Characteristics and Evaluation of Leaching Behavior of Uranium Mineralization in Qash Amir Granite, South Eastern Desert, Egypt

Abstract

In the Halaib area, South Eastern Desert, Egypt, numerous occurrences of uranium have been found. Uranium occurs as disseminated minerals (uraninite, uranophane, beta-uranophane) in G. Qash Amir muscovite monzogranite. The muscovite monzogranite (G. Qash Amir) is affected by deutric alteration and characterized by gradational contact with two-mica monzogranite, peraluminous in nature with visible primary and secondary uranium minerals, beryl and columbite. Uranium dissolution efficiency of 81.0 % was obtained using acid agitation leaching without oxidant addition, while dissolution efficiency increased to about 92% when ORP was increased to about 475mV using MnO2 as an oxidizing agent in Qash Amir uranium mineralization. Column tests were performed to study the effect of the parameters on uranium leaching and acid consumption. After 40 days of column leaching tests, uranium recovery of 74.2% was obtained at a flow rate of 10 l/m2/h and acid consumption was achieved by 26.2 kg per ton of ore. The addition of MnO2 as oxidant leads to a significant increase in the column leaching efficiency to 87% and decreasing acid consumption to 22kg per ton of ore in 35 days. The plot of 1-(1-x) 1/3 vs. t is linear and the R squared values for particle diffusion control line is 0.98, therefore the shrinking-core model is verified.