Wang Xingrun, Jin Yiying, Wang Zhiyu, Nie Yongfeng, Huang Qifei, Wang Qi
Chinese Research Academy of Environmental Science, Beijing 100012, China.
Waste Manag. 2009 Apr;29(4):1330-5. doi: 10.1016/j.wasman.2008.09.006. Epub 2008 Nov 12.
In this study, dry sewage sludge (DSS) as the principal material was blended with coal ash (CA) to produce lightweight aggregate. The effects of different raw material compositions and sintering temperatures on the aggregate properties were then evaluated. In addition, an environmental assessment of the lightweight aggregate generated was conducted by analyzing the fixed rate of heavy metals in the aggregate, as well as their leaching behavior. The results indicated that using DSS enhanced the pyrolysis-volatilization reaction due to its high organic matter content, and decreased the bulk density and sintering temperature. However, the sintered products of un-amended DSS were porous and loose due to the formation of large pores during sintering. Adding CA improved the sintering temperature while effectively decreasing the pore size and increasing the compressive strength of the product. Furthermore, the sintering temperature and the proportion of CA were found to be the primary factors affecting the properties of the sintered products, and the addition of 18-25% of CA coupled with sintering at 1100 degrees C for 30 min produced the highest quality lightweight aggregates. In addition, heavy metals were fixed inside products generated under these conditions and the As, Pb, Cd, Cr, Ni, Cu, and Zn concentrations of the leachate were found to be within the limits of China's regulatory requirements.
在本研究中，以干污泥（DSS）为主要原料与粉煤灰（CA）混合制备轻质骨料。随后评估了不同原料组成和烧结温度对骨料性能的影响。此外，通过分析骨料中重金属的固定率及其浸出行为，对所制备的轻质骨料进行了环境评估。结果表明，由于DSS有机质含量高，使用DSS增强了热解-挥发反应，并降低了堆积密度和烧结温度。然而，未改性DSS的烧结产物由于烧结过程中形成大孔而多孔且松散。添加CA提高了烧结温度，同时有效减小了孔径并提高了产物的抗压强度。此外，发现烧结温度和CA的比例是影响烧结产物性能的主要因素，添加18-25%的CA并在1100℃下烧结30分钟可制备出质量最高的轻质骨料。此外，重金属被固定在这些条件下生成的产物内部，且浸出液中As、Pb、Cd、Cr、Ni、Cu和Zn的浓度均在中国监管要求的限值范围内。
