Deep removal of copper from cobalt sulfate electrolyte by ion-exchange
(School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract: SP-C was applied for the removal of Cu2+ from simulated cobalt sulfate electrolyte containing Co2+ 50 g/L and Cu2+ 0.5−2.0 g/L. Experimental conditions included pH of 2−4, temperature of 20−60 °C and contact time of 10−40 min. The investigation demonstrated that SP-C had recommendable efficiency in adsorbing Cu2+ from the electrolyte with 25- to 100-fold of Co2+. The optimal adsorption conditions of SP-C were pH of 4, contact time of 30 min and ambient temperature. The study also showed that the loaded resin could be effectively eluted with 2.0 mol/L H2SO4 solution at a contact time of 40 min; the peak concentration of Cu2+ in the eluate was about 35 g/L. The sorption characteristics of Cu2+ by SP-C could be described by Langmuir isotherm and the pseudo second-order kinetic equation. Infrared spectra showed that nitrogen atoms in the functional group coordinated with Cu2+ to form coordination bands.
Key words: cobalt sulfate electrolyte; removal of copper; chelating resin; ion exchange