Removal of Iron from Hard Zinc for Production of Refined Zinc

ABSTRACT

Refining of hard zinc through removal of iron has been investigated in this study. Zinc powder, aluminum turnings, and mixture of both of them have been tested and evaluated as refining agents. The hard zinc samples with the additives were charged in an electric muffle furnace at a temperature range from 600 to 900°C. Iron oxide and its intermetallic compounds of Fe with Zn have been formed as a slag of refining in the sink of the crucible, while that of the intermetallic compounds of Fe with Al have been floated on the melt bath surface and skimmed. Several characterization and analytical tools, such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX), and Atomic Absorption Spectroscopy (AAS) were used to investigate the phases, surface microstructure, and composition of the hard and refined zinc samples. Different parameters affecting the refining process such as amount of the refining agents, refining duration and temperature have been studied. Results obtained revealed that removal of iron from hard zinc was achieved with different refining agents in the order; aluminum turnings > zinc dust> Al/Zn mixture. A refined zinc was obtained by adding 0.4 wt % Al at 700 °C after 2h of refining with lowering the iron concentration from 3.2 % in the hard zinc to 0.5% in the refined product.

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