基于地聚物体系的电解锰渣污染物的溶出风险及固化机理

Leaching risk and solidification mechanisms of electrolytic manganese residue pollutants based on the geopolymer system

为降低电解锰渣(EMR)的潜在环境风险,采用了地质聚合反应对其进行固化稳定化处理,通过浸出毒性试验和BCR连续提取法试验确定电解锰渣基地聚物(EMRGP)的溶出风险,并借助于XRF、XRD、SEM-EDX和XPS等表征手段对固化机理进行探究.结果发现,EMRGP浸出液中的Mn^(2+)和NH^(4+)浓度仅为0.005mg/L和0.996mg/L,满足相关标准的排放和再利用要求.BCR连续提取法试验结果显示EMRGP的溶出风险较低.在固化稳定化过程中,生成了硅铝凝胶,NH^(4+)以NH3挥发或以鸟粪石被沉淀,Mn^(2+)除被氧化成Mn^(3+)和Mn^(4+)外,还与其余重金属元素一同以氢氧化物沉淀形式,或以被硅铝凝胶吸附包裹的形式固定.这一方法显著减轻了EMR的潜在环境风险.

In order to mitigate the potential environmental risks associated with electrolytic manganese residue(EMR),a geological polymerization reaction was employed to carry out its solidification and stabilization.Through leaching toxicity tests and consecutive BCR extraction experiments,the leaching risk of electrolytic manganese residue-based polymer(EMRGP)was ascertained.Characterization techniques such as XRF,XRD,SEM-EDX,and XPS were utilized to investigate the solidification mechanism.The results revealed that the concentrations of Mn^(2+)and NH^(4+)in the leachate from EMRGP were merely 4.64μg/L and 0.99mg/L,meeting the standards for discharge and reutilization.BCR continuous extraction experiments showed a lower leaching risk for EMRGP.During the solidification and stabilization process,the formation of silica-alumina gel occurred.NH^(4+)either volatilized as NH3 or precipitated as struvite,while Mn^(2+),apart from being oxidized to Mn^(3+)and Mn^(4+),concomitantly precipitating with other heavy metal species in the guise of hydroxide precipitates or enshrouded within the protective vestiges of silico-aluminous gels.This approach significantly alleviated the potential environmental risk associated with EMR.