Contamination by oxygen and nitrogen during the high-temperature synthesis of rare earth element carbides and the hydrocarbon contents of their hydrolysis products

1986 ◽  
Vol 51 (7) ◽  
pp. 1411-1418 ◽  
Author(s):  
Pavel Karen ◽  
Bohumil Hájek
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Earth Element ◽  
High Concentration ◽  
Temperature Synthesis ◽  
Hydrolysis Products ◽  
High Temperature Synthesis ◽  
Type Carbide ◽  
The Stability ◽  
Slight Contamination

Contamination of reaction mixtures of rare earth elements and carbon by air oxygen and nitrogen at high temperatures results in changes in the phase composition of the products, which in turn lead to changes in the composition of the hydrolysis gas. La, Ce, Pr, and Nd give carbide-oxides Ln2O2C2 of acetylide nature, in concentrations increasing with increasing extent of contamination. For the smaller rare earth elements from Dy, Ho to Lu, the contamination leads to methanide-type carbide-oxides (or nitrides) M(C, N, O, ). A slight contamination of mixtures of the metals with carbon which are somewhat carbon-deficient with respect to the 1 : 2 composition gives rise to a phase which evolves a gas containing C3 hydrocarbons in a high concentration (nearly 50%), while its methane content is very low. The stability of this allylenide phase, which is not the M15C19 carbide, increases in the direction towards Lu to an extent such that the phase forms even besides higher amounts of the carbide-oxide-nitride, i.e., also on extensive contamination.

Study on Recovery of Rare Earth Elements from NdFeB Magnet Scrap by Using Selective Leaching

2020 ◽  
Vol 1009 ◽  
pp. 149-154
Author(s):  
Tanongsak Yingnakorn ◽  
Piamsak Laokhen ◽  
Loeslakkhana Sriklang ◽  
Tapany Patcharawit ◽  
Sakhob Khumkoa
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Rare Earth Element ◽  
Earth Element ◽  
Rare Earth Metals ◽  
Hard Disk Drives ◽  
Selective Leaching ◽  
High Concentration ◽  
Neodymium Magnets ◽  
The Rare Earth

High power neodymium magnets have been used extensively, such as components of hard disk drives, electric vehicles, and maglev trains. This type of magnet contains of high concentration of rare earth elements. After the device is out of service, the magnet will be removed and the rare earth element contained in the magnet will be extracted in order to reuse for any purposes. Recently, the study on extraction of rare earth elements (REE) from neodymium magnets is increased. However, there was only few research regarding to the extraction of rare earth metals by using a water leaching method. In this study, rare-earth elements were extracted from neodymium magnet scrap by using selective leaching technique. Initially, magnets were leached with 2 M of sulfuric acid for 24 hrs. Then, the leached solution was heated at 110°C in order to remove water and the green powder was remained. The green powder was further roasted in a muffle furnace at various temperatures from 750°C to 900°C for 2 hrs. and subsequently leached by water. Finally, the iron oxide residue was separated from rare earth element solution by filtration. Based on this experiment, it was found that the purity of the rare earth metals can be achieved up to 99.4%.

scholarly journals Tracing method of Rare Earth Elements in surrounding rock of geological formation based on three-dimensional positioning algorithm

2021 ◽  
Vol 25 (1) ◽  
pp. 21-28
Author(s):  
Yan Lv ◽  
Laijun Lu ◽  
Mengxue Cao
Keyword(s):  
Mass Spectrometry ◽  
Rare Earth ◽  
Mass Spectrum ◽  
Rare Earth Elements ◽  
Earth Element ◽  
Three Dimensional ◽  
Test Sample ◽  
Surrounding Rock ◽  
Geological Formation ◽  
Positioning Algorithm

Because of the interference of mass spectrum and non-mass spectrum, the tracing accuracy of rare earth elements in the surrounding rock of geological formation is low. Pretreatment of test sample reagent, dissolution of test sample residue, characterization of rare earth element doped materials, analysis of mass spectrometry and non-mass spectrometry interference in rare earth element tracking, using three-dimensional positioning algorithm to track rare earth elements in geological strata surrounding rock. In the experiment, five samples of surrounding rock of geological strata are selected as experimental indexes. The experimental results show that the tracking accuracy of four rare earth elements is high.

The Obtaining Layered Composite Materials that Contain Rare Earth Element

2019 ◽  
Vol 822 ◽  
pp. 117-121
Author(s):  
A.N. Burlova ◽  
Fedor Y. Isupov ◽  
Sergey A. Kotov ◽  
Maria G. Livintsova
Keyword(s):  
Plastic Deformation ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Earth Element ◽  
Spent Nuclear Fuel ◽  
Layered Composite ◽  
Structural Elements ◽  
Friction Stir ◽  
Combination Of Methods ◽  
Metallurgical Processes

Materials with high content of rare-earth elements can be used for the manufacture of structural elements of containers for the transport of spent nuclear fuel. The combination of methods of powder metallurgy and methods of intensive plastic deformation allows to introduce a greater number of additives into the composition of the material than in the classical metallurgical processes. The article shows the possibility of using a combination of friction stir welding and friction stir processing in order to create a layered composite with a high content of rare-earth elements.

scholarly journals Rare earth element mobility in and around carbonatites controlled by sodium, potassium, and silica

2020 ◽  
Vol 6 (41) ◽  
pp. eabb6570 ◽  
Author(s):  
Michael Anenburg ◽  
John A. Mavrogenes ◽  
Corinne Frigo ◽  
Frances Wall
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Rare Earth Element ◽  
Earth Element ◽  
Element Mobility ◽  
Sodium Potassium ◽  
Ree Mineralization ◽  
Anionic Species ◽  
Ree Mobility ◽  
Modern Technologies

Carbonatites and associated rocks are the main source of rare earth elements (REEs), metals essential to modern technologies. REE mineralization occurs in hydrothermal assemblages within or near carbonatites, suggesting aqueous transport of REE. We conducted experiments from 1200°C and 1.5 GPa to 200°C and 0.2 GPa using light (La) and heavy (Dy) REE, crystallizing fluorapatite intergrown with calcite through dolomite to ankerite. All experiments contained solutions with anions previously thought to mobilize REE (chloride, fluoride, and carbonate), but REEs were extensively soluble only when alkalis were present. Dysprosium was more soluble than lanthanum when alkali complexed. Addition of silica either traps REE in early crystallizing apatite or negates solubility increases by immobilizing alkalis in silicates. Anionic species such as halogens and carbonates are not sufficient for REE mobility. Additional complexing with alkalis is required for substantial REE transport in and around carbonatites as a precursor for economic grade-mineralization.

scholarly journals The Occurrence States of Rare Earth Elements Bearing Phosphorite Ores and Rare Earth Enrichment Through the Selective Reverse Flotation

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 698
Author(s):  
Wenxiang Chen ◽  
Feng Zhou ◽  
Hongquan Wang ◽  
Sen Zhou ◽  
Chunjie Yan
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Rare Earth Element ◽  
Earth Element ◽  
Ion Beam ◽  
Western China ◽  
Reverse Flotation ◽  
Flotation Process ◽  
Element Bearing ◽  
Element Contents

The reserve of rare-earth element-bearing phosphorite ores in Guizhou province in western China is huge. Increased demand for the different products manufactured from rare-earth elements has resulted in an extreme need for reasonable and comprehensive extraction of rare-earth elements. An improved understanding of rare-earth element occurrence states in single minerals of ores is important for their further processing. In this paper, rare-earth element contents were analyzed by inductively coupled plasma (ICP), and the occurrence states in single minerals were further investigated through SEM-EDS and focused ion beam-scanning electron microscope (FIB-SEM) methods. The results indicate that rare-earth element contents of apatite are far more than that of dolomite. No independent mineral of rare-earth elements exists for the studied sample. Rare-earth elements are present in the form of ions in the lattices of apatite. Based on the analysis of occurrence states and properties in single minerals, the distribution of rare-earth elements in the flotation process was investigated by reverse flotation technology. It shows that rare-earth elements are mainly concentrated in apatite concentrate. Under the optimized conditions, the P2O5 grade increases from 11.36% in the raw ore to 26.04% in the concentrate, and the recovery is 81.92%, while the total rare-earth oxide grade increases from 0.09% to 0.21% with the recovery of 80.01%, which is similar to P2O5 recovery. This study presents the feasibility of extracting rare-earth elements from rare-earth element-bearing phosphorite ores through the flotation of apatite.

Study on Mechanisms of Rare Earth Elements on Improving Thermoelectric Properties of RExCo4Sb12

2011 ◽  
Vol 71-78 ◽  
pp. 3737-3740
Author(s):  
Ke Gao Liu ◽  
Jing Li
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Mechanical Alloy ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Rare Earth Element ◽  
Figure Of Merit ◽  
Earth Element ◽  
Plasma Sintering ◽  
Spark Plasma

It is the important way to improve thermoelectric properties of skutterudite materials by doping with rare earth elements. The mechanisms of improving properties of bulk RExCo4Sb12materials prepared by mechanical alloy and spark plasma sintering (MA-SPS) at 650°C were investigated by analyzing the composition, microstructure and atomic occupying locations. According the results it can be considered that the mechanism to improve the thermoelectric properties of rare earth elements is that rare earth element Ce in the samples mainly plays the doping role in reducing the resistivity of the sample and improving the conductivity, so that it makes the figure of merit ZT of samples increase significantly.

Optimization of Rare Earth Dope on MAl2O4 (M = Ba, Sr) by Self-Propagating High Temperature Synthesis

2012 ◽  
Vol 488-489 ◽  
pp. 442-446 ◽  
Author(s):  
Taschaporn Sathaporn ◽  
Sutham Niyomwas
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Broad Band ◽  
Emission Spectra ◽  
Rare Earth Ions ◽  
Ocean Optics ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Microscope Technique

The Eu2+ doped barium aluminate (BaAl2O4:Eu2+) and strontium aluminate (SrAl2O4:Eu2+) with high brightness were synthesized by self-propagating high temperature synthesis (SHS) method. The influence of doping rare earth ions (Eu2+) on the luminescence of MAl2O4:Eu2+ were described in this study. The reactions were carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The morphologies and the phase structures of the products have been characterized by X-ray diffraction (XRD) and scanning electron microscope technique (SEM). The emission spectra of the products have been measured by an Ocean optics spectrometer at room temperature. Broad band UV excited luminescence was observed for BaAl2O4:Eu2+ and SrAl2O4:Eu2+ in the green region peak at λmax = 501 nm and 523 nm, respectively. The optimum Eu2+ doping ratio were 10.5 mol% and 6 mol% for BaAl2O4:Eu2+ and SrAl2O4:Eu2+, respectively

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