Upgrading of Egyptian Nonsulfide Zinc Ore by ...

This paper aimed at evaluation and beneficiation of a nonsulfide zinc ore from Um Gheig deposits in the eastern desert of Egypt using gravity separation process. The zinc ore of Um Gheig is called “calamines”. It consists of a mixture of zinc carbonates (smithsonite, hydrozincite) and zinc silicates (hemimorphite), with variable amounts of Pb bearing minerals. The ore sample has 47.5 % ZnO, 1.55% PbO and ~29.3 % L.O.I. Liberation study, using mineralogical and SEM investigations, indicated that maximum liberation can be obtained by grinding the ore to 0.125 mm. Beneficiation techniques involved crushing and grinding of the ore to 100 % -0.125 mm. This was followed by classification of the ground ore using a 0.080 mm screen. Shaking table was used to upgrade the coarse fraction (-0.125+0.080 mm) while the fines below 0.080 mm was separated by Falcon concentrator. The results of shaking table showed that a high grade concentrate can be obtained at the following optimum parameters: inclination angle (4 degree), stroke length (2.5 cm), feed rate (150 gm/min), and water flow rate (25 l/min). At such optimum conditions maximum grade (62.2 % ZnO) and operational recovery (~ 93.8 %) were obtained. In the mean time, Falcon concentrator gave a concentrate of 54.85 % ZnO with 76.6% operational recovery from the fine fraction below 0.080 mm.