Samara National Research University, Samara, Russia

O. S. Bondareva, Associate Professor at the Department of Metals Technology and Aviation Materials Engineering, Candidate of Technical Sciences, e-mail: osbond@yandex.ru
O. S. Dobychina, Postgraduate Students at the Department of Metals Technology and Aviation Materials Engineering

The companies dealing with hot galvanizing are seeing a continuously rising demand for high-grade zinc — i. e. TsV0 grade / Special High Grade. At the same time, Russia is experiencing a shortage of zinc and will, in the short term, fully depend on the only supplier – Chelyabinsk Zinc Plant JSC. Because of this, of interest would be to consider the use of cathode zinc for the above purpose, which is a type of middlings in the hydrometallurgical production of zinc. It would also be relevant to analyze potential process issues associated with the use of cathode zinc. This paper looks at the structure and elemental composition of the cathode zinc produced by Almalyk MMC JSC. The authors conducted a scanning electron microscopy study using a Tescan Vega SB microscope with an INCAx-act detector to establish that the initial surface of the specimens in view were covered with oxides and sulphates. It is demonstrated that one can use a 5–10% hydrochloric acid solution to soak the surface for a short or long time for effective removal of sulphur compounds. When cathode zinc was charged in the zinc pot, apart from dross, some metal foam was found on the pot surface which contained pieces of cathode zinc that had not melted. In spite of pre-treatment with acid, a small amount of sulphur was found in the metal foam. Its presence in the melt that has not been treated for a long time may lead to intensified corrosion impacting the pot walls at the melt mirror boundary. Hence, cathode zinc can only be used instead of zinc ingots during periods of shortage. It is also recommended that cathode zinc be used together with high-purity zinc.

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