Utilization of Palm Oil Fuel Ash (POFA) as an Admixture for the Synthesis of a Gold Mine Tailings-Based Geopolymer Composite

The repurposing of gold (Au) mine tailings from artisanal and small-scale mining (ASGM) operations via alkali activation technology is a promising strategy for waste reduction in developing countries. Direct tailings, however, challenging because these materials contain relatively low aluminum (Al)-bearing minerals. In this study, palm oil fuel ash (POFA) was elucidated as high Al-bearing derived-admixture the synthesis an ASGM tailings-based geopolymer composite. Semi-quantitative XRD analysis showed that contained quartz (SiO2) (~58%), pyrite (FeS2) (~20%) calcite (CaCO3) (~15%) with minor to trace amounts aluminosilicates (~7%). Substantial environmentally regulated pollutants such mercury (Hg) (40 mg/kg), lead (Pb) (8430 mg/kg) arsenic (As) (300 were also found tailings. SEM-EDS, ATR-FTIR results successful formation hybrid geopolymer-CASH matrix, which improved unconfined compressive strength (UCS) composites ~5 MPa ~7 MPa. Furthermore, POFA did not significantly affect thermal resistivity based on analysis. Finally, TCLP Pb leaching concentrations exceeded environmental standards (~15,000 µg/L), suppressed after 300–500 µg/L. This means addition composite only its applicability backfill, pavements bricks but ability immobilize toxic elements.