| Electroplating sludge contains a large amount of toxic and harmful heavy metals,which is hazardous waste.The use of electroplating sludge to prepare ceramsite can effectively solidify heavy metals in sludge,reduce the risk of polluting the environment,realize resource utilization,and reduce the use of ceramsite raw materials such as shale and clay to achieve sustainable green development.It has certain social and economic benefits.This experiment mainly studies the feasibility of preparing ceramsite from solid waste such as electroplating sludge.The electroplating sludge was mixed into aluminum sludge and mica sand to investigate the influence of different electroplating sludge incorporation and main sintering influence factors on the physical properties(strength,density,water absorption)of ceramsite and heavy metal leaching toxicity(Cu,Cr,Cd,Ni,Pb,Zn)and judge the best preparation conditions for ceramsite.The conclusions are as follows:(1)The amount of different electroplating sludge in the ceramsite has a certain influence on the physical properties of the ceramsite.When the ratio is 15% of electroplating sludge,65% of mica sand,and 20% of aluminum sludge,the physical properties of ceramsite are better than the other ratios.The ceramite crystal is mainly composed of quartz,with smooth interior,compact structure and high strength.The amount of different electroplating sludge incorporation has little effect on the short-term heavy metal leaching results of ceramsite.However,when the acid environment is extracted for a long time,it has a significant effect on the leaching results.The more electroplating sludge is added,the higher the cumulative leaching is.The cumulative leaching amount of heavy metals in long-term leaching generally shows acidic environment>neutral environment>alkaline environment;when the incorporation of electroplating sludge in the short-term is 15%,20%,25%,the ceramsite leachate can reach the groundwater quality class II standard and the surface water environmental quality class II standard;for long-term leaching in neutral alkaline environment,the single leaching concentration of ceramsite leaching solution can reach Class III standard of groundwater quality and Class II standard of surface water environmental quality.Combined with physical properties and leaching concentration,15% of the proportion of electroplating sludge,65% of mica sand and 20% of aluminum sludge were selected as the best ratio of ceramsite raw materials.(2)Through the orthogonal test,the optimal sintering conditions can be selected according to the test results: preheating temperature 600 ?,preheating time 15 min,sintering temperature 1150 ?,sintering time 20 min.The ceramsite has excellent physical properties under optimal sintering conditions and can be applied to building materials such as concrete aggregates;the leaching concentration of each heavy metal in the leachate is low,the water quality of the leachate reaches the Class III standard of groundwater quality and the Class II standard of surface water environmental quality,and the safety performance meets the requirements.Through analysis of variance and single factor test,the sintering temperature has a significant effect on the single crushing strength,water absorption and Cr leaching concentration of ceramsite.When the sintering temperature is 1100 ?,the single crushing strength is low,the water absorption rate is high,the Cr leaching concentration is high,and the excessive sintering temperature also affects the strength of the ceramsite.The remaining factors have a certain impact on the difference in test results,but not significant.Through the research in this paper,it shows that under the optimal conditions,Ceramsite prepared by electroplating sludge has superior physical properties,low heavy metal leaching and the conditions for practical application.It is a harmless disposal method for electroplating sludge that realizes resource utilization and green sustainable development,and has more in-depth research value. |
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