矿渣基胶凝材料固化垃圾焚烧飞灰中重金属的研究

以矿渣部分或全部替代水泥,与垃圾焚烧飞灰和脱硫石膏组成胶凝材料,研究随矿渣掺量变化,胶凝材料对垃圾焚烧飞灰重金属的固化效果。结果表明:随着矿渣替代水泥量的增大,净浆试块抗压强度呈现先增大后减小的趋势;当飞灰掺量为20%、矿渣掺量为70%、脱硫石膏掺量为10%时制成的净浆试块,在温度为35℃、湿度为95%下养护28 d,试块的抗压强度达到47 MPa,重金属元素Cr、Cd、Cu、Hg、Pb、Zn的浸出浓度均低于饮用水标准;对Pb、Cr的固化效果明显优于纯水泥胶凝体系。XRD和FT-IR检测表明:该矿渣基胶凝材料水化生成的主要产物有钙矾石、C-S-H凝胶和水铝钙石,水化产物对重金属离子有良好的包裹作用。矿渣基胶凝体系比水泥基胶凝材料体系在固化垃圾焚烧飞灰重金属方面优越性明显。

The Study on Solidification of Heavy Metal Ions from Garbage Incineration Fly Ash Using Slag-based Cementitious Materials

The slag， which is used with garbage incineration fly ash and desulfurization gypsum in the composition of cementitious material， replaces cement in whole or in part. The solidification effect of the cementitious materials on heavy metals from waste incineration fly ash was studied with the change of slag content. The results showed that compressive strength of the paste block first increases and then decreases with the increasing of the slag content. When the paste block is made of fly ash 20%， slag 70% and desulphurization gypsum 10%， compressive strength of the paste reaches 47 MPa for 28 days maintenance in the temperature of 35 ℃ and the humidity of 95%. The heavy metal irons leaching concentration of Cr， Cd， Cu， Hg， Pb and Zn were all lower than the standard of drinking water. The solidification effect of Pb and Cr is better than that of cement cementitious system. The detection results of XRD and FT-IR indicated that the major hydration products of slag-based cementitious materials are ettringite， C-S-H gel and hydrocalumite， which show good encapsulation effect on heavy metal ions. Compared with cement gelled system， slag-based cementitious material system has obvious superiority in curing heavy metals irons from garbage incineration fly ash.