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ASSESSING CYANEX 272 and BINARY EXTRACTANTS for the SEPARATION of PRASEODYMIUM and NEODYMIUM in EXTRACTION of ESKİŞEHİR – BEYLİKOVA RARE EARTH ORES
(Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu (TENMAK), 2024-04-26) Gezici, Utku Orçun; Baştürkcü, Esra; Arslan-Kaba, Mehtap; Ertürk, Selim; Sözer, Belma Soydaş; Kartal Şireli, Güldem; Timur, Servet
Rare earth elements (REEs) are essential in various industrial applications due to their high magnetic susceptibility, low density, and thermal stability. Praseodymium is used in producing yellow pigments for glass and ceramics, while Neodymium is crucial in producing powerful permanent magnets and laser applications. Technological advancements have driven the demand for Pr and Nd and increased the need for a reliable supply chain. The primary sources of Pr and Nd are minerals like monazite, bastnasite, and xenotime, which require complex separation processes due to their mixed contents. The main secondary sources include electronic waste, particularly from permanent magnets. The difficulty in the extraction of REEs lies in their closely related chemical and physical properties. Solvent extraction (SX), based on differences in ionic radii, is a widely used method for REE separation in industrial applications. Nevertheless, the similarity in Pr and Nd ionic radius complicates their separation compared to other REEs. This research examined the effectiveness of Cyanex 272 in the SX process for separating Pr and Nd, as well as its potential for improvement through the use of binary extractant combinations viz. Cyanex 572, Cyanex 801, Cyanex 923, as well as DEHPA. The synthetically prepared aqueous solution was composed of 400 ppm Pr and 800 ppm Nd. The extraction efficiency and selectivity were determined by using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The findings revealed that the loading efficiencies for Pr and Nd varied with the concentration of Cyanex 272, namely Pr loading efficiencies ranging from 5.5% to 24.4%, and Nd from 6.7% to 31.3%. Notably, binary extractant experiments indicated that mixtures incorporating Cyanex 272 with DEHPA, Cyanex 572, and Cyanex 801 exhibited enhanced extraction efficiencies compared with the sole Cyanex 272. On the other hand, the combination of Cyanex 272 and Cyanex 923 resulted in a diminished extraction efficiency. These obtained outcomes could potentially adapt to the development of domestic technology for the extraction of REEs from the Eskişehir Beylikova REE Ores.
Efficient Purification and Production of Rare Earth Metals from Bastnasite Ore: Beneficiation, Leaching, Solvent Extraction, and Metallothermic Reduction Approaches
(Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu (TENMAK), 2024-10-30) Koç Delice, Tülay; Türker, Gülşah; Kutluata, Onur Berk; Şeşen, Halil; Soydaş Sözer, Belma; Pıtıcescu, Radu Robert; Bogdanescu, Cristian
Rare earth elements (REE) are one of the indispensable raw materials of modern technologies and are used in many critical applications such as magnetic materials, catalysts and batteries. The economic and efficient recovery of REE from ores is of great importance to reduce global supply risks [1,2] This study investigates the production of high purity rare earth metals by physical pre-benefication, leaching, solvent extraction and metallothermic reduction steps applied in the process of recovery of rare earth elements from bastnasite ore containing rare earth elements. Bastnasite occurs naturally with fluorite, barite, calcite, quartz, hematite and some silicates. Various methods, mainly gravity separation, magnetic separation, flotation and electrical separation, can be used to extract these gangue minerals [3]. In the present study, bastnasite ore was subjected to crushing-grinding-sieving processes and pre-enrichment process was carried out. The direct leaching and roasting methods were applied to the screened ore and the pre-beneficatio ore sample with a particle size of -45 µm was then subjected to mineral acid leaching with and without roasting. The effects of roasting temperature, roasting type, acid type, acid concentration on the leaching efficiency of the pre-enriched ore concentrate were investigated. Solvent extraction parameters were investigated for the purification and selective recovery of REEs from the REE loaded solution obtained. In the following stage of the study, we focused on the production of high purity rare earth metals from rare earth oxides purified by solvent extraction by metallothermic method. The metallothermic process is based on a reduction reaction, usually using reactive metals such as Ca or Mg. In this study, neodymium metal (Nd) production by metallothermic reduction method using neodymium oxide (Nd₂O₃) obtained after solvent extraction process with 95%-97% Nd content is discussed. Mg was selected as the reactive metal. The reduction reaction was carried out in vacuum under high temperature conditions (800-1000°C). As a result of metallothermic reduction, high purity neodymium sponge was obtained.
Impact of Extractant Type and pH on Yttrium Recycling from End of Life Fluorescent Lamp
(Scopus, 2023-11-14) Koç Delice, Tülay; Türker, Gülşah; Obuz, Hüseyin Eren; Soydaş Sözer, Belma
Rare-earth elements (REEs), which are indispensable for high technology and renewable energy, are becoming more significant due to their distinct properties (e.g., catalytic, metallurgical, magnetic, etc.) and their diverse applications in a wide range of contemporary technologies, environmental initiatives, and economic domains. In the pursuit of an environmentally friendly, sustainable, circular approach, recycling and utilizing secondary rare-earth resources as potential reservoirs of REEs may present an alternative to primary mining, addressing future raw material demands. Secondary REE sources include various products such as fluorescent lamps, light-emitting diodes (LEDs), magnets, wind turbines, electric motors, and batteries. Powders used in fluorescent lamps contain approximately 3% phosphorus, and these powders comprise a high ratio of precious REEs such as Y, Eu, La, Ce, and Tb. This study involves the recovery of yttrium from end-of-life fluorescent lamps. The composition of the end-of-life fluorescent lamp was analyzed using X-ray fluorescence (XRF) and X-ray diffraction (XRD) techniques subsequent to grinding. The leaching process was conducted to investigate the effects of leach parameters on the efficiency of the reaction. In the subsequent phase of the study, a solution obtained with the optimum leaching efficiency was subjected to the purification of Y using the solvent extraction (SX) method. The effect of each different extractant and pH values on Y-recovery were investigated for SX process. Yttrium oxide powders were characterized by XRF and ICP(OES) techniques, and high-purity Y2O3 powders were obtained with high yield.
Mineralogic assessment of natural radionuclide rich beach sands in Western Anatolia (Çanakkale) Mineralogic assessment of natural radionuclide rich beach sands in Western Anatolia (Çanakkale)
(Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu (TENMAK), 2024-05-13) Yıldırım, Fatma Gülmez; Yıldırım, Aydın
Natural radioactivity concentrations in beach deposits and surrounding magmatic rocks at Ezine, Çanakkale, are notably high. The specific activities of 238U, 232Th and 40K are in the range of 40-361, 50-341 and 670-1572 Bq kg-1, respectively, for the magmatic rock suites. Bulk sand samples from the beaches exhibit even higher concentrations of natural radioactivity: Hantepe beach, located near the contact of Kestanbol pluton with pre-Tertiary basement units displays extremely high 238U (1885 Bq kg -1) and 232Th (4360 Bq kg -1) with the lowest 40K (687 Bq kg -1) activity concentrations. This enrichment at Hantepe beach was attributed to the U-bearing accessory minerals (zircon, apatite, thorite, uranothorite, monazite, etc.) selectively rich along the northern margin of Kestanbol Pluton. These minerals serve as Rare Earth Elements (REE) repositories, prompting an extensive investigation into the economic potential of radionuclide-rich beach sands at Ezine. In this study, gamma ray spectrometry measurements were conducted on fractions of beach sands to identify the source minerals of the radioactivity. The sand fraction concentrated in diamagnetic and felsic minerals (K-feldspar + Plagioclase ± Quartz) with grain sizes ≥ 250 µ, exhibits the highest 40K specific activity (1173.3 ± 133.5 Bq kg-1) but the lowest concentrations of 238U (176.4 ± 18.1 Bq kg-1) and 232Th series (197.8 ± 21.9 Bq kg-1). On the contrary, the fraction rich in paramagnetic and mafic minerals (Pyroxene + Amphibole + Biotite + Epidote ± Granat) with the grain sizes < 125 µm has the most elevated concentrations of 238U (884.5 ± 56.6 Bq kg-1) and 232Th (1332.9 ± 99.1 Bq kg-1) series and slightly elevated 40K (436.4 ± 50.3 Bq kg-1), compared to the Earth’s average. These findings suggest that the rock-forming minerals in the magmatic rocks are also responsible for the natural high radioactivity in the region. Batı Anadolu’da Ezine (Çanakkale) dolaylarındaki plajlara ait kumların ve plajların yakınındaki magmatik kayaların doğal radyoaktivite konsantrayonları oldukça yükektir. Magmatik kaya grupları için 238U serisi, 232Th serisi ve 40K spesifik aktiviteleri sırasıyla 40-361, 50-341 ve 670-1572 Bq kg-1 aralığındadır. Plajlardan derlenen dökme kum örneklerinde ise radyoaktivite konsantrasyonların daha da yüksek olduğu ortaya konulmuştur: Kestanbol plütonu ile Tersiyer öncesi temel kayaların sınırına yakın bir alanda konumlanmış olan Hantepe plajına ait kum örnekleri en yüksek 238U serisi (1885 Bq kg -1) ve 232Th serisi (4360 Bq kg -1) ile en düşük 40K (687 Bq kg -1) aktivite konsantrayonlarına sahiptir. Hantepe sahilindeki bu zenginleşme, Kestanbol Plütonu'nun kuzey kenarı boyunca seçici olarak zengin olduğu öne sürülen Uranyumlu aksesuar minerallere (zirkon, apatit, torit, uranotorit, monazit, vb.) atfedilmiştir. Bu mineraller, yüksek Nadir Toprak Elementleri (NTE) içeriklerine sahip olduklarından, Ezine'deki radyonüklid zengin plaj kumlarının ekonomik potansiyelleri önem kazanmıştır. Bu çalışmada, radyoaktivitenin kaynak minerallerini belirlemek için pplajlardan derlenen dökme kum örneklerinden elde edilen fraksiyonlar üzerinde gama ışını spektrometresi ölçümleri yapılmıştır. Tane boyutları ≥ 250 µm olan, diyamanyetik ve felsik minerallerin (K-feldispat+ Plajiyoklaz ± Kuvars) yoğun olduğu fraksiyonda 40K spesifik aktivitesinin (1173.3 ± 133.5 Bq kg-1) en yüksek değerlere ulaştığı, 238U (176.4 ± 18.1 Bq kg-1) ve 232Th serisinin (197.8 ± 21.9 Bq kg-1) ise en düşük değerlerde olduğu belirlenmiştir. Bununla birlikte, tane boyu < 125 µm olan, paramanyetik ve mafik minerallerce (Piroksen + Amfibol + Biyotit + Epidot ± Granat) zengin olan fazda ise 238U (884.5 ± 56.6 Bq kg-1) ve 232Th (1332.9 ± 99.1 Bq kg-1) serisi spesifik aktivitesinin en yüksek değerlere ulaştığı, 40K spesifik aktivitesinin ise (436.4 ± 50.3 Bq kg-1), Dünya ortalamasının hafifçe üzerinde olduğu tespit edilmiştir. Bu bulgular, magmatik kayalardan türeyerek plaj kumlarına katılan kayaç yapıcı minerallerin de bölgedeki yüksek doğal radyoaktivite değerlerinden sorumlu olduğunu gösterir.
Production of Metallic Lanthanum from Its Oxide Form via Molten Salt Electrolysis
(Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu (TENMAK), 2024-04-26) Özer, Osman Can; Arslan Kaba, Mehtap; Kartal Şireli, Güldem; Soydaş Sözer, Belma; Timur, Servet
Lanthanides, including the elements with the atomic number of 57 to 71, scandium, and yttrium are the seventeen chemically related elements known as rare earth elements (REEs). Despite their misleading name, “rare earth”, these elements are not rare in the Earth’s crust. Instead, the term refers to the challenge of separating and obtaining them in their pure form due to their similar chemical properties. REEs are crucial in a variety of high-technology applications, namely the military, the automobile industry, electrical engineering, optics, catalysts, wind turbines, and other sustainable energy systems, due to their exceptional physical and chemical properties. Because of the growing demand for REEs in functional materials, the recovery of REEs from secondary resources has become critical to the transition to a green economy. The primer REEs extraction process consists of mining, physical beneficiation, chemical treatments, separation, and reduction. In the reduction step, where REEs reduce to metal form, electrolytic methods (molten salt electrolysis) and metallothermic methods are prominently discussed in the open literature. Electrolytic methods can operate continuously and outperform metallothermic techniques in terms of production capacity and controllability, as well as product purity. Nowadays, two types of electrolytes are commonly used in the electrolytic production of REEs: fluoride- and chloride-based molten salts. The main issues with the widely used electrochemical extraction of rare earth oxides in fluoride-based molten electrolytes are lower solubility and lower energy efficiencies, as well as higher emissions of greenhouse gases, such as CO2 and perfluorocarbons, which are extremely harmful to the environment. Given the current limitations of fluoride systems, molten chloride-based electrolytes appear to be a preferable option. To achieve lower melting points (e.g., 650 °C) and higher product purities (i.e., 99%), common chloride electrolytes are composed of RECl3 (RECl3= rare earth chlorides) and additional chlorides, such as NaCl, KCl, BaCl2, and CaCl2. Thus, we concentrated on molten salts based on chlorides containing RECl3. To overcome the low solubility of rare earth oxides in molten chloride salts and toxic oxychloride formations, RECl3 salts were used. RE2O3 was converted to RECl3 in a separate system through chlorination. Furthermore, the need to work in a controlled atmosphere due to REEs high oxygen affinity made the electrolysis cell design critical. As a result, the electrochemical cell was designed and installed, and the effects of process parameters such as electrolyte composition, temperature, current efficiency, and electrolysis time were investigated systematically. X-ray diffractometry (XRD) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) were used to characterize the produced La. The maximum current efficiency was found to be 73.5%. These obtained results could potentially be implemented during the development of domestic technology for the electrolytic extraction of REEs from Turkey Eskişehir Beylikova REEs ores.
RECOVERY OF PLATINUM GROUP METALS FROM SCRAP AUTOMOTIVE CATALYSTS BY HYDROMETALLURGICAL METHOD
(IMNR, 2024-10-30) Kaya, Yasemin; Arda, Tuğba; Güldür, Fatma Çiğdem
Based on their economic importance and supply risk, platinum group metals (PGMs) are classified as critical elements by the European Commission. Meeting the increasing demand for PGMs is becoming more and more difficult due to the limited natural resources and depletion of high-grade ores [1,2]. A catalytic converter contains 0.1-0.5% PGMs such as Pt, Pd, and Rh, and the PGM content in catalytic converters is approximately a thousand times higher than the amount found in the ore [2]. For this reason, it is of great importance to obtain PGMs from non-traditional materials, such as scrap autocatalytic converters. This work aims to obtain high-efficiency, environmentally friendly, and economical PGM from the scrap catalytic converters with hydrometallurgical method. The scrap catalytic converter sample purchased from a Turkish supplier company in ground form was analysed to determine its PGM content. In order to investigate the roles of leaching temperature, T, solid to liquid ratio, S/L, and leaching time, t, the samples were treated with HCl and H2O2 solution under different leaching conditions. During leaching step, more than 98% Pt and Pd were taken into solution while Rh was leached more than 60% efficiency. Following the leaching step, the elements were separated from the leach solution by precipitation.
SELECTIVE SEPARATION of LANTHANUM USING DEHPA: INVESTIGATING THE POTENTIAL of EXTRACTING RARE EARTH ELEMENTS from ESKISEHIR BEYLIKOVA ORES
(Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu (TENMAK), 2024-04-26) Tunç, Melike; Gezici, Utku Orçun; Özer, Osman Can; Arslan Kaba, Mehtap; Soydaş Sözer , Belma; Kartal Şireli, Güldem; Kartal Şireli, Güldem; Timur, Servet İ.
Rare Earth Elements (REEs) are essential components of advanced technology applications such as renewable energy, electronics, and defense. Their unique magnetic, catalytic, and luminescent properties render them essential for the development of high-performance materials. However, efficient and selective separation of individual REEs is a significant challenge owing to their chemical and physical similarities. This study focuses on the selective separation of lanthanum (La) from complex mixtures of REEs as it is crucial for the sustainable extraction of Eskişehir Beylikova Rare Earth Ore. In this study, solvent extraction (SX), a critical method for separating REEs, was carried out by using di (2-ethylhexyl) phosphoric acid (DEHPA) as the extractant. The selection of DEHPA was done based on its proven efficiency in REE SX processes, which offers a balance between selectivity and extraction capacity. For this purpose, various DEHPA concentrations in the organic phase were studied to obtain the optimal conditions for the selective separation of La from the leach liquor. The synthetically prepared leach liquor contained 5000 ppm La, 400 ppm Pr, 800 ppm Nd, and 200 ppm Sm. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) was utilized to determine the precise ion concentrations in the initial and extracted aqueous phases which ensured the accurate assessment of the extraction efficiency and selectivity. These initial findings revealed that the loading pattern is as follows: initial larger ionic radius La3+ (1.16 Å) loaded than after Pr3+ (1.13 Å), Nd3+ (1.11 Å), and Sm3+ (1.08 Å) came. The organic concentration was prepared ranging from 0.03M to 0.9M in kerosene. The loading efficiencies for La varied from 1.95% to 84.5%, whereas those for Sm, Pr, and Nd varied from 77.61% to 100%, from 41.69% to 99.17%, and from 27.78% to 97.68%, respectively, with increasing DEHPA concentrations. The outcomes demonstrated the feasibility of selective separation of La from other REEs using 0.03M DEHPA. The obtained results could be potentially adopted for the domestic production of REEs in the Eskişehir Beylikova Rare Earth Ores.
SELECTIVE SEPARATION OF SAMARIUM FROM LIGHT RARE EARTH ELEMENTS via pH-CONTROLLED SOLVENT EXTRACTION
(Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu (TENMAK), 2024-04-26) Tunç, Melike; Gezici, Utku Orçun; Baştürkcü, Esra; Ertürk, Selim; Soydaş Sözer, Belma; Kartal Şireli, Güldem; Timur, Servet
Rare Earth Elements (REEs) are essential for advanced technologies due to their unique properties. This study presents a pH-controlled solvent extraction method to separate Samarium (Sm) from light REEs simulating Beylikova REE leaching liquid. The process, utilizing 0.75 M DEHPA in kerosene, showed that Sm achieved a 59% extraction efficiency at pH 0.5, significantly higher than La, Pr, and Nd. This pH optimization enhances the sustainability and efficiency of REE extraction, promoting the effective utilization of Turkey's REE resources and domestic technologies.
Shielding effect of boron carbide-tungsten carbide-aluminum metal matrix hybrid composite against different type of radiations
(SSRN, 2024-11-12) AKKAS, Ayhan; TUGRUL, A. Beril; TAZEGUL, Onur
The present study examined the shielding effect of composite materials containing varying proportions of aluminum, boron carbide and tungsten carbide compounds against different radiation types. The transmission technique was used to investigate the attenuation properties of the materials against gamma, beta and neutron radiation. The linear and mass attenuation coefficients of the samples were determined by 0.059 MeV (Am-241), 0.662 MeV (Cs-137) and 1.25 MeV (Co-60) energetic gamma rays and Emax = 2.25 MeV energetic beta rays. Furthermore, the total macroscopic cross section (T) was calculated for the materials in the presence of the Pu-Be neutron source. The gamma mass attenuation coefficient values were compared with theoretical values obtained from the XCOM programme code. Calculations of the half-value thickness (HVT) were conducted utilising linear attenuation coefficient and total macroscopic cross-section values. The results demonstrated that an increase in the tungsten carbide content of the materials resulted in an enhancement of the HVTs against gamma and beta radiation from Am-241, Cs-137 and Co-60. Furthermore, an increase in the boron carbide ratio resulted in an enhancement of the HVTs against the Pu-Be neutron source. The findings of this study may prove useful in the selection of effective shielding materials against mixed radiation in nuclear industries.
Synthesis, Characterizations and Applications of Organo-Rare-Earth-Metal Complexes for Organic Light Emitting Diode Applications
(Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu (TENMAK), 2024-04-26) MARAŞLIOĞLU, Cem; CEVHER, Şevki Can; CANIMKURBEY, Betül; CAMCI, Merve Taner; ÇIRPAN, Ali
Lighting technologies are an indispensable part of this era and cover a wide area in many fields such as primary lighting and lighting in imaging sectors. Among these lighting technologies, organic light emitting diodes (OLEDs) attract attention due to their low potential operation, easy application to large areas, flexibility, lightness and high resolution. On the other hand, it is seen in the literature that organometallic complexes synthesized by using transition metals and some rare earth metals operate with high efficiency. This study is initiated by the motivation to increase the diversity in OLED applications and to synthesize applicable electroluminescent organometallic materials with high performance criterias. While imidazole derivatives, which are known to emit blue light are easy to synthesize and derivatize, were chosen as organic components, Europium (Eu), Lanthanium (La) and Terbium (Tb) metals were preferred as metals to be used in organometallic complexes. Imidazole-derivatives, which have electroluminescence alone, are expected to have high-intensity and narrow emission band possessing emission in their metal complexes taking advantage of the shielding properties of electrons in the outer orbit of rare earth metals (REMs) and inhibition of f-f electron transition. Structural characterizations are done by using infrared (IR) spectroscopy, 1H-NMR and 13C-NMR, optical characterizations are performed by UV-Vis spectroscopy (UV) and photoluminescence (PL) spectroscopy, electronical characterizations are completed by Cyclic Voltammetry (CV). Finally, the OLED applications has been completed and measured as external quantum efficiencies (EQEs), photoluminescence quantum yields (PLQYs), turn-on voltages and current density-voltage curves.
Transfer Factors of 238U, 232Th, 40K, 210 Pb to selected some Crops and radiation impact assessment in Semi Arid Environment
(Springer, 2024-05-22) Dirican, Abdullah; Dikmen, Hasan; Şahin, Mihriban; Gülay, Yusuf; Özkök, Yücel Özel; Kaya, Nihal; Vural, Mustafa
Research on the safety of staple agricultural food products has always been one of humanity's priorities and provides input for dose assessment models. Within this important priority, activity concentrations, transfer factors (TF), and radiological effects of 238U, 232Th, 210Pb, and 40 12 K were studied for selected crops in a village close to the NORM area, located in Central Anatolia region of Turkey. The RESRAD-onsite code has been used to assess the total dose rate. The simulation of the risk analysis covered 80 years. The maximum total dose of 0.5 mSv/yr was obtained at t = 30 years.

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