Abstract

Gattar uranium mineralization in eastern desert is of comparatively low grade containing about 300 ppm uranium. A pilot plant for leaching of uranium and produce commercial yellow cake was set up in 2000. A huge amount, of residues resulted during leaching process with uranium assay about 85 ppm uranium. The present study was performed mainly to leach of uranium from the already present residues resulted from previous uranium vat leaching from gattar uranium mineralization. Vat leaching, is a static process in which the mineralized granite is crushed, disposed in vats and irrigated with a sulfuric acid solution with proper concentration to leach the uranium. The flowsheet adopted is of sulfuric acid leach-ion exchange process, the leaching was optimized to leach uranium with low acid concentration. Uranium is finally recovered by precipitation with sodium hydroxide. The uranium leaching from the residues (tailings) were examined by re-crashed coarse size via a batch experiments as a function of contact time, grind size, L/S ratio and lixiviant concentration at ambient temperature. To verifying the feasibility of uranium leaching in large-scale applications, column leaching of uranium was carried out. The results indicate the feasibility of treating the residue of the vat leaching through dynamic leaching. recovery of about 83% of uranium in the residue was obtained using a 1.5%w/w consumption of acid, grain size is ˂10 mm and total liquidsolid ratio is 0.8 m³/t.

Keywords: Residue; Uranium; Leachability; Granite