医疗垃圾焚烧飞灰的水泥固化效果实验

Experiment on Solidification of Hospital Waste Incineration Fly Ash Using Cement

为检验医疗垃圾焚烧飞灰的水泥固化处理效果,对不同飞灰/水泥配比下水泥固化体的凝结时间、抗压强度、重金属浸出毒性等特性方面进行了实验研究.结果表明:掺60%飞灰的水泥固化体终凝时间长达63 h,超出48 h的限值;掺40%飞灰、60%飞灰的水泥固化体7 d的抗压强度仅为0.187 MPa、0.16 MPa,未达到0.2 MPa的要求值;掺40%飞灰、60%飞灰的水泥固化体中Pb的渗沥浓度分别为5.634 mg/L、6.032 mg/L,均超过5 mg/L的限值.根据本实验结果,医疗垃圾焚烧飞灰水泥固化中水泥掺量宜在70%左右,若按照目前国内生活垃圾焚烧飞灰水泥固化工艺的配比(水泥掺量40%以下),各项固化指标均不能达到填埋要求.

In order to inspect the treatment effect of cement solidification of hospital waste incineration fly ash （FA）, experimental studies have been carried out on characteristics such as setting time,compressive strength and leaching toxicity of heavy metals of the solidified products with different FA/cement ratios. The results show that the final setting time of the FA-cement mixture with 60% FA is 63 h, exceeding the limit of 48 h;the compressive strengths of the cement solidified products with 40% FA and 60% FA concentration are only 0.187 MPa and 0.16 MPa,respectively, after 7 days,which does not meet the requirement of 0.2 MPa;the Pb leaching concentrations of solidified products incorporating 40% FA and 60% FA are 5.634 mg/L and 6.032 mg/L,respectively,both in excess of the limit of 5 mg/L. According to the above results,it is appropriate to have about 70% cement content in the cement solidification of FA. If the percentage of cement content is in accordance with the current domestic ratio in the solidification process of municipal waste incineration fly ash （cement content below 40%）, the solidification indexes cannot meet the landfill requirements.