Study On Emission Characteristics Of PBDFs In The Process Of Recycling Waste Printed Circuit Boards

Waste Printed Ccircuit Boards?WPCB?not only contains basic industrial materials and rare metal with valuable recycling value,but also contains a large number of persistent toxic chemical pollutants,which will produce and release pollutants such as heavy metals and polybrominated flame retardants during their recycling process.In this paper,the brominated flame retardant-Polybrominated Diphenyl Ether?PBDEs?was used as the target to study the emission characteristics and emission factors of PBDEs in the process of recycling waste printed circuit boards.After preliminary investigation,we selected two typical wastes printed circuit board resource-recycling enterprises in Hubei Province,which applied the“physical treatment method”and“physical pretreatment+deep heat treatment method”respectively.And the research method is to combine the research process,the operating conditions and the sewage disposal nodes of the workshop,then develop a sampling analysis plan to separately sample and quantify the flue gas discharged from the organized workshop and the solid waste generated in the production process,and perform systematic analysis on the basis of this data.Concluded as follows:?1?In the process of recycling the WPCB by the"physical sorting",the PBDEs in the raw material are not removed,and the PBDEs in the raw material migrate in the flue gas and the discharge solids,mainly flowing into the resin.powder and dust ash.Among them,the emission factor of PBDEs is organized exhaust gas,and its emission coefficient is:0.17mg·?₁₀PBDEs/kg WPCB;the emission factors of PBDEs mainly include resin powder,dust ash and metal materials,and the total carrying emission coefficient is 435.06 mg·?.₁₀PBDEs/kg WPCB,the emission factors for each carrying factor were:273.4 mg·?₁₀PBDEs/kg WPCB,135.2mg·?₁₀ PBDEs/kg WPCB,and 26.46 mg·?₁₀ PBDEs/kg WPCB.Due to the high concentration of PBDEs in resin powder and dust ash,these solid residues can not be disposed of or landfilled at will in the post-treatment process.Government departments and enterprises should manage them as hazardous wastes and attach great importance to their direction and disposal methods.?2?In the process of applying the"physical pretreatment+deep heat treatment"to treat WPCB as resource,the removal rate of PBDEs in the raw material amounts to 95%.The residual PBDEs flow mainly to the metal in the pretreatment plant and the pyrolysis products in the heat treatment plant.Among them,the PBDEs emission factor is organized emission,and the emission coefficient of PBDEs from two workshops to atmospheric environment is 11.47?g·?₁₀PBDEs/kg WPCB.The main carrying factors of PBDEs are metal mixtures,pyrolysis products and dust removal in two workshops.The total carrying coefficient of PBDEs is 8.35 mg·?₁₀PBDEs/kg WPCB.and the carrying factors of each carrying factor were:5 mg·?₁₀ PBDEs/kg WPCB,3 mg·?₁₀ PBDEs/kg WPCB,0.34mg·?₁₀ PBDEs/kg WPCB and 0.0053 mg·?₁₀ PBDEs/kg WPCB.Through comparative analysis,it is known that the pollution level of PBDEs generated by WPCB using the"physical pretreatment+heat treatment"process is much lower than the"physical sorting"process.