Copper electrowinning using a pulsed bed three-dimensional electrode

Abstract

This work concerns the electrowinning of copper from an acidic medium using a membraneless three-dimensional pulsed bed electrode (PBE). The effect of current density (i), packed bed time (tp), and fluidized bed time (tf) on current efficiency (CE), energy consumption (EC), and space-time yield (Y) was investigated using a fractional factorial design (FFD). The results showed that the most important variables affecting the electrodeposition process were i and tp. Experiments using i greater than 3000Am−2 and tf lower than 2s revealed that the process rapidly short circuited, mainly due to a non-uniform overpotential distribution inside the porous cathode. An important improvement of the reaction kinetics and EC was achieved by increasing tp and decreasing tf. The best values of CE (76.7%) and EC (2.5kWhkg−1) were obtained by applying 3000Am−2, with tf=2s and tp=60s. Although the CE value was lower than reported elsewhere, the EC value was within the range commonly found for industrial processes. The FFD results indicated ways by which copper electrowinning using a PBE reactor could be further optimized.