摘要
为了有效处理城市垃圾,一般需要对城市垃圾进行焚烧,但在焚烧过程中会产生大量危险固废物飞灰。赤泥中的氧化铝、二氧化硅和氧化钠可以与飞灰中的活性氧化铝、二氧化硅发生地聚反应,生成的地聚合物能够有效固定飞灰中的镉(Cd)、铅(Pb)等重金属,防止其浸出。采用X-射线衍射(XRD)、热重差热分析(TG-DTA)和扫描电镜(SEM)测试手段,对实验相关样品的化学成分、形貌特征进行表征分析。结果表明:在800℃和5%(质量浓度)氢氧化钠(NaOH)的条件下,赤泥的活化效果最佳;赤泥活化后,将赤泥与飞灰(质量比为1∶1,水灰比为0.5)进行均匀混合,赤泥与飞灰的混合物置于养护箱中养护14天(d),即可获得地聚合物样品;XRD表明,聚合物样品中有新矿物[Ca_(6)Al_(2)(SO_(4))(OH)_(12)·6H_(2)O]的衍射峰出现,证明赤泥和飞灰之间发生了地聚合反应;抗压强度测试表明,最佳地聚合物样品的抗压强度为1.63兆帕(MPa);赤泥固化飞灰后的地聚合物渗滤液中的重金属含量达到垃圾焚烧飞灰卫生填埋标准(GB 16889-2008),说明利用赤泥基能够有效固定飞灰中的重金属,证明“以废治废”的技术是可行的。
In order to effectively handle urban waste,it is generally necessary to incinerate it,but during the incineration process,a large amount of hazardous solid waste fly ash is generated.The alumina,silica,and sodium oxide in red mud could undergo geopolymerization reaction with the active alumina and silica in fly ash,and the resulting geopolymer could effectively fix heavy metals such as cadmium(Cd)and lead(Pb)in fly ash,preventing their leaching.The chemical composition and morphological characteristics of the experimental samples were characterized and analyzed using X-ray diffraction(XRD),thermogravimetric differential thermal analysis(TG-DTA),and scanning electron microscopy(SEM)testing methods.The results showed that the activation effect of red mud was optimal under the conditions of 800℃and 5%(mass concentration)NaOH;After activation,the red mud was mixed with fly ash(mass ratio of 1:1,water cement ratio of 0.5);After mixing evenly,the mixture of red mud and fly ash was placed in a curing box for 14 days(d)to obtain geopolymer samples;XRD analysis showed the appearance of diffraction peaks of a new mineral[Ca_(6)Al_(2)(SO_(4))(OH)_(12)·6H_(2)O]in the polymer sample,indicating the occurrence of geopolymerization reaction between red mud and fly ash;The compressive strength test shows that the optimal compressive strength of the geopolymer sample is 1.63 MPa;The heavy metal content in the geopolymer leachate of the solidified fly ash from red mud meets the sanitary landfill standard for incineration fly ash(GB16889-2008),indicating that the use of red mud based materials could effectively fix heavy metals in fly ash,proving that the technology of"treating waste with waste"is feasible.
作者
吴辉勇
成岳
董婷婷
WU Huiyong;CHENG Yue;DONG Tingting(School of Materials Science and Engineering,Jingdezhen Ceramic University,Jingdezhen Jiangxi 333403,China;School of Chemistry and Environmental Science,Shangrao Normal University,Shangrao Jiangxi 334001,China)
出处
《上饶师范学院学报》
2024年第3期27-35,75,共10页
Journal of Shangrao Normal University
基金
江西省教育厅科技计划项目(GJJ190892)。
关键词
赤泥
飞灰
固废物治理
地聚反应
red mud
fly ash
solid waste management
geopolymerization reaction
