摘要
为了提高危险废物电镀污泥的高值化利用程度,研究了掺加CaSO_(4)对含磨细粉(由电镀污泥协同建筑渣土高温处理渣料磨细得到)水泥基材料力学性能、微观结构特征及重金属浸出的影响及机理。结果表明:CaSO_(4)掺量(基于其在胶凝材料的质量占比)为0.6%时,其长期力学性能较优,含磨细粉水泥基材料养护60 d后抗压强度和抗折强度比未掺加CaSO_(4)时分别提升20.1%和22.2%。适量的CaSO_(4)可以补充含磨细粉水泥基材料基体中Ca 2+含量,促进水泥和磨细粉中具有潜在水化活性的组分充分进行水化,同时使基体中生成更多的钙矾石填充孔隙,从而增强了基体结构密实度。研究还发现多余钙矾石的形成对重金属离子的固结起到了正向作用,适量的CaSO_(4)掺加能明显降低含磨细粉水泥基材料基体中有害重金属离子的浸出浓度。当CaSO_(4)掺量为0.6%时,含磨细粉水泥基材料养护28 d后,Cu、Ni、Zn的浸出率比未掺加CaSO_(4)时分别降低了33.6、31.0、53.0百分点,更好地确保了其浸出安全性。
To improve the high value utilization degree of electroplating sludge,the effect and mechanism of CaSO_(4)on mechanical properties,microstructure and heavy metal leaching of cement-based materials mixed with ground powder(preparation from electroplating sludge and construction residue after high-temperature treatment and grinding)were studied.The results showed that the long-term mechanical properties were better when CaSO_(4)dosage(mass fraction of CaSO_(4)in cementing material)was 0.6%.The compressive strength and flexural strength were increased by 20.1%and 22.2%respectively after 60 d curing period compared with those without adding CaSO_(4).Microscopical study results showed that the appropriate dosage of CaSO_(4)could supplement the Ca 2+content in the matrix pore solution of the cement-based material mixed with the ground powder.It could also promote the hydration of the active components with potential hydration in the cement and ground powder.Simultaneously the addition of CaSO_(4)caused more ettringite to fill the pores in the matrix and enhanced its compactness.It was found that the formation of ettringite played a positive role in the consolidation of heavy metal ions,and appropriate content of CaSO_(4)could significantly reduce the leaching concentration of certain harmful heavy metals in cement-based materials mixed with ground powder.When CaSO_(4)dosage was 0.6%,the leaching rates of copper,nickel and zinc was 33.6,31.0 and 53.0 percent points lower than those of cement-based materials without CaSO_(4)after 28 d curing period,ensuring better leaching safety.
作者
成伟
高琦
张宇驰
初汉增
巴明芳
CHENG Wei;GAO Qi;ZHANG Yuchi;CHU Hanzeng;BA Mingfang(College of Civil and Environmental Engineering,Ningbo University,Ningbo Zhejiang 315211;Yuyuan Ninghai Environmental Protection Technology Co.,Ltd.,Ningbo Zhejiang 315211)
出处
《环境污染与防治》
CAS
CSCD
北大核心
2023年第4期469-476,共8页
Environmental Pollution & Control
基金
浙江省公益技术项目(No.LGF22E080020)
宁波市科技创新2025重大专项(No.2020Z100)
国家自然科学基金资助项目(No.51978346、No.51778302)。
