垃圾焚烧灰高温重构矿渣水泥复合体系安全应用研究

Study on the Security Applications of Cement-blended Municipal Solid Waste Incineration Fly Ash Reconstructed Slag

将不同冷却方式(风冷、水冷)下得到的垃圾焚烧灰高温重构矿渣掺入水泥,研究了重构矿渣水泥复合体系在(冻融+干湿+硫酸盐侵蚀)循环条件下的重金属浸出性能、力学性能,并对固化体破坏机理进行分析。结果表明:(1)经过28次侵蚀循环后,固化体重金属浸出浓度均低于危险废物浸出毒性鉴别标准限值;(2)在本实验条件下制备的重构矿渣,当风冷重构渣掺量小于30%,水淬渣掺量小于50%时,固化体均能够保持结构的完整,无溃散现象,即风冷重构渣和水淬渣在建筑材料中的安全应用阈值分别为30%、50%;(3)在(冻融+干湿+硫酸盐侵蚀)循环条件下,固化体主要经受盐结晶压、渗透压、结冰压、钙矾石结晶破坏、石膏结晶型破坏等物理、化学破坏作用。

The heavy metal leaching performance of reconstituted slag cement composite system under the cycle conditions of freeze-thaw ＋ wet-dry ＋ sulphate erosion was studied by incorporating the waste incinerated fly ash from different cooling systems （air cooling and water cooling） into cement. Mechanical propertiesand the damage mechanism of the solidified body was analyzed. The results show that： ①After 28 cycles, the leaching concentration of heavy metals in the cured solid was lower than the limit value of leaching toxicity of hazardous wastes. ②When the content of water quenched slag is less than 50%, the solidified body of the reconstituted slag prepared under the experimental conditions can keep the integrity of the structure without collapsing phenomenon, that is, the safe application threshold of air-cooled remold slag and water quenching slag in building materials is 30%, 50%, respectively. ③Under the cycle conditions of （freeze-thaw ＋ wet- dry＋sulfate erosion）, the solidified body is mainly subjected to salt crystallization pressure, osmotic pressure, icing pressure, crystallization of ettringite, chemical destruction.