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Kinetics of leaching process of REE fromEl-Missikat shear zone eastern Desert, Egypt

Y.M.Khawassek,E.A.Gawad, E.A.HaggagandA.A.Eliwa

The leaching process of uranium-REE ore from El-Missikat in a sulfuric acid solution using hydrogen peroxide as an oxidant was investigated. The leaching condition temperature, hydrogen peroxide concentration, sulfuric acid concentration, contact time, particle size, solid-liquid ratio and agitation rate were studied. The optimum process operating parameters were ore particle size 74 µm; sulfuric acid concentration 2.5M; contact time 240 min; solid-liquid ratio 1:2; H2O2 concentration 0.5 M and agitation rate 600 rpm at temperature 25°C. The leaching efficiency of REE was about 70%, while the uranium leaching efficiency was about 95%. The experimental data were well interpreted with a shrinking core model with diffusion control through a porous product layer. The leaching process follows the kinetic model:1-3 (1-X) 2/3 + 2 (1-X) = k1t with an apparent activation energy of 24kJ/mole.