重金属污泥高温处理磨细粉对改性硫氧镁水泥基材料性能的影响

Effects of high-temperature treatment of heavy metal sludge and ground powder on the performance of modified magnesium oxysulfide cement

为了探究重金属污泥高值资源化利用途径,研究了重金属污泥高温处理渣料磨细粉(简称磨细粉)对改性硫氧镁(MMOS)水泥基材料的工作性能、力学性能、早期自由收缩变形及其重金属浸出行为的影响.结果表明:随着磨细粉掺量的增加,MMOS水泥基材料的净浆流动度呈现逐渐增大趋势;早期(3 d)力学性能则呈现明显的降低趋势,90 d后磨细粉掺量对MMOS水泥基材料的力学性能的影响程度降低;磨细粉可以显著降低MMOS水泥基材料早期的自由收缩变形值,其中含10%磨细粉的MMOS水泥基材料早期的自由收缩变形比未掺加磨细粉MMOS水泥基材料的自由收缩变形值降低了57.1%.微观分析结果表明:掺加30%磨细粉后MMOS水泥基材料中水化产物5Mg(OH)_(2)·Mg SO_(4)·7H_(2)O(517相)的相对含量降低,MMOS水泥基材料硬化体的平均孔径提高了31.0%,表明磨细粉降低了MMOS水泥基材料的力学性能.当磨细粉掺量增加至40%时MMOS水泥基材料硬化体中重金属Ni、Cr、Zn和Cu的浸出浓度指标均能满足GB30760-2014的浸出要求.

To explore the utilization of high-value resource such as heavy metal sludge,the effects of grinding powder of high temperature treated slag containing heavy metal sludge on the working performance,mechanical properties,early free shrinkage deformation,and heavy metal leaching behavior of modified magnesium sulfide oxide cement-based materials (MMOS) are investigated.The results show that with the increase of the content of ground powder,the net slurry fluidity of MMOS cement increases gradually,while its early mechanical properties decrease obviously.After 90-day observation,the effect of the content of ground powder on the mechanical properties of MMOS cement decreases.Grinding powder can significantly reduce the early free shrinkage deformation value of MMOS cement,in which the early free shrinkage deformation value of MMOS cement containing 10%ground powder decreases by 57.1%compared with the controlled sample.Microanalysis results suggest that the relative content of hydration product 5Mg(OH)_(2)·Mg SO_(4)·7H_(2)O (517 phase) in MMOS cement decreases with the addition of ground powder,and the average pore size of the hardened body of MMOS cement increases by 31.0%,which explains why the ground powder reduces the mechanical properties of MMOS cement.Leaching concentrations of Ni,Cr,Zn,and Cu in hardened MMOS cement with grind powder content of 40%are all lower than the requirements of the standard GB 30760-2014.