Opiso Einstine M, Tabelin Carlito B, Maestre Christian V, Aseniero John Paul J, Park Ilhwan, Villacorte-Tabelin Mylah
Geo-environmental Engineering Group, Civil Engineering Department, Central Mindanao University, Bukidnon, Philippines.
School of Minerals and Energy Resources Engineering, The University of New South Wales, Sydney, NSW, Australia.
Heliyon. 2021 Apr 5;7(4):e06654. doi: 10.1016/j.heliyon.2021.e06654. eCollection 2021 Apr.
The continuous accumulation of artisanal and small-scale gold mining (ASGM) tailings in the Philippines without adequate storage and disposal facility could lead to human health and environmental disasters in the long run. In this study, ASGM tailings was simultaneously stabilized and repurposed as construction material via geopolymerization using coal fly ash, palm oil fuel ash and a powder-based alkali activator. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) identified iron sulfides in the tailings containing arsenic (As), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn), which could be released via weathering. The average unconfined compressive strengths (UCS) of tailings-based geopolymers at 14 days curing were 7.58 MPa and 7.7 MPa with fly ash and palm oil fuel ash, respectively. The tailings-based geopolymers with palm oil fuel ash had higher UCS most likely due to CASH reaction product formation that improved strength formation. The toxicity characteristic leaching procedure (TCLP) results showed very low leachabilities of As, Pb and Fe in the geopolymer materials suggesting ASGM tailings was effectively encapsulated within the geopolymer matrix. Overall, the geopolymerization of ASGM tailings is a viable and promising solution to simultaneously stabilize mining and industrial wastes and repurpose them into construction materials.
在菲律宾，手工和小规模金矿开采（ASGM）尾矿持续积累，却没有足够的储存和处置设施，从长远来看可能会导致人类健康和环境灾难。在本研究中，通过使用粉煤灰、棕榈油燃料灰和粉末状碱激发剂进行地质聚合，ASGM尾矿被同时稳定化并重新用作建筑材料。扫描电子显微镜结合能量色散X射线光谱（SEM-EDS）在尾矿中鉴定出含有砷（As）、镉（Cd）、铜（Cu）、铅（Pb）和锌（Zn）的硫化物，这些硫化物可能通过风化释放出来。在养护14天时，基于粉煤灰和棕榈油燃料灰的尾矿地质聚合物的平均无侧限抗压强度（UCS）分别为7.58MPa和7.7MPa。含棕榈油燃料灰的尾矿地质聚合物具有更高的UCS，这很可能是由于形成了改善强度形成的CASH反应产物。毒性特性浸出程序（TCLP）结果表明，地质聚合物材料中As、Pb和Fe的浸出率非常低，这表明ASGM尾矿有效地包裹在地质聚合物基质中。总体而言，ASGM尾矿的地质聚合是一种可行且有前景的解决方案，可同时稳定采矿和工业废物，并将它们重新用作建筑材料。
