scholarly journals The Kinetic Aspects of the Dissolution of Slightly Soluble Lanthanoid Carbonates

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1793
Author(s):  
‪Tatiana Litvinova ◽  
Ruslan Kashurin ◽  
Ivan Zhadovskiy ◽  
Stepan Gerasev
Keyword(s):  
Activation Energy ◽  
Rare Earth ◽  
Raw Materials ◽  
Earth Metal ◽  
Dissolution Process ◽  
Complexing Agent ◽  
System Temperature ◽  
Reaction Orders ◽  
Technogenic Raw Materials ◽  
Degree Of Extraction

The problem of the complex use of mineral raw materials is significant in the context of many industries. In the rare earth industry, in the context of limited traditional domestic reserves and dependence on imports of lanthanides, an unambiguous and comprehensive solution has not yet been developed. Promising areas include the involvement of technogenic raw materials in the industrial turnover. The present study examines the kinetics of the dissolution process of poorly soluble lanthanide compounds when changing the parameters of the system. The results obtained reflect the dependence of the degree of extraction of lanthanide on the following variable parameters of the system: temperature, concentration of the complexing agent, and intensity of mixing. On the basis of the experiment, the values of the activation energy and the reaction orders were calculated. The activation energy of the carbonate dissolution process, in kJ/mol, was as follows: 61.6 for cerium, 39.9 for neodymium, 45.4 for ytterbium. The apparent reaction orders of the carbonates are equal to one. The prospect of using the research results lies in the potential to create a mathematical model of the process of extracting a rare earth metal by the carbonate alkaline method.

Viscosity Of Molten Rare Earth Metal Trichlorides I. Cecl3, Ndcl3, Smcl3, Dycl3 And Ercl3

2003 ◽  
Vol 58 (7-8) ◽  
pp. 457-463 ◽  
Author(s):  
A. Potapov ◽  
V. Khokhlov ◽  
Y. Satoa
Keyword(s):  
Activation Energy ◽  
Rare Earth ◽  
Viscous Flow ◽  
Rare Earth Metal ◽  
Dynamic Viscosity ◽  
Kinematic Viscosity ◽  
Arrhenius Equation ◽  
Earth Metal ◽  
Capillary Viscometer ◽  
Density Data

The kinematic viscosity of molten CeCl3, NdCl3, SmCl3, DyCl3 and ErCl3 has been measured by using a capillary viscometer. The dynamic viscosity was computed by using density data taken from the literature. The viscosity increases with going from CeCl3 to ErCl3. The activation energy of the viscous flow, calculated by the Arrhenius equation, rises in the same order.

Cathodes based on rare-earth metal nickelate ferrites prepared from industrial raw materials for solid oxide fuel cells

2014 ◽  
Vol 50 (6) ◽  
pp. 548-553 ◽  
Author(s):  
I. Yu. Yaroslavtsev ◽  
N. M. Bogdanovich ◽  
G. K. Vdovin ◽  
T. A. Dem’yanenko ◽  
D. I. Bronin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Rare Earth Metal ◽  
Raw Materials ◽  
Earth Metal ◽  
Solid Oxide ◽  
Oxide Fuel

scholarly journals Increasing the efficiency of rare earth metal recovery from technological solutions during processing of apatite raw materials

2021 ◽  
Vol 252 ◽  
pp. 1-10
Author(s):  
Maria Ponomareva ◽  
Olga Cheremisina ◽  
Yulia Mashukova ◽  
Elena Lukyantseva
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Ion Exchange ◽  
Anion Exchanger ◽  
Raw Materials ◽  
Earth Metal ◽  
Mass Action ◽  
Exchange Equilibrium ◽  
Static Conditions ◽  
Sulfate Complexes

The issues of complex processing of mineral resources are relevant due to the depletion of available raw materials. So, it is necessary to involve technological waste, generated during the processing of raw materials, to obtain valuable components. In the process flow of apatite concentrate treatment using the sulfuric acid method, a large amount of phosphogypsum is produced with an average content of light rare earth metals (REMs) reaching 0.032-0.45 %. When phosphogypsum is treated with sulfuric acid solutions, a part of REMs is transferred to the sulfate solution, from which it can be extracted by means of ion exchange method. The study focuses on sorption recovery of light REMs (praseodymium, neodymium and samarium) in the form of anionic sulfate complexes of the composition [ln(SO4)2]– on polystyrene anion exchanger AN-31. The experiments were performed under static conditions at a liquid-to-solid ratio of 1:1, pH value of 2, temperature of 298 K and initial REM concentration in the solutions ranging from 0.83 to 226.31 mmol/kg. Thermodynamic description of sorption isotherms was carried out by the method based on linearization of the mass action equation, modified for the ion exchange reaction. As a result of performed calculations, the authors obtained the constants of ion exchange equilibrium for Pr, Nd and Sm, as well as the values of the change in the Gibbs energy for the ion exchange of REM sulfate complexes on the AN-31 anion exchanger and the values of total capacity of the anion exchanger. Calculated separation factors indicated low selectivity of AN-31 anionite exchanger for light REMs; however, the anion exchanger is suitable for effective recovery of a sum of light REMs. Based on the average value of ion exchange equilibrium constant for light REMs, parameters of a sorption unit with a fluidized bed of anion exchanger were estimated.

Particle Coarsening of Dispersoids In Rapidly Solidified Ti-5Sn-3Y

1985 ◽  
Vol 58 ◽  
Author(s):  
Y.Z. Lu ◽  
B.C. Giessen ◽  
S.H. Whang
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Rare Earth ◽  
Elevated Temperature ◽  
Growth Kinetics ◽  
Diffusion Rate ◽  
Earth Metal ◽  
Ti Alloys ◽  
Rapidly Solidified ◽  
Determining Factor

ABSTRACTRapidly solidified Ti alloys containing rare earth metal dispersoids, such as La or Er, have excellent resistance to coarsening at elevated temperature (700–900°C). In particular, the coarsening of the dispersoid particles in RSP Ti-5Sn-3Y was studied; these particles were found to be Y5Sn3. The measured growth kinetics were found to be compatible with the modified LSW model; it was concluded from the observed parameters that in this alloy the diffusion rate of Y is the rate determining factor, providing a measurement of the diffusion coefficient of Y in a Ti matrix and yielding its activation energy Q = 272 kJ/mole.

scholarly journals Rare-earth metal ore processing technologies when developing new deposits

2020 ◽  
pp. 47-53
Author(s):  
T. I. Yushina ◽  
◽  
I. M. Petrov ◽  
S. A. Cherny ◽  
A. I. Petrova ◽  
...  
Keyword(s):  
Rare Earth ◽  
Raw Materials ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Dense Medium ◽  
Clear Trend ◽  
Processing Technologies ◽  
Hydrometallurgical Processing ◽  
Mass Fractions ◽  
Materials Used

The article provides a brief overview of processing technologies for rare-earth raw materials used under greenfield development projects in different countries of the world (Africa, Greenland, Australia, Canada). The projects feature deposits with different mineral compositions, mass fractions of rare-earth metals (REM) in ores of 0.2 to 15 %, and the presence of niobium, zirconium, tantalum, phosphorus, uranium, and thorium. The resulting production facilities will extract 180 kt to 7.2 Mt rare-earth ore annually to generate 1.5 to 20 kt oxides of heavy and light groups of rare-earth metals along with the rare metals. The analysis of technologies for the projects considered demonstrates that magnetic and radiometric separation, dense-medium concentration and flotation with hydrometallurgical processing in the form of leaching with sulfuric or hydrochloric acid, followed by extraction of the target products, will be used for the processing of rare-earth raw materials. A characteristic feature of a number of projects is, first of all, the direct hydrometallurgical processing of the feed. The concentration technologies for ores containing rare-earth metals also indicate a clear trend towards a more active use of high-intensity magnetic separation. The main products to be obtained with these technologies will include composite concentrates of oxides or carbonates of rare-earth metals. At the same time, the commissioning dates for the projects are being repeatedly postponed; the implementation of many projects remains uncertain, which is largely due to the stagnant dynamics of global prices for rare-earth metals.

scholarly journals Solvent Extraction and Separation of Nd, Pr and Dy from Leach Liquor of Waste NdFeB Magnet Using the Nitrate Form of Mextral® 336At in the Presence of Aquo-Complexing Agent EDTA

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 269 ◽  
Author(s):  
Aarti Kumari ◽  
Kamala Kanta Sahu ◽  
Sushanta Kumar Sahu
Keyword(s):  
Rare Earth ◽  
Solvent Extraction ◽  
Ethylenediaminetetraacetic Acid ◽  
Earth Metal ◽  
Leach Solution ◽  
Complexing Agent ◽  
Analysis Method ◽  
Ndfeb Magnet ◽  
Extraction And Separation ◽  
The Fourier Transform

：Solvent extraction and separation of Pr, Nd and Dy from a synthetic leach solution of spent NdFeB magnet from wind turbines in the presence of aquo-complexing agent Ethylenediaminetetraacetic acid (EDTA) was studied using the nitrate form of Mextral® 336At ([336At][NO3]) as an extractant. The effect of different process parameters such as pH, extractant, nitrate, and EDTA concentrations on the extraction of Pr, Nd and Dy was studied. The extraction of these rare earths elements follows the order Pr > Nd > Dy, whereas EDTA forms stable complexes in the order Dy > Nd > Pr. The synergy of these two effects improved the selectivity among these elements as compared to when no aquo-complexing agent was used. The mechanism of extraction of rare earth elements was established by slope analysis method. The Fourier-Transform Infrared Spectroscopy (FTIR) spectra of [336At][NO3] and extracted Nd complex were recorded to understand the interaction of extractant with rare earth metal ions in the organic phase.

scholarly journals Study of the Solubility of Sediments of Certain Lantanoids in Carbonate Solutions

2020 ◽  
Vol 12 (4) ◽  
pp. 63-71
Author(s):  
R. Kashurin ◽  
◽  
S. Gerasev ◽  
A. Suslov
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Ion Concentration ◽  
Dissolution Process ◽  
Factors Affecting ◽  
Advantages And Disadvantages ◽  
Extraction Degree ◽  
Red Sludge

The study examines the dissolution process for the precipitates of the rare-earth carbonates and phosphates with a change in the concentration parameters of the system. The objective of the study is to determine the nature of the dissolution process at variable composition of the studied solutions. As a result of the theoretical base analysis, the qualitative and quantitative content of rare-earth metals in red sludge and phosphogypsum is presented, which governs the interest in this problem under consideration. The available techniques for extraction of rare-earth metals from red sludge and phosphogypsum have also been considered, their advantages and disadvantages are presented. A promising carbonate-alkali method for the extraction of rare-earth metals has been considered. Thermodynamic parameters of the system have been calculated to determine the possibility of the process. During the experiment the factors affecting the dissolution process have been examined: the carbonate ion concentration, the nature of the solvent cation and rare-earth metal cation. Carbonates and phosphates of europium, holmium, and neodymium have been considered as the analyzed components. Carbonates and phosphates of neodymium, europium, and holmium have been dissolved in model solutions of K2CO3 with the concentrations of 0.2–4.5 mol/L until reaching equilibrium. The obtained results show the dependence of solubility of the precipitates of rare-earth metals on the solvent nature and concentration. The explored data are presented as solubility isotherms. On the basis of experimental data the values of the extraction degree of a rare-earth metal into the solution have been calculated. For neodymium, europium, and holmium carbonates, the maximum recovery degree αmax is 72.8 %, 81.2 %, 83.0 %, respectively. During the experiment with dissolution of lanthanide phosphates, the following results have been obtained: the maximal degree of neodymium extraction is 60.59%, while for europium it equals 51.66 % and 93.01 % for holmium

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