The use of organic additives to suppress acid mist in copper electrowinning

The objective of this study was to evaluate the behaviour and effectiveness of organic surfactants as additives to the copper electrowinning process for the purpose of suppressing the formation of acid mist. Two experimental techniques, namely a micro-flotation procedure and an electrowinning procedure, were employed. Ten surfactants were considered in this study including Dowfax 2AO, FC- 1100, Saponin, Tergitol TMN-10 and sodium lauryl sulphate (SLS). The results indicated that some of the surfactants could suppress the formation of acid mist. Certain surfactants such as Tergitol TMN-10 and SLS appeared to have the desired properties of an effective surfactant; however, in the interest of minimizing the adverse effects of any organic on the overall electrowinning performance, an optimum level of addition should be pursued. Microstructural analysis of the copper cathode deposits was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) which served to illustrate the possible negative effects of particular surfactants on the physical properties of the deposits such as demonstrating the degree of copper dissolution.