scholarly journals Leaching the Unleachable Mineral: Rare Earth Dissolution from Monazite Ore in Condensed Phosphoric Acid

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 931
Author(s):  
Harry Watts ◽  
Tonya Fisher
Keyword(s):  
Rare Earth ◽  
Phosphoric Acid ◽  
Caustic Soda ◽  
Rare Earths ◽  
New Process ◽  
Poorly Soluble ◽  
Rare Earth Phosphate ◽  
Solid Compounds ◽  
Monazite Ore ◽  
Strong Acids

Monazite is a poorly soluble mineral of rare earth phosphate. It is an ore of the rare earths which is difficult to break down; in industry either concentrated sulphuric acid or caustic soda is used to attack finely ground monazite at between 140 °C and 400 °C. In these processes, the rare earths are converted into different solid compounds, undergoing an incomplete conversion. Here we show a new process for a direct and much faster breakdown of monazite by simple dissolution under milder conditions. Condensed phosphoric acid was used to dissolve rare earths (up to 96 g/L) from unground monazite sand from four sources. Greater than 99% of light rare earths dissolved within 30 min at 260 °C. The cooled solution can be diluted to an extent with water to reduce viscosity for analysis or further processing. This method of dissolution avoids the use of strong acids/bases and reduces the risk of dusk exposure from fine grinding of particles.

scholarly journals New Trident Molecule with Phosphoric Acid Functionality for Trivalent Rare Earth Extraction

2017 ◽  
Vol 17 (3) ◽  
pp. 491 ◽  
Author(s):  
Keisuke Ohto ◽  
Hiromasa Murashima ◽  
Hiroshi Murakami ◽  
Shintaro Morisada ◽  
Hidetaka Kawakita ◽  
...  
Keyword(s):  
Rare Earth ◽  
Phosphoric Acid ◽  
Rare Earths ◽  
Equilibrium Constants ◽  
Extraction Equilibrium ◽  
Ph Values ◽  
Extraction Behavior ◽  
Separation Factors ◽  
Trivalent Rare Earth ◽  
Rare Earth Extraction

Tripodal extraction reagent with three phosphoric acid groups, together with the corresponding monopodal molecule has been prepared to investigate some metals extraction behavior, in particular, trivalent rare earth elements (REEs). The tripodal reagent exhibited extremely high selectivity for metals with high valency such as Zr(IV), In(III), Lu(III), and Fe(III). Tripodal reagent also exhibited exceptionally high extraction ability compared with the corresponding monopodal one in the extraction of trivalent rare earths. The result for the stoichiometry of tripodal reagent to heavy rare earths showed the inflection point between Er (2:1 for a ligand with ion) and Tm (1:1). The extraction reactions were determined for all rare earths with both reagents. The extraction equilibrium constants (Kex), the separation factors (β), half pH values (pH1/2), difference half pH values (ΔpH1/2) for extraction of REEs with both reagents are estimated.

scholarly journals SORPTION OF RARE-EARTH METALS FROM NO EVAPORATED DIHYDRATE PHOSPHORIC ACID ON MACROPOROUS STRONGLY ACIDIC CATIONITE

2018 ◽  
Vol 59 (4) ◽  
pp. 50
Author(s):  
Aleksandr V. Firsov ◽  
Aleksandr V. Artamonov ◽  
Dar'ya N. Smirnova ◽  
Aleksandr P. Ilyin ◽  
Segreiy P. Kochetkov
Keyword(s):  
Rare Earth ◽  
Phosphoric Acid ◽  
Dynamic Characteristics ◽  
Rare Earths ◽  
Rare Earth Metals ◽  
Diffusion Region ◽  
External Diffusion

The kinetic and dynamic characteristics of the sorption of rare earths metals (REE) from no evaporated extration phosphoric acid (EPA) of dihydrate production on macroporous strongly acidic cation Rurolite C150 were investigated. The process of sorption of rare earth metals was established to take place in the external diffusion region.

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.

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.

Extraction of rare earths from the leach liquor of the weathered crust elution-deposited rare earth ore with non-precipitation

2011 ◽  
Vol 98 (3-4) ◽  
pp. 125-131 ◽  
Author(s):  
Tian Jun ◽  
Yin Jingqun ◽  
Chen kaihong ◽  
Rao Guohua ◽  
Jiang Mintao ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Leach Liquor ◽  
Weathered Crust

Effects of Transition Metals and Rare Earths on Iron-Carbon Micro Electrolysis Degrading Dyeing Effluent

2014 ◽  
Vol 1010-1012 ◽  
pp. 928-933
Author(s):  
Ju Chi Kuang ◽  
Xiao Gang Chen ◽  
Min Hua Chen
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Valence Electron ◽  
Zero Valent Iron ◽  
Effluent Treatment ◽  
Related Factors ◽  
Valence Electron Structure ◽  
Iron Catalysis ◽  
Orthogonal Experiments ◽  
Dyeing Effluent

The principle and methodology of effluent treatment by iron-carbon micro electrolysis were introduced in the paper. Then design of the orthogonal experiments for dyeing effluent treatment was formulated. Discussion of influences of related factors on effluent treatment followed. Results were got after the detailed analysis. Therefore, we deduced the mechanism that the cations of Transition Metal (TM) and rare earth (RE) assist of zero-valent irons catalyzing degradation of dyeing effluent. The mechanism is formed based on the following explanation. Cations of manganese and cobalt easily penetrate Fe0lattices, while Ce4+cations do it difficultly because of their larger radius. Thus Ce4+is weaker than both of Mn2+and Co2+for helping zero-valent irons to improve their activity. Furthermore, because the valence electron structure of Mn2+is more stable than that of Co2+, Mn2+is better for assisting zero-valent iron catalysis of degradation of dyeing effluent than Co2+. Therefore, ranking of influence for zero-valent iron catalysis activity from greatest to smallest is Mn2+, Co2+and Ce4+.

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