1S5G
J. L. RYAN
l i i i i t e surface do not extend much beyond the monolaycr arid that the adsorbed cation plays the
Vol. 65
dominate role in influencing water interaction as the water film thickens.
ACTINIDE(1V) CHLORIDE SPECIES ABSORBED BY ANION EXCHANGE RESINS FROM CHLORIDE SOLUTIONS BYJ. L. RYAN Hnnford Laboratories Operation, General Electric Cornpanu, Richland, Washington Received April 10, 1861
Spectrophotometric studies of anion-exchange resins, of solid crystalline salts, and of non-aqueous solutions were used to identify the tetravalent actinide chloride species absorbed by anion-exchange resins. The absorbed species were found to be UCls-. NpCL'and PuC18' when the resin was loaded from either hydrochloric acid or lithium chloride solutions. h at,tempt was made t o determine the degee of formation of the hexachloro complexes in concentrated hydrochloric acid.
hion-excha:nge resins have been shown to abExperimental sorb uranium(IV), neptunium(IV), and plutoPreparation of Actinide(IV) Chloride Stock Solutions.nium(1V) frorn concentrated hydrochloric acid Uranium trioxide, which had been prepared by ignit,ion of uranyl nitrate, was used as source ma,terial for preparation solution^,^-^ and this absorption has been used as of uranium(1V) chloride solutions. The trioxide was disthe basis for various separation procedures. Pre- solved in concentrated hydrochloric acid, taken to dryness, vious work has shown that the complex anion and redissolved in concentrated hydrochloric acid. The species absorbed by anion-exchange resins can be uranium then was reduced to the (IV) state with aluminum metal. Aluminum was chosen since it does not yield double identified by spectrophotometric studies of the chlorides cesium or quaternary ammonium chlorides resin phase and of non-aqueous solutions and solid and does with not absorb on anion-exchange resin from hydrocrystalline salts of the complex anions.6.6 Ura- chloric acid. After reduction with aluminum the uranium nium(1V) and plutonium(1V) are known to form was loaded onto a column of Dowex 1,X-l (50 to 100 mesh) resin. The column was washed with 12 M salts of the type R/IzCC~~ and M&u'C16, respectively, anion-exchange HCI to remove aluminum and the U(1V) then was eluted where M is a large monovalent cation. The salts with 4 M IICI. At this concentration U(V1) is still rather Cs2UCl6, [ (CH&N]&Cla and [ (C2H&N]2UCl6were strongly held by the resin.* Uranium(1V) solutions were reported by Dieke and Duncan.' Anderson pre- made up in this manner immediately before using to miniair oxidation. pared and idontified CsJ'uCla, [(CH3)4N]2PuC16 mize Anion-exchange purified plutonium nitratela.14 and and othem8 E'erraro has reviewed the preparation neptunium nitrate's were used as source materials for the of the cesium, tetramethylammonium and tetra- preparation of plutonium( IV) and neptunium( IV) chloridc ethylammonium U(1V) salts and has shown that solutions. The neptunium was isotopically pure Np237 they do not form hydrate^.^ Crystallographic and contained about 0.01 weight % plutonium. Both the neptunium and plutonium could be espccted from past studies of Cs2F'uCla,10cs2uc&,11and of the tetra- experience1aJ4 to contain other impurities to the extent methylammonium and tetraethylammonium salts of less than 100 parts per million parts of plut,onium or of U(1V) and P u ( I V ) ' have ~ shown that the actinide neptunium. Plutonium( IV) nitrate was loaded onto nnion-exchange ions are octahedrally coordinated to six chlorides resin a t 60" from 7 M HNOl. The resin then was washed in the crystal. The purpose of this paper :is to ext,ensively with 12 fii IICl a t 2 j 0 , completely converting compare the absorption spectra of crystalline salts the green P U ( N O ~ ) ~ion ' on the resin to the yellow chloro known to coniain the hexachloro anion and the complex. During elution with 0.5 M HCI, considerable absorption spectra of non-aqueous solutions of some disproportionation of Pu(1V) occurs. This is due to the that both Pu( IV) and Pu(V1) absorb on the resin from of these salts with the absorption spectra of anion- fact !iydrochloric acid and Pu(II1) does not, thus allowing the exchange resins loaded with the quadrivalent acti- Fu(V1) and Pu(II1) to form separate elution bands. The nides from chloride media, and thus identify the product was adjusted t.o about 6 Jf €IC1 t,o promote rcconversion to Pu( I V ) . species absorbemd by the anion-exchange resins. (1) This paper is based on work performed under Contract No. AT(45-11-1350 for the United States Atomic Energy Commission. (2) Ior was tilled with helium to about 200 mm. of pressure and kept in contact with the catalyst for about 0.5 hour, in ordcr t,o bring the catalyst to the temperature of the bath or the furnarc surrounding the reactor. Helium t,hen was pumped oil1 . Electrolytic hydrogen was used, which was purified by passing it through a palladium cat>alyst,a liquid nitrogc'ri trap, and finally through charcoal kept at, liquid nitrogcii temperature. Deuterium and helium used wercs of w r y high purity. Each of the gases was purified further by passiig through activated charcoal maintained a t t,ho temperature of liquid nitrogen. An equimolal mixture of hydrogen and deuterium was used for the exchange studies. 2. Catalysts.-The catalysts were prepared according to the gcneral method described previously.3 Catal.yst A.-Aluminum isopropoxide was disti1lt.d twice and then hydrolyzed with distilled water. The precipitatf of aluxhurn hydroxide was washed, filtered, dried a t 120 for 7'2 hours, compressed and screened to obtain 8-10 mesh granules. Catalyst B.-Aluminum turnings made from hiqh purity (13) J. S.Watson, Can. J . Technol., 14, 373 (195tr).
