Component Analysis And Dechlorination Research Of Automotive Shredder Residue(ASR)

In recent years,a large number of toxic and hazardous substances are produced because of the simple landfill and accumulation of automotive shredder residue（ASR）.Therefore,it is very important to develop the recycling technology of ASR for the harmless,stability,reduction and resource utilization of ASR.In this paper,we use ASR which generated from manual dismantling and mechanical crushing as the research objects,we focused on summarizing the research status,fuel utilization technology research progress and dechlorination technical research progress of ASR,discussing the composition features of ASR,measuring the total amount of heavy metals in the ASR,and investigating the distribution,leaching characteristics and sources of heavy metals of ASR.Besides,we also studied the precipitation behavior of chlorine from ASR and established a suitable dechlorination process for ASR through the optimization of technology.Through related literatures and reviews surveys,we concluded that dispose ASR by isothermal pyrolisis dechlorination at low temperature is the most effective way for its fuel use as cement production.Combustion residues are used as raw material for cement production and almost 100%utilization can be achieved.The results of manual sorting,elemental analysis,X-fluorescence analysis and infrared spectroscopy（FTIR）analysis show that ASR is a highly heterogeneous mixture,all the components are affected by the pollution of petrol,oil,lubricants,PCBs and heavy metals.The chlorine content of Guangzhou samples and Qingdao samples were 12.00 mg/g and 28.38 mg/g respectively.Meanwhile,industrial analysis results show that both of them have potential to be used as fuels for cement production after dechlorination.The contents,distribution and extracting regularity of heavy metals in ASR show that Pb and Zn have high contents in ASR,which widely present in each component of ASR,especially in powders like sediment etc.Heavy metals such as Pb,Zn,Ni and Cu etc.can be detected in the extracts,which show that heavy metals in ASR are mainly exist in the form of metallic elementary substances,metallic oxides and metallic salts.The study of precipitation behavior of chlorine from ASR indicates that the isothermal pyrolysis dechlorination of ASR and PVC at low temperature has a big difference.As the existence of Ca CO₃ filler,heavy metals and a variety of additives of plastics,rubber,leather and so on in ASR,it has a certain fixed action for the formation of HCl in the pyrolysis process,and the formed chloride is adsorbed in the pores of calcium carbonate,which is not easy to be removed by washing.The isothermal pyrolysis dechlorination rate of ASR can be improved by adding APP,and the generated NH₄Cl can be easily removed by washing.The dechlorination research results of ASR show that,when the mass ratio of ASR and APP is 9:1,carry out the isothermal pyrolysis process at 300°C and keep the samples under this temperature for 30 min,we found that the two samples have higher dechlorination rates after washing,the dechlorination rates are 89.17%of Guangzhou samples and 90.14%of Qingdao samples respectively.Organic gas products generated by the isothermal pyrolysis dechlorination of ASR are mainly from antioxidants and additives etc.,they can be easily decomposed;Cu,Cd,Pb,Zn,Ni and Cr are found in the scrub solution of isothermal pyrolysis residues,the contents are higher than ultrapure water leaching before pyrolysis.The scrub solution of Qingdao samples has the highest content of Pb,which reached to 317 mg/Kg.