The potential use of geopolymer containing fly ash produced in heavy fuel power plants for toxic metals fixation: Chemical and physical characteristics

Author(s): Mohammad A.Al-Ghouti, Yahya S.Al-Degs, Ayoup Ghrair, Hani Khoury, Mohammad Ziedan

In Jordan, large amounts of fly ash (FA) are produced from heavy fuel composition in power stations. The produced fly ash is highly contaminated with heavymetals includingV,Ni,Zn and Fe.Geopolymer containing different amounts of FAwas fabricated for sake of minimising the mobility of toxic elements in the repository site. Using local kaolinite, fly ash and NaOH mixture, five geopolymers were prepared at roomtemperature and cured at 80oCat the following ratios: Si/Al: 1.68–4.71, Na2O/Al2O3: 1.48–1.84, Na/Al: 0.74–0.92. The maximum compressive strength was observed for the geopolymer containing no fly ash, 28 Mpa at day 1 and dry sample. A geopolymer containing 10% FA showed promising results where a compressive strength of 23Mpa was reported. The porosity of FAhas been partially destroyed after polymerisation process as indicated from SEM pictures and XRD analysis; new phases have been created under the action of applied pressure. The leachability test indicated that the samples of higher FA are more leachable. The results proved that involving FA in geopolymerisation was significantly decreased the mobility of the toxic metals like Ni and V. Therefore, the prepared geopolymers will definitely have important industrial applications.

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