US 2,873,169 (Basic Peroxide Precipitation Method of Separating Plutonium from Contaminants) G.T. Seaborg, I. Perlman; Feb 10, 1959.
A process is described for the separation from each other of uranyl values, tetravalent plutonium values and fission products contained in an aqueous acidic solution. First the pH of the solution is adjusted to between 2.5 and 8 and hydrogen peroxide is then added to the solution causing precipitation of uranium peroxide which carries any plutonium values present, while the fission products remain in solution. Separation of the uranium and plutonium values is then effected by dissolving the peroxide precipitate in an acidic solution and incorporating a second carrier precipitate, selective for plutonium. The plutonium values are thus carried from the solution while the uranium remains dissolved. The second carrier precipitate may be selected from among the group consisting of rare earth fluorides, and oxalates, zirconium phosphate, and bismuth lihosphate.
US 2,875,021 (Method of Separating Uranium Values, Plutonium Values and Fission Products by Chlorination) G.T. Seaborg, H.S. Brown; Feb 24, 1959.
The separation of plutonium and uranium from each other and from other substances is described. In general, the method comprises the steps of contacting the uranium with chlorine in the presence of a holdback material selected from the group consisting of lanthanum oxide and thorium oxide to form a uranium chloride higher than uranium tetrachloride, and thereafter heating the uranium chloride thus formed to a temperature at which the uranium chloride is volatilized off but below the volatilization temperature of plutonium chloride.
US 2,882,124 (Solvent Extraction Process for Plutonium) G.T. Seaborg; Apr 14, 1959.
The separation of plutonium from aqueous inorganic acid solutions by the use of a water immiscible organic extractant liquid is described. The plutonium must be in the oxidized state, and the solvents covered by the patent include nitromethane, nitroethane, nitropropane, and nitrobenzene. The use of a salting out agents such as ammonium nitrate in the case of an aqueous nitric acid solution is advantageous. After contacting the aqueous solution with the organic extractant, the resulting extract and raffinate phases are separated. The plutonium may be recovered by any suitable method.
US 2,886,406 (Recovery of Plutonium and Neptunium from Aqueous Solutions) G.T. Seaborg, R.C. Thompson, F.W. Albaugh; May 12, 1959.
A method is presented of reducing neptunium and plutonium to a +4 state of oxidation so that plutonium may be carried with bismuth phosphate from a solution containing uranyl ion and fission products. The reduction process consists of treating a nitric acid solution of neutron irradiated uranium with oxalate ions, manganous ions, and fluoride ions. The presence of any sodium nitrite is advantageous since it destroys any hydrazine formed in the reduction of nitric acid and assures the more complete carrying of plutonium. The reduction is carried out for 1 hour at 15 degrees C in the presence of a 0.09 molar oxalic acid, 0.0075 to 0.01 molar Mn++ ions and 0.02 molar (NH4)2SiF6. Sodium nitrite to the extent of 0.1 molar may also be present under these conditions. 98% of the plutonium is carried by the bismuth phosphate precipitate.
US 2,887,357 (Dry Fluorine Separation Method) G.T. Seaborg, J.W. Gofman, R.W. Stoughton; May 19, 1959.
Preparation and separation of U 233 by irradiation of ThF4 is described. During the neutron irradiation to produce Pa233 a fluorinating agent such as HF, F2, or HF + F2 is passed through the ThF4 powder to produce PaF5. The PaF5, being more volatile, is removed as a gas and allowed to decay radioactively to U233 fluoride. A batch procedure in which ThO2 or Th metal is irradiated and fluorinated is suggested. Some Pa and U fluoride volatilizes away. Then the remainder is fluorinated with F2 to produce very volatile UF6 which is recovered.
US 2,900,228 (Selective Separation of Uranium from Thorium, Protactinium and Fission Products by Peroxide Dissolution Method) G.T. Seaborg, J.W. Gofman, R.W. Stoughton; Aug 18, 1959.
A method is described for separating U233 from thorium and fission products. The separation is effected by forming a thorium-nitric acid solution of about 3 pH, adding hydrogen peroxide to precipitate uranium and thorium peroxide, treating the peroxides with sodium hydroxide to selectively precipitate the uranium peroxide, and reacting the separated solution with nitric acid to re-precipitate the uranium peroxide.
US 2,903,335 (Separation of Fission Products from Plutonium by Precipitation) G.T. Seaborg, S.G. Thompson, N.R. Davidson; Sep 8, 1959.
Fission product separation from hexavalent plutonium by bismuth phosphate precipitation of the fission products is described. The precipitation, according to this invention, is improved by coprecipitating ceric and zirconium phosphates (0.05 to 2.5 grams/liter) with the bismuth phosphate.
US 2,908,621 (Producing Energy and Radioactive Fission Products) G.T. Seaborg, E. Segre, J.W. Kennedy; Oct 13, 1959.
This patent broadly discloses the production of plutonium by the neutron bombardment of uranium to produce neptunium which decays to plutonium, and the fissionability of plutonium by neutrons, both fast and thermal, to produce energy and fission products.
US 2,917,358 (Uranous Iodate as a Carrier for Plutonium) G.T. Seaborg, S.G. Thompson, D.R. Miller; Dec 15, 1959.
A process is described for precipitating plutonium on a uranous iodate carrier from an aqueous acid solution containing the plutonium in a valence state not greater than +4. A plutonium solution more concentrated than the original solution can then be obtained by oxidizing the uranium to the hexavalent state and dissolving the precipitate, after separating the latter from the original solution, by means of warm nitric acid.
US 2,917,361 (Method of Recovering Transuranic Elements of an Atomic Number below 95) G.T. Seaborg, R.A. James; Dec 15, 1959.
The concentration of neptunium or plutonium by two carrier precipitation steps with identical carriers but using (after dissolution of the first carrier in nitric acid) a reduced quantity of carrier for the second precipitation is discussed. Carriers suitable are uranium(IV) hypophosphate, uranium(IV) pyrophosphate, uranium(IV) oxalate, thorium oxalate, thorium citrate, thorium tartrate, thorium sulfide, and uranium(IV) sulfide.
US 2,918,349 (Extraction of Plutonium Values from Organic Solutions) G.T. Seaborg; Dec 22, 1959.
A process is described for back-extracting plutonium, present in an organic solvent in at least the tetravalent state, with nitric acid.
