城市垃圾焚烧飞灰的硅酸盐水泥稳定化效果研究

采用南方某城市生活垃圾焚烧厂的飞灰进行了硅酸盐水泥稳定化效果及工艺的研究,实验分别就水泥添加量、添加剂的使用、养护时间和浸取剂pH值等因素,考察了飞灰中重金属(Cd,Pb,Cu,Zn)的稳定化效果.结果表明,当硅酸盐水泥/飞灰=10%(质量比)时,采用硅酸盐水泥处理焚烧飞灰的稳定化产物中重金属的浸出浓度都已满足危险废物填埋场入场控制标准;当使用硅酸盐水泥对焚烧飞灰进行稳定化处理时,1d后其水化反应基本完成,此后稳定化处理后焚烧飞灰的重金属浸出毒性趋于稳定;pH相关性实验表明,当使用浸取剂的pH值在3～11的范围变化时,处理后的焚烧飞灰其浸出液的pH基本稳定在7左右,证明该法产生的稳定化产物对环境pH值有很好的适应性.

Investigation of Leaching Characteristics of Heavy Metals During Cement Stabilization of Fly Ash from Municipal Solid Waste Incinerator

Leaching characteristics of heavy metals during cement stabilization of fly ash from municipal solid waste incinerator was investigated.We investigated stabilization of heavy metal,such as Cd,Pb,Cu and Zn in fly ash from municipal solid waste incinerator,through the national standard method,with the factors as follows: addition quantity of cement and Na₂S,curing time,and pH of leaching liquor.The results show that the more addition the less of heavy metal leached, except Pb which is sensitive to pH of the leachate,and the worse effect of Cd. Cement/fly ash=10% is the most appropriate parameter according to national standard method.The hydratation of cement finished basically and stabilization of heavy metal doesn't vary after curing for 1 day.The mixtures of cement and fly ash have excellent adaptability to environmental pH;the pH of leachate maintain at 7 steadily when pH of leaching liquor varied from 3 to 11.