Potentiodynamic and galvanostatic investigations of copper deposition from sulphate electrolytes containing large amount of zinc

The electroextraction of copper was studied on platinum cathode from sulphate electrolytes containing large amount of zinc. It was established that in electrolytes, containing 50 g.dm(-3) Zn2+ and 1 or 5 g.dm(-3) Cu2+ at potentials more negative than -1.6 V vs. SSE both copper and zinc deposition takes place. At concentration higher than 5 g.dm(-3) Cu2+ and in the presence of 130 g.dm(-3) H2SO4 (independently of Cu2+ concentration) only copper is deposited. The addition of H2SO4 to the electrolyte leads to abrupt increase in cathodic current but it decreases the current efficiency of both copper and zinc deposition, which means that the current increase is a result of enhanced hydrogen evolution. The additive hydroxyethylated-2-butyne-1,4-diol (Ferasine) decreases the areas of Cu and Zn dissolution peaks, showing that the deposition process is inhibited. Dense, smooth and bright coatings of pure copper are deposited at current densities 0.5-2 A.dm(-2) in electrolytes with Cu2+ concentration higher than 5 g.dm(-3) in the presence of Ferasine. Non-adherent, dark-red slime of copper is obtained at lower Cu2+ concentrations.