富含重金属的焚烧飞灰对磷酸钾镁水泥体系性能的影响

Effect of MSW FA on Properties of Magnesium Potassium Phosphate Cement

为了研究富含Pb、Cd的模拟垃圾焚烧飞灰对磷酸钾镁水泥(MKPC)性能的影响,测试了含垃圾焚烧飞灰的MKPC体系的流动度、凝结时间、抗压强度和其中重金属Pb、Cd的浸出浓度,分析了MKPC体系的水化放热特性、物相组成和微观形貌,结果表明:复合缓凝剂和适量垃圾焚烧飞灰可有效延缓MKPC浆体的凝结时间。垃圾焚烧飞灰的加入和含量增加使MKPC浆体的早期抗压强度明显降低,随着水化龄期的延长,其抗压强度逐步提高,水化28 d时,掺50%飞灰的MKPC的抗压强度仍大于20 MPa。含垃圾焚烧飞灰的MKPC浆体中Pb、Cd的浸出浓度随垃圾焚烧飞灰含量的增加而增加、随水化龄期的延长而明降低。但含50%飞灰的MKPC硬化体(28 d)中Pb、Cd的浸出浓度均满足《危险废物鉴别标准》(GB5085.3-2007)要求。

To study effect of imitating MSW FA with excess lead and cadmium on properties of magnesium potassium phosphate cement（ MKPC）,its fluidity,setting time,compressive strength were tested and hydration heat,phase compositions and micro structure were analyzed. The result indicated that,the composite retarder and some MSW FA were able to effectively relay setting time of MKPC paste. Adding in some MSW FA obviously reduced the early compressive strength of MKPC paste. The compressive strength of MKPC paste with some MSW FA gradually improved with time and 28 d compressive strength of MKPC paste with 50% MSW FA was greater than 20 MPa. The leaching concentration of lead and cadmium in MKPC paste with MSW FA increased with increase of MSW FA content and decreased with time,and the leaching concentration of lead and cadmium in MKPC paste with 50% MSW FA（ 28 d）were satisfied with the standard of ＂Identification of standard for hazardous wastes＂（ GB5085. 3-2007）.