฀ ฀ournal of International Scientific Publication: Materials, Methods & Technologies, 2009, Vol.3, Part 1, p.493-500 ฀NFLUENCE OF Z฀NC ฀ONS ON COPPER ELECTRODEPOS฀T฀ON FROM SULPHUR฀C AC฀D ELECTROLYTES Gyunver A. Hodjaoglu*, Ivan S. Ivanov Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad.G.Bonchev Str., bl.฀฀, ฀฀฀3 Sofia, Bulgaria (*author for correspondence, e-mail: gyunver@ipc.bas.bg) Abstract By means of potentiodynamic and galvanostatic methods the influence of H 2 SO 4 , Zn 2+ and hydroxyethylated-2-butyne-l, 4-diol (Ferasine) on the electroextraction of copper from sulphate electrolytes was studied. It was established that Zn 2+ - ions and organic additive Ferasine decreases the cathodic currents and quantities of deposited copper during scanning to different vertex potentials only in electrolytes containing sulphuric acid. Thus they inhibit the process of copper deposition. Dense and smooth copper coatings on with current efficiency higher than 95% are deposited when Cu 2+ concentration is higher than 5.0 g.dm -3 and current density is in the range 0.5 ÷ 2.0 A.dm -2 . More fine-grained coatings are obtained in the presence of H 2 SO 4 and organic additive hydroxyethylated-2-butyne-l, 4-diol (Ferasine). Key words: copper, cyclic voltammogram, deposition, electroextraction, zinc 1. ฀NTRODUCT฀ON After a number of pyro- or hydrometallurgical ores treating, large amount of wastes with high metal content remains. For example, the waste product known as “blue powder” that results by condensing furnace gases during the thermometallurgical processing of non-ferrous ores contains: Zn (25-4฀%), Pb (20-25%), Fe (3-5%), Cu (0.5-฀%), Cd (0.5-฀%), etc. (Muresan et al. ฀999, 2000). The purification of the electrolytes for Zn electrowinning by cementation is another process that produces wastes containing large amount of different metals such as: copper cake, containing Cu (36-54%), Zn (5-฀0%) and Cd (0.08-0.฀6%); copper-cadmium cake, containing Cu (฀0%), Zn (30%), Cd (฀2%); collective cake, containing Cu (5.8%), Zn (35.9%), Cd (7.2%); cobalt-nickel cake, containing Cu (25%), Zn (20%), Cd (3%), Co (0.75%), Ni (0.05%) (Кaroleva, ฀986). Cementates obtained during the hydrometallurgical zinc winning process, where the sulphate leach liquor is treated with arsenic trioxide and zinc powder for the removal of Cu, Ni, Co, Cd and other impurities contain: Cu (28.6%), Zn (22.4%), Cd (6.7%), Co (฀.32) and Ni (0.฀6%) (Melzner et al., ฀984). Flue dusts at a secondary copper smelter treated in the electrowinning zinc plant contain: Zn (40-65%), Cu (฀-6%), Pb (6-20%), Cd (0.5- 0.8%), Ni (0.฀-฀%), Sn (฀-2%), etc. (Kammel et al., ฀987) These industrial wastes are a source of different valuable metals like copper, zinc, cobalt, nickel, cadmium, etc. Muresan et al. studied the process of Cu electrowinning from sulphate acidic electrolytes and observed that the addition of small amounts of Zn 2+ had no effect on the composition of the Cu deposits, but it increased their microscopic roughness (Muresan et al. ฀999). The effect of