Research On The Recovery Of Metal From Waste Printed Circuit Boards Using Liquid-solid Fluidized Bed

Research on the recovery of waste PCB is the demands of the pressure forresources and the environment, and is also the mandate of our country’s laws andregulations. The recovery of waste PCB can protect our environment; it also can provideresources for us.So the research on the recovery of waste PCB is very useful.By studying the principle of particle sedimentation in the liquid-solid fluidized bed,the text calculate the settling velocity, and also explore the factors that affect particlesettling velocity.With the software FLUENT,it verify the correctness of the calculated watervelocity in theory.The simulation results show that the rising water speed0.1674m/s，0.0768m/s，0.0299m/s，0.0120m/s can be used for the-1.25+0.56mm，-0.56+0.300mm，-0.300+0.130mm，-0.130+0.074mm four size fraction’s sorting test.The waste PCB were broken into different size fraction by the dedicatedcrusher.Screening the material to-1.25mm,-1.25+0.56mm,-0.56+0.300mm,-0.300+0.130mm,-0.130+0.074mm,-0.074mm six size fraction. Analysis of thedissociation characteristics of waste PCB were made by digital cameras and scanningelectron microscope. According to the analysis from the materials after crushing,89.58%of the metal concentrated in-1.25+0.56mm,-0.56+0.300mm,-0.300+0.130mmthree size fraction.Waste PCB mainly as selective fragmentation in the process ofcrushing,on the one hand,metallic materials were enriched in the larger size fractionwhile nonmetallic materials were enriched in the smaller size fraction.This paper established a new process for the recovery of waste PCB after reading alot of literature.Through the processes of dismantling,crushing and sorting achieved theseparation of metallic and nonmetallic.Evaluation index based on the recovery andgrade, experimental study makes the water velocity is better.After experimental studythe water velocity can make the recovery rate and the grade of metal are better thanbefore.With the water velocity increases, the recovery rate of metal showed a downwardtrend while the grade of metal showed an upward trend.The feeding had little effect onthe results of sorting in the experimental range. The results showed that the technology of liquid-solid two-phase flow can be used for the separation of metallic andnonmetallic from waste PCB, and have a good separation effect.