Published in: Holistic Approach Environ. 8(2018) 4, pp. 108 – 114
Paper reference number: HAE-146
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CHARACTERIZATION OF THE HARD ZINC ORIGINATED FROM THE HOT-DIP GALVANIZING
Katarina Blašková*, Jarmila Trpčevská*, Marianna Dorková*
* Technical University of Košice, Faculty of Materials, Metallurgy and Recycling, Košice, Slovakia
The aim of the present paper is to refine hard zinc from the iron presented in the form of intermetallic compounds. During hot-dip galvanizing steel parts are galvanized to ensure corrosion protection. Due to the process zinc coatings create. Hard zinc originates in the hot-dip galvanizing process as a result of exceeding of maximum iron solubility in the molten zinc bath. The maximum iron solubility in the molten zinc is 0.03 %. Iron segregates in the form of FeZn13, which has a higher density than molten zinc and thus accumulates on the bottom of the kettle. Such intermetallic compound is called hard zinc or bottom dross. This hard zinc is drawn from the bottom of the kettle in regular intervals. Due to the high metal content up to 94 % of Zn, hard zinc should be treated in order to zinc recovery. The present paper is focused on zinc recovery by pyrometallurgy due to its high metal content.
Keywords: hard zinc, zinc refining, recycling, waste