Ion exchange separation of light rare earths by gradient elution

This paper describes an ion exchange separation method for light rare earths by gradient elution with AHIB as eluant. The yield of the individual rare earths is about 95%. This method is adaptable for separation of La, Ce, Pr, Nd, Pm, Sm, and Y from the rare earths which were separated from fission product solutions.     

Activation analysis of rare earths : The determination of rare earths in minerals by the single comparator technique

The determination of rare earths in minerals by activation analysis is described. The rare earths are separated as a group from the bulk of the material before irradiation. After irradiation the rare earths are separated from each other by gradient elution with ammonium α-hydroxyisobutyrate on a cation-exchange column. The elements are determined by the single comparator technique. This method permits a practical application of activation analysis to the routine determination of rare earths in complex matrices,     

Selective determination of yttrium in geological materials by ion-interaction chromatography

Selective separation and determination of yttrium in rare earth ores have been achieved by high performance ion-interaction chromatography. Ores are decomposed by sulfuric acid and the rare earths are precipitated in a group as oxalates. Yttrium is then separated from the other rare earths on a C-18 bonded phase silica column modified with 1-octanesulfonate by linear concentration gradient elution for 20 min with 0.15 to 0.40M glycolic acid(pH 3.5). Yttrium elutes at about 10 min between samarium and neodymium, being separated selectively from all the rare earths as well as scandium, thorium and uranium. Post-column reaction detection and quantitation with Arsenazo III [2,7-bis(2-arsonophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid] are carried out at 650 nm. Quantitative results are quoted for yttrium in sophisticated, synthetic rare earth mixtures, monazite and xenotime.     

The determination of sc,y, nd,ce and la in silicate rocks by a combined cation exchange-spectrochemical method

The combined use of cation exchange enrichment and spectrochemical analysis for the determination of rare earths in common silicate rocks is described. Rare earth elements are more strongly adsorbed by cation exchange resins than the abundant elements, hence the latter can be eluted with a concentration of acid which does not desorb the rare earths. The rare earths are then eluted by stronger hydrochloric acid and the effluent is evaporated to an amount of material sufficiently small to are spectrographically. This procedure allowed the determination of Sc, Y, Nd, Ce and La. in 13 South African'granite rocks and Y, Nd, Cu and La in 6 South African basic rocks.     

Microchemical determination of nine rare earth elements in silicate rocks by cation-exchange preconcentration — Ion-interaction chromatography

Summary A method of applying ion-interaction chromatography to the determination of the rare earth elements in silicate rocks on a 100 to 200 mg sample basis has been developed. The rare earths are first separated as a group from matrices by cation-exchange chromatography in hydrochloric acid-thiocyanate media and isolated in a small, defined volume (3.00 ml). Using fractions of this, on-column concentration of the rare earths on a C-18 bonded phase silica coated with 1-octanesulfonate and a subsequent concentration gradient elution with glycolate (0.05 to 0.35 M) at pH 3.5 allows the respective separation of La, Ce, Pr, Nd, and Y (100 l aliquot used) and of Er, Tm, Yb, and Lu (2.00 ml aliquot used). Sm, Eu, Gd, Tb, and Dy elute together, and Ho is not sufficiently well resolved from these middle rare earth elements. The eluted rare earth elements are detected and quantified by post-column reaction with Arsenazo III photometrically, using a UV-VIS spectrophotometer at a wavelength of 650 nm. The method is shown to be capable of determining nine of the rare earth elements in a variety of international reference rock samples with good precision and accuracy.     

萃取色谱分离稀土元素进展

评述了近年来我国学者对萃取色谱分离稀土元素各种体系的研究及其在高纯稀土分离方面的应用，并对高纯稀土制备的发展方向进行了展望。     

Study on the Spectrophotometric Determination of Rare Earths with a New Chromogenic Reagent Dibromo-p-methyl-chlorosulfonazo(DBMCSA)

IntroductionAbstract:Anewmethodforthedeterminationofceriumsubgrouprareearthswasstudiedandreportedinthispaper.ItwasfoundthaiceriumsubgrouprareearthelementsreactwithDBMCSAin0.6mol/Lhydrochloricacidmediumtol'ormstablebluecomplexes.Theabsorbancesofequalamountsofceriumsubgrouprareearthsareclosetoeachotherattheirmaximumadsorptivewavelength(641"m).Beer'slawisobeyedfor0-20igofrareearthsin25mlofsolution.Themethodhasbeenappliedtothedeterminationofthetotalamountofceriumsubgrouprareearthsinsteelandcas…     

Separation of high purity gadolinium for reactor application by solvent extraction process

A solvent extraction process for the production of nuclear grade Gd₂O₃ for its applications in pressurized heavy water reactor (PHWR) from a crude concentrate of rare earths containing ~70 % Gd₂O₃ has been developed and tested on bench-scale and continuous counter-current operations. The separation of gadolinium from other rare earths with similar chemical properties has been successfully accomplished by adopting a dual cycle solvent extraction employing 2-ethylhexylphosphonic acid, mono-2 ethylhexyl ester (EHEHPA) as an extractant. Taking advantage of the extraction order of rare earths with EHEHPA, in the first cycle, heavy rare earths including Tb, Dy and Y were separated in the product strip solution, while gadolinium was separated in the raffinate solution along with samarium and neodymium. In the second cycle, gadolinium was purified to the extent of >99.5 % with respect to other rare earths. Effects of process variables such as aqueous acidity, phase ratio, metal concentration in the aqueous feed, scrubbing and stripping acidity etc. on separation of terbium and other heavy rare earths in the first cycle and upgrading the purity of Gd₂O₃ in the second cycle have been investigated. The experimental conditions were optimized using computer simulation and validated by bench scale counter-current operations. Under optimized conditions of process parameters, continuous operations of mixer settler yielded kilogram quantity of nuclear pure Gd₂O₃ which was subsequently converted to gadolinium nitrate for PHWR application. The overall recovery was found to be >98 %.     

The sequential analysis of long range fallout debris

A method for the determination of the principal radionuelides of Sr, Ba, Ce, Cs, Y, Zr, Nb, and W in single fallout samples containing bulk Si, Fe, and Ca is presented. The sample and added carriers are dissolved by fusion with sodium carbonate. The melt is leached first with hot water and then with hydrochloric acid. W and Cs are recovered from the water leach. Sr, Ba, Y, and the heavier rare earths appear in the hydrochloric acid leach. Ce is found in the leach residue and Nb in both the residue and the hydrochloric acid leach. The Zr and Nb in the residue are separated from Ce by absorption on an anion-exchanger from hydrochloric acid. The Zr and Nb in the hydrochloric acid leach are separated from Sr and Ba by precipitation of Sr and Ba as nitrates and then separated from Y and the heavier rare earths by absorption on the anion-exchanger. The combined Zr fractions are eluted with dilute hydrochloric acid and Nb with a hydrochloric-hydrofluoric acid mixture.     

Dynamic ion-exchange chromatography with post-column reaction detection for the determination of the rare earth elements in monazites

Summary Separation and determination of lanthanum, cerium, praseodymium, neodymium and samarium in monazites have been achieved by dynamic ion-exchange chromatography. The ore samples are decomposed by sulfuric acid and the rare earths are separated in a group as oxalates. The rare earth elements are then separated from each other on a column of bonded phase silica by gradient elution with 0.05 to 0.5 M lactic acid (pH 3.5) in the presence of 0.01 M sodium 1-octanesulfonate. Post-column reaction with Arsenazo III is used for detection and quantification of the individual rare earth elements. Results are quoted for lanthanum, cerium, praseodymium, neodymium and samarium in monazites. Detection limit is 1 μg ml⁻¹ with a S/N ratio of 3. The separation is complete within 27 min valley to valley resolution. Precision of better than 1% can usually be obtained.     

Determination of yttrium in rare earths by photon activation analysis

The determination of yttrium in the presence of large amounts of the rare earths by the thermal neutron reaction (89)Y(n, gamma)(90)Y is complicated because of frequent problems of sample self-shielding from major constituents of the sample, and the difficulty of separating (90)Y, a pure beta-emitter, from other elements which are very similar chemically. A non-destructive photon activation analysis method has been developed for this determination. Bremsstrahlung from a 35-muA beam of 35-MeV electrons induces the photonuclear reaction (89)Y(gamma, n)(88)Y. Optimum sensitivity is obtained by coincidence counting of the 0.90 and 1.84 MeV gamma-rays associated with the decay of (88)Y. The detection limit is less than 1 mug of yttrium.     

对甲基二溴偶氮胂的合成及其与稀土显色反应的研究

本文报道了对甲基二溴偶氮胂的合成,该显色剂在酸性介质中与稀土元素产生高灵敏度显色反应,大多数常见元素不干扰,所拟分析方法已成功地应用于小麦和铝合金中稀土总量的测定     

ICP-AES and D.C.arc-AES determination of Sc, Y and lanthanides in nuclear grade graphite

Summary Inductively Coupled Plasma-Atomic Emission Spectrometric and Direct Current Arc-Emission Spectrometric methods have been developed for the determination of rare earths in nuclear grade graphite. The graphite matrix was selectively removed from the analytes by controlled heating in air at 900°C in a muffle furnace. The residual ash containing analytes was dissolved and analysed by ICP-AES for rare earths specially required for assessing the nuclear purity, viz. Dy, Eu, Gd and Sm and for all rare earths, Sc and Y by D.C.arc-AES by photographing their spectra in III order on an 3.4 M Ebert Spectrograph. The recovery of rare earths after ashing was confirmed using -activities of¹⁴¹Ce,^152–154Eu,¹⁵³Gd,¹⁷⁰Tm and¹⁶⁹Yb which was found to be quantitative within experimental error.

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Bestimmung von Sc, Y und Lanthaniden in nuklear-reinem Graphit mit Hilfe der ICP-AES und der Gleichstrombogen-Spektrometrie

     

Dosage par activation neutronique des terres rapes dans des roches uraniferes

The determination of rare earths by activation analysis in uranium containing rocks is disturbed either by fission-produced rare earths, or by neptunium-239 originating from uranium-238. In order to eliminate of these interferences the chemical separation of rare earths from uranium prior to activation should be performed. The purpose of this work was the elaboration of a chemical process to separate rare earths prior to irradiation in a nuclear reactor. The rock sample is fused with sodium borate, then, after addition of hydrochloric acid, the resulting solution is passed through a Dowex 1×8 column. Uranium is retained on the resin and rare earths and scandium are eluted. Aluminium is added as a carrier to the solution and rare earths and scandium are coprecipitated with aluminium hydroxide. This precipitate is irradiated in the nuclear reactor. Gamma spectrometry is used for the determination of each radionuclide. Activities measurements are performed in successive steps during one month. The following elements are determinated: Pr, La, Sm, Nd, Yb, Lu, Ce, Tb, Eu, and Sc. The chemical yield is measured by using scandium as an internal standard.     

Complexation between rare earth metals and 1, 5-di(2-hydroxy-5-sulfophenyl)-3-cyanoformazan occurring on cetyltrimethylammonium bromide micelle

The microsurface adsorption-spectral correction technique (MSASC) has been applied to investigation of the ternary interaction of 1,5-di(2-hydroxy-5-sulfophenyl)-3-cyanoformazan (DHSPCF) with cetyltrimethylammonium bromide (CTAB) and rare earths Y, Eu, Dy and Yb. The CTAB micelle enriched DHSPCF molecules on its microsurface in monolayers and then sensitized the complexation between rare earths and DHSPCF. The binary aggregate and the ternary complex both were characterized.     

Activation analysis of rare earths : Part II. Determination of lutetium in gadolinite

Two precise and accurate methods for the determination of lutetium in the presence of other rare earths and after separation from a mineral, gadolinite, are described. Both methods require separation of lutetium and ytterbium from the other rare earths. A complete separation of Lu and Yb is necessary when integral counting is used. The other method differentiates between the two elements by γ -spectrometry.     

稀土对肝脏作用的机制

综述了稀土对肝脏作用的机制，稀土不仅能引起肝脏形态学的改变，当稀土进入肝细胞后可与多种蛋白质等分子发生相互作用，并影响多种酶的活性，还能通过信使分子干扰肝脏正常的生理功能。     

High speed separation of the light rare earths on centri-fugally accelerated ion-exchange paper

The separation of the rare earths, La, Cc, Pr, Nd, Sm and Y on centrifugally accelerated Amberlitc SA-2 cation-exchange paper was studied. All combinations of the elements can be completely separated except the Pr-Nd pair by using as cluant glycolic acid of a 'properly-chosen concentration (0.30 or 0.40 M) and pH (3.0 to 4.5). The Pr-Nd pair can be partially separated. The average number of ligand glycolato ions per rare earth ion in the resin phase was determined for each rare earth over the pa range 0.7 to 1.0.     

多壁碳纳米管对稀土元素的吸附性能

研究了改性多壁碳纳米管(MWCNTs)对稀土元素的吸附。 采用硝酸、次氯酸钠、过氧化氢、高锰酸钾4种方法对MWCNTs进行改性,考察了改性MWCNTs对稀土元素的吸附能力。 采用紫外-可见分光光度法测定稀土元素的浓度,比较了未处理和不同方法处理的MWCNTs对稀土元素的吸附能力。实验结果表明,NaClO改性的MWCNTs对稀土元素的吸附能力最强。以稀土元素钐(Sm)、钆(Gd)、镱(Yb)为代表,研究了NaClO改性MWCNTs对稀土元素的吸附性能。 考察了溶液pH值、离子强度、吸附剂用量、温度等因素对吸附性能的影响。当溶液pH值在2~7范围内,NaClO改性的MWCNTs对Sm、Gd、Yb的吸附随pH值增大而增强。 当离子强度和MWCNTs的用量增大时,对稀土元素的吸附能力降低。3种元素在NaClO改性的MWCNTs上的吸附均为放热过程,其反应焓变ΔH分别为：-6.44、-5.63和8.31 kJ/mol。吸附等温线符合Langmuir和Freundlich等温吸附方程。     

Chelating resins for the concentration of trace elements from sea water and their analytical use in conjunction with atomic absorption spectrophotometry

An investigation has been made of the uptake of trace elements from both distilled water and sea water by the chelating ion-exchange resins Chelex-100 and Permutit S1005. The resins retained the following elements with an efficiency of ca. 100%: Ag, Bi, Cd, Cu, In, Pb, Mo, Ni, rare earths, Re (90% only), Sc, Th, W, V, Y and Zn. Manganese was retained quantitatively only by the Chelex resin. The following elements are removed with 100% efficiency by means of₂N mineral acids: Bi, Cd, Co, Cu, In, Ni, Pb, rare earths, Sc, Th, Y and Zn. Ammonia (4 N) completely removes molybdenum, tungsten, vanadium and rhenium. The resins have been used in conjunction with atomic absorption spectrophotometry for the simultaneous determination of zinc, cadmium, copper, nickel and cobalt in sea waters.