The novelty of silver extraction by leaching in acetic acid with hydrogen peroxide as an organic alternative lixiviant for cyanide

Abstract

In this article, the dissolution kinetics of pure metallic silver in acetic acid with a hydrogen peroxide solution were carried out. The effects of stirring speed, acetic acid concentration, hydrogen peroxide concentration, and temperature were examined. The results show that increasing the stirring speed decomposes the hydrogen peroxide and negatively affects the dissolution rate of silver. In addition, an acetic acid concentration in the range of 0.25–1 M has a positive effect and a negative effect in the range of 1–3 M. A hydrogen peroxide concentration in the range of 0.5–2 M has a significantly positive effect on the dissolution rate, while it has a negative effect in the range of 2–3 M. The temperature in the range of 61.5–70 °C has a negative effect due to the decomposition of hydrogen peroxide. The shrinking core model was applied to all parameters to obtain the dissolution kinetics. The dissolution process of silver was controlled by the surface reaction-controlled shrinking core model, i.e. 1-(1-X)1/3 = kst, with an activation energy of 28.80 kJ/mol.