Waste CPU Sockets Reutilization By Slurry Electrolysis

With the rapid development of social economy and the improvement of people's consumption level,the service life of electronic and electric equipment products is decreasing year by year,resulting in the annual growth of waste electronic and electric equipment?WEEE?.The two attributes of electronic waste,which is high hazard and high value,make it a hot spot of attention nowadays.With the progress of science and technology and the enhancement of people's environmental awareness,the research on the recycling of WEEE,waste printed circuit boards?WPCBs?and other electronic wastes is inclined to classified recycling,such as the recovery of electronic components.There are many kinds of electronic components.The metal types and content of every kind of electronic component is different due to the different functions.Waste CPU sockets are chosen as the research object of this study.We try to recycle metal from waste CPU sockets by slurry electrolysis,preliminarily explore the reuse of electrolyte in the slurry electrolysis system,and study the reaction mechanism of this system by cyclic voltammetry.The main conclusions are as follows:1.In this work,metals can be successfully recycled from waste CPU sockets by one-step slurry electrolysis.From the perspective of total metal recovery,the best recycling conditions are:current density is 80 mA/cm²,pulp density is 100 g/L,HCl concentration is 4 mol/L,electrolysis time is 5 h,and the total metal recovery rate is92.72%.From the perspective of obtaining cathode copper powder,when current density is 80 mA/cm²,pulp density is 75 g/L,HCl concentration is 4 mol/L,electrolytic time is 4 h,better cathode copper powders can be obtained,and the copper recovery rate and purity is 96.67%and 98.16%,respectively.The copper powders under this condition were analyzed by SEM.It is found that the cathode copper powder is mainly dendrite.2.The research on reusing the electrolytes during the metals recycle from waste CPU sockets by slurry electrolysis shows that the existence forms of metals after slurry electrolysis are quite different.Al,Ni and Pb,mainly exist in the electrolyte or anode slag.Cu,Pb,and Au mainly exist in the cathode powders and the electrolyte.Pt mainly exists in the anode slag,and the existence of Ag is influenced by the concentration of chloride in the solution.The recycling of the electrolyte causes the metal to be recycled in the form of cathode powder,and the recovery rate of cathode powder increases from40.31%to 66.64%;the metal content in the electrolyte is greatly reduced from 45.47%to 8.59%.In addition,the circling use of electrolytes reduces the use of chemical reagents and the production of waste acid,which plays an important role in industrial production.3.The study on the characteristics of cyclic voltammetry in the slurry electrolysis system shows that the main electrode reactions include H₂O₂ oxygen evolution with an oxidation potential of 0.10 V,Cu oxidation reaction with an oxidation potential of 0.45V,Pt-O reduction reaction with a reduction potential of 0.93 V,hydrogen evolution with a reduction potential of-0.47 V,Cu ion reduction with a reduction potential of0.02 V and Ni ions reduction reaction of-0.76 V.Besides,the results also show that stirring makes the deposition potential of metal ions obviously negative move and stirring increases the peak current.The control steps of electrode reaction under the slurry electrolysis system are all diffusion control.