The inhibition of hydrogen formation during cementation of cobalt onto zinc

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The use of zinc dust cementation for removal of trace impurities from zinc sulphate solution prior to zinc electrowinning is the standard industrial technology. The process involves stirring finely divided zinc dust into the impure zinc solution, in the presence of activators, in order to remove key impurities to the part per billion level in solution. This technology enables high current efficiency in zinc electrowinning. The use of zinc dust is inefficient as zinc dust must be obtained by melting and water atomizing some of the cathode zinc product produced at the refinery. The key mode of zinc dust inefficiency is the formation of hydrogen gas via reaction with water and acid. The objective of this research is to investigate the use of hydrogen inhibition to control the formation of hydrogen during zinc dust cementation. Both inorganic and organic inibitors will be investigated. The three steps in the study include a literature search, an electrochemical investigation of the role of inhibitors on the hydrogen generation rate and finally a study of cementation with inhibitors. The project will allow for training of one Masters student and two undergraduate student assistants.