Heavy Metals Adsorption of Light-Burned Dolomite-Sodium Carbonate-Activated Slag Binders
In order to enhance the application of alkali-activated slag cementitious materials in the waste solidification field,this paper prepared light-burned dolomite-sodium carbonate-activated slag binders,and analyzed the impact of light-burned dolomite content on the strength development,phase assemblage and microstructure evolution.The adsorption efficiency of heavy metal ions was also evaluated.The results showed that light-burned dolomite as an auxiliary activator could accelerate the reaction kinetics of sodium carbonate-activated slag.When the dosage was 4%,the highest 28 d compressive strength of binder was achieved,which was increased from 23.1 MPa to 36.5 MPa.The strength growth rate was 58.0%.When the content of light-burnt dolomite was 8%,the densest pore structure of the binder was achieved,and the total porosity decreased from 18.9%to 11.7%.The dense pore structure reduced the water absorption rate of the cementitious materials from 16.0%to 10.1%.The incorporation of light-burned dolomite promoted the formation of hydrotalcite-like phase in the binder,and the Mg-Al layered double hydroxide molecular structure improved the adsorption of heavy metal ions.The adsorption rates of Pb2+,Cd2+ and Zn2+ could reach 76.5%,51.0%and 57.2%,respectively.
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