CONCENTRATION AND FINAL PURIFICATION OF NEPTUNIUM BY ANION EXCHANGE

It was demonstrated that neptunium(IV) can be readily absorbed onto anion exchange resins from 6 M HNOsub 3/ containing ferrous sulfamate and hydrazine or semicarbazide, separated from plutonium, uranium, and common metallic impurities by washing the resin at 25 deg C with 6 M HNO/sub 3/ containing ferrous sulfamate and hydrazine or semicarbazide, separated from fission products and thorium by washing the resin at 60 deg C with S M HNO/sub 3/- 0.01 M HF containing hydrazine or semicarbazide, and eluted at concentrations greater than 40 g Np/l with 0.35 M HNO/sub 3/ at 25 deg C. Decontamination factors of greater than 10,000 from uranium, plutonium, and common metallic contammants, greater than 25,000 for fission products normally expected in the feed (mainly Zr-Nb with some Ru-Rh), and greater than 1000 for thoriuin are obtainable under proper operating conditions. Because of the low processing rates, the necessity for carrying out the absorption cycle at 25 deg C and the absence of radiation daraage problems, Dowex 1, X-4 (50-100 mesh) or Dowex 21K (50-100 mesh) resins are considered the best choices for this application. Gassing occurs with the use of ferrous sulfamate - semicarbazide reductant but is not a serious problem and does not occur with ferrous sulfamate -hydrazine reductant in 6 M HNO/sub 3/. (auth