重金属污泥磨细粉对硅酸盐水泥基材料性能的影响

为了更好地实现对重金属污泥的资源化利用,研究了高温无害化处理重金属污泥与建筑渣土混合渣料磨细粉对硅酸盐水泥基材料工作性、力学性能、早期收缩变形、抗氯离子渗透性能及重金属浸出的影响及机理。研究结果表明,随着磨细粉掺量的增加,硅酸盐水泥基材料的工作性没有降低,但其力学性能均有一定程度下降,这说明磨细粉与硅酸盐水泥的需水比相差不大,但其掺量越大水泥基材料中水泥的量越低,其强度均会有一定程度下降。磨细粉不会引起硅酸盐水泥基材料的体积安定性问题,可以提高早期抗裂性,但会降低其抗氯离子渗透性能。含磨细粉试件中重金属的浸出浓度、水胶比的下降与龄期的上升呈负相关,且在28 d龄期下含40%(质量分数)磨细粉的硅酸盐水泥基材料中重金属Cu、Ni、Zn和Cr的浸出量均低于GB 30760—2014《水泥窑协同处置固体废弃物技术规范》规定的浸出浓度限值。

Effect of Heavy Metal Sludge Ground Powder on Properties of Portland Cement-Based Materials

In order to better realize the resource utilization of heavy metal sludge,ground powder mixed with heavy metal sludge and architecture sediment for high-temperature harmless treatment was investigated on the work performance,mechanical properties,early shrinkage deformation,chloride ion permeability resistance,and heavy metal leaching of Portland cement-based materials.The results show that with the increase of ground powder content,the work performance of Portland cement-based materials does not decrease,but the mechanical properties decrease to a certain extent,which indicates that the water requirement ratio of ground powder and Portland cement is not much different.But the larger the content of ground powder is,the lower the cement content in cement-based materials is,and the strength decreases to a certain extent.The ground powder does not cause the volume stability of the Portland cement-based materials and improves the early crack resistance,but it reduces chloride ion permeability resistance.The leaching concentration of heavy metals and the decrease of water-binder ratio are negatively correlated with the increase of age,and the leaching amount of heavy metals Cu,Ni,Zn and Cr in Portland cement-based materials containing 40%(mass fraction)ground powder at 28 d is lower than the limit value of cement clinker leaching concentration specified in GB 30760—2014“Technical specification for cement kiln cooperative disposal of solid waste”.