Leaching kinetics of uranium from Playa deposits at Atmur El-Kibeish area, South Western Desert, Egypt

Abstract

ABSTRACT The leaching process of uranium (VI) from Atmur El-Kibeish rock sample located in the South Western Desert of Egypt in sulphuric acid solution by agitation leaching technique was investigated. The optimum leaching conditions achieved of acidic leaching are 150 g/L H2SO4, one-third solid/liquid ratio, 4 h agitation time, 125 µm size and at 60°C temperature. Under these conditions, the leaching efficiency of uranium was about 95%. The experimental data interpreted by 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 = kt with an apparent activation energy of 26.11 KJ/mole. Temperature, H2SO4 concentration and particle size are the main factors influence on the rate of leaching. Reaction order in H2SO4 was 1.22.