scholarly journals Thermochemical Preparation and Properties of Low-Cost Polylanthanide Manganite Materials of Ln(La, Ce, Nd, Pr)xCayMnO3-Type with Perovskite-Fluorite Structure

2020 ◽  
Vol 19 (6) ◽  
pp. 528-535
Author(s):  
V. A. Gorbunova ◽  
L. M. Sliapniova ◽  
A. V. Gorbunov
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Low Cost ◽  
Ceramic Materials ◽  
Fluorite Structure ◽  
Chemical Investigation ◽  
Physical And Chemical

A physical and chemical investigation of ceramic materials based on manganites of mixed rare earth elements  –

scholarly journals Production of Porous Ceramic Materials from Spent Fluorescent Lamps

2021 ◽  
Vol 11 (13) ◽  
pp. 6056
Author(s):  
Egle Rosson ◽  
Acacio Rincón Rincón Romero ◽  
Denis Badocco ◽  
Federico Zorzi ◽  
Paolo Sgarbossa ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
High Speed ◽  
Porous Ceramic ◽  
Ceramic Materials ◽  
Porous Ceramics ◽  
Fluorescent Lamps ◽  
Naoh Solution ◽  
Commercial Glass ◽  
Triton X

Spent fluorescent lamps (SFL) are classified as hazardous materials in the European Waste Catalogue, which includes residues from various hi-tech devices. The most common end-of-life treatment of SFL consists in the recovery of rare earth elements from the phosphor powders, with associated problems in the management of the glass residues, which are usually landfilled. This study involves the manufacturing of porous ceramics from both the coarse glass-rich fraction and the phosphor-enriched fraction of spent fluorescent lamps. These porous materials, realizing the immobilization of Rare Earth Elements (REEs) within a glass matrix, are suggested for application in buildings as thermal and acoustic insulators. The proposed process is characterized by: (i) alkaline activation (2.5 M or 1 M NaOH aqueous solution); (ii) pre-curing at 75 °C; (iii) the addition of a surfactant (Triton X-100) for foaming at high-speed stirring; (iv) curing at 45 °C; (v) viscous flow sintering at 700 °C. All the final porous ceramics present a limited metal leaching and, in particular, the coarse glass fraction activated with 2.5 M NaOH solution leads to materials comparable to commercial glass foams in terms of mechanical properties.

scholarly journals Adsorption of Rare Earth Elements from Aqueous Solutions Using Geopolymers

Proceedings ◽  
2018 ◽  
Vol 2 (10) ◽  
pp. 567 ◽  
Author(s):  
Željka Fiket ◽  
Ana Galović ◽  
Gordana Medunić ◽  
Martina Furdek Turk ◽  
Maja Ivanić ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Aqueous Solutions ◽  
High Efficiency ◽  
Low Cost ◽  
Coal Ash ◽  
Industrial Sector ◽  
Efficient Removal ◽  
Model Solutions ◽  
Technology Applications

Rare earth elements, i.e., lanthanides, are important components of many recently developed technology applications. However, their increasing use in the industrial sector, medicine, and agriculture over the last few decades has provided them with the title of “new pollutants”. Different methods are now applied for the removal of various pollutants from wastewaters, whereby the emphasis is placed on adsorption due to its simplicity, high efficiency, and low cost. In the present study, geopolymers prepared from coal ash were examined regarding their capacity for the adsorption of lanthanides from model solutions. The obtained results indicate the efficient removal of lanthanides by prepared geopolymers, depicting them as effective adsorbents for this group of elements.

scholarly journals Pengaruh Berbagai Parameter Ekstraksi dalam Pemisahan Unsur Tanah Jarang dengan Metode Emulsion Liquid Membrane (ELM)

2021 ◽  
Vol 17 (1) ◽  
pp. 1
Author(s):  
Handias Meilinda ◽  
Novi Noviyanti ◽  
Anni Anggraeni ◽  
Diana Hendrati ◽  
Husein H Bahti
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Liquid Membrane ◽  
Chemical Properties ◽  
Membrane Phase ◽  
Emulsion Liquid Membrane ◽  
Phase Concentration ◽  
Stirring Time ◽  
Feed Phase ◽  
Physical And Chemical

<p>Unsur Tanah Jarang (UTJ) adalah 15 elemen kelompok lantanida, ditambah skandium dan itrium yang termasuk kelompok aktinida. UTJ memiliki banyak manfaat di berbagai bidang. Sifat fisik dan kimia yang mirip antar UTJ membuatnya sulit dipisahkan sehingga pemisahan UTJ menarik dipelajari dengan berbagai macam metode, salah satunya adalah dengan menggunakan <em>Emulsion Liquid Membrane </em>(ELM). ELM merupakan metode pemisahan yang dikembangkan dari ekstraksi pelarut terdiri dari tiga fase, yaitu fase eksternal (fase umpan) yang berisi UTJ yang akan dipisahkan, fase internal (fase pengupasan), dan fase membran. Fase membran berisi surfaktan sebagai penstabil dan ligan yang akan membentuk kompleks dengan UTJ pada antarmuka fase umpan dan membawanya berdifusi ke dalam fase pengupasan. ELM merupakan metode efektif untuk pemisahan karena tahap ekstraksi dan pengupasan (<em>stripping</em>) terjadi secara bersamaan dalam satu tahap dan fase membrannya dapat digunakan kembali. Pemisahan UTJ menggunakan metode ELM dengan berbagai ligan, seperti D2EHPA, Cyanex 572, P204, dan (RO)2P(O)OPh-COOH dipengaruhi oleh berbagai parameter, seperti konsentrasi ligan, pH fase umpan, waktu pengadukan ekstraksi, kecepatan pengadukan ekstraksi, rasio fase umpan, konsentrasi fase pengupasan, konsentrasi surfaktan, dan konsentrasi fase umpan. Parameter tersebut diseleksi untuk mendapatkan kondisi optimum sehingga meningkatkan efisiensi ekstraksi dan pengupasan yang berbeda.</p><p><strong>Effect of Various Parameters in Separation of Rare Earth Elements using the Emulsion Liquid Membrane (ELM) Method. </strong>Rare Earth Elements (REEs) are 15 elements of the lanthanide group, plus scandium and yttrium, which belong to the actinide group. REEs have many benefits in various fields. Similar physical and chemical properties between REEs make it difficult to separate, thus REEs separation is interesting to study by various methods, one of which is by using an emulsion liquid membrane (ELM). ELM is a method developed from solvent extraction consisting of three phases: the external phase (feed phase) which contains REEs to be collected, the internal phase (stripping phase), and the membrane phase. The membrane phase contains surfactants as stabilizers and ligands which will form complexes with REEs in the feed phase and are designed to diffuse into the stripping phase. ELM is an effective method to involve because extraction and stripping occur together in one glass and the membrane phase can be reused. Separation of REEs using the ELM method with various ligands, such as D2EHPA, Cyanex 572, P204, and (RO)2P(O)OPh-COOH influenced by various parameters, such as ligand concentration, feed phase pH, extraction stirring time, extraction stirring speed, feed phase ratio, stripping phase concentration, surfactant concentration, and feed phase concentration. These parameters are selected to obtain optimum conditions thereby increasing the efficiency of different extraction and stripping.</p><p> </p>

scholarly journals Analytical Chemical Investigation of Sulfide of Rare Earth Elements in Steel

1974 ◽  
Vol 60 (13) ◽  
pp. 1935-1943 ◽  
Author(s):  
Kazuo KAWAMURA ◽  
Shiro WATANABE ◽  
Tokio SUZUKI
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Chemical Investigation

scholarly journals Substantial thermal conductivity reduction in mischmetal skutterudites MmxCo4Sb12 prepared under high-pressure conditions, due to uneven distribution of the rare-earth elements

2019 ◽  
Vol 7 (14) ◽  
pp. 4124-4131 ◽  
Author(s):  
J. Gainza ◽  
F. Serrano-Sánchez ◽  
J. Prado-Gonjal ◽  
N. M. Nemes ◽  
N. Biskup ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Lattice Thermal Conductivity ◽  
Low Cost ◽  
Uneven Distribution ◽  
Filling Fraction ◽  
The Rare Earth

Low-cost n-type Mischmetal-filled CoSb3 skutterudites with elemental filling-fraction separation, prepared at high pressure, exhibit markedly low lattice thermal conductivity.

scholarly journals Thin Films and Glass–Ceramic Composites of Huntite Borates Family: A Brief Review

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 487
Author(s):  
Elena A. Volkova ◽  
Daniil A. Naprasnikov ◽  
Nikolay I. Leonyuk
Keyword(s):  
Rare Earth ◽  
Glass Ceramic ◽  
Optical Waveguides ◽  
Optical Glass ◽  
Ceramic Materials ◽  
Ceramic Composites ◽  
Epitaxial Layers ◽  
Waveguide Lasers ◽  
Laser Systems ◽  
Physical And Chemical

Rare-earth aluminum borates, RAl3(BO3)4 (where R = Y, Pr–Lu), are of great interest because of their attractive multifunctional properties, depending on their structure and composition. The combination of desirable physical and chemical characteristics makes them promising materials for lasers and nonlinear optics. Research focusing on RAl3(BO3)4 (RAB) compounds and their solids solutions has continued for more than five decades and has been reflected in numerous articles and several reviews. The last decade’s enhanced interest is being conducted towards epitaxial layers because of the availability of other possible applications, for instance, as scintillators, visible emitting phosphors or optical waveguides and waveguide lasers. On the other hand, the tendency of borate melts to form glasses makes them attractive for research of micro-crystallization processes in these systems and can be effortless towards finding relatively inexpensive optical glass–ceramic materials with similar composition as alternative components to laser systems. This article reviews the recent progress carried out hitherto on epitaxial layers and glass–ceramic composites of huntite-type rare-earth aluminum borates.

Application of Complex Concentrate of Rare-Earth Elements for Obtaining Electrometallic Coatings

2020 ◽  
Vol 992 ◽  
pp. 621-626
Author(s):  
N.F. Struchkov ◽  
G.G. Vinokurov ◽  
A.K. Kychkin
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Materials Science ◽  
Cored Wire ◽  
Modifying Additives ◽  
Promising Area ◽  
Structure Of Coatings ◽  
The Republic ◽  
Physical And Chemical ◽  
Cored Wires

The unique physical and chemical characteristics of rare earth elements make them attractive for use in a number of existing and innovative production lines. The use of complex concentrates of various deposits to obtain new materials is a promising area of modern materials science. The article presents the results of studies of electroarc metallization coatings of flux-cored wires with modifying additives. As additives, a complex concentrate of rare-earth metals from the deposits of the Republic of Sakha (Yakutia) and other modifying powders were used to obtain hardening phases. To determine the optimal composition of the modifying additives, various compositions of cored wires were made. An analysis of the structure of coatings showed a uniform distribution of the main elements of the cored wire, as well as a local distribution of unmelted particles of the modifying additives. The levels of open porosity and microhardness of the phase components of the coatings are determined. The prospects of using complex concentrate with rare-earth elements from deposits of the Republic of Sakha (Yakutia) as modifying additives for coatings with enhanced performance properties is shown.

scholarly journals Studies of the Effect of Crosslinking in the Strongly Basic Anion Exchanger Dowex 1 and the HNO3 Concentration Employed on the Separation of the SmIII–NdIII Pair in the Polar Organic Solvent–H2O–HNO3 System

2001 ◽  
Vol 19 (3) ◽  
pp. 219-228
Author(s):  
Z. Hubicki ◽  
M. Olszak
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Anion Exchanger ◽  
High Temperature Superconductors ◽  
Ceramic Materials ◽  
Modern Technology ◽  
Separation And Purification ◽  
Structural Stabilization ◽  
Component Content ◽  
Dowex 1

Because of their specific structure, rare earth elements are used for the modification or structural stabilization of many metallic or ceramic materials employed in modern technology and also in the metallic form, i.e. in alloys and compounds with unique properties. Industrial demand for rare earth metals has increased lately due to their new application possibilities, e.g. in supermagnets of the Nd–Fe–B type or in ceramic high-temperature superconductors. Equally, the application of rare earth elements in metallurgy, catalysis, ceramics, etc. remains of significant importance. The separation and purification of rare earth elements(III) which occur in groups with similar physicochemical properties involve extremely difficult and complex processes. Ion exchange is one method which enables such separation. This paper presents the results of studies of the influence of the extent of crosslinking in the anion exchanger Dowex 1 and the concentration of nitric acid on the separation of the SmIII–NdIII pair by frontal analysis in 90% v/v CH3COCH3– or the CH3OH–10% v/v × M HNO3 systems. The most effective results were obtained in the 90% v/v CH3OH–10% v/v 7 M HNO3 system employing the anion exchanger Dowex 1 × 4 allowing 0.11 kg samarium(III) to be purified on 1 dm3 ion exchanger in the nitrate form and leading to a decrease in the micro-component content to a value below 10−3%.

scholarly journals Critical Compilations of Atomic Energy Levels

1984 ◽  
Vol 86 ◽  
pp. 207-207
Author(s):  
J. Sugar ◽  
W.C. Martin ◽  
J. Reader ◽  
A. Musgrove ◽  
C. Corliss
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Reference Data ◽  
Energy Levels ◽  
Atomic Energy ◽  
Atomic Energy Levels ◽  
Physical And Chemical

We have been publishing new compilations of energy levels for single elements in all stages of ionization as each is completed. Those now in print in the Journal of Physical and Chemical Reference Data are helium (1973), sodium (1981), magnesium (1980), aluminum (1979), silicon (1983), potassium (1979), calcium (1979), scandium (1980), titanium (1979), vanadium (1978), chromium (1977), manganese (1977), iron (1982), cobalt (1981) and nickel (1981). A volume containing atomic energy levels of all rare earth elements was issued in 1978. We have now updated our compilations for the iron period (K through Ni, 235 spectra), which will be published in a single volume.

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