Research On The Production And Suppression Of Brominated Dioxins During The Incineration Of Waste Circuit Boards

In recent years,with the rapid increase in the level of technology,the life cycle of electronic products has been shortened,resulting in a sharp increase in the production of electronic waste.As a typical electronic waste,the waste circuit boards(WPCBs)has the characteristics of high recovery value and high potential pollution.How to effectively and reasonably recycle the waste circuit board is an important direction for scholars to explore.Compared with other technologies,such as mechanical physics and chemical methods,the incineration method has many advantages,like large in handling capacity,good volume reduction,and high recovery rate of precious metals.However,WPCBs contains a large amount of brominated flame retardants(BFRs),it is easy to generate polybrominated dibenzo-p-dioxins and dibenzofurans(PBDD/Fs)pollution during WPCBs combustion.Based on this background,the generation and emission characteristics of PBDD/Fs in the process of high-temperature incineration of WPCBs were studied.In this paper,the influence of temperature and BFRs on the emission characteristics of PBDD/Fs during high temperature incineration of WPCBs was studied by using tubular furnaces.The results show that the concentration of PBDD/Fs increases first and then decreases in the temperature range of 800 ? to 1200 ?.The concentration of PBDD/Fs reaches the maximum at 1000 ?.The Toxic Equivalent Quantity(TEQ)continued to decrease in the temperature range of 800 ? to 1200 ?.In this temperature range,the value of PBDFs/PBDDs is always greater than 1,and the PBDFs predominate in PBDD/Fs products between 800 ? and 1100 ?.The addition of BFRs greatly increases the amount of PBDD/Fs generated in the WPCBs incineration flue gas,and promotes the generation of low brominated PBDD/Fs.Through data analysis,it is found that the type of BFRs will affect the amount of PBDD/Fs.Tetrabromobisphenol A produces a smaller amount of PBDDFs than decabromodiphenyl ether.The impact of calcium-based additives on the emission characteristics of PBDD/Fs during high-temperature incineration of circuit boards was also researched with the tubular furnace.The results show that Ca O,Ca CO3 and Ca(OH)2 have an inhibitory effect on the formation of PBDD/Fs in the high-temperature incineration flue gas of the WPCBs,and the inhibition effect is Ca O>Ca(OH)2>Ca CO3,reaching 97%,89%,and 84%,respectively.The addition of Ca CO3 increases the TEQ,and the addition of Ca O and Ca(OH)2 reduces the TEQ.