Research On Methodology And Process Of Waste PCB Recycling With Supercritical Fluid CO₂

With the rapid development of electric industry and the incessant application of advanced technologies,the number of electric and electronic equipment(WEEE) increases rapidly and their service life becomes ever shorter,which make a large of waste electric and electronic equipment come in to being.The world are facing an ever growing stream of electronics waste.As a typical of electronics waste with great quantity,waste printed circuit board(PCB)is recognized a challenge to effective reutilization.Therefore,recycling of this kind of wastes properly has been laid store by researchers all over the world.The method for waste PCB recycling with supercritical fluid CO₂(SCF-CO₂) is a novel technology.Based on explaining the characteristic of supercritical fluid and the structure of PCB,the way of waste PCB recycling with SCF-CO₂ is proposed.A typical kind of FR-4 PCB used widely is chosen as the experimental material,which is treated by SCF-CO₂ using the designed experimental system. According to the analysis of the influence of different conditions on PCB delaminating ratio,thermogravimetric analysis of PCB and gas chromatographymass spectrometry(GC/MS)determination of solid products,the foundational principle of PCB delamination is illuminated.Decomposition characteristic of resin is studied in PCB processing by SCF-CO₂ based on its definition.The influence of temperature,pressure and treatment time on decomposition characteristic of resin and the relationship between PCB delaminating ratio and decomposition characteristic of resin are analyzed.By designing a technology model,the process of waste FR-4 PCB recycling with SCF-CO₂ is studied using central composite design.The quadratic polynomial equation model of every output parameter in recovery process is obtained,by which optimal temperature and treatment time for FR-4 PCB recycling with SCF-CO₂ were found and their veracity is validated by a series of experiments.Finally,general summary of the thesis is presented,and the important context about research of PCB recycling with SCF-CO₂ is analyzed.