The polarization curves and AC impedance spectroscopy of gold and platinum electrodes were measured by an electrochemical workstation to study the effect of sodium sulfite on the dissolution of gold in alkaline thiourea solution. The results showed that the corrosion potential (Ecorr) of gold with sodium sulfite was -0.776 V, which is far below that of thiourea, and that the corrosion rate was 0.014 mm/a, so it is an effective reagent for gold dissolution. For a platinum electrode, thiourea underwent irreversible oxidative decomposition under alkaline conditions, however, sodium sulfite had no significant inhibition effect on the oxidative decomposition of thiourea. With the addition of thiourea, the Ecorr decreased, and the corrosion rate increased, while the electrochemical impedance arc value is significantly reduced, synergisticallypromoting the dissolution of gold. The solution consisting of 0.15 mol/L thiourea +0.15 mol/L sodium sulfite has the best gold solubility. |