Effect of temperature on dezincification of galvanized scrap in reducing atmosphere
XIAO Li-jun1, YIN Zhi-hong2, ZHAO Teng-fei2, ZHU Zheng-hai2, SUN Qian-jin3
1. National Engineering Research Center of Continuous Casting Technology, Central Iron and Steel Research Institute, Beijing 100081, China; 2. College of Metallurgical Engineering, Anhui University of Technology, Ma'anshan 243032, Anhui, China; 3. Ouyeel Reproductive Resource Recycling Co., Ltd., Ma'anshan 243011, Anhui, China
Abstract:The changes of zinc and matrix for galvanized scrap in reducing atmosphere were studied by means of SEM, EDX, XRF and pyrometallurgical. The mechanism of dezincification was discussed by thermodynamics theory. The results show that zinc forms a thin oxide film on surface of scrap matrix at low temperature. The film thickness increases with the increase of temperature. The obvious yellow zinc oxide layer formed above 850 ℃ and disappeared at 950 ℃. The best dezincification effect was obtained at 950 ℃ in reducing atmosphere, and the zinc content on surface of scrap matrix was less than 2%. In the process of pyrometallurgical dezincification, zinc on surface of scrap matrix went through three stages, oxidation, reduction and gasification. The research has great significance for development of fire dezincification technology of galvanized scrap.
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