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A geochemical study of rare earth elements (REEs), uranium (U), thorium (Th) and major elements was conducted in mylonitic rocks found in north Abu Rusheid, south eastern desert, Egypt, a well-known uranium ore deposit area. The concentrations of REEs, U, and Th were measured using inductively coupled plasma mass spectrometry. ∑REEs varied from 38 to 183 µg/g with a mean value of 90 µg/g. U and Th concentrations varied from 67 to 171 and 98 to 454 µg/g, respectively. The mean value of the U/Th ratio was higher than the upper continental crust value and the mylonitic rocks were concluded to have high U content. [ABSTRACT FROM AUTHOR]

The paper presents data on selecting curium and americium simulants for the lab-scale development of a displacement complexing chromatography-based separation technique. Being eluted with the eluents based on DTPA and a mixture of DTPA and citric acid, the rare earth element holmium behaves exactly as curium and terbium—as americium. Conversely, the tracer additives of transplutonium radionuclides are a perfect option for rare earth separation studies. [ABSTRACT FROM AUTHOR]

Joint application of energy dispersive X-ray fluorescence analysis (EDXRF) and instrumental neutron activation analysis (INAA) was considered to determine the contents of sixteen rare earths elements (REE) in the corresponding mineral resources. K series of the majority of REEs was excited by the bremsstrahlung of the X-ray tube operating at accelerating voltage 70 kV, the modified version of a portable X-ray spectrometer is equipped with. A range of ore samples collected from three REE deposits of the Republic of Kazakhstan essentially differing in their elemental composition was investigated. A way of EDXRF and INAA optimum integration to analyze REE resources was proposed taking account of the advantages and drawbacks of both methods. [ABSTRACT FROM AUTHOR]

The behavior of 88Y, 152Eu, 228Ac, 241Am, and 244Cm was studied with 2-thenoyltrifluoroacetone resin with batch uptake, kinetics and column studies. Studies were performed in acetate buffer solutions (pH ~ 2 to ~ 6) and there was high uptake of all isotopes, except 228Ac, at pH > 4.5. The kinetics of uptake were reasonable, although slower for the actinides, and sufficient for column studies. The retention of 88Y, 152Eu, and 241Am on the resin in column studies was demonstrated as well as a reasonable separation of these isotopes from 228Ac. [ABSTRACT FROM AUTHOR]

Applications for machine learning (ML), deep learning, and other artificial intelligence models have shown great promise in nuclear physics, including not only in classification systems but also in the analysis of numerical data. This study used various ML algorithms to estimate the concentrations of six rare earth elements (Sm, La, Ce, Sc, Eu, and Tb) in both archaeological and marine sediment samples. An interesting aspect of this analysis is that 80% of the 235 data points were used for training data, which included two parameters: specific activity ( A sp ) and concentration (ρ ) by the k0-method for the purpose of model development. The remaining 20% of the dataset was held out for testing the model's accuracy. The fundamental principle of this approach is the use of regression analysis between A sp and ρ to construct a machine learning regression model. This machine learning model was subsequently applied to estimate element concentrations based on A sp values obtained from gamma spectra. The mean absolute error (MAE), root mean square error (RMSE) and the statistical measure R-squared (R2) were employed for evaluating the accuracy of the predicted models. The random forest (RF) algorithm produces smaller MAE and RMSE values and achieves better R2 values compared to other algorithms. In addition, RF shows the lowest relative bias of the concentration values of elements in reference material (NIST 2711a) compared to other prediction models. The work focuses on demonstrating that machine learning models can effectively predict the concentrations of rare earth elements, even though this is a fundamental issue in NAA and one previous study has addressed this issue for one single element. The extension of the current work and potential directions for further development will be presented in the results and discussion section. [ABSTRACT FROM AUTHOR]

The removal of rare earth fission products and thorium from LiCl–KCl system is of great significance to purification and recovery LiCl–KCl during pyroprocessing flow. The removal efficiency of rare earth elements or thorium was investigated by adding precipitant Li3PO4 in LiCl–KCl molten salt. The characteristics of precipitation products were determined by XRD, SEM, and EDS analysis and the removal ratios of rare earth elements were compared under different conditions. The removal ratio of Th and rare earth elements (except Eu) can reach 95% when adding a slightly excess of Li3PO4 at 823 K. About 50% LiCl–KCl was entrained after precipitation reaction in mixture salt containing 20wt%ThF4, which showed the potential challenges to achieve the removal of Th and rare earth and the recovery of LiCl–KCl salt in the actual process. It is expected that the combination of precipitation and distillation method can improve to efficiently recover the LiCl–KCl mixed salt. [ABSTRACT FROM AUTHOR]

Separation of thorium, uranium, and rare earth elements (REEs) requires selective materials with high capacity, good thermal, chemical and radiation resistance. For this aim, Zr, Si and Ti oxide nanoparticles (NPs) have been prepared using metal alkoxide precursors via hydrothermal method. Polyacrylonitrile (PAN) was used as a supporting material to obtain nanocomposite (NC) beads for the potential use in industrial scale applications. The surface characteristics and morphological properties of nano metal oxide powders and composites were determined. Metal uptake and separation studies of thorium and REEs were carried out from sulfuric acid leach solution of Beylikova ore. [ABSTRACT FROM AUTHOR]

The uptake behavior of 88Y, 140Ba, 140La, 141Ce, 152Eu, 228Ac, and 241Am was studied with batch uptake, kinetics and column studies in a synergistic extraction system with Pb resin and 2-thenoyltrifluoroacetone in acetate-ethanol solutions. The k′ values are very high (> 10,000) at near neutral pH (~ 5 to 6) for all of the radioisotopes studied. The kinetics are reasonably fast for column separations, though the uptake rate is dependent on the concentration of 2-thenoyltrifluoroacetone. Column studies were performed to demonstrate the separation of the trivalent actinides and lanthanides from barium and common fission products (99Mo, 103Ru). [ABSTRACT FROM AUTHOR]

Two samples of zircon concentrate by local manufacturers were investigated for the first time for their rare earth elements (REE) content by instrumental neutron activation analysis (INAA) and energy dispersive X-ray fluorescence analysis. Comparator variant of INAA based on an external standard (Fe) and two internal standards (Th, La) was used to determine the elements divided into three groups depending on the detector type, radionuclide half-lives, and suitable comparator. High Y and heavy REE contents of the samples exceeding their crustal averages up to two orders of magnitude confirmed significance of the zircon concentrate as an important source of these elements production as a by-product. [ABSTRACT FROM AUTHOR]

In this study, a synthetic BaSO4·CaSO4 composite was prepared by co-precipitation technique, characterised and examined for REE sorption. The sorption parameters were; pH = 4, equilibrium time = 20 min, temperature = 303 K, and REE liquor volume to composite mass ratio of 0.2:1 L g−1. The sorption reaction was controlled by pseudo 2nd order kinetic mechanism and Langmuir adsorption isotherm with an adsorption capacity of 168.63 mg g−1. 90.14% of REE (III) was desorbed using 1 mol L−1 HNO3. The process was endothermic and spontaneous. Accordingly, 1:1 barite-gypsum (natural ingredient for BaSO4·CaSO4), with 136 mg g−1 loading capacity, was used for REEs extraction. [ABSTRACT FROM AUTHOR]

The separation of the rare earth elements is essential for numerous scientific applications but remains a significant challenge due to the nearly identical chemical properties of the adjacent lanthanide elements. Eichrom’s LN series of extraction chromatographic resins feature organophosphorus extractants and are widely used to achieve adjacent lanthanide separations. While extensive characterization of these resins has been completed for nitric acid matrices, the use of hydrochloric acid is preferred for a variety of applications. The extraction of the rare earth elements, La–Lu and Y, has been characterized on LN and LN2 resins in hydrochloric acid via batch uptake and column chromatographic studies. [ABSTRACT FROM AUTHOR]

A method has been developed for the determination of Rare Earth Elements (REEs) in ferrocarbonatite using Inductively Coupled Plasma—Atomic Emission Spectrometer (ICP-AES) and Inductively Coupled Plasma—Mass Spectrometer (ICP-MS). The conventional dissolution procedures are tedious, with large measurement uncertainty and are thus not suitable for certified reference material (CRM) production and exploration of REEs. The described method involves leaching of sample using 3 M HCl followed by dissolution of residue (silica and REEs) by HF then determined REEs using ICP-AES and ICP-MS. The leaching step prevents formation of fluoride precipitates of matrix (Ca, Mg, Ba and Al). The method has been validated using CRMs. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) are important tracers used in the modeling of various geochemical processes. This work aims to establish the current contents and geochemical pattern of uranium and rare earth elements in the soil of Ras Tanura, Saudi Arabia. The instrument utilized was the ICPE-9820 Shimadzu Japan, which employs inductively coupled plasma optical emission spectrometry (ICP-OES) to measure eight REEs (Eu, Hf, La, Lu, Sm, Tb, Yb, and Ce) and uranium. The values of uranium concentrations ranged from 0.07 to 5.72 mg/kg with an average of 3.30 mg/kg. The concentrations of rare earth elements (mg/kg) varied from 6.35 to 0.25 for Eu, 21.2–0.53 for La, 1.74–0.11 for Lu, 5.14–0.20 for Sm, 13.6–0.64 for Tb, 6.42–0.07 for Yb and 13.4–0.87 for Ce. The contents of REEs were in the following arrangement: La > Tb > Ce > Eu > Yb > Sm. The Eu/Sm and La/Lu ratio values ranged from 1.17 to 1.52 and 0.56 to 1.24, respectively. The measured data were compared with similar studies worldwide. This study provides valuable insights into the current status of uranium and rare earth element concentrations in the soil of Ras Tanura, Saudi Arabia. The results can be used to model geochemical processes and serve as a baseline for future environmental monitoring and assessment in the region. [ABSTRACT FROM AUTHOR]

The present study focuses on investigating the conditions for acid leaching of Th and REEs and sequential oxalate precipitation to remove impurities from leach liquor. The effects of preheat treatment, leaching time, liquid/solid ratio, and acid concentration on Th, Sm, Pr, Nd, Ce, La, and U leaching yields were investigated. The best results were obtained at 400 °C preheated sample using 1 mol/L H2SO4, liquid/solid ratio of 1 mL/g, 60 min leaching time, and 30 °C leaching temperature. The leaching yields of Th, Sm, Pr, Nd, Ce, La, and U were found to be 41.7, 65.0, 68.2, 66.9, 84.3, 82.6, and 55.0% respectively. Th and REE liquors were treated with 0.5–1.5 mol/L H2C2O4 solutions in the precipitation step. Purity was enhanced through three sequential precipitation cycles, resulting in a purity grade of 98.59%. [ABSTRACT FROM AUTHOR]

Rapid and efficient isolation of individual rare earth element (REE) radioisotopes from complex mixtures is necessary to support the fields of nuclear forensics, medical isotope production and nuclear physics measurements. The separations must be robust and generate sufficiently high purity samples for subsequent radiological analysis. Current methodologies utilize a laborious two step Ce(IV)-iodate precipitation followed by Ce(IV)-nitrate di-(2-ethylhexyl)phosphoric acid/n-heptane extraction. This work reports an alternative method to isolate Ce fission product isotopes equilibrated with milligrams of cold carrier, from the remaining REE's using a Ce(IV)/LN-resin (Eichrom Technologies) based separation. Optimization of Ce(IV) loading, REE(III) elution volume and subsequent Ce(III) stripping step utilized 166mHo tracer. Mixed fission product experiments provided a further test of this LN-resin method, with analysis of purified 141/144Ce, 147Nd and 91Y. While decontamination factors were lower for the LN-resin method, (vs. the combined precipitation/extraction) the simplicity of the technique and the satisfactory fission product analysis results point to the efficacy of this method. [ABSTRACT FROM AUTHOR]

Utilization of actinides and rare earth elements is only possible by separating these metals with high purity. The materials used in separation must have thermal, chemical, mechanical, and radiation resistance. In the present study, separation experiments of actinides and rare earth elements (REEs) were carried out using purified H2SO4 leach liquor. Polyacrylonitrile (PAN)-supported Ti, Zr, and Si oxide nanocomposites were tested for the selective separation of Th, U, Gd, Eu, Sm, Pr, Nd, La, Ce, and Y. The effects of pH, contact time, adsorbent/solution ratio, and temperature on distribution coefficient (KD) and adsorption capacity (Q) were investigated. The synthesized nanocomposites tend to separate the elements into two main groups: Th, U, Gd, Eu and Sm, Pr, Nd, La, Ce. Notably, it was observed that the separation of Th and U from the remaining elements is promising at 15 °C. Additionally, the separation can be further improved depending on the differences in desorption efficiency. [ABSTRACT FROM AUTHOR]

The present work is concerned with preparing pure oxides of U, Zr, Th and REE from Abu Dob mineralized pegmatitic rock. The dissolution kinetic profiles were assigned to chemical reaction model for all interesting elements. The calculated apparent activation energy was 33.8, 23.67, 22.5, and 24.40 kJ mol−1 for U, Zr, Th, and REE respectively. Almost complete U extraction (99%) and 90.2% of Zr were first achieved using Alamine 336 at pH 0.8. Furthermore, Th was selectivily separated from REE in the raffinate solution through its precipitation using MgO followed by REE precipitation as oxalates at pH 1.1. [ABSTRACT FROM AUTHOR]

This paper reported creating the all-chromatographic technique for the recovery of americium radionuclides from solutions of the complex composition generated in the radiochemical industry. The technique was based entirely on the displacement complexing chromatography; neither additional precipitation nor extraction stages were necessary. The technology used the elution with DTPA and NTA-based solutions containing the citric acid additives and the sequential elution with these eluents, emphasizing the separation of americium from the heavy rare earth elements, lead, and cadmium. The complete separation of americium from lead and cadmium was a peculiar exercise; the elution order of lead and cadmium changed in the presence of the citric acid additives. The recovery and separation of americium from actual radioactive waste solutions of different origins demonstrated 96 and 99% chemical purity of the final product. [ABSTRACT FROM AUTHOR]

Measurement uncertainty (MU) associated with the determination of the light rare earth elements (La, Ce, Pr, Nd, Sm, Eu), yttrium and uranium in different types of rock samples by an ICP-OES method has been evaluated by the three principal approaches: the GUM modelling approach, the Nordtest single laboratory approach and the Horwitz equation. A within-laboratory validation data for specificity, linearity, range, accuracy and precision was used for the MU calculations. Procedures have been described for the MU calculations by the three approaches and MU results for an in-house rock sample by the three approaches have been compared. MU results by the GUM approach were in good agreement with those obtained using the Horwitz equation, but were lower than those obtained by the Nordtest approach. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate temporal variability of rare earth elements (REE) in soils of citrus agroecosystems. Instrumental neutron activation analysis was applied for measuring La, Ce, Nd, Sm, Eu, Tb, Yb, Lu and Sc. Sampling was performed in four citrus farms, with Valencia variety (Citrus sinensis L. Osbeck) grafted onto 'Rangpur' lime (Citrus limonia Osbeck), comprising both organic and conventional production systems in the Borborema region, São Paulo State, Brazil. There was slight temporal variability of some REE in different farms, however no clear positive or negative trend could be observed along the 3 years. [ABSTRACT FROM AUTHOR]

This study was aimed at developing methodology for the characterization and differentiation of iron ores from different ore deposits. X-ray diffractometry (XRD) was used for the determination of major and minor chemical phases in the ores, k0-instrumental neutron activation analysis (k0-INAA) and inductively coupled plasma optical emission spectrometry (ICP-OES) were employed for the determination of elemental profiles of iron ores. The quality of the ores was evaluated to establish their suitability to serve as a raw material for iron production. Principal component analysis was performed on the elemental data for the classification of ores. It was also shown that ores can be differentiated on the basis of rare earth elemental profiles. In this paper a new indicator, based on four elements (Ca, S, Sb, Yb), was proposed for the classification. [ABSTRACT FROM AUTHOR]

The process of curium and americium separation from solutions after spent fuel reprocessing by displacement complexing chromatography on sulfonic cation exchange resins was reported. Separation runs were performed using a 2-stage chromatographic process sequence. Stage 1 constituted the primary purification and produced the enriched trans-plutonium elements (TPE) concentrate by means of removing the principal quantity of light rare earth elements, namely, La, Ce, Nd, and Pr. Deep refining of the TPE concentrate from the residual chemical and radiochemical impurities was performed at Stage 2. The paper reports the results of three experimental cycles of americium and curium separation. The best results were obtained in Cycle 3, where the key factor was the application of the monodispersed Tokem-308 cationite. The purity of curium in the fraction containing 50% of the feed curium-244 was 99% relative to americium. About 60% of the enriched americium-241,243 fraction contained < 0.1% of Eu-154,155 by radioactivity and < 0.8% of Cm-244 by mass. [ABSTRACT FROM AUTHOR]

The study shows geochemical characterization of placer deposit in parts of coastal Odisha, India using Instrumental Neutron Activation Analysis (INAA). Twenty seven elements were estimated in ten heavy mineral beach sand samples. The characterisation was mostly based on the trace element, radioactive element and Rare Earth Element (REE) content of the bulk sand samples. The results indicate elevated concentration of thorium and the REE's. The concentration of Scandium has been reported for the first time along this area. Positive correlation between thorium and REE was observed in beach placer samples collected from study area. [ABSTRACT FROM AUTHOR]

Separation of rare earth elements (REE) as a model system for transplutonium elements (TPE) partitioning via displacement complexing chromatography technique was investigated using sulfocationites commercially available from Purolite (UK), Dow Chemical (USA), Rohm and Haas (USA), and LLC SPA ‘Tokem’ (Russia). The specific volume, total mass and volume capacity of the sorbents were determined. Effects of the dispersity (monodispersed and polydispersed), grain size and cross-linking degree on the REE and TPE separation performance were discussed. Materials and conditions for the highest REE and TPE separation process efficiency were selected. [ABSTRACT FROM AUTHOR]

The paper deals with two rare earth elements (REE) concentrates recovered from uranium leach liquors after sorption separation of uranium. Activity of the REE concentrates was found to be 106 Bq kg−1; Ac-227 and its short-lived daughter products were the main radioactive impurities contributing more than 99% of total activity. Activity of both U-238 + Th-232 in the REE concentrates did not exceed 0.2% of total activity. Extraction by 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (P-507 extractant) in Shelsol D90 diluent was suggested for REE deactivation. It was shown that thorium may be eliminated by extraction in strong acidic media (pH − 0.5 to − 1), whereas radium extraction was suppressed over the whole studied pH range. Further REE separation to heavy and light groups at pH 1 resulted in selective concentration of actinium in light REE group. The suggested separation flowsheet was tested on the real REE concentrate. It was shown that obtaining non-radioactive fraction of heavy REE is possible. [ABSTRACT FROM AUTHOR]

Previously unknown hexauranates M[(UO)O(OH)]·7HO (M-Nd, Sm, Eu, Gd, Dy) were obtained by reaction of UO·2.25HO with aqueous solutions of M(NO) under hydrothermal conditions at 200 °C. Composition and structure of these compounds were defined, processes of dehydration and thermal decomposition were studied, the state in aqueous solutions was investigated. Solubility data were used for calculation of solubility products and standard formation Gibbs functions of M[(UO)O(OH)]·7HO. The theoretical solubility curves of studied compounds depending on pH were calculated, U(VI) and M(III) speciation diagrams both in aqueous solutions and equilibrium solid phases were plotted. [ABSTRACT FROM AUTHOR]

The variation in thermophysical properties along the lanthanide series for REUO(s) was investigated. Structural characterization of ErUO(s) was carried out by Rietveld refinement method. The trend in heat capacity along the rare earth series for REUO(s) and REO(s) as function of ionic radius of RE was found to be similar. Hence, the sole cause of excess heat capacity in rare earth uranates was concluded to be the rare earth ion. Linear relation was found between the thermal expansion coefficient of REUO(s) (RE = La, Gd, Lu) and the ionic radii of rare earth ion. [ABSTRACT FROM AUTHOR]

Chondrites are the most frequently studied extraterrestrial material. We present new data on the concentrations of 43 major and trace elements found in the Uhrovec, Veľké Borové (Nagy-Borove), Rumanová, Košice and Chelyabinsk meteorites, which were analyzed using INAA. The results are in good agreement with the mean data for an average ordinary chondrite of the respective class; normalization of the values to CI chondrites also showed similar outcome. Additionally, for the Rumanová, Košice and Chelyabinsk meteorites, INAA results of the bulk chemical composition are reasonably consistent with the data obtained by the same and/or different methods published earlier. [ABSTRACT FROM AUTHOR]

Instrumental neutron activation analysis (INAA) of soil, coal, water, and crops from the village of Awdarda in the North Gondar, Ethiopia, where the residents suffer from various disabilities, was performed in an attempt to elucidate the existing health problems. More than forty elements were determined in the samples analyzed. Comparison of our results with literature values indicates highly elevated contents of terrigenous elements in Awdarda cereals, possibly due to contamination by excavation and indoor combustion of local coal-bearing sediments. Impact is discussed of the elevated aluminium and the rare earth elements levels in crops on the health problems. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) have several applications and their market demands have increased. Recently, coal fly ash (CFA) has been considered as a source of these elements. The purpose of this study was to evaluate the REEs content in a CFA from a Brazilian coal power plant by instrumental neutron analysis, to classify it according to commercial purposes and to assess the weathering impact in the REEs content, since it is held in fields nearby the power plant. The results pointed no significant REEs leachability and indicated this CFA as a promising REEs source. [ABSTRACT FROM AUTHOR]

Uranium determination by delayed neutron activation analysis is carried out by comparing the delayed neutron counts of a test sample to those of a uranium standard irradiated under identical conditions. Inaccurate results are obtained at high uranium concentrations (greater than approximately 0.05 mg U), due to the deterioration of the linear relationship between delayed neutron counts and uranium content, and also when the sample matrix contains other elements that are neutron enhancers or absorbers, for example rare earth elements. In this paper, a correction method has been developed for the accurate analysis of samples with high uranium content (e.g. uranium peroxide). A second correction method, based on the thermal neutron self-shielding calculation developed by Chilian et al., has been applied to DNAA for the first time to correct for neutron absorption interferences in uranium analysis of rare earth-containing samples. [ABSTRACT FROM AUTHOR]

Radiopharmaceuticals based on Y are widely used for therapeutic purposes. Several experimental studies have been reported on adsorptive separation processes for recovery of Y, however there has been relatively less theoretical study on adsorption mechanism of Sr-Y group. We have attempted to carry out theoretical studies on adsorption of Y(III) and Sr(II) with N, N, N', N'-tetraoctyldiglycolamide (TODGA) using density functional theory. Adsorption energies are strongly dependent on charge transfer from TODGA to empty valence orbitals of the metal ions. This work might provide a theoretical basis for designing highly effective adsorbent for rare earth elements separation. [ABSTRACT FROM AUTHOR]

Naturally occurring radionuclides and Cs were measured in a sediment core and surface deposit collected from the bed channel of the Oualidia Lagoon located in the western Morocco. Major and rare earth elements (REE) profiles were determined by instrumental NAA technique. Pb and Cs were used to establish the sedimentation chronology over the last decades by using conventional models. Pb displayed relatively higher concentrations and rate of supply to the sediment than typical levels found in other coastal areas in Morocco. REE ratios and Ce anomalies showed that the direct incorporation of particles from seawater to the bed sediment is the most important, followed by the terrigenous component. [ABSTRACT FROM AUTHOR]

Elemental concentrations of contaminated sediment samples were determined by instrumental neutron activation analysis, particle induced X-ray emission and particle induced gamma-ray emission. Sediment samples were collected from the Godavari estuary, Kakinada Bay, East Coast of India. A total 35 elements were determined through the aforementioned analytical techniques. International Atomic Energy Agency reference materials including SL-1, SL-3 were used for method validation. Hazardous elements such as As, Ba, Cr, Mn, Fe and Zn were compared with United States Environmental Protection Agency data and previous studies data to determine their preliminary contamination levels in Kakinada Bay. [ABSTRACT FROM AUTHOR]

In this paper an accurate and highly reproducible separation method for determination of trace amounts of uranium and rare earth elements (La-Lu and Y; abreviated as REEs) in the refractory zircon mineral concentrates by inductively coupled plasma-optical emission spectrometer (ICP-OES) is described. The precipitation method used for separation of zirconium is simple, selective, rapid and environmental friendly. All the 16 geochemically important analytes were determined in a single solution with marginal improvement in detection limits (1.2-4.5 times) after separation. The method was validated by analyzing certified reference materials. [ABSTRACT FROM AUTHOR]

The mutual separation of rare earth elements based on the ion exchange chromatography has been studied. The effect of alcohols on separation behavior of rare earth elements using the benzimidazole-type anion-exchange resin embedded in high-porous silica beads was investigated in nitric acid/alcohol mixed solvent systems. It was confirmed that the mutual separation of rare earth elements is possible by using our proposed methods. It was found that the distribution coefficients of rare earth elements depend on the corresponding alcoholic relative permittivity and on the steric hindrance due to the hydrophobic interaction among each alcoholic molecule. [ABSTRACT FROM AUTHOR]

Multielements, including some rare earth elements, have been determined by k -NAA in three types of ore reference materials from Australia Nuclear Science and Technology Organization. The samples were irradiated in China Mianyang Research Reactor. High purity iron wire and Zr foil were used to monitor the neutron spectrum parameters ( f, φ ) at irradiation positions. Uranium fission interferences for Nd, Ce, La were determined and corrected for by Ik method. The effective interaction depth was employed to normalize efficiencies at different counting positions. The results are in good agreement with the values reported other laboratories. [ABSTRACT FROM AUTHOR]

A study is carried out on the concentrations of rare earth element (REE) elements present in surface mangrove sediments from 10 locations throughout west coast Malaysia. In carrying out the analysis, the best and most convenient method being the instrumental neutron activation analysis (INAA). Samples were obtained, dried, crushed to powdery form and samples prepared for INAA. All the samples for analysis were weighted approximately 150 mg for short irradiation and 200 mg for long irradiation time. As calibration and quality control procedures, blank samples, standard reference material SL-1 were then irradiated with thermal neutron flux of 4 × 10 cm s at the MINT TRIGA Mark II research reactor which operated at 750 kW by using a pneumatic transport facility. The REE elements of surface sediment samples in this study are Dy, Sm, Eu,Yb, Lu, Tb, La and Ce. It was found that the level of concentrations of all the REE elements varies in the range (0.35-117.4 mg/kg). The geochemical behavior of REEs in surface sediments and normalized pattern (chondrite and shale) has been studied. The degree of sediments contaminations were computed using an enrichment factor. The results showed that the enrichment factor varied in the range (0.75-6.75). [ABSTRACT FROM AUTHOR]

Delayed neutron activation analysis (DNAA) is a rapid and sensitive analytical method for the determination of fissile elements in a variety of samples. The present work describes two different analytical applications of delayed neutron activation for the analysis of biological and environmental samples, respectively. In the first application, DNAA was utilized to determine the natural uranium content in NIST standard reference materials (SRM) 1547 peach leaves and 1573a tomato leaves. Measured uranium mass fractions are comparable to the non-certified values listed on the certificates for these materials. In the second application, delayed neutron activation is coupled with instrumental neutron activation analysis (INAA) for the measurement of rare earth elements (REE) (cerium, lanthanum, neodymium, and ytterbium) in NIST SRM 2586, Trace Elements in Soil Containing Lead from Paint. DNAA was utilized to determine the uranium mass fraction in SRM 2586 for the subsequent application of a correction factor to account for cerium, lanthanum, and neodymium produced as part of the INAA irradiation. Measured and corrected mass fractions for the REEs described here are all within the uncertainty limits provided on the NIST certificate for SRM 2586. These results and the demonstrated sensitivity of the DNAA system establish and validate the use of this method for the determination of REEs and for potential nuclear forensics applications. [ABSTRACT FROM AUTHOR]

One-hundred-two years ago, on 21 April 1910, the Austrian chemist Carl Auer von Welsbach published a short comment on a fundamental discovery he had made in the field of nuclear sciences. He reported that 'jonium' (Th) was able to induce radioactivity in other materials if stored in contact with the ionium sample. He was well aware that this observation was 'not quite in agreement with current theories', because, as a basic principle, a radioactive substance cannot activate an inactive substance. Since he could not remove any superficial contamination, he concluded that the previously inactive materials had become radioactive themselves. Auer von Welsbach predicted that this observation 'might be of importance for the mysterious field of radioactivity research'. In fact, we believe that in this experiment he incidentally discovered neutron activation and the production of artificial radionuclides (24 years before I. Curie and F. Joliot) or even induced nuclear fission. The neutron source in his experiments is yet unknown and shall be identified in this project. The neutrons could have been produced from nuclear reactions with impurities of beryllium in the sample. Auer von Welsbach may even have observed nuclear fission 29 years before O. Hahn, F. Straßmann, L. Meitner and O. R. Frisch. In any case, he may have noticed the effects of neutron radiation-22 years before its discovery by J. Chadwick. The main aim of this interdisciplinary project (of which preliminary results are presented herein) is to repeat the 1910-experiment and to identify the source of the neutrons. It will be equally important to investigate the historical reasons and circumstances why Auer's report remained mostly uncommented in the scientific community. The hypothetical consequences are worth discussion: Auer's publication could have started the 'nuclear age' much earlier than it finally began, with all the consequences for mankind. [ABSTRACT FROM AUTHOR]

The uptake of lanthanide elements by naturally abundant materials, is a matter of great economic and environmental interest. This study is an exploration of the potential utilization of malt spent rootlets (MSR), which are by-products of malting process, for a cost effective pre-concentration of Eu(III). The effect of solution pH, contact time and initial concentration under constant ionic strength and temperature were studied. Kinetic data were applied to pseudo-first, second order and Elovich equations, as well as intra-particle diffusion model. Pseudo-second order and Elovich equation seem to fit our data equally well, whereas diffusion contributes to the whole process. Equilibrium data were evaluated using Langmuir, Freundlich and Dubinin-Radushkevich equations. According to Langmuir model, which fits the data better, europium maximum capacities for MSR and active carbon were found 156 and 86 mg/g respectively, indicating that MSR is a promising biosorbent. [ABSTRACT FROM AUTHOR]

A method has been developed for the analysis of rare earth elements (REEs) in kimberlite samples using inductively coupled plasma mass spectrometer (ICP-MS). The samples were dissolved using sodium peroxide fusion and after appropriate dilutions the solutions were analyzed using ICP-MS. The paper presents the concentration of rare-earth elements as determined by ICP-MS in eight kimberlite samples from Central India. The method was validated using certified reference materials STSD-1 and STSD-2 from Canadian Certified Reference Material Project. The method detection limit of various REEs varies from 0.12 to 1.54 mg kg. The total REE concentrations range from 418 to 726 mg kg and fall within the interval of those reported in the literature for kimberlites. Despite the marked difference in the REE contents, all the analyzed samples show similar REE patterns that resemble those for kimberlites. In order to compare ICP-MS results, the samples were analyzed using instrumental neutron activation analysis which is a reference method for determination of REEs in geological samples. [ABSTRACT FROM AUTHOR]

Native plant species, lichens and tailings, sampled from a copper-sulphide mining area located in southern-eastern Portugal, were analysed by neutron activation analysis (INAA) for determination of rare earth elements (REEs). Values of ΣREEs and individual REEs concentration of tailing samples are higher than those of natural background concentrations. The higher values of REEs are found in modern slags and the mixture of oxidized gossan and sulphide disseminated country rocks when compared with the alluvial sediments contaminated by mine tailings. The total concentrations of light REEs are higher than those of heavy REEs in all tailing samples. Distribution patterns of PAAS-normalized REEs in mine tailings show slightly LREE enriched and flat HREE pattern with negative Eu anomaly. Lichens accumulated higher concentration of lanthanides than vascular plants. The elevated levels of REEs in lichen, native plant species and tailing samples reflect the contamination of REEs in São Domingos mining area. The Carlina corymbosa, Erica australis and Lavandula luisierra accumulated the higher amounts of La, Ce and other REEs than the other plant species grown in this mining area. [ABSTRACT FROM AUTHOR]

Harbour activities such as loading, unloading and transport of materials may be an important source of Atmospheric Particulate Matter (APM). Depending on the materials, the type of operation and the meteorological conditions, these activities may have an impact on the levels of APM around harbour areas. The aim of this work was to characterize the emissions of dust providing from operations associated with phosphorite handling in harbours. Phosphorite is a non-detrital sedimentary rock which contains high amounts of phosphate bearing minerals and is used for the production of phosphorous based fertilizers. When handled in harbours frequently cause visual and environment impacts due to its physical and chemical characteristics. The techniques Instrumental Neutron Activation Analysis and Particle Induced X-ray Emission were applied as sensitive analytical tools for the determination of heavy metals and rare earth elements in phosphorite and in the APM sampled in the harbour during the unloading operations. Results showed that manipulation of phosphorite during harbour operations resulted in high emissions of particles, principally from the coarse fraction. These emissions were enriched in rare earth elements and heavy metals and were very affected by the provenience of the phosphorite. [ABSTRACT FROM AUTHOR]

In geochemistry, the distribution of the Rare Earth Elements (REEs) in earth crust and mantle allows to understand geochemical cycles and origin and age of igneous rocks. In this article REEs (Ce, Dy, Eu, La, Nd, Sm, Tb, and Yb), Th and U in ores of the North-Latium (Bracciano area, Ceriti Mt., Fate Mt., Sabatini Mt., Vulsini Mt., Acqua Rossa basin), have been investigated for evaluating the extraction feasibility for industrial applications. 107 samples were irradiated in the rotating rack of the TRIGA Mark II reactor of the R.C. Casaccia (ENEA) at neutron flux of 2.6 × 10 n × cm× s for 12 h together with primary and secondary standards. The gamma spectrometry measurements were performed after 8 h, 3 and 30 days of decay by means of HPGe detector (FWHM 1.75 keV at 1332.5 keV, peak/Compton ratio 55.1, relative efficiency of 22%) connected to a multi-channel analyzer. The total REE mean content is 105 μg g, ranging widely between 2.23 and 410.5 μg g (average coefficient of variation 112%). A similar behavior is found for Th and U: their average levels are 13.5 and 6.0 μg g, respectively. A quite good correlation between REEs and Th (and U) is found for Ceriti Mt. ( r > 0.8) whereas for the other areas the correlation is <0.7. The results obtained evidence the low U content in the investigated locations. [ABSTRACT FROM AUTHOR]

The availability of chemical elements for plants is mainly dependent on the nature of the soil and characteristics of each species. The transfer factors of lanthanides from the soil to the tree leaves of the Atlantic Forest, Brazil, were calculated for one fern species ( Alsophila sternbergii-Pteridophyta division) and four magnoliophytes species ( Bathysa australis, Euterpe edulis, Garcinia gardneriana and Guapira opposita-Magnoliophyta division) obtained in two areas of Serra do Mar State Park and collected in two different seasons. Samples were analyzed by instrumental neutron activation analysis (INAA). The soil-to-plant transfer factor (TF = C:C) in magnoliophytes species was correlated to the mass fraction of lanthanides in the soil, described by a exponential model (TF = a.C). Despite the tree fern Alsophila sternbergii presented a hyperaccumulation of lanthanides, this species did not have a significant relationship between TF and mass fraction in soil. Results indicated that plants of Magnoliophyta division selected the input of lanthanides from the soil, while the same was not observed in Alsophila sternbergii. [ABSTRACT FROM AUTHOR]

The Itingussú drainage basin is situated at 22°44′-22°55′ SL and 44°53′-43°55′ WL, in Coroa-Grande district, Sepetiba Bay, southwest of Rio de Janeiro, Brazil. Its total area is less than 10 km and includes a waterfall with three drop offs. The study area is located in a granitic pre-Cambrian embasement, discharging in a mangrove forest fringe. This work attempts to investigate the influence of lithology types in the elemental composition of soil of region and sediments of related mangrove. Instrumental neutron activation analysis and subsequent gamma-ray spectrometry were used. This technique enabled the measurement of at least twenty-one chemical elements. The more representative soil samples were enriched with U and Th. Multivariate Statistical Analysis showed that the soil and sediments formed in this area have been influenced by the leucocratic rocks, enriched with LREE and Th. The factorial analysis enables the identification of five factors of influence in the ordination of elements: presence of iron minerals (biotite); presence of allanite; marine influence in the sediment; differentiated kinetic of transport and diagenesis. [ABSTRACT FROM AUTHOR]

Using physicochemical methods we showed that continuous (15 days) exposure of monazite powder in humic acid (HA) solutions with different acidity gives rise to one to two orders of magnitude growth in the concentration of the monazite' p-, d- and f-elements of Periodic Table (Mg, Al, Si, P, Pb, Ti, Bi, Sc, Ti-Zn, REE, Th, U). The growth in the elements concentration in the humic solutions contacting monazite is shown to depend on the initial concentration of HA in the solutions, pH. It is concluded that these factors should be taken into consideration when inorganic phosphates and alike phases are used as a matrix for the radionuclide wastes solidification. [ABSTRACT FROM AUTHOR]

This work addresses the chemical features of topsoils from São Domingos mine, Portugal, an abandoned mining area since middle of twentieth century. The fractions below 1 mm of the surface-soil samples (0-15 cm) were measured by k-standardized, instrumental neutron activation analysis in order to determine the levels of rare earth element concentrations in comparison to control soils. A fractionation between the heavy and light rare-earth elements (REEs) occurred, with the latter enriched relatively to the first ones. The REEs pattern is similar in all sites with higher concentrations in the mine area as compared to the control site. The ratios between REEs are conventional for three subsamples but slightly diverge for the other sites. The REEs pattern is similar to one of the volcanic islands still with activity as Sao Miguel in Azores, Portugal, and similar to the one of an industrial area containing coal power plant and refinery. [ABSTRACT FROM AUTHOR]