Abstrakt

Kinetic study of the oxidative dissolution of metamorphosed sandstone-type uranium in aqueous H2SO4 solution

M.E.Ibrahim, T.A.Lasheen, H.B.Hassib, A.S.Helal

Bench scale experiments were conducted to determine the oxidative dissolution kinetics of metamorphosed sandstone-type uranium in dilute H2SO4 solution with H2O2 as oxidizing agent. The kinetics results showed that, the rate is controlled by diffusion through the “product” layer composed of the associated concomitants. The leaching process follows the kinetic model 1–2/3X–(1–X)2/3=kt with an apparent activation energy of 22.803 kJ/mole. Itwas found that both sulfuric acid and hydrogen peroxide have significant effects on the leaching rate of uraniumspecies. The reaction orders ofH2SO4 and H2O2 were determined as 1.073 and 2.084, respectively. It is also found that particle size presents a clear effect on uraniumleaching rate, and the rate constant (k) is proportional to d-2.