The electrochemistry of the leaching reactions in the caron process. I. anodic processes
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The Caron process involves the oxidative dissolution of pre-reduced iron alloys containing nickel, cobalt and copper in ammoniacal carbonate solutions. This study has demonstrated that passivation is exhibited by nickel and cobalt at higher potentials than previously established for iron. It is shown that alloys of iron with nickel and cobalt also undergo passivation at low potentials resulting in inhibition of the dissolution of the valuable metals. The potential regions of active dissolution of each of these metals in ammonia-ammonium carbonate solutions have been established. The effect of thiosulphate and cobaltammine complex ions on the dissolution of iron and nickel was found to be significant in that thiosulphate appears to partially prevent the passivation of nickel while the presence of cobaltammine ions leads to lower apparent anodic current densities. Possible mechanisms for the passivation processes and for the effects of thiosulfate and cobaltammines on the dissolution are presented.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Chemical and Mathematical Science|
|Publisher:||The Electrochemical Society|
|Copyright:||© 2006 ECS - The Electrochemical Society|
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