The Study Of The Formation And Inhibition Of PBDD/Fs From PCB Thermotreatment Process

As a typical e-waste, the hazard-free treatment and resource of PCB(Printed circuit board) has become hotspot of the national and international research units. This study focused on the PBDD/Fs emission problem of the PCB heat treatment during the resource process of the discarded PCB. The analysis method for PBDD/Fs has been established, the distribution characteristics of PBDD/Fs during PCB pyrolysis and combustion process, and the effect on PBDD/Fs emission of basic additives has been studied to lay a foundation of next research on PBDD/Fs emission control techniques.The PBDD/Fs sample pretreatment flow and the HRGC-HRMS analysis method has been established according to EPA method 1613 and 1614, which is for PCDD/Fs and PBDEs. The MSW flyash, the industrial incinerator flyash and the medical incinerator flyash have been detected by this method. The result proved the availability of the method.By the PCB TG-FTIR test, the sample TG curve has been calculated by Ozawa method to analyze the pyrolysis kinetic parameters of the sample; while, the gas product has also been analyzed by FTIR unit.The pyrolysis and combustion of PCB experiment has been carried out on the small scale quartz furnace. The emission characteristic of PBDD/Fs has been studied. The results indicated that PBDD/Fs maximum emission temperature 600℃during pyrolysis process, as well as the combustion mode reported several times and tens times emission amount of PBDD/Fs.The CaO additive effect on PBDD/Fs emission during PCB pyrolysis processes has been investigated. Tests of different Ca/Br ratio and different basic additives, such as Al2O3,MgO,CaCO3,Ca(OH)2 and NaOH have been proceeded to compare with each other. The result revealed that NaOH have the most efficient inhibition ability. The next was CaCO3, Ca(OH)2, AI2O3,CaO and MgO.The next research work about PBDD/Fs has been mentioned in this study.