Carmen Sharaby^a, Yasser Khawassek^b, Ahmed Eliwa^b* and Shimaa Abdo^b

^aAL-Azhar University, Chemistry Department, Faculty of Science, P.O. Box 11651 cairo, Egypt.

^b,d,cNuclear Materials Authority, P.O. Box 530 El Maadi, Cairo, Egypt

Summary-Abu Zenima wastes with significant contents of uranium and rare earths were leached with sulphuric acid which achieve maximum dissolution for Uranium and Rare earths. A complete dissolution for uranium and about 97.4% for rare earths were performed using 3 mol/L sulfuric acid; 15 min contact time; 1/10 solid/liquid ratio and 500 rpm agitation speed at 90°C leaching temperature. The experimental data were interpreted with a shrinking core model with diffusion control through a porous product layer. The dissolution reaction for uranium and rare earths was found to be pseudo first order, with apparent activation energy of 19.93 and 16.03 kJ /mole.