Recovery of Uranium from Mine Waste by Leaching with Carbonate-Based Reagents

Abstract

Waste materials, stored in inappropriate places, are one of the most significant environmental issues concerning mining activities. In Brazil, one closed uranium mine has faced such a problem. The waste, produced during the neutralization of acid drainage and containing several metals including uranium, has been disposed into the mine opening as a temporary alternative for over 20 years. The present work aimed at the recovery of the uranium present in the aforementioned waste. The effect of the following parameters on the leaching procedure was investigated: solid/liquid ratio, time, temperature, extracting agents, concentration of reagents, and the use of oxidants. The chemical characterization showed that the main constituents of the sample are Ca, S, Mn, and Al. Uranium is around 0.25%. The crystallized phases are ettringite (Ca(6)Al(2)(SO(4))(3)·(OH)(12)·26H(2)O) as the major phase followed by gypsum (CaSO(4)·2H(2)O), calcite (CaCO(3)), and bassanite (CaSO(4)·0.5H(2)O). Carbonate and bicarbonate were observed to be effective extractants for the uranium. However, a combination of both reagents proved to be a better option than their individual use, and extractions around 100% were achieved. The optimum experimental condition for attaining the maximum dissolution is 0.11 solid/liquid ratio, 0.50 mol L(-1) Na(2)CO(3), 1.00 mol L(-1) NaHCO(3), 20 h, and room temperature.

Study on the Oxidative Leaching of Uranium from the Lignite in the CO32-/HNing1, Li2, Zhang3 et al. 2017Geofluids2000View full textAdd to dashboardCite

“…Santos and Ladeira [18] found out that, in the pH range of 9∼ 10.2, the precipitation of sodium diuranate could be reduced by using NaCO 3 /NaHCO 3 mixture, which is similar to the result obtained in our study…”

Radiometric Evaluation in a Uranium Mine under a Decommisioning Processs

“…Other studies are evaluating several questions related to the acid mine drainage and the recovery of uranium (Gomes et al, 2011;Santos & Ladeira, 2011;Ladeira & Gonçalves, 2008). It is expected that soon new hydrogeological studies will begin, since a new project that has technical support from the University of Queensland -Australia, was endorsed.…”

Adsorption capacity of kelp-like electrospun nanofibers immobilized with bayberry tannin for uranium(vi) extraction from seawater

“…1,2 Uranium resources from terrestrial ores are limited, so it is desired to extract uranium from seawater, in which the quantity of uranium is around 4.5 billion tons. 3 To date, lots of technologies have emerged for the extraction of uranium, such as solvent extraction, 4 chemical precipitation, 5 ion-exchange, 6 and adsorption. 7,8 Among these methods, adsorption is considered to be an effective and economic way forward to extract uranium from seawater.…”