In-situ stacking and aging of electrolytic manganese residue:Speciation of heavy metals and environmental risk evolution
In order to clarify the influence of the storage process on the speciation and environmental risk evolution of heavy metals in electrolytic manganese residue,a series of microscopic experiments such as XRF,XRD,and SEM were conducted to compare and analyze the differences in microscopic properties including soluble salt content,chemical composition,microscopic morphology,and phase composition of fresh and aged electrolytic manganese residue.In addition,batch leaching experiments and improved BCR sequential extraction method were used to evaluate the environmental risks of heavy metals and ammonia nitrogen in fresh and aged electrolytic manganese residue.The research findings demonstrate that throughout the in-situ stacking and aging process,the microstructure of electrolytic manganese residue undergoes a transition towards a loose configuration.The content of soluble salts decreases from 12.25％to 4.38％.The proportions of acid-soluble and reducible heavy metals gradually diminish,resulting in the reclassification of manganese from a"very high risk"to a"medium risk"environmental category.However,the total heavy metal content remains notably elevated at 3.28×104mg/kg,thereby posing a significant environmental hazard.Although there has been some reduction in the leaching of ammonia nitrogen,it still exceeds the 15.00mg/L threshold by a factor of 2.54 to 3.84.Furthermore,some ammonia nitrogen and heavy metals are released into the surrounding ecosystem during the stacking and aging process,necessitating the implementation of essential measures for the treatment of electrolytic manganese residue.
electrolytic manganese residuestorage-agingheavy metal speciationleaching toxicityenvironment risk
万方数据
维普
