THE EXTRACTION OF THORIUM AND SOME LOWER LANTHANIDE NITRATES BY DIBUTYL BUTYL PHOSPHONATE

1962 ◽  
Vol 40 (8) ◽  
pp. 1684-1689 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Nitric Acid ◽  
National Laboratory ◽  
Nitric Acid Concentration ◽  
Distribution Coefficients ◽  
Metal Species ◽  
Trace Metal Concentration ◽  
Oak Ridge ◽  
Separation Factors ◽  
Lanthanide Nitrates ◽  
Aqueous Nitric Acid

The distribution of thorium and a number of lanthanides between nitric acid and solutions of dibutyl butyl phosphonate in odorless kerosene has been examined as a function of the aqueous nitric acid concentration. Experiments were conducted at trace metal concentration using radioisotopes. Separation factors (denoted by S and defined as the ratio of the distribution coefficients, K, for two metal species) have been measured for some lanthanide–lanthanide couples and also for some thorium–lanthanide couples. Results indicate that separation factors between successive lanthanides (given by S = KZ+1/KZ) at the lower end of the rare-earth series are superior to those obtained with either tributyl phosphate (TBP) (D. Scargill et al. J. Inorg. & Nuclear Chem. 4, 304 (1957)) or trioctyl phosphine oxide (TOPO) (J. M. Schmitt. Oak Ridge National Laboratory. Unpublished data), but as Z increases, SDBBP ~STBP > STOPO. For thorium–lanthanide couples, S′DBBP > S′TBP. Measurements over a range of extractant concentrations indicate that the lanthanides are extracted as trisolvates.

scholarly journals Separation of tungsten and rhenium on alumina

2004 ◽  
Vol 69 (8-9) ◽  
pp. 683-688 ◽  
Author(s):  
Jurij Vucina ◽  
Dagoljub Lukic ◽  
Milovan Stoiljkovic
Keyword(s):  
Nitric Acid ◽  
Sodium Chloride ◽  
Aqueous Phase ◽  
Aqueous Media ◽  
Distribution Coefficients ◽  
Experimental Conditions ◽  
Efficient Separation ◽  
Separation Factors ◽  
Ph Range

The conditions for the efficient separation of tungsten(VI) and rhenium (VII) on alumina were established. The distribution coefficients K d for tungstate and perrhenate anions, as well as the separation factors ?(? = KdWO42-/Kd ReO4-) were determined using hydrochloric or nitric acid as the aqueous media. Asolution of sodium chloride in the pH range 2?6 was also examined. Under all the tested experimental conditions, alumina is a much better adsorbent for tungsten than for rhenium. The obtained results indicated that the best separation of these two elements is achieved when 0.01? 0.1 mol dm-3HCl or 1.0mol dm-3 HNO3 are used as the aqueous media. If NaCl is used as the aqueous phase, the best separation is achieved with 0.20 mol dm-3 NaCl pH 4?6. Under these experimental conditions, the breakthrough and saturation capacities of alumina for tungsten at pH4 are 17 and 26 mg W/g Al2O3 respectively. With increasing pH, these values decrease. Thus, at pH 6 they are only 4 and 13 mg W/g Al2O3, respectively.

Demonstration of the Feasibility of Recovering Americium and Curium Isotopes from a Lanthanide Borosilicate Glass

2002 ◽  
Vol 713 ◽  
Author(s):  
Tracy S. Rudisill ◽  
David K. Peeler ◽  
Thomas B. Edwards
Keyword(s):  
Nitric Acid ◽  
Specific Activity ◽  
National Laboratory ◽  
High Specific Activity ◽  
Rate Of Change ◽  
Radioactive Isotopes ◽  
Small Scale ◽  
Particle Model ◽  
Lanthanide Oxides ◽  
Oak Ridge

ABSTRACTA solution containing kilogram quantities of highly radioactive isotopes of americium and curium (Am/Cm) is currently stored in a process tank at the Department of Energy's Savannah River Site. This tank and its vital support systems are old, subject to deterioration, and prone to possible leakage. To address the stabilization of this material, vitrification of the isotopes has been considered. Potentially, the glass could be shipped to the isotope production and distribution programs at the Oak Ridge National Laboratory for californium-252 production and use by the transplutonium research community. However, before the Am/Cm could be used in these programs, it must be recovered from the glass.To demonstrate the feasibility of recovering the Am/Cm isotopes from a glass, a series of small-scale experiments was performed as part of a compositional variability study. Glasses fabricated during the study utilized lanthanide elements as surrogates for Am/Cm due to the high specific activity of these materials. In the dissolution tests, glass formulations representative of potential uncertainties in the composition of the Am/Cm solution were fabricated, ground to a -35 to +60 mesh particle size, and dissolved in 8M nitric acid at 110°C. Under these conditions, at least 98% of the lanthanide oxides in the glass dissolved in less than 2 h meeting a recoverability criterion established for the vitrification process and imposing no limitations on the acceptable glass composition region.Dissolution of the lanthanide borosilicate glasses was described by a spherical particle model based on the observation that the rate of change of the mass to surface area ratio remains constant. Calculation of dissolution rates using the model showed that the rate was proportional to the lanthanide oxide concentration in the glass. When silicon oxide (SiO2) was replaced with a lanthanide element at higher (simulated Am/Cm) loadings, the glass became more easily dissolved in nitric acid due to the solubility of the lanthanide oxides compared to SiO2.

Immobilization and Recovery of Thorium, A Neptunium Surrogate, using Phase-Separated Glasses

1996 ◽  
Vol 465 ◽  
Author(s):  
T. F. Meaker ◽  
D. Karraker ◽  
M. Tosten ◽  
J. M. Pareizs ◽  
W. G. Ramsey
Keyword(s):  
Heat Treatment ◽  
Phase Separation ◽  
Nitric Acid ◽  
Ion Exchange ◽  
National Laboratory ◽  
Target Material ◽  
The United States ◽  
Sodium Borate ◽  
Oak Ridge ◽  
Treatment Conditions

ABSTRACTThe Savannah River Site has the majority of the United States' supply of neptunium currently stored in an acid solution in one of their canyon facilities. A program is being developed that could be utilized to ship this material, as glass, to Oak Ridge National Laboratory where the Np could be leached from the glass, purified by ion exchange and made into target material for the production of Pu-238. Ion exchange purification dictates no material be in the leachate making the isolation of the Np difficult. We have developed a process using thorium as a surrogate for Np that could immobilize the Np into a soda borosilicate glass for shipment. To achieve recovery of the Np, the glass can be phase separated prior to leaching with nitric acid. Phase separation would produces a Np-rich sodium-borate phase and a Si-rich phase similar to a Vycor® glass. The nitric acid selectively attacks the sodium-borate phase allowing high Np recovery in a solution that contains only sodium and boron. These can be easily separated from Np by ion exchange. Essentially all of the silicon which would interfere with ion exchange by precipitation is retained in the Vycor®-type phase. This technology may also be applied to other actinides stored in relatively pure solutions.This paper will report the optimization of variables for maximizing Th (a Np surrogate) recovery while minimizing Si release. Th solubility in glass, heat treatment conditions and leaching parameters will be discussed. Transmission Electron Microscopy (TEM) with energy dispersive spectroscopy (EDS) data will be included to show phase separation after heat treatment.

Plug-in scripts for EFTEM automation

1996 ◽  
Vol 54 ◽  
pp. 546-547
Author(s):  
N. D. Evans ◽  
M. K. Kundmann
Keyword(s):  
Electron Microscopy ◽  
National Laboratory ◽  
Oak Ridge ◽  
Multiple User ◽  
Transmission Electron ◽  
Short Period ◽  
User Facility ◽  
Instrument Control ◽  
And Control ◽  
Research Equipment

Post-column energy-filtered transmission electron microscopy (EFTEM) is inherently challenging as it requires the researcher to setup, align, and control both the microscope and the energy-filter. The software behind an EFTEM system is therefore critical to efficient, day-to-day application of this technique. This is particularly the case in a multiple-user environment such as at the Shared Research Equipment (SHaRE) User Facility at Oak Ridge National Laboratory. Here, visiting researchers, who may oe unfamiliar with the details of EFTEM, need to accomplish as much as possible in a relatively short period of time.We describe here our work in extending the base software of a commercially available EFTEM system in order to automate and streamline particular EFTEM tasks. The EFTEM system used is a Philips CM30 fitted with a Gatan Imaging Filter (GIF). The base software supplied with this system consists primarily of two Macintosh programs and a collection of add-ons (plug-ins) which provide instrument control, imaging, and data analysis facilities needed to perform EFTEM.

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