20]. The study also looks into metal leachability over time which few other studies have conducted.…”