| 摘要 |
<p><PICT:0850887/III/1> Uranium and thorium are separately recovered from nitric acid solutions of neutron-irradiated fuel rod material by extraction from the solution with a solvent consisting of 10-60% tributyl phosphate in deca-hydronaphthalene. The resulting solution, after scrubbing, is first treated with dilute nitric acid to remove the thorium and thereafter with water to remove the uranium as an aqueous solution. As shown in the Figure, a three column system is preferably employed, the nitric acid solution of the fuel rod element entering the middle of the first column and passing downwardly therethrough counter current to an up flow of a tributyl phosphate/deca-hydro-naphthalene mixture which removes and entrains the uranium and thorium values to pass upward through the column counter-current to a down flow scrub solution consisting of a nitric acid/aluminium nitrate solution. The solvent solution then passes through column 2 where it is scrubbed with .25 molar nitric acid to remove the thorium, fresh tributyl phosphate and diluent entering the bottom of the column. The resulting tributyl phosphate solution of uranium nitrate is treated finally in column 3 with water to recover uranium nitrate solution.</p> |
