Metal recovery from low concentration solutions using a flow-by reactor under galvanostatic approach

Resumo

A recently proposed method using constant current steps were applied for a period of time on a reticulated vitreous carbon cathode. The current steps were calculated from a theoretical analysis of the metal concentration profile assuming that the metal was deposited under mass transport control. A model was developed to predict the concentration decay of metal ions during the process. The current required to reduce the metal at the mass transfer limit at each time step was predicted from the concentration decay obtained from the model. This process should enable one to maintain high metal recovery rates whilst maximizing current efficiency. This concept was tested on Cu(II) deposition from an acidified sulfate electrolyte using a flowby reactor system with a reticulated vitreous carbon electrode. The model was good for predicting copper metal removal using a three dimensional cathode in dilute rinse waters. Also, the predicted current efficiency was in good agreement with that obtained using the experimental data.