Separation Of Thorium Research Articles

THE SYNERGISTIC EXTRACTION OF THORIUM(IV) AND URANIUM(VI) BY 2-ETHYLHEXYL PHENYLPHOSPHONIC ACID AND MICELLES OF DINONYL NAPHTHALENE SULPHONIC ACID

ABSTRACT The extraction of thorium(IV) and uranium(VI) from nitric acid solutions into ligroine solutions of 2-ethylhexyl phenylphosphonic acid (HEHφP), micellar dinonyl naphthalene sulphonic acid (HDNNS) extractants and mixture of the two extractants is reported. A synergistic enhancement factor of 66.9 and 10.8 were observed for Th and U, respectively, when extracted from 1 M HNO3 Although HDNNS shows better separation of thorium and uranium, the mixed ligand system exhibits superior extractability for both metals ions. Slope analysis method was used to establish the extraction stoichiometry. The extraction stoichiometry varies as the concentration of the micellar HDNNS in the organic phase and the acidity of the aqueous phase changes.

Recovery of234Th from natural uranium using liquid emulsion membrane based on HDEHP-HCl system

Comparative studies between column and batch liquid emulsion membrane techniques based on HDEHP/HCl system were carried out to develop a system for isolation of234Th from natural uranium. For column investigations a spray column was constructed and used with two different modes. In the first mode the feed solution was circulated through the membrane while in the second mode the membrane phase was circulated through the feed solution. The results showed that, kinetically, the equilibrium for thorium separation using batch technique is faster than the continous column system. Quantitative permeation of thorium was achieved within one minute of mixing whereby the permeation of uranium reached equilibrium after 3 minutes with a permeation percentage less than 6%. A procedure was developed to separate234Th from natural uranium with high radiochemical purity of more than 98%.

Extraction studies of thorium(IV) with triphenylphosphine oxide

A simple method is described for the solvent extraction of thorium. Thorium is extracted quantitatively from 5·10−3M sodium salicylate solution at pH 2.5–3.25 using 2.16·10−2M triphenylphosphine oxide as an extractant dissolved in toluene. The extracted metal ion is stripped with hydrochloric acid (0.1M) and determined spectrophotometrically with Thoron-1 at 540 nm. The method permits separation of thorium from lanthanum, cerium, neodymium, samarium and uranium from binary mixtures and is applicable to the analysis of monazite sand. The method is precise, accurate and selective.

Separation of thorium from lanthanides by solvent extraction with ionizable crown ethers

Thorium and the lanthanides are extracted by α-(sym-dibenzo-16-crown-5-oxy)acetic acid and its analogues in different pH ranges. At pH 4.5, Th is quantitatively extracted by the crown ether carboxylic acids into chloroform whereas the extraction of the lanthanides is negligible. Separation of Th from the lanthanides can be achieved by solvent extraction under this condition. The extraction does not require specific counteranions and is reversible with respect to pH. Trace amounts of Th in water can be quantitatively recovered using this extraction system for neutron activation analysis. The nature of the extracted Th complex and the mechanism of extraction are discussed.

トロトラスト患者臓器中のトリウムの定量 アルセナゾＩＩＩによる比色定量の適用

The formerly used X-ray contrast medium, Thorotrast—a colloidal thorium dioxide—causes a chronic exposure to α-particles. In this paper, a method for the colorimetric determination of thorium content in Thorotrast patient's organs is described. The sequential chemical separation of thorium has been studied on the basis of coprecipitation, ion exchange, and solvent extraction methods, followed by colonmetric analysis using Arsenazo III.The experimental values were compared with those obtained by radiation measurement or neutron activation analysis of patient's organs.

Separation of thorium, uranium and plutonium by neutral and basic organic extractants

Separation of thorium, uranium and plutonium by basic tertiary amine, Alamine-336 and neutral organophosphoric extractant tri-n-octylphosphinoxide in xylene and cyclohexane solutions has been investigated. According to results obtained, Alamine-336 was chosen for the extraction of atmospheric precipitation samples. Separation process with tri-n-octylphosphinoxide based extraction can lead to higher chemical yields, but according to our results reproducibility is worse due to incomplete back-extraction of elements from organic phase. Analysis of simulated 1001 sample concentrate has shown significant effect of Ca2+, Fe3+ and Mn2+ ions concentration.

Liquid-liquid distribution studies of thorium salicylate with tris-(2-ethylhexyl)phosphate

A method is proposed for the extraction of thorium(IV) from salicylate media using tris-(2-ethylhexyl)phosphate dissolved in toluene as an extractant. The optimum conditions were evaluated from a critical study of pH, salicylate concentration, extractant concentration, period of equilibration and diluent. The method permits the separation of thorium from the associated elements and is applicable to the analysis of monazite sand. The method is precise, accurate, fast and selective.

Solvent extraction separation of thorium as picrate complex with 18-crown-6

Thorium was quantitatively extracted from 0.04M picric acid with 0.065M of 18-crown-6 at pH 2.0–3.5. It was stripped from organic phase with 0.5M nitric acid and was determined spectrophotometrically at 655 nm as its Arsenazo-III complex. Thorium was separated from mixture containing cerium, uranium, zirconium, hafnium, yttrium and lead in complex mixtures. The method was extended for the analysis of thorium in monazite.

Separation of Thorium from Trivalent Rare Earths in Monazite and its Gravimetric Determination using o-Carboxyphenylazo-β-naphthol

Separation of Thorium from Trivalent Rare Earths in Monazite and its Gravimetric Determination using o-Carboxyphenylazo-β-naphthol

Separation of thorium as ascorbato complex by extraction with Aliquat 336S

Thorium was quantitatively extracted with 0.1M Aliquat 336S at pH 4.5 from 0.01M ascorbic acid. It was then stripped with 2M hydrochloric acid. Thorium arsenazo III complex was determined spectrophotometrically at 655 nm. It was separated from binary and tertiary mixtures by exploiting the difference in distribution ratios of various elements from ascorbic acid media. Some separations were accomplished by selective stripping of thorium from nitric and hydrochloric acid. The method was extended for the analysis of thorium in monazite and gas mantles.

SOLVENT EXTRACTION OF ZIRCONIUM(IV) MID URANIUM(VI) FROM CHLORIDE MEDIA WITH BIDEHTATE SCHIFF BASES

ABSTRACT The systematic licuid-liquid extraction behaviour of zlrconium(IV)and uranium(VI) with bidentate Schiff bases (HSB) in benzene as the diluent has been studied. Quantitative extraction of zirconium(IV)has been achieved. Four consecutive extractions are, however, necessary for quantitative extraction of uranium(VI) at pH 6.0. The extracted species seem to be [Zr4(OH)8(H2O)4(HSB)6]Cl8and [(UO2)2(OH)2(HSB)[Cl2.The extraction efficiency is in the order : Zr4+> Th4+UO2 2+. It is possible to separate zirconium from thorium and uranium by solvent extraction with HSB. Exchange reaction technique has been employed for separation of thorium and uranium.

Radiochemical separation of thorium by isotope ion exchange

The aim of the present work is to obtain the separation of233Th from the radioisotopes formed in the irradiation of Mn, U, Ba, Cs, Co and the lanthanide elements with thermal neutrons, because they may interfere in the neutron activation analysis of Th, when the activity of233Th is used. The experiments were performed with the resin Bio-Rad AG 50W X-4 and X-8 (100–200 mesh) in the thorium form. The separation of233Th from the interfering radioisotopes is based on the retention of233Th by the resin (isotope exchange) and the elution of the interfering radioisotopes with a dilute solution of Th in 0.5M HCl. Batch experiments were made in order to determine the equilibrium time for the isotopic ion exchange of thorium and also the distribution coefficients of the interfering elements between the solution and the resin. Column experiments were carried out with the purpose of establishing the conditions that allow the maximum isotope exchange of233Th and the minimum retention of the interfering radioisotopes in the resin. With this purpose, a statistical interpretation of a four variable experimental design is presented.

Solvent extraction of lanthanum(III) from sulphuric acid solutions by Primene JMT

The distribution of lanthanum(III) between aqueous H 2SO 4 solutions and Primene JMT in the organic phase is described. The dependence of the extraction on acidity, extractant concentration and type of diluent was investigated. Aggregation numbers are calculated and a mechanism for the extraction is suggested. The separation of thorium(IV) from lanthanum(III), cerium(III) and cerium(IV) is outlined.

Thin Layer Chromatographic Separation of Thorium, Titanium, Zirconium and Some Rare Earths on Cellulose Impregnated Layers

Abstract The chromatographic saparation of Thorium, Titanium, Zirconium and eight rare earths has been attempted on DBBP, HDEHP and HDEHP-TOPO impregnated cellulose plates using the solvent system MaOH-6N HNO3−Acatyl acetone (20:15:5). An efficient seperation of 4–5 rare earths on HDEHP-TOPO impregnated plates has been achieved.

Reversed phase extraction chromatographic separation of thorium with Amberlite LA-1 from malonate solutions

Thorium was extracted at pH 5.0 from 0.01 M malonic acid on a column of silica gel coated with Amberlite LA-1. Thorium was separated from alkali and alkaline earths, managenese, iron, cobalt, nickel, zinc, tin, in binary mixtures by taking advantage of the difference in the pH of formation of malonato complexes. Thorium was separated from zirconium, uranium, scandium, molybdenum, titanium, by exploiting the difference in the stability of malonato complexes. The method was extended for the analysis of thorium in monazite.

Cation-exchange separation of thorium(zirconuim), scandium(uranium) and rare earth with arsenazo m as the eluant

Strong inorganic acids [1,2] and organic complexing agents [3,4] have been usually used as eluants for cation-exchange separation of U(VI), Th, Zr, Sc and RE. However, the elution volume of strong inorganic acid is large, the organic complexing agents always interfere the determination of metals in the effluent. In this paper Arsenazo M has been developed as an eluant, the effluent may be used for direct spectrophotometric determination. The simple and rapid methods for cation-exchange and direct spectrophotometric determination of Zr/Sc/RE, Zr/U/RE, Th/Sc/RE mixture have been proposed. ▪ The ion exchange behaviour of U, Th, Zr, Y, La, Gd and Lu on the strong acidic cation exchange resin in Arsenazo M in various media (aqueous, acetic acidsodium acetate and hydrochloric acidsodium acetate buffer solution) has been investigated by equilibrium. The adsorption coefficients of the above metals have been measured. From the experimental results the acetic acidsodium acetate buffer solution is favourable for the metals (Fig. 1). The mechanism of the effects of the media has been studied, with La as a representation, because the media greatly affect the adsorption coefficients of the metals. When the Arsenazo M solution contains some single bonded ligands such as Ac −, we found that the shape and peak place of the absorption spectra of the complexes formed with La change distinctly (as shown in Fig. 2). It is clear that Lanthamum has formed a ternary complex, acetatemetal ion-Arsenazo M. Thus the adsorption coefficients of La are much smaller in the Arsenazo M solution containing Ac − medium. The results for the other elements (Th, Sc, etc.) are similiar to La. ▪ t001 TABLE I. Results for Separation of Determination of Mixtures. Mixtures Rations of metals Taken (μg) Found (μg) Recovery (%) ZrScRE 1000:1:1 Zr 2000 1967 98 Sc 2.0 2.1 105 RE 2.0 1.9 95 2:1:60 Zr 10 10.3 103 Sc 5.0 5.0 100 RE 300 290 97 ZrURE 500:5:1 Zr 1000 1000 100 U 10 9.8 98 RE 2.0 2.2 110 5:200:1 Zr 10 9.7 97 U 400 406 102 RE 2.0 2.0 100 ThScRE 40:4:1 Th 200 188 94 Sc 20 19 95 RE 5.0 5.0 100 1:3:10 Th 10 10 100 Sc 30 31 103 RE 100 95 95 ThRE 2000:1 Th 4000 3900 98 RE 2.0 2.2 110 1:100 Th 5.0 5.1 102 RE 500 500 100 URE 2000:1 U 4000 4100 102 RE 2.0 1.9 95 1:100 U 10 10 100 RE 1000 935 94 ScRE 2000:1 Sc 4000 4125 103 RE 2.0 2.1 105 1:500 Sc 2.0 2.0 100 RE 1000 975 98 ▪ According to the experimental results the complete separation of the ternary mixtures may be achieved by a column (0.8 cm × 10 cm). The flow rate was 0.5–1.0 ml/min. The elution was carried out at room temperature. Procedure of column separation: Solution of mixture of Zr/Sc(U)/RE (or Th/Sc/RE) added to the column. Elution was carried out with Arsenazo M in the different media and pH. Elution curves for these mixture are given in Fig. 3 and 4. The metals were directly determined by spectrophotometry. The spectrophotometric determination of each element is presented in the literature [5]. The results of percentage recovery are shown in Table I. The method was applied to the analysis of Th (0.017–0.17%) Sc (0.005–0.13%), and RE (0.6–2.9%) in ore samples with satisfactory results.

Separation of Thorium, Protactinium and Uranium by Ion Exchange and Extraction

Separation of Thorium, Protactinium and Uranium by Ion Exchange and Extraction

Studies on the Extraction of Ti(IV), Ce{IV), Th(IV) and U(VI) with 1-Phenyl-3-methyl-4- benzoyl-pyrazole-5-one from Different Mineral Acids. Separation of Thorium from Titanium, Uranium and Rare Earths

Studies on the Extraction of Ti(IV), Ce{IV), Th(IV) and U(VI) with 1-Phenyl-3-methyl-4- benzoyl-pyrazole-5-one from Different Mineral Acids. Separation of Thorium from Titanium, Uranium and Rare Earths

Separation of metal ions on a new amide resin

The synthesis and characteristics of a new resin containing an amide fnctional group are described. The resin selectively retains uranium, thorium and zirconium from aqueous perhlorate solutions, and also strongly retains the noble metals fro aqueous or methanolic hydrochloric acid solutions. Unlike conventional anion-exchange resins, the platilnum-group metals and gold can be asil eluted with hydrochloric acid solutions containing sodium perchlorate and acetone, respectively. The chromatographic separation of thorium, uranium and zirconium, as well as that of some of the noble metals, has been demonstrated by using continuous spectrophotometric detection.

Kinetic studies on the foam separation of thorium (IV) with sodium lauryl sulphate

The effects of pH, gas flow rate and collector concentration on the rate of thorium removal by foaming with sodium lauryl sulphate have been investigated. The obtained data indicate that only aged hydrated thorium oxide is removed by a flotation mechanism. All the other colloidal and condensed thorium species as well as the colloidal sublates which are formed between the dissolved thorium species and the collector anions appear to be removed by partition and their removal rates could be described by a reversible first-order rate equation. The obtained results are discussed in terms of thorium hydrolysis.