Study on Behavior of Arsenic Secondary Release from Waste SCR Catalyst
To reduce the hazard caused by the secondary release of arsenic(As)in waste SCR catalysts,a bench-scale experi-ment was conducted with analytic instruments including XRD,XRF,SEM-EDS and ICP-OES,and for observing As second-ary release behavior a leaching device was designed and set up to simulate the As secondary release of waste SCR catalysts in the condition of natural precipitation and water erosion.In addition,an online system was developed for monitoring As being released out of waste SCR catalysts under heated condition.Consequently,the experiment indicated as contained in waste SCR catalysts was as high as up to 1.477％.The rate of As separated out from the waste SCR catalyst was 39.71％under the condition of acid condition(pH of 5),the rate of As separation being negatively correlated to the pH value of the leaching water;and at the temperature 800～1 000 ℃ the releasing ratio of As could be up to 100％.Therefore,the discarded waste SCR catalysts during the period of storage and transportation should avoid rainwater flushing,and when recycling waste SCR cata-lysts it is necessary to adopt low-temperature recycling approaches to lower the secondary pollution of arsenic.
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维普
