Potentialities of low-temperature chlorination of aluminum and its alloys with uranium

Potentialities of low-temperature (300–500°C) chlorination to remove the aluminum cladding of fuel elements and separate uranium and aluminum were studied.     

Possibility of electrochemical control over the composition of uranium-aluminum alloys

Possibility of preferential dissolution of uranium or aluminum from U-Al alloys in salt electrolytes was examined by performing thermodynamic calculations and experimentally.     

Nuclear magnetic resonance study of aluminum chloride-n-Butylpyridinium chloride melts

High resolution proton and ¹³C-NMR measurements were used to follow the variation of the n-butylpyridinium (BP⁺) cation spectra in BP⁺Cl^?AlCl₃ molten mixtures. The mole fraction of AlCl₃ was varied between 0.45 and 0.60. It was found that chemical shifts and proton coupling constants are significantly affected by the BP⁺-Cl^? and BP⁺ -AlCl^?₄ associations. Analysis of the NMR results shows that in the melts the ionic association into ion pairs is essentially quantitative. Lithium-7 NMR of BPCl-AlCl₃-LiCl melt shows that when the mole-fraction of AlCl₃ is < 0.50 (basic melt) LiCl₂^? ion is formed, while in the acidic melts the Li⁺ ion probably interacts with two AlCl₄^? ions to form LiAl₂Cl^?₈ ion.     

Electrochemistry of uranium in sodium chloroaluminate melts

The electrochemical behaviour of uranium has been studied in basic, NaCl-saturated NaAlCl₄ melts at 175°C. Solutions of UO₃ exhibit two oxidation/reduction waves (cyclic voltammetry). The first wave corresponds to the U(VI)/U(IV) redox couple and is irreversible (slow electron transfer). The second wave corresponds to the deposition and stripping of an insoluble U(III) compound (U(IV)/U(III)). Solutions of UO₂ or UCl₄ and U(IV) solutions prepared by exhaustive electrolysis of UO₃ behave identically. The cyclic voltammograms of U(IV) solutions are the same as those of UO₃, but they show additional anodic peaks. Analysis of the peak currents (cyclic voltammetry), the limiting currents (pulse polarography) and the non-linear log i-t curves (anodic controlled potential coulometry) leads to the conclusion that uranium (IV) in the basic chloroaluminate melt exists as two different species in slow equilibrium with one another, of which only one species can be oxidized to U(VI). E.m.f. measurements of U(VI)-U(IV) mixtures indicate that the electron transfer process involves the formation of an intermediate U(V) species in a disproportionation equilibrium.     

A study of the kinetics of electrochemical dissolution of aluminum alloys in alkaline electrolytes

Electrochemical dissolution of aluminum alloyed with tin, indium, and lead in a NaOH solution in the concentration range 4.4–12.0 M at 75°C was studied by the method of chronopotential and current-voltage curves. The influence exerted by alloying elements on the electrochemical parameters of the process was revealed.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1654–1658.Original Russian Text Copyright © 2004 by Krasnobryzhii, Rusin, Varypaev, Nikolskii, Alekseev.     

The application of the spectroelectrochemical method in the studies of molybdenum,tungsten, and uranium in chloride melts

The behavior of molybdenum(III), tungsten(IV), and uranium(VI) ions in NaCl-2CsCl-eutectic-mixture-based melt at 550°C is studied by spectroelectrochemical method. Anodic oxidation of MoCl₆³⁻ and WCl₆²⁻ yields melt-soluble chloride compounds MoCl₆²⁻ and WCl₆⁻ respectively. It is shown that the electrochemical recharging in the Mo(III)/Mo(IV) system is reversible; the formal standard potential E*_{Mo(IV)/Mo(III)}and the Gibbs energy $ \Delta G_{MoCl_4 (melt)}^* $ \Delta G_{MoCl_4 (melt)}^* are evaluated. The cathodic reduction of U(VI) yields U(V) ions. The cathodic reduction of W(IV) ion does not yield melt-soluble tungsten compounds of lower oxidation state.     

氟氯烷烃与三氯化铝的反应

Park等从全氟丙烯与三氯化铝的反应产物中,分离出一系列氟氯烯烃,并指出该反应中全氟丙烯氟原子被氯原子取代的次序.CF_2ClCFClCF_2CFCl_2(1)与三氯化铝反应,仅得到CF_2ClCFClCF_2CCl_3,产率58％.我们研究了1及CFCl_2CF_2CFCl_2(2)分别与三氯化铝的反应.由1的反应得CF_     

Reaction of aluminum chloride with dialkylcyclosiloxanes

Summary During the reaction between aluminum chloride and cyclic dilakylsiloxanes —octamethylcyclotetrasiloxane, octaethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, and hexaethylcyclotrisiloxane —ring opening occurs with the formation of -chloro--dichloroaluminoxydialkylpolysiloxanes, which further split out ,-dichloropolysiloxanes and form cyclic compounds-1-chloro-3,3,5,5-tetramethylcycloaluminoxydisiloxane and 1-chloro-3,3,5,5tetraethylcycloaluminoxydisiloxane. These compounds were separated and characterized in the form of complexes with aluminum chloride.     

Raman study of gallium chlorosulphides in chloride melts

The reaction between sulphur and gallium in chlorobasic melts at ca. 500°C was studied by visual observation and by Raman spectroscopy. The results suggest the formation of charged long chains (-GaCl₂-S-GaCl₂-S-) in these melts and the presence of the radical anion S₃^? under certain conditions.     

Recovery of uranium from uranium refining waste water by using immobilized persimmon tannin

Some attempts were made to examine the practical conditions for uranium recovery from uranium refining waste water. The adsorbent was highly effective in recovering uranium. The uranium adsorption was affected by pH, temperature, and uranium concentration of the uranium refining waste water. The adsorbent also recovered uranium effectively in column system. It aquires better mechanical properties and can be used repeatedly in the uranium adsorption-desorption cycles.     

Activity of components of binary chloride melts

Activities of components of the systems NaCl-AgCl, KCl-AgCl, NaCl-FeCl₂, and NaCl-CoCl₂ were calculated using the model of regular solutions and data on the enthalpies of mixing of binary chloride melts.     

Oxoacidic properties of some Ba-based chloride melts

Solubilities of CdO and ZnO in molten BaCl₂–KCl–NaCl (0.43:0.29:0.28) and BaCl₂–KCl (0.26:0.74) at 700°C have been determined by the potentiometric titration technique. Oxobasicity indices of these melts are estimated as 2.01 and 1.83, respectively. A correlation between oxobasicity indices and the content of most acidic cation (Ba²⁺) is shown to exist.     

Kinetics of the yttrium fluoride electroreduction in chloride melts

To establish the effect of the nature of supporting electrolytes KCl; K, Na/Cl; K, Na, Cs/Cl; and K, Na, Ba/Cl on the electrochemical deposition of yttrium from melts, the electroreduction of yttrium fluoride in the said melts is studied by a linear voltammetry method. The discharge of ions Y³⁺ in all the melts occurs via one stage. The diffusion coefficients, activation energy, product of transfer coefficients and the number of electrons n , diffusion layer thickness, diffusion constant, and rate constant of charge transfer are determined.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 48–53.Original Russian Text Copyright © 2005 by N. Gasviani, Dzhaparidze, Kipiani, S. Gasviani, Abazadze.     

Chlorination of uranium metal to uranium trichloride using ammonium chloride

Journal of Radioanalytical and Nuclear Chemistry - Given that the most feasible option for fabricating chloride-based molten salt fuel for molten-salt reactors (MSRs) is to use uranium/transuranic...     

Cu-Ni alloys in electrochemical oxygen analysis

Cu-rich Cu-Ni alloys (containing 70–90% Cu) are shown to be excellent indicator electrode materials for voltammetric measurements at cathodic potentials. These electrodes have been characterised using a variety of methods: rotating disk voltammetry, amperometric measurements and sono-ring-disk voltammetry. The mechanism of electrochemical oxygen reduction at the Ni-30Cu alloy has been established. The results are compared with the surface study results. Received: 2 December 1999 / Revised: 17 February 2000 / Accepted: 25 February 2000     

Improvement of the efficiency of electrochemical refining of cobalt

To improve the purity of cobalt produced by electrochemical refining, the optimal electrolyte composition and electrolysis mode were determined and a method for diminishing the electrochemical activity of impurity metals in anodic dissolution of the raw metal and a system for deep purification of the electrolyte solution to remove impurities were developed. Cathode deposits with a conditional cobalt content exceeding 99.999 wt %, found in an analysis for the 11 main impurities, were obtained by using the above results in refining of K1A cobalt (≥99.30 wt % Co) in an electrolyzer of distinctive design.     

Complexes of N-derivatives of silicon hydrides with aluminum chloride

Conclusions A study was made of the reaction of the N-derivatives of silicon hydrides with aluminum chloride, and it was shown that aluminum-containing organosilicon complexes can be obtained from them.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2149–2150, September, 1973.     

Ion exchange separations in the analysis of bismuth base alloys : Binary alloys with uranium and thorium

Procedures are described for the determination of uranium (0.001–10%) and thorium (0.05–10%) in binary mixtures with bismuth. A preliminary separation of the bismuth is effected by the passage of a hydrochloric acid solution of the sample through a column of Deacidite FF For thorium contents greater than 1%, the determination is completed volumetrically with EDTA using pyrocatechol violet as indicator, smaller amounts are determined absorptiometrically with thoronol Similarly the higher uranium contents are determined volumetrically after reduction to the tetravalent state with a lead reductor, and an absorptiometric method based on the coloured complex formed by tetravalent uranium with thoronol is used for the smaller amounts.     

Polarographic determination of aluminum in titanium alloys

Considerable interest has been shown in titanium metal because of its combination of desirable properties, including its favorable strength to weight ratio and its resistance to corrosion. Since titanium-aluminum alloys are fairly common, there is need for an accurate method of determining aluminum over a wide range of concentrations. This paper describes an accurate and fairly rapid polarographic method for determining aluminum based on the reduction of an aluminum-azo dye complex after removing titanium, and other interferences by cupferron precipitation, followed by electrolysis at a mercury cathode when necessary. The reduction takes place at — 0.44 volt versus the saturated calomel electrode in a solution buffered at pH 4.6 with acetate. The method is sensitive from 0.01 mg to 0.50 mg of aluminum per 50 ml, covering a range of 0.005 to 10.0 per cent aluminum.