How to apply pyrolysis technology in PCB
Because the particle size is usually large. The energy consumption is low in the process of mechanical crushing. There is no doubt that this process has a broader application prospect.
Pyrolysis technology, as an efficient means of waste treatment and recycling, can play an important role in the recycling of waste circuit boards. With the development of the basic theory of pyrolysis technology and the development of pyrolysis equipment, it will become one of the most important methods of PCB recycling in the future.
Although the existing research on the measurement of bromine products in PCB pyrolysis is limited to qualitative analysis, or based on the analysis of total bromine content, the exact quantitative analysis and detection of a specific bromine containing substance can not be achieved, so it can not provide enough complete information to determine the transformation and migration of bromine containing flame retardants in the pyrolysis process.
However, many researchers have carried out some attempts to remove brominated pollutants based on pyrolysis technology, and made some breakthrough progress.
If improper technology and equipment are used for recycling, the circuit board will generate more shielding smoke, bromine and hydrogen bromide gas, brominated phenol, polybrominated biphenyldioxin / furan and other toxic and harmful substances in the process of pyrolysis or combustion. These substances not only cause incalculable serious harm to the environment, but also corrode the treatment equipment and reduce the quality of oil products. Therefore, no matter from the perspective of PCB safety treatment or PCB recycling, it is necessary to have a clear understanding of the transformation and migration rules of brominated flame retardants in the pyrolysis process of PCB, and pay attention to the control of secondary pollution and product debromination in the pyrolysis process of waste PCB.
The circuit board condenses the pyrolysis oil and gas from the reactor. Condensate gas and liquid pyrolysis oil are obtained. The metal and glass fiber remained in the reactor to form solid residue, and then the metal and non-metal components were separated and recovered by physical method. The advantage of this process is that it can prevent the temperature rise caused by excessive crushing, thus effectively avoiding the escape of toxic and harmful gases.
At present, the recovery of circuit board mainly focuses on the recovery of precious metals such as pyrometallurgy and hydrometallurgy. The waste gas, waste water and waste residue produced in the treatment process are easy to cause serious secondary pollution. However, the recycling and innocuity of nonmetallic components, which account for more than 50% of the total mass of circuit board, are relatively less involved. Except for a few used as fillers, they are more used as landfill.