Effect of nettle plant extract on the overconsumption diminution of zinc as sacrificial metal during cementation of copper

In this work, we study the cementation reaction of copper by zinc in acid sulphate media in the presence of nettle plant extract (Urtica dioica L.). The effect of some parameters, namely concentration of nettle extract, temperature and initial copper ions concentration have been studied. This extract obtained by refluxed technique in water, has proved to be a good inhibitor of the parasitic reactions of hydrogen and dissolved oxygen that accompanied the cementation process in acidic media. These reactions are the main causes of the zinc over-consumption and the decrease of copper recovery efficiency. The results showed that the maximum of copper recovery efficiency (85.2%) was obtained at the optimal concentration of nettle extract, equal to 1.5 g.L-1. At this concentration, we recorded a decrease in zinc overconsumption of about 43.5% compared to the solution without additives. The rate of the cementation reaction increases with increasing temperature up to 37 degrees C and this effect is more pronounced when the extract is present in solution.