Research On The Copper Recovery From Bacterial Leaching Of Waste Printed Circuit Boards By Electrolysis

The bacterial leaching of bio-hydrometallurgy technology turns the "WPCBs" into " bio-leaching solution which is rich in metal resources". Recycling the metal from bioleaching solution, it is also realized the recovery of WPCBs and the treatment to heavy metal wastewater, which become a hot spot for the utilization of metal resources in WPCBs. Taking the artificially formulated copper sulphate solution, acid leaching solution and biological leaching solution of WPCBs as the research object, this study used electrodeposition method to reclaim copper, examined the related factors that affecting deposition, the main conclusions of this study are as follows:(1)This paper takes acid leaching lixivium and configuration of copper sulfate electrolyte as research object, the effect of current density, initial pH and other metal ions in the electrolyte on the electrodeposition are systematic investigated. Set the initial concentration of copper ions as 4.00 g·L-1, 6.00 g·L-1, cathodic current efficiency can reached 90% only in 30 minutes, cathodic current efficiency decreased significantly when continue to electrodeposit, cathodic current efficiency is less than 20% after 120 minutes. Under the optimum conditions(the concentration of copper ion 9.75 g·L-1, pH = 3.00, current density 200 A·m-2), their copper recovery rate reached 92.24% and 89.41% respectively, and the cathode current efficiency was 71.01% and 62.84% after the deposition of two WPCBs simulated leaching for 180 minutes.Results show that, copper recovery rate was significantly increased with the increasing of current density, while the cathodic current efficiency declined. Keep the deposition conditions and increased the initial concentration of copper ion, the time of recovery become longer while the cathodic current efficiency improved; It is beneficial to the deposition efficiency of copper by improving initial pH value in either copper sulfate electrolyte solution or acid leaching solution. High pH value may lead to precipitation and adsorption reaction of Cu2+.(2) Study on the influencing factors of copper recovery from WPCBs bacteria leaching solution and optimization of electro deposition conditions After removal of the organic matter, the recovery rate of copper and the cathode recovery efficiency were obviously improved to 90.41% and 92.14% in 120 minutes. When the copper recovery rate reaches about 90% in the electrodeposition process, the cathodic current efficiency of bioleaching lixivium which have oxidation treatment was 92.14%, which was significantly higher than that untreated(68.23%). Under the same optimum conditions(pH = 3.00, current density 200 A·m-2), the recovery effect of copper in the leaching solution was obvious: The deposition effect of the bacterial extract was better than that of the acid leaching lixivium, especially in the early stage of deposition of 90 minutes, the copper recovery rate can reach 77.04%, higher than the acid leaching lixivium(67.66%), the cathode current efficiency is more than 90% and the cathodic deposition of copper is relatively flat with higher quality. The results showed that the content of organic had a significant effect on the recovery rate of copper and cathodic current efficiency. After removal of the organic matter, the recovery rate of copper and the cathode recovery efficiency were obviously improved; The deposition effect of the bacterial extract was better than that of the acid leaching lixivium under the same optimum conditions.