scholarly journals High Pressure Sintering of WC-10Co Doped with Rare-Earth Elements

10.5772/35147 ◽  
2012 ◽  
Author(s):  
C.M.F.G. Marques ◽  
G.S. Bobrovnitchii ◽  
J.N.F Hol
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
High Pressure Sintering

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 Structural and Compositional Features of Garnet-Containing Samples Synthesized in a System with Samarium at High Pressure and High Temperature

2021 ◽  
pp. 43-46
Author(s):  
V.V. Lin ◽  
A.A. Chepurov ◽  
E.I. Zhimulev
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
High Temperature ◽  
Rare Earth Elements ◽  
Distinctive Feature ◽  
Light Rare Earth ◽  
Individual Grains ◽  
Light Rare Earth Elements ◽  
High Pressure Apparatus

A distinctive feature of garnets associated with diamonds is specific containing of “light” rare earth elements. In the paper, the garnet-containing samples obtained at high pressure and high temperature in the system introduced with samarium (Sm) are studied. The experiments are carried out using a multianvil high-pressure apparatus of the “split-sphere” type (BARS) at a pressure of 5 GPa and a temperature of 1300 °С. The accuracy of measuring the pressure and temperature is ± 0.2 GPa и ± 25 °С, respectively. As a result, pyrope grains are synthesized with a CaO content no higher than 0.15 wt.% and Cr2O3 concentration within the range of 3.61-7.55 wt.%. The garnets are characterized by the stable presence of an impurity in the form of the Sm constituent. The garnets contain a significant amount of olivine inclusions. Crystals of the synthesized spinel are observed mainly in the interstices. This study demonstrates that the interaction of the components in the serpentine — chromite — corundum — Sm system leads to the crystallization of pyrope garnet, which forms large intergrowths of individual grains. The zoning observed in garnet is due to the transfer of components by fluid during the experiment. It is concluded that the Sm content in garnet can significantly increase depending on its content in the system.

scholarly journals To the Issue of the Presence of the Occurrence of Rare Earth Elements in the Structure of Chromium Pyrope Garnet

2021 ◽  
Vol 38 ◽  
pp. 71-87
Author(s):  
V. V. Lin ◽  
◽  
A. I. Turkin ◽  
A. A. Chepurov ◽  
◽  
...  
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Total Content ◽  
Kimberlite Pipe ◽  
Distribution Coefficients ◽  
Water Soluble ◽  
Refractory Oxide ◽  
Mineral Association ◽  
Initial Charge

Rare earth elements (REE) in garnet are of interest in various fields of modern geology. The geochemistry of REEs in magmatic minerals is widely used in determining the distribution coefficients of crystal/melt and crystal/fluid, modeling the processes of melting and crystallization of magmatic rocks, studying deep mantle processes, age estimates and other issues of petrogenesis. The aim of the present work was a synthesis of a peridotite mineral association including the garnet containing REE at high pressure and high temperature. The initial sample consisted mainly of natural serpentine collected from ophiolites of the Eastern Sayan (Russia). As is known, the extreme stage of the regressive metamorphism of peridotites is serpentinization. It is depleted in calcium, but can recrystallize at high PT conditions into a harzburgite paragenesis, and at the initial stage of the experiment the chemical composition of the sample was a model harzburgite depleted in calcium and chromium, as well as a fluid of predominantly aqueous composition. As a source of chromium, chromite grains of 1–2 mm in size from peridotite xenoliths of the Udachnaya kimberlite pipe (Yakutia) were used. REE were added to the initial charge in the form of water-soluble salts. The experiment at a pressure of 5 GPa and temperature 1300 was performed on a multi-anvil high-pressure apparatus of the “split sphere” type (BARS) designed and developed at the V.S. Sobolev Institute of Geology and Mineralogy SB RAS. A container based on refractory oxide ZrO2 was used as a highpressure medium. The pressure in the cell before sample heating was estimated using the reference substances Bi and PbSe. The temperature was measured by a platinum-platinum-rhodium thermocouple PtRh30-PtRh6. The quenched was performed by switching off the voltage in the heater circuit. The experiment products contain an association of olivine + garnet + orthopyroxene + newly formed spinel. The predominant phase was olivine of a forsterite composition. A low-Fe orthopyroxene (1.49 – 1.68 wt% FeO) was found in elongated grains uniformly distributed throughout the sample. The newly formed spinel shows the faceted grains. The chromium content in the spinel significantly exceeds that of the initially added to the initial charge, 61.63 and 54.04 wt% Cr2O3, respectively. The garnet is characterized by a purple color, and was identified in the sample volume between olivine grains in the form of individual faceted crystals or their clusters. The largest garnets reached 0.5 mm in size. The synthesized garnet was determined as a high-Cr low-Ca pyrope variety. The contents of Cr2O3 and CaO are 10.15-11.21 and 0.06-0.11 wt%, respectively. The total content of REE in the garnet identified by the microprobe analysis is relatively high reaching 5-7 wt%. As a result of the work a mineral association corresponding to the peridotite paragenesis was obtained, including the subcalcic Crrich pyrope containing rare earth elements in significant amounts. It was estimated that their content in garnet mainly depends on the size of the ionic radius and, accordingly, on the atomic weight. This is consistent with the known facts about the preferable position of heavy REEs into the garnet structure compared to the light REEs.

scholarly journals Mg-Al-RE Magnesium Alloys for High-Pressure Die-Casting

2014 ◽  
Vol 14 (2) ◽  
pp. 49-52 ◽  
Author(s):  
K.N. Braszczyńska-Malik
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Intermetallic Compound ◽  
Rare Earth Elements ◽  
Magnesium Alloys ◽  
Die Casting ◽  
High Pressure Die Casting ◽  
Cold Chamber ◽  
Pressure Die Casting

Abstract Experimental Mg-Al-RE type magnesium alloys for high-pressure die-casting are presented. Alloys based on the commercial AM50 magnesium alloy with 1, 3 and 5 mass % of rare earth elements were fabricated in a foundry and cast in cold chamber die-casting machines. The obtained experimental casts have good quality surfaces and microstructure consisting of an α(Mg)-phase, Al11RE3, Al10RE2Mn7 intermetallic compound and small amount of α+γ eutectic and Al2RE phases.

Sampling and Characterizing Rare Earth Elements in Groundwater in Deep-Lying Fractures in Granitoids Under In Situ High-Pressure and Low-Redox Conditions

2014 ◽  
Vol 20 (4) ◽  
pp. 405-418 ◽  
Author(s):  
Linda J. Alakangas ◽  
Frédéric A. Mathurin ◽  
Mikko Faarinen ◽  
Bill Wallin ◽  
Mats E. Åström
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Redox Conditions

Behaviour of rare-earth elements during high-pressure metamorphism

Lithos ◽  
1990 ◽  
Vol 25 (1-3) ◽  
pp. 219-226 ◽  
Author(s):  
V.S. Shatsky ◽  
O.A. Kozmenko ◽  
N.V. Sobolev
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
High Pressure Metamorphism

scholarly journals Advances in Understanding of the Application of Unit Operations in Metallurgy of Rare Earth Elements

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 978
Author(s):  
Srecko Stopic ◽  
Bernd Friedrich
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Molten Salt ◽  
Water Solution ◽  
Extractive Metallurgy ◽  
Supersaturated Solution ◽  
Molten Salt Electrolysis ◽  
Selective Precipitation ◽  
Unit Operations

Unit operations (UO) are mostly used in non-ferrous extractive metallurgy (NFEM) and usually separated into three categories: (1) hydrometallurgy (leaching under atmospheric and high pressure conditions, mixing of solution with gas and mechanical parts, neutralization of solution, precipitation and cementation of metals from solution aiming purification, and compound productions during crystallization), (2) pyrometallurgy (roasting, smelting, refining), and (3) electrometallurgy (aqueous electrolysis and molten salt electrolysis). The high demand for critical metals, such as rare earth elements (REE), indium, scandium, and gallium raises the need for an advance in understanding of the UO in NFEM. The aimed metal is first transferred from ores and concentrates to a solution using a selective dissolution (leaching or dry digestion) under an atmospheric pressure below 1 bar at 100 °C in an agitating glass reactor and under a high pressure (40–50 bar) at high temperatures (below 270 °C) in an autoclave and tubular reactor. The purification of the obtained solution was performed using neutralization agents such as sodium hydroxide and calcium carbonate or more selective precipitation agents such as sodium carbonate and oxalic acid. The separation of metals is possible using liquid (water solution)/liquid (organic phase) extraction (solvent extraction (SX) in mixer-settler) and solid-liquid filtration in chamber filter-press under pressure until 5 bar. Crystallization is the process by which a metallic compound is converted from a liquid into a crystalline state via a supersaturated solution. The final step is metal production using different methods (aqueous electrolysis for basic metals such as copper, zinc, silver, and molten salt electrolysis for REE and aluminum). Advanced processes, such as ultrasonic spray pyrolysis, microwave assisted leaching, and can be combined with reduction processes in order to produce metallic powders. Some preparation for the leaching process is performed via a roasting process in a rotary furnace, where the sulfidic ore was first oxidized in an oxidic form which is a suitable for the metal transfer to water solution. UO in extractive metallurgy of REE can be successfully used not only for the metal wining from primary materials, but also for its recovery from secondary materials.

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