Effect of time of electrode exposure to the solution on gold dissolution rate in thallium-containing thiosulfate electrolytes

The effect of TlNO₃ additive on the gold dissolution in the thiosulfate electrolyte is studied by using chronoammetry on the electrode, which was renewed by cutting-off a thin surface metal layer immediately in the solution. It is shown that the ascending branches of anodic polarization curve shift in the negative direction with increasing time of electrode exposure prior to the onset of potential scan Δt (from 0 to 120 s) to the solution containing thallium(I) ions. It is shown that solution stirring and a twentyfold increase in the concentration of thallium ions have a weak effect on the current transients. It is found that the duration of gold dissolution current transients decreases significantly with a potential shift in the positive direction. Based on this data, a mechanism of the effect of thallium(I) ions on the gold dissolution rate is proposed.