Jacobs, J.C.Groot, D.R.2021-01-132021-01-132019-11Jacobs, J.C. and Groot, D.R. Improving cathode morphology at a copper electrowinning plant by optimizing Magnafloc 333 and chloride concentrations. Journal of the Southern African Institute of Mining and Metallurgy 2019, vol.119, n.11, pp.983-987. ISSN 2411-9717. http://dx.doi.org/10.17159/2411-9717/686/2019.2225-6253 (print)2411-9717 (online)10.17159/2411-9717/686/2019http://hdl.handle.net/2263/77999Electrowinning circuits normally use a number of additives in the electrolyte to promote smooth, compact deposits. These cathodes have the best levels of purity. When electrowinning is coupled to a solvent extraction operation, it is important to minimize the amount of surface-active additives used, as their presence tends to increase phase-disengagement times. In the present work the effects of Magnafloc 333 and chloride concentration were studied with the aim of minimizing the amounts currently being added, while producing an acceptable copper cathode morphology. Magnafloc 333 is a non-ionic polyacrylamide that promotes the plating of smooth, dense copper deposits with minimal impurities. Chloride is added to promote the growth of dense, fine-grained, low-impurity copper deposits on the cathode. A Hull cell was used for the test work. Optimum Magnafloc 333 and chloride concentrations for a synthetic plant electrolyte were found to be 0.01 g/L and 0.025 g/L, respectively. These concentrations were then used to plate laboratory-scale copper cathodes from synthetic and plant electrolytes. Scanning electron microscopy was used to analyse the morphology of the cathodes plated. Many polyhedral crystals were deposited from the synthetic electrolytes, but deposits from the plant electrolytes tended to be spherical, with a large degree of porosity at the lower Magnafloc 333 concentration of 0.01 g/L. Polyhedral deposits were associated with high-quality, smooth plated cathodes.en© The Southern African Institute of Mining and Metallurgy, 2019. This article is licensed under a Creative Commons Attribution License.ElectrowinningCopperHull cellMagnafloc 333Chloride ionEngineering, built environment and information technology articles SDG-08SDG-09: Industry, innovation and infrastructureEngineering, built environment and information technology articles SDG-09SDG-08: Decent work and economic growthEngineering, built environment and information technology articles SDG-12SDG-12: Responsible consumption and productionEngineering, built environment and information technology articles SDG-13SDG-13: Climate actionArticle