[en] The aqueous solution is contacted with an aminated compound of low solubility in water, for instance a trialkylamine, and the complex formed is separated. Application is made to the recovery of organic phosphorus compounds in effluent for reuse in uranium or plutonium extraction or for extraction of degradation products of TBP

[en] HDEHP is used as the metal ion extractant in an extractive scintillator solution for the assay of alpha emitters. In this application it is necessary that the HDEHP be as color-free as possible to minimize quenching in the scintillator and as free of monoalkyl phosphoric acid and polyphosphates as possible. HDEHP was purified by various methods: copper precipitation, vacuum distillation, caustic scrubbing. The results are presented. (U.K.)

[en] Reduction condition of Fe(III) to extract uranium and vanadium with HDEHP from sulphuric acid leaching liquors of uranium ore was examined. It was shown that in the system of oxidation-reduction consisted of many ionic pairs can reduce Fe(III) with iron scraps selectively and at this time factors affected on its reduction is hydro-ionic concentration in solution and diffusion factor. (Author)

No abstract available

[en] The extraction of uranium(VI) through a W/O/W liquid membrane containing DEHPA was studied in the counter transport system. The optimum stable conditions of W/O emulsion were determined; the optimum concentrations of surfactant span 80 and paraffine oil were 2 Vol. %, respectively. The extraction results showed that more than 95 % of uranium(VI) was extracted during 10 minutes when the carrier concentration was 4 Vol. %, internal aqueous phase; IN-Hsub(2)SOsub(4) solution, external aqueous phase; pH 2 and mixing speed; 350 rpm. (Author)

[en] The separation of metal ions of groups II and III from uranium, in an aqueous solution containing uranyl ions is described. The method comprises the following steps: extracting the solution by means of a suitable solvent containing a reagent likely to react with the uranyl ion and provide a complex which is soluble in the solvent; mixing said solvent with an aqueous solution containing ammonium carbonate and/or di-carbonate in the proportion of from 0.5 to 1 mole per liter, sufficient amount of sulphite ions for causing the metal ions to precipitate; letting said solvent be separated from the aqueous solution; collecting the metal ion precipitate. That inexpensive method provides ceramic grade uranium, which can be used as reactor fuel

[en] In the present paper an attempt has been made to separate dysprosium (Dy) from the chloride solution comparable to the scrap of Nd -Fe-B permanent magnet by solvent extraction technique. Di-2-ethyl hexyl phosphoricacid (D2EHPA) and 2-ethyl hexyl phosphoric acid (PC88A)have been evaluated as extractants under wide range of experimental variable. The two phase extraction reaction was found to be exothermic in nature for the both the extraction systems. D2EHPA was found to be superior compared to PC88A. Increase in metal ion concentration, aqueous acidity and temperature lead to decrease in distribution ratio for Dy extraction. Selective separation of Dy from mixed rare earth feed consisting of Dy, Nd and Pr was achieved with 0.25 M D2EHPA at feed acidity 0.5M HCL. The purity and recovery of Dy was found to be ∼98% and 95%respectively. (author)

[en] A two cycle solvent extraction process employing 2-ethyl hexyl, 2-ethyl hexyl phosphonic acid (EHEHPA) has been developed for the separation of high purity gadolinium. Intermediate rare earth concentrate obtained during samarium purification process, comprised of 70% gadolinium along with lighter rare earths (Sm, Nd) as well as heavier rare earths (Tb, Dy, Y) have been processed for obtaining >99.5 % gadolinium oxide. The oxide was subsequently converted to its nitrate form for use as a secondary shut down device in PHWR system. The experimental conditions were optimized using computer simulation and validated by bench scale counter-current operations. (author)

[en] Sodium diuranate (SDU) obtained at Heavy Water Board (HWB) during uranium recovery from phosphoric acid by D2EHPA-TBP process contains significant amount of iron and valuable rare earths particularly heavier rare earths such as Y, Er, Yb, Dy etc. Separation of valuable rare earths and iron from SDU is essential to get nuclear grade pure uranium. In the present work efforts have been made to devise a solvent extraction cum precipitation process to separate uranium from rare earths and iron followed by selective separation of rare earths from iron by precipitation route

[en] We have investigated the extraction of cadmium with di(2-ethylhexyl) phosphoric acid (HDEHP) in various solvents from perchloric and phosphoric solutions. The distribution coefficient D obtained is not very dependent on the nature and the polarity of the diluent used. The extraction of Cd(II) by HDEHP dissolved in benzene, from sulfophosphoric solutions shows the absence of sulfuric or mixed sulfophosphoric complexes of the metal. However, the presence of iodide anions in aqueous perchloric or phosphoric media results in enhanced extraction coefficient of cadmium with HDEHP (HX) in benzene. The extracted species were found to be CdIX,3(HX)₂ and CdI₂,3(HX)₂ and their formation constants are 0.033 and 0.036, respectively. The recovery of cadmium from phosphoric medium by tributylphosphate (TBP), trioctyl phosphine oxide (TOPO), triphenyl phosphine oxide (TPPO), diphenylamine or their mixtures with HDEHP is lesser than with HDEHP alone