Strength development, leachability and microstructure of heavy metals from the solidified waste using synthesis rice husk ash （sRHA） and lime blended at the weight ratio of 1：1 were used as binders. The heavy metal...Strength development, leachability and microstructure of heavy metals from the solidified waste using synthesis rice husk ash （sRHA） and lime blended at the weight ratio of 1：1 were used as binders. The heavy metal-containing sludge was used at the level of 0 wt.%, 30 wt.%, and 50 wt.% dry weight, respectively. The sample specimens with and without 1.5 wt.% of sodium silicate （SiO2/Na2O = 1.0） were cured under the ambient condition and elevated temperature curing at 50℃ for 24 hr. Experimental results showed that the introduction of sodium silicate solution and elevated temperature curing to sRHA-based solidified waste containing 30 wt.% of heavy metal sludge gave one day strength of 20 kg/cme compared to 0.9 kg/cm^2 for the control sample. XRD patterns indicated that most metal-sulfides present in the sludge were appeared in the solidified waste and SEM coupled with EDX techniques reveal these metal-sulfide particles were trapped within the lime-sRHA matrices. In addition, cumulative leaching behavior by tank test （EA NEN 7375：2004） showed that solidified waste containing up to 30 wt.% of heavy metal sludge was suitable to dispose in a secured landfill.展开更多
基金funded by TRF Research Scholar(No. RMU5080007)the Royal Golden Jubilee Ph.D. Program under the Thailand Research Fund
文摘Strength development, leachability and microstructure of heavy metals from the solidified waste using synthesis rice husk ash （sRHA） and lime blended at the weight ratio of 1：1 were used as binders. The heavy metal-containing sludge was used at the level of 0 wt.%, 30 wt.%, and 50 wt.% dry weight, respectively. The sample specimens with and without 1.5 wt.% of sodium silicate （SiO2/Na2O = 1.0） were cured under the ambient condition and elevated temperature curing at 50℃ for 24 hr. Experimental results showed that the introduction of sodium silicate solution and elevated temperature curing to sRHA-based solidified waste containing 30 wt.% of heavy metal sludge gave one day strength of 20 kg/cme compared to 0.9 kg/cm^2 for the control sample. XRD patterns indicated that most metal-sulfides present in the sludge were appeared in the solidified waste and SEM coupled with EDX techniques reveal these metal-sulfide particles were trapped within the lime-sRHA matrices. In addition, cumulative leaching behavior by tank test （EA NEN 7375：2004） showed that solidified waste containing up to 30 wt.% of heavy metal sludge was suitable to dispose in a secured landfill.
