Contents lists available at ScienceDirect Hydrometallurgy journal homepage: www.elsevier.com/locate/hydromet 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 F. Arroyo-Torralvo b,⁎ , A. Rodríguez-Almansa a , I. Ruiz a , I. González a , G. Ríos a , C. Fernández-Pereira b , L.F. Vilches-Arenas b a Atlantic Copper, S.L.U., Francisco Montenegro Avenue, E-21001 Huelva, Spain b University of Seville, Higher Technical School of Engineering, Department of Chemical and Environmental Engineering, Camino de los Descubrimientos, s/n, E-41092 Seville, Spain ABSTRACT 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, be- cause 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. 1. Introduction The Atlantic Copper (AC) Metallurgical Complex is located in the province of Huelva (Spain). It belongs to the Association of Chemical, Basic and Energy Industries of Huelva, which accounts for 8.5% of the province's GDP (gross domestic product). Using the most advanced technologies, AC transforms raw materials into high-purity copper cathodes and other products, such as anode slime, from which valuable metals, nickel carbonate, copper telluride, silicates, granulated iron, gypsum and sulfuric acid are recovered (www.atlantic-copper.es con- sulted 8/10/2016). Copper concentrate is the name given to the raw material used to make high-purity copper. It is produced by grinding up and treating the ore dug out of mines. Copper is generally found in very low percentages in nature, but ore can be ground up and concentrated to around 25 to 30% by froth flotation. Grinding and froth flotation are done directly at the mine, and it is the resulting concentrated ore that is sent to the smelting works; hence, the name copper concentrate. The main components of copper concentrate, apart from copper, are iron and sulfur. The whole process described below is aimed at separating the copper from the other components, which are treated in different plants at the metallurgical complex until they are ready for marketing and use. When the copper concentrate reaches the plant after moisture reduction, it is introduced into the flash smelting furnace, a process in which copper matte (63–64% Cu) is obtained. In the matte conversion, copper is separated from the leftover sulfur, iron and other metals not eliminated in smelting. Conversion yields a product called blister copper, with a copper content of approximately 99%, which is later introduced in the refining stage in the form of anodes (99.7% Cu). The final step is electrolytic refining (electrolysis), which produces copper cathodes, the main product of Atlantic Copper's metallurgical complex, containing 99.99% copper (Schlesinger et al., 2011). While the copper dissolves, the anode impurities which are above copper in the electro-chemical series (As, Ca, Fe, Ni and Zn), and which are not deposited on the cathode unless a large concentration in the electrolyte is reached, also dissolve (Cooper, 1985; Braun et al., 1986). Conversely, other anode impurities (Pb, Se, Te, Ag, Au, etc.) do not dissolve, as they are more noble than copper. These form the so-called anode slime, which sediments at the bottom of the electrolysis cell during the process (Abe and Takahashi, 1987; Petkova, 1997). Other impurities present in the electrolyte which could significantly http://dx.doi.org/10.1016/j.hydromet.2017.06.009 Received 27 October 2016; Received in revised form 25 April 2017; Accepted 3 June 2017 ⁎ Corresponding author. E-mail address: fatimarroyo@us.es (F. Arroyo-Torralvo). Hydrometallurgy 171 (2017) 285–297 Available online 04 June 2017 0304-386X/ © 2017 Elsevier B.V. All rights reserved. MARK