Successive Recovery of Uranium and Valuable Elements from Mineralized Dolostone, Gabal Alluga, Southwestern Sinai, Egypt
Fatma S. Hassen
Abstract:
The present work was conducted in two stages of leaching processes, stage one, an alkaline leaching of uranium and zinc from Alluga rock sample, Sinai area, using sodium hydroxide solution. The leaching conditions, including sodium hydroxide concentration, stirring time, temperature and liquid-solid ratio were studied. The optimum conditions were sodium hydroxide concentration (5mol/L), stirring time (180 min), liquid-solid ratio (4/1) and temperature (70oC), the leaching efficiency was about 91.2% for uranium and 93.5% for zinc.
The second stage took place on the spent residue left behind for leaching the rare earth elements using mixture of sulfuric acid and magnesium sulfate solution, the optimum conditions were achieved at sulfuric acid concentration (1mol/L), magnesium sulfate concentration (0.8 mol/L), temperature (200o C), stirring time (120 min), and liquid-solid ratio (3/1), under these conditions leaching efficiency of rare earth was 96.5%. The experimental leaching kinetic data of uranium, zinc and rare earth elements were well identified by a shrinking core model with diffusion control through a product layer, with apparent activation energies of 8.74 KJ/mol for uranium, 21.3 KJ/mol for zinc and 18.26 KJ/mol for rare earth elements.