scholarly journals An Overview of Rare Earth Ores Beneficiation in Vietnam

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Thi Kim Dung NHU ◽  
Van Luan PHAM ◽  
Thi Chinh VU ◽  
Van Duoc TRAN
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnetic Materials ◽  
Animal Feed ◽  
Rare Earth Metals ◽  
Earth’S Crust ◽  
Research Projects ◽  
Essential Minerals ◽  
Different Types ◽  
Earth's Crust

Rare earth metals are used in electricity, electronics, nuclear, optics, space, metallurgy,superconducting and super magnetic materials, glass and ceramics, and agriculture. Some rare earthelements are added to fertilizers for crops and some trials for animal feed. Rare earth elements, exceptfor radioactive promethium, are relatively abundant in the earth's crust. Vietnam has a tremendous rareearth potential, distributed mainly in the Northwest, including Nam Xe, Dong Pao, Muong Hum, andYen Bai. There are many research projects on rare earth ores of different types globally, but the focus ismainly on the essential minerals, including monazite, xenotime, and bastnaesite. This report summarizesresearch data on rare earth ore intending to produce a general assessment of rare earth ore and itsbeneficiation technology in Vietnam.

scholarly journals Rare earth elements in soils of saline agrolandscapes of the Baraba plain

2021 ◽  
Vol 51 (3) ◽  
pp. 5-14
Author(s):  
N. V. Semendyaeva ◽  
A. A. Morozova ◽  
N. I. Dobrotvorskaya ◽  
N. V. Elizarov
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Soil Profile ◽  
Humus Content ◽  
Total Content ◽  
Agricultural Landscapes ◽  
Earth’S Crust ◽  
Depth Study ◽  
Earth's Crust ◽  
Humus Horizons

The total content of rare earth elements in the soil profile of saline agricultural landscapes catena of the Baraba plain within Novosibirsk region was studied. The total content of zirconium, yttrium, scandium, gallium, including lanthanides - cerium, lanthanum and ytterbium was determined. Rare earth elements are extremely poorly analyzed. At present, their influence on plants, organisms of animals and humans is being actively studied, although the maximum permissible and tentatively permissible concentrations for them have not yet been developed. The total content of rare earth elements, determined in the soils of the catena, depends on the granulometric composition and the degree of humus content of the soil horizons. It was revealed that in the studied soils they are mainly contained in the number of clarkes of the earth's crust, with the exception of lanthanum in the humus horizons, where its content is almost 1.5 times (44-48 mg/kg) higher than the clarke in the earth's crust (29 mg/kg), and ytterbium (10 times higher than the clarke). Along the soil profile, an insignificant movement of rare earth elements in both vertical and horizontal directions was noted, which indicates a low mobility of their compounds. Zirconium predominates in the profile of the studied soils from the group of rare earth elements. Its content in the humus horizons of soils of eluvial positions is within the clarke of the earth's crust; variations along the profile are insignificant. Ytterbium is contained in large quantities - from 1.89 to 4.05 mg/kg of soil, which is significantly higher than the clarke of the earth's crust (0.3 mg/kg of soil). The role of lanthanides in the soil -plant - animal - human system requires further in-depth study.

scholarly journals An Updated Review of Toxicity Effect of the Rare Earth Elements (REEs) on Aquatic Organisms

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1663
Author(s):  
Nemi Malhotra ◽  
Hua-Shu Hsu ◽  
Sung-Tzu Liang ◽  
Marri Jmelou M. Roldan ◽  
Jiann-Shing Lee ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Chemical Elements ◽  
Life Forms ◽  
Department Of Energy ◽  
Earth’S Crust ◽  
Aquatic Biota ◽  
Aquatic Life ◽  
Toxicity Effect ◽  
Earth's Crust

Rare earth elements (REEs) or “technology metals” were coined by the U.S. Department of Energy, a group of seventeen elements found in the Earth’s crust. These chemical elements are vital and irreplaceable to the world of technology owing to their unique physical, chemical, and light-emitting properties, all of which are beneficial in modern healthcare, telecommunication, and defense. Rare earth elements are relatively abundant in Earth’s crust, with critical qualities to the device performance. The reuse and recycling of rare earth elements through different technologies can minimize impacts on the environment; however, there is insufficient data about their biological, bioaccumulation, and health effects. The increasing usage of rare earth elements has raised concern about environmental toxicity, which may further cause harmful effects on human health. The study aims to review the toxicity analysis of these rare earth elements concerning aquatic biota, considering it to be the sensitive indicator of the environment. Based on the limited reports of REE effects, the review highlights the need for more detailed studies on the hormetic effects of REEs. Aquatic biota is a cheap, robust, and efficient platform to study REEs’ toxicity, mobility of REEs, and biomagnification in water bodies. REEs’ diverse effects on aquatic life forms have been observed due to the lack of safety limits and extensive use in the various sectors. In accordance with the available data, we have put in efforts to compile all the relevant research results in this paper related to the topic “toxicity effect of REEs on aquatic life”.

scholarly journals How Rare Are Rare-Earth Elements in Living Things?

2021 ◽  
Vol 8 ◽  
Author(s):  
Rocío Bustillos-Cristales ◽  
Yagul Pedraza-Pérez ◽  
Luis Ernesto Fuentes-Ramírez
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Chemical Elements ◽  
Living Organism ◽  
Earth’S Crust ◽  
Future Research ◽  
Living Things ◽  
Earth's Crust ◽  
Living Organisms

Rare-earth elements (REEs) are a group of metallic chemical elements that share some properties and that despite their name are not too rare in the Earth’s crust. Until recently, we did not know of any REEs that were necessary for any living organism. Now we know that there are some bacteria that use REEs to perform reactions that let them consume alcohol. Humans are also interested in REEs because these elements are valuable for many technological applications. In this article, we will explain the only known participation of REEs in living organisms and explain why future research on REEs is important.

The distribution of Curie points in basalts from different types of earth's crust

1970 ◽  
Vol 2 (5) ◽  
pp. 378-380 ◽  
Author(s):  
V.I. Bagin ◽  
S.Yu. Brodskaya ◽  
D.M. Perchersky ◽  
G.N. Petrova
Keyword(s):  
Earth’S Crust ◽  
Different Types ◽  
Earth's Crust

THERMODYNAMICS OF THE PROCESSES OF INTERACTION OF LIQUID METAL COMPONENTS IN Fe – Mg – Al – La – O SYSTEM

2018 ◽  
Vol 61 (6) ◽  
pp. 460-465
Author(s):  
G. G. Mikhailov ◽  
L. A. Makrovets ◽  
L. A. Smirnov
Keyword(s):  
Rare Earth ◽  
Liquid Metal ◽  
Rare Earth Elements ◽  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Equilibrium Constants ◽  
Rare Earth Metals ◽  
Oxide Systems ◽  
Metal Melts ◽  
Steel Deoxidation

At the present time, rare-earth elements in metallurgy are used in  the form of mischmetal – a rare-earth elements natural mixture (with  atomic numbers from 57 to 71). It contains about 50  wt.  % of cerium.  The remaining elements are mainly lanthanum and niobium. The specific composition is determined by the ore deposit. Inconstant composition of the modifier containing rare-earth metals (REM) can significantly reduce its efficiency. Experimentally, for every branded steels  composition the ratio of various REMs can’t be selected because of the  high costs of obtaining technically pure rare-earth metals. The task of  determining the each rare earth element optimum concentrations and  complex ligature composition can be solved by thermodynamic modeling. In the framework of thermodynamic modeling, the interaction  between magnesium, aluminum and lanthanum with oxygen in liquid  iron is presented. And the thermodynamic model of steel deoxidation  by these active metals composition is considered. On the basis of available literature data on the phase diagrams of the systems MgO – Al2O3 ,  MgO – La2O3 and La2O3 – Al2O3 , the coordinates of the invariant equilibria points in the system MgO – La2O3 – Al2O3 were determined. The  phase diagram of the system MgO – La2O3 – Al2O3 was constructed. It  made possible to establish all phase equilibria realized in the process  of deoxidation of steel with magnesium, lanthanum and aluminum and  to describe these phase equilibria by chemical reactions equations. The  activity of the components in liquid oxide melts was determined using  the theory of subregular ionic solutions, which takes into account the  dependence of the coordination number of cations on the composition  of the oxide melt. The activity of components in metal melts conjugated with oxide systems were determined by Wagner’s theory using the  parameters of the first order interaction. Equilibrium constants values  for the steel deoxidation reactions are installed indirectly by thermodynamic calculations. On the basis of the obtained data the components  solubility surface in the metal melts of Fe – Mg – Al – La – O system  was constructed, which allowed to determine the liquid metal composition regions associated with the corresponding oxide phase.

Development of nanostructured magnetic materials based on high-purity rare-earth metals and study of their fundamental characteristics

2014 ◽  
Vol 56 (9) ◽  
pp. 1778-1784 ◽  
Author(s):  
I. A. Pelevin ◽  
I. S. Tereshina ◽  
G. S. Burkhanov ◽  
S. V. Dobatkin ◽  
T. P. Kaminskaya ◽  
...  
Keyword(s):  
Rare Earth ◽  
Magnetic Materials ◽  
High Purity ◽  
Rare Earth Metals
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