Effect of Membrane Pore Size on Copper Recycling from Waste Printed Circuit Boards by Slurry ElectrolysisEffect of Membrane Pore Size on Copper Recycling from Waste Printed Circuit Boards by Slurry ElectrolysisTian, Yan, Pang, Liang, and Chen

Slurry electrolysis could directly recover copper from waste printed circuit boards. However, in this process, separating the cell into a membrane of cathode and anode cavities can lead to differences in copper concentration and thus increase energy consumption. Thus, a serial of membranes with a pore size of 200, 300, 400, 500. 800, 1000 mesh were chose to discuss their effects on the copper concentration difference between cathode and anode chamber, cell voltage, cathode copper purity, copper recovery rate and current efficiency. The results show that, in the NH3·H2O-NH4+-CuSO4-NaCl slurry electrolysis system, copper concentration differences in the cathode and anode chamber increase with a decrease of membrane pore size to 4.60 g/L at 200 mesh while increase to 18.02 g/L at 1000 mesh. Cell voltage also increases with the decrease of membrane pore size. While cathode copper purity is hardly impacted, all values are > 99%. Current densities of the six runs are > 90%, and the copper recovery rates are around 90%. When the pore size is 300 mesh, copper recovery rate, current efficiency, copper purity, and copper concentration difference are respectively 96.92%, 100.22%, 99.617%, 8.81 g/L, with a lowest energy consumption of 11.32 × 104 kJ/t.