Optimizing operating conditions in an ion-exchange column treatment applied to the removal of Sb and Bi impurities from an electrolyte of a copper electro-refining plant

Atlantic Copper is a copper cathode producer located in Spain. One of the most important steps in the production process is electrorefining, and this is strongly influenced by elements dissolved in the electrolyte. The presence of some metals or semi-metals, such as As, Sb or Bi, adversely affects the current efficiency and quality of the cathodes. Therefore, it is very important to control the level of such impurities in the electrolyte. This paper describes the study of the separation of Sb and Bi from a real electrolyte by means of ion-exchange columns (using aminophosphonic resins). Possible variations of the composition of the electrolyte were considered, because the presence of Fe(III) could poison the resins. Thus, the main result of the work is a complete operating protocol (load + elution + regeneration) of ion-exchange columns. Different alternatives to resin regeneration are also described in order to adapt the designed installation to the variability of Sb, Bi and Fe impurity levels in the electrolyte.