| In this paper, taking the waste computer circuit board as the research object, through theICP-AES and other detection methods to determine the waste printed circuit board contained inthe main metal elements as copper, lead, nickel, zinc and iron and other elements, in addition alsocontains gold, silver and other precious metal elements, a small amount of. In order to avoid thevaluable metal resources waste, using reasonable methods the valuable metals such as copper andeffective recovery, not only meet the requirements of environmental protection, but also canchange waste into treasure, while alleviating the shortage of copper resources problems of China.Through this study integrated the advantages and disadvantages of all kinds of newelectrolytic process and electronic waste pretreatment method, with crushing and separation ofplastic machinery, and then by means of different heat pretreatment is taken out of nonmetalelements, improve the content of metal elements, especially the Cu element, using stainless steelcathode technology electrolytic copper. Electrolytic methods are divided into two kinds, a kind ofafter pretreatment of waste PCB powder after high temperature melting into the anode, cathode forduplex stainless steel plate through the direct current electrolysis; After another for thepretreatment of waste PCB powder after electrolytic study directly, including circuit board withduplex stainless steel powder do anode for conductor, duplex stainless steel plate as cathodeelectrochemical experiments.First, the samples were thermally pretreated by mechanical crushing and sorting afterexperiment. The results show that the metal content after heat pretreatment have improved, inwhich the Cu by the previous28%increase to up to75%. Through the GC-MS analysis that thecircuit board contains many toxic and harmful substances, in the recovery of the circuit board inthe process, we must take preventive measures, in order to avoid environmental especially hurtoperator.Second, thermally pretreated samples with the highest Cu elements by high temperaturemelting cooling after the anode made of stainless steel cathode technology, combined with dualphase stainless steel plate as cathode for electrolysis, electrolysis using equipment designed byourselves. To determine the optimum condition for electrolysis: electrolytic temperature of50℃current density, electrode spacing is5cm,300A/m2in copper electrolyte acid ratio of 150g/L:180g/L. Under this condition, the copper Cu purity was99.5%,98%current efficiency,energy consumption per unit of0.258W/g.Third, thermally pretreated samples powder Cu element with the highest through theself-made electrolytic equipment direct electrolysis experiments, first by single factor experimentstudy of electrolytic temperature, current density, electrode spacing, the electrolyte copper acidratio effect on the quality of cathode copper; then through the orthogonal optimization experimentthe best electrolysis conditions: electrolytic temperature50℃, current density, electrode spacingis5cm,400A/m2in copper electrolyte acid ratio of150g/L:180g/L.Finally, study the pretreatment on the extraction of copper from waste circuit board influenceelectrolytic method. Research shows that waste circuit board after mechanical crushing andseparation, product after heat pretreatment in N2atmosphere temperature of600℃, then thecopper electrolysis refining effect is the best, the purity of copper is99.6%, current efficiency is98%. And the two electrolysis in electrolytic current efficiency, energy consumption per unit, thepurity of copper cathode and cathode copper SEM analysis and other aspects of the comparativestudy, the results of the two methods are relatively flat income copper surface no largeragglomerates, and through comparison and analysis of current efficiency, energy consumption andthe purity of copper electrolysis cathode data show that the powder method, more in the promotionof industrialization in the future. |
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