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 2.5 
M; 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 13.16 
kJ/mole.