Recovery of uranium from (U,Gd)O2 nuclear fuel scrap using dissolution and precipitation in carbonate media

Technique for recovering uranium from sludge-like uranium-bearing wastes using hydrochloric acid

“…The results indicate that the aluminum compounds dissolved almost selectively and completely in NaOH (1 M). It is suspected that the aluminum hydroxide was dissolved as tetrahydroxyaluminate ions ([Al(OH) 4 ] − ) in the solution even though other hydroxides were not dissolved. Approximately 25 wt% of the entire precipitate remained as insoluble residue.…”

“…Wet chemical decontamination processes using inorganic or organic acids have been developed as effective decontamination methods for metal wastes [2,3]. The technique for recovering uranium dissolved in sodium carbonate solutions has also been investigated [4]. These reports suggest that a wet acid-based process would be ideal for completely recovering the uranium from uranium-bearing wastes.…”

“…In addition, it has been reported that Ti(IV) forms fluoro-complexes in the presence of fluorine [29], which are more stable than aluminumfluoro-complexes. Hence, it seems that the existence of fluoro-complexes inhibits the precipitation of Ti(OH) 4 in the CaF 2 solution. Based on the results for the calculated distribution of dissolved species, Fe(III) is expected to be precipitated as hydroxide (Fe(OH) 2.7 Cl 0.3 ) below pH 3 for the compositions of the waste solutions.…”

“…The difference in the content of Fe in the precipitated uranium for two wastes is also attributed to that in the original contents of Fe in the solutions. 4 : 120 mg/L) using the UR40H resin at pH 3. The results show that the removal of uranium is hardly affected by the presence of large amounts of magnesium, calcium, aluminum, sulfate, and fluoride ions in the solutions.…”

Novel precipitation technique for uranium recovery from carbonate leach solutions

“…Their results indicate that the precipitation of uranium as AUC was a second order chemical reaction and the activation energy (E a ) for the process was found as 17.4 kJ mol -1 . Kim et al described the precipitation of uranium from carbonate medium using H 2 O 2 solution [15]. In this process a uranium gadolinium oxide (U, Gd)O 2 nuclear fuel scrap was dissolved in carbonate medium using 0.5 M Na 2 CO 3 solution in presence of trace amount of H 2 O 2 at pH *8 and uranium was selectively precipitated as UO 4 [16].…”