The kinetics of dissolution of copper and iron in aqueous cupric ammine solutions

The dissolution rate of metallic copper plate in aqueous cupric ammine solutions was studied at 0.05-1.0 mol/ CuSO₄ concentration, 0-3000 rpm rotation speed and temperatures between 10-90°C. The dissolution rate was mainly controlled by chemical reaction at the temperature below 30°C, and by diffusion of cupric complex at temperatures higher than 40°C. It was found that the dissolution rate of copper increases with an increase in temperature and rotation speed, while a maximum rate was observed for increasing Cu(II) concentration. The effect of different anion showed significant results on dissolution rate of copper and iron, and carbonate ion was found to prevent the corrosion of iron. The selective dissolution of copper from iron scrap was suggested.