Study On The Transfer Characteristics Of Bromine In Combustion Of Waste Printed Circuit Boards At High Temperature

The rapid development of modern science and technology accelerates the obsolescence of electronic and electrical equipments (EEEs) that have become one of the fastest growing waste streams around the world. Such worldwidely growing waste stream has naturally increased the number of waste printed circuit boards (PCBs) that serve as one of the main component in all EEEs. The local environment would be severely damaged during the disposal of waste PCBs because of their complex composition. For that reason, many researchers have dedicated to find safe and efficient methods for the disposal of waste PCBs.Incineration has been widely used to dispose the municipal solid wastes (MSWs), but the research on the incineration of PCBs is scarce. A large quantity of inorganic brominated compounds, which would cause equipment corrosion and damages to human health and local environment, emitted in the gaseous fraction during combustion of PCBs. Therefore, the aim of this paper is to investigate the transfer characteristics of bromine in combustion of waste printed circuit boards at high temperature.The characteristic and products during the thermal composition of PCBs have been investigated by TG—FTIR under nitrogen and oxygen atmosphere, respectively. The results show that two main stages occurred during combustion and each stage can also be subdivided into two stages, which is different from the result during pyrolysis.The method for separating HCl and Cl2 was successfully improved to separate HBr and Br2, which play a crucial role to the whole experiment.The influence of temperature, oxygen concentrations, and content of steam on the conversion of bromine was investigated by using a quartz tube furnace. The results indicated that bromine was mainly evolved as HBr and Br2. Compared with pyrolysis, more Br2 was generated and increased with temperature increasing during combustion.Co-combustion of waste PCBs with calcium oxide and sulfur were also investigated and found that both of them can increase the conversion from organic bromine in the PCBs to inorganic bromine. Moreover, the percentage of Br2 obviously decreases during co-combustion with sulfur, but obviously increases during co-combustion with sulfur at lower temperature.