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By using radioactive tracers the solvent extraction of plutonium(III), americium(III) and europium(III) from 0·01 N hydrochloric acid, 0·001 N nitric acid, and an acetate buffer of pH 3·95 respectively into mixtures of 1,1,1-trifluoro-3-2′-thenoylacetone (TTA) and tri-n-butyl phosphate (TBP) in cyclohexane has been studied. The extraction coefficient has been found to be greater for such mixtures than for either component alone and the extractable species has the composition MX3·2TBP (where TTA = HX and M = Pu, Am, or Eu). This demonstrates the possibility of eightfold co-ordination in these elements. When the TBP is replaced by tri-n-butyl phosphine oxide (TBPO) a synergic enhancement of the extraction coefficient is again found. Here the TBPO replaces some of the chelating molecules and the species MX2(NO3)·2TBPO and MX3 (M = Am or Eu) appear to be co-extracted. Some equilibrium constants are reported.

With 60Co, 64Cu and 65Zn as tracers, the solvent extraction of their divalent ions from hydrochloric acid-sodium acetate buffers into mixtures of 1,1,1-trifluoro-3,2′-thenoylacetone (TTA) with tributyl phosphate (TBP) or tri-n-butyl phosphine oxide (TBPO) in cyclohexane has been studied. The extraction coefficient has been found to be greater for such mixtures than for either component alone and the extractable species have been identified as CoX2·TBP and CoX2·2TB, CuX2·TBP and CuX2·TBPO, and ZnX2·TBP (where HX = TTA). The probable structure of these co-ordination compounds is discussed and several equilibrium constants are reported.

By using 230 Th, 237 Np, and 239 Pu as tracers, the solvent extraction of the tetravalent actinides from nitric acid into mixtures of 1,1,1-trifluoro-3-2′-thenoylacetone (TTA) with tri- n -butyl phosphate (TBP) or tri-n-butylphosphine oxide (TBPO) in cyclohexane has been studied. The extraction coefficients have been found to be larger for certain mixtures than for either component alone. With thorium and TTA, the addition of TBP effects the displacement of some of the chelated molecules and a mixture of ThX 4 , ThX 3 (NO 3 )·TBP, and ThX 2 (NO 3 ) 2 ·2TBP (where HX = TTA) is co-extracted. Unlike the systems hitherto studied the anion of the mineral acid in the aqueous phase now participates in the composition of the extractable species. With mixtures of TTA and TBPO the displacement of the chelated TTA is even greater and the extractable species ThX(NO 3 ) 3 ·TBPO must be involved. With mixtures of TTA and TBP the extraction of Pu(IV) and Np(IV) appears to involve only the species MX 4 and MX 3 (NO 3 )·TBP (M = Np or Pu). With mixtures of TTA and TBPO, however, the species extracted are MX 2 (NO 3 ) 2 ·2TBPO with MX 3 (NO 3 )·TBPO and MX 4 . A number of equilibrium constants have been calculated and their significance is discussed. Synergic effects among the tetravalent actinides appear to depend upon their ability to achieve a co-ordination number of eight.

By using 239 Pu and 237 Np the solvent extraction of plutonium (VI) and neptunium (V) from nitric acid into mixtures of 1,1,1-trifluoro-3-2′-thenoylacetone (TTA) and tri- n -butyl phosphate (TBP) in cyclo hexane has been studied. The extraction coefficient is found to be greater for such mixtures than for either component alone. The formula of the species extracted from plutonyl nitrate has been shown to be PuO 2 X 2 , TBP (where HX = TTA). The species extracted from neptunyl nitrate appears to be HNpO 2 X 2 , TBP. Some equilibrium constants are reported.

The extraction of the chlorides of Fe 3+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , UO 2 2+ and In 3+ from hydrochloric acid into a mixture of tri- n -butyl phosphate and diluents has been studied using radioactive tracers except for nickel, copper and uranium, which were determined spectrophotometrically. The formula of the species extracted from a solution of cobalt in hydrochloric acid was found to be CoCl 2 ·2TBP. The extraction of hydrochloric acid itself has been compared with that of nitric acid under comparable conditions.

By using U/sup 233/, the solvent extraction of urarium(VI) from nitric acid into mixtures of 1,1,1-trifluoro-3-2'thenoylacetone (TTA) and tri-n-butyl phosphate (TBP) or tri-n-hutyl phosphine oxide (TBPO) in cyclohexane was studied. The extraction coefficient was found to be greater for such mixtures than for either component alone, the maximum enhancement in extraction being of the order of 10/sup 3/ and 10/sup 4/, respectively. The formulas of the extracted species were shown to be UO/sub 2/X/sub 2/ TBP amd UO/sub 2/X/sub 2/ 3TBPO (HK = TTA), and their mixed equilibrium constants were calculated. The general problem of synergism in the solvert extraction of metal complexes was discussed. (auth)

A method for determining thorium and uranium at the sub-microgram level (down to 10−3 μg) is described. Bone which has previously been ashed at 600°C is irradiated in a neutron flux of 2 × 1013 cm−2 sec−1 for 20 min. After chemical separation which involves elution from an anion exchange column using a mixture of hydrochloric and hydrofluoric acids, the induced Pa223 and Np239 activities were measured and compared to a standard. The method was tested using samples of ashed cow bone to which were added known concentrations of uranium and thorium and results for the analysis of several bones with widely differing histories are presented.