scholarly journals Recovery of rare earths from glass polishing waste for the production of aluminium-rare earth alloys

2021 ◽  
Vol 174 ◽  
pp. 105766
Author(s):  
Chenna Rao Borra ◽  
Thijs JH Vlugt ◽  
Yongxiang Yang ◽  
Jeroen Spooren ◽  
Peter Nielsen ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Rare Earth Alloys ◽  
Glass Polishing

scholarly journals Characterization and Feasibility Studies on Complete Recovery of Rare Earths from Glass Polishing Waste

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 278 ◽  
Author(s):  
Chenna Borra ◽  
Thijs Vlugt ◽  
Jeroen Spooren ◽  
Peter Nielsen ◽  
Yongxiang Yang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Alkali Treatment ◽  
Thermo Gravimetric Analysis ◽  
Acid Leaching ◽  
Complete Recovery ◽  
Emission Spectrometry ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Glass Polishing

One of the main applications of ceria (CeO2) is its use in glass polishing. About 16,000 tonnes of rare earth oxides, which is about 10% of total rare earth production, are used for polishing applications. The waste generated in glass polishing contains rare earths, along with other impurities. In this study, two different glass polishing waste samples were characterized and two different processes were proposed for the complete recovery of rare earths from polishing waste, i.e., an acid-based process and an alkali-based process. The polishing waste samples were characterized with inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA) and particle size analysis. Chemical analysis showed that sample A (CeO2-rich waste from plate glass polishing) contained a high amount of impurities compared to sample B (CeO2-rich waste from mirror polishing). XRD analysis showed that sample B contained CeO2, LaO0.65F1.7 and LaPO4 compounds, whereas sample A contained CaCO3 in addition to rare earth compounds. SEM-EDX analysis showed the presence of alumino-silicates in sample A. Leaching experiments were carried out at 75 °C at different acid concentrations for the recovery of rare earths from polishing waste samples. The leaching results showed that it is difficult to dissolve rare earths completely in acid solutions due to the presence of fluorides and phosphates. Hence, undissolved rare earths in the leach residue were further recovered by an alkali treatment with NaOH. In another approach, polishing waste samples were directly treated with NaOH at 500 °C. After alkali treatment followed by water leaching, rare earths can be completely dissolved during acid leaching. Rare earths from polishing waste can be recovered completely by both the acid-based process and the alkali-based process.

Acoustic properties of rare-earth alloys Tb0.27Dy0.73(Fe1-xMnx)1.9

1994 ◽  
Vol 04 (C5) ◽  
pp. C5-705-C5-708
Author(s):  
V. PREOBRAZHENSKY ◽  
I. DUBENKO ◽  
N. ECONOMOV ◽  
A. ZAIKIN
Keyword(s):  
Rare Earth ◽  
Acoustic Properties ◽  
Rare Earth Alloys

A glance on rare earth oxides: importance, reserves, demand, applications, critical uncertainties, global economy, and zeta potential characterization

2020 ◽  
Vol 05 ◽  
Author(s):  
Silas Santos ◽  
Orlando Rodrigues ◽  
Letícia Campos
Keyword(s):  
Rare Earth ◽  
Zeta Potential ◽  
Sample Preparation ◽  
Rare Earths ◽  
Smart Materials ◽  
Global Economy ◽  
Materials Science ◽  
Functional Materials ◽  
Rare Earth Oxides ◽  
Interparticle Forces

Background: Innovation mission in materials science requires new approaches to form functional materials, wherein the concept of its formation begins in nano/micro scale. Rare earth oxides with general form (RE2O3; RE from La to Lu, including Sc and Y) exhibit particular proprieties, being used in a vast field of applications with high technological content since agriculture to astronomy. Despite of their applicability, there is a lack of studies on surface chemistry of rare earth oxides. Zeta potential determination provides key parameters to form smart materials by controlling interparticle forces, as well as their evolution during processing. This paper reports a study on zeta potential with emphasis for rare earth oxide nanoparticles. A brief overview on rare earths, as well as zeta potential, including sample preparation, measurement parameters, and the most common mistakes during this evaluation are reported. Methods: A brief overview on rare earths, including zeta potential, and interparticle forces are presented. A practical study on zeta potential of rare earth oxides - RE2O3 (RE as Y, Dy, Tm, Eu, and Ce) in aqueous media is reported. Moreover, sample preparation, measurement parameters, and common mistakes during this evaluation are discussed. Results: Potential zeta values depend on particle characteristics such as size, shape, density, and surface area. Besides, preparation of samples which involves electrolyte concentration and time for homogenization of suspensions are extremely valuable to get suitable results. Conclusion: Zeta potential evaluation provides key parameters to produce smart materials seeing that interparticle forces can be controlled. Even though zeta potential characterization is mature, investigations on rare earth oxides are very scarce. Therefore, this innovative paper is a valuable contribution on this field.

China and the Geopolitics of Rare Earths

2017 ◽  
Author(s):  
Sophia Kalantzakos
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Resource Competition ◽  
Renewable Energy Sources ◽  
High Tech ◽  
Trade Dispute ◽  
Policy Responses ◽  
Economic Statecraft ◽  
The Rare Earth

In 2010, because of a geopolitical incident between China and Japan, seventeen elements of the periodic table known as rare earths became notorious overnight. An “unofficial” and temporary embargo of rare-earth shipments to Japan alerted the world to China’s near monopoly position on the production and export of these indispensable elements for high-tech, defense, and renewable energy sources. A few months before the geopolitical confrontation, China had chosen to substantially cut export quotas of rare earths. Both events sent shockwaves across the markets, and rare-earth prices skyrocketed, prompting reactions from industrial nations and industry itself. The rare-earth crisis is not a simple trade dispute, however. It also raises questions about China’s use of economic statecraft and the impacts of growing resource competition. A detailed and nuanced examination of the rare-earth crisis provides a significant and distinctive case study of resource competition and its spill-over geopolitical effects. It sheds light on the formulation, deployment, longevity, effectiveness, and, perhaps, shortsightedness of policy responses by other industrial nations, while also providing an example of how China might choose to employ instruments of economic statecraft in its rise to superpower status.

Effects of non-axial electric field gradients on the ferromagnetic state of amorphous rare-earth alloys

1980 ◽  
Vol 58 (5) ◽  
pp. 629-632 ◽  
Author(s):  
H. Hernandez ◽  
R. Ferrer ◽  
M. J. Zuckermann
Keyword(s):  
Rare Earth ◽  
Electric Field ◽  
Ferromagnetic State ◽  
Rare Earth Alloys ◽  
Electric Field Gradients ◽  
Axial Electric Field ◽  
Ferromagnetic Alloys ◽  
Field Gradients ◽  
Ordered State

We discuss the influence of non-axial electric field gradients on the ordered state of amorphous ferromagnetic alloys containing rare-earth atoms.

scholarly journals Separation of Radionuclides from a Rare Earth-Containing Solution by Zeolite Adsorption

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Deniz Talan ◽  
Qingqing Huang
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Contact Time ◽  
Separation Efficiency ◽  
Ph Value ◽  
Solid Phase ◽  
Separation Performance ◽  
Solution Ph ◽  
Zeolite Sample ◽  
Alternative Sources

The increasing industrial demand for rare earths requires new or alternative sources to be found. Within this context, there have been studies validating the technical feasibility of coal and coal byproducts as alternative sources for rare earth elements. Nonetheless, radioactive materials, such as thorium and uranium, are frequently seen in the rare earths’ mineralization, and causes environmental and health concerns. Consequently, there exists an urgent need to remove these radionuclides in order to produce high purity rare earths to diversify the supply chain, as well as maintain an environmentally-favorable extraction process for the surroundings. In this study, an experimental design was generated to examine the effect of zeolite particle size, feed solution pH, zeolite amount, and contact time of solid and aqueous phases on the removal of thorium and uranium from the solution. The best separation performance was achieved using 2.50 g of 12-µm zeolite sample at a pH value of 3 with a contact time of 2 h. Under these conditions, the adsorption recovery of rare earths, thorium, and uranium into the solid phase was found to be 20.43 wt%, 99.20 wt%, and 89.60 wt%, respectively. The Freundlich adsorption isotherm was determined to be the best-fit model, and the adsorption mechanism of rare earths and thorium was identified as multilayer physisorption. Further, the separation efficiency was assessed using the response surface methodology based on the development of a statistically significant model.

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