scholarly journals Removal of Fluorine from RECl3 in Solution by Adsorption, Ion Exchange and Precipitation

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 31
Author(s):  
DongLiang Zhang ◽  
Kai Gao ◽  
XiaoWei Zhang ◽  
MiTang Wang
Keyword(s):  
Rare Earth ◽  
Reaction Time ◽  
Ion Exchange ◽  
Reaction Temperature ◽  
Rare Earths ◽  
Chloride Solution ◽  
Lanthanum Carbonate ◽  
Injection Flow ◽  
Rare Earth Chloride ◽  
Initial Ph

In this paper, methods of effective removal of fluorine from rare earth chloride solution by adsorption, ion exchange and precipitation with lanthanum carbonate or CO2 gas as fluorine-removal agent, respectively, were studied. The relevant parameters studied for fluorine-removal percentage were the effects of the type and dosage of fluorine-removal agent, the injection flow and mode of CO2, the initial concentration of rare earth solution and initial pH value, contact time, temperature and stirring. XRD, SEM and EDS were used to analyze and characterize the filter slag obtained after fluorine removal. SEM and EDS results showed that RECO3(OH) with a porous structure was formed in rare earth chloride solution when lanthanum carbonate was used as fluorine-removal agent, and it had strong selective adsorption for F−. The XRD spectra showed that F− was removed in the form of REFCO3 precipitates, which indicates that the adsorbed F− replaced the OH- group on the surface of RECO3(OH) by ion exchange. The experimental results showed that a fluorine-removal percentage of 99.60% could be obtained under the following conditions: lanthanum carbonate dosage, 8%; initial conc. of rare earths, 240 g/L; initial pH, 1; reaction temperature, 90 °C; reaction time, 2 h. Simultaneously, a fluorine-removal process by CO2 precipitation was explored. In general, RE2(CO3)3 precipitation is generated when CO2 is injected into a rare earth chloride solution. Interestingly, the results of XRD, SEM and EDS showed that the sedimentation slag was composed of REFCO3 and RE2O2CO3. It was inferred that RE2(CO3)3 obtained at the initial reaction stage had a certain adsorption effect on F− in the solution, and then F− replaced CO32− on the surface of RE2(CO3)3 by ion exchange. Therefore, F− was finally removed by the high crystallization of REFCO3 precipitation, and excess RE2(CO3)3 was aged to precipitate RE2O2CO3. The fluorine-removal percentage can reach 98.92% with CO2 precipitation under the following conditions: venturi jet; CO2 injection flow, 1000 L/h; reaction temperature, 70 °C; initial pH, 1; reaction time, 1.5 h; initial conc. of rare earths, 240–300 g/L; without stirring. The above two methods achieve deep removal of fluorine in mixed fluorine-bearing rare earth chloride solution by exchanging different ionic groups. The negative influence of fluorine on subsequent rare earth extraction separation is eliminated. This technology is of great practical significance for the further development of the rare earth metallurgy industry and the protection of the environment.

Synthesis of Lanthanum Oxide Using Hydrogen Peroxide as Auxiliary Reagent by Spray Pyrolysis Method

2014 ◽  
Vol 1081 ◽  
pp. 38-42
Author(s):  
Zhen Feng Wang ◽  
Wen Yuan Wu ◽  
Xue Bian ◽  
Shou Feng Xue
Keyword(s):  
Hydrogen Peroxide ◽  
Rare Earth ◽  
Spray Pyrolysis ◽  
Reaction Temperature ◽  
High Purity ◽  
Chloride Solution ◽  
Lanthanum Oxide ◽  
Lanthanum Chloride ◽  
Spray Pyrolysis Method ◽  
The Rare Earth

With lanthanum chloride solution as raw material, and use the hydrogen peroxide of clean and pollution-freeobtained from oxidation reaction as auxiliary reagent, and with the carrier gas together form spray pyrolysis to obtain lanthanum oxide. On the one hand, in the hydrogen peroxide system, the temperature of direct pyrolysis reaction of lanthanum chloride solution decreased obviously, The reaction temperature is decreased from 1280°C to 1000°C or less. That reduce the energy consumption and simplify the requirements of pyrolysis equipment technology. The production process does not use NH3.H2O and NaOH to precipitate. It does not produce the traditional process of NH4+, Na+ to pollute water. It can greatly reduce the damage to the environment, and can product with high yield, high purity of the rare earth oxide. This method not only applies to the pyrolysis of the rare earth chloride solution, also applies to metal chloride solution, such as FeCl3, AlCl3, NiCl2. It was shown that the reaction temperature has been effectively reduced, VLaCl3: VH2O2 with 1: 1.5 can get high purity of La2O3.

Orthogonal Investigation of Influencing Factors on the Modification of Montmorillonite by THPC in Acid Conditions

2014 ◽  
Vol 936 ◽  
pp. 1017-1021
Author(s):  
Pan Chen ◽  
Jin Cheng Wang
Keyword(s):  
Reaction Time ◽  
Ion Exchange ◽  
Influencing Factors ◽  
Reaction Temperature ◽  
Orthogonal Test ◽  
Test Results ◽  
Phosphonium Salts ◽  
Exchange Reactions ◽  
Quaternary Phosphonium Salts

Na-MMT was modified with quaternary phosphonium salts, tetramethylolphosphonium chloride (THPC), via ion-exchange reactions, in acid conditions. Different factors such as reaction time , reaction temperature, the types of solvent, and CEC ratios, were investigated using orthogonal test. Results showed that the best combination of these four factors were A1B3C1D1, that is, the type of the solvent was acetone and water (1:1), reaction time was 3h, CEC ratio was 1:1, and the reaction temperature was 80°C.

Clean production of rare earth oxide from rare earth chloride solution by electrical transformation

2020 ◽  
Vol 197 ◽  
pp. 105372
Author(s):  
Deliang Meng ◽  
Qiuyue Zhao ◽  
Xijuan Pan ◽  
Ting-an Zhang
Keyword(s):  
Rare Earth ◽  
Chloride Solution ◽  
Rare Earth Oxide ◽  
Clean Production ◽  
Rare Earth Chloride

Numerical simulation of fluid dynamics in rare earth chloride solution in jet-flow pyrolysis reactor

2015 ◽  
Vol 25 (3) ◽  
pp. 997-1003 ◽  
Author(s):  
Chao LÜ ◽  
Qiu-yue ZHAO ◽  
Zi-mu ZHANG ◽  
Zhi-he DOU ◽  
Ting-an ZHANG ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Rare Earth ◽  
Chloride Solution ◽  
Jet Flow ◽  
Rare Earth Chloride ◽  
Pyrolysis Reactor

Recovery of europium from a rare earth chloride solution

1998 ◽  
Vol 49 (1-2) ◽  
pp. 167-177 ◽  
Author(s):  
C.A. Morais ◽  
V.S.T. Ciminelli
Keyword(s):  
Rare Earth ◽  
Chloride Solution ◽  
Rare Earth Chloride

Advanced Treatment of Biochemical Treated Coking Wastewater by Ozonation Process

2013 ◽  
Vol 726-731 ◽  
pp. 2515-2520 ◽  
Author(s):  
De Min Yang ◽  
Jian Mei Yuan
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Ozone Concentration ◽  
Ph Value ◽  
Removal Rate ◽  
Color Removal ◽  
Advanced Treatment ◽  
Coking Wastewater ◽  
Initial Ph ◽  
Ozonation Process

Advanced treatment of biochemical treated coking wastewater was studied experimentally with ozonation process. The effects of initial pH value, ozone concentration, reaction temperature, and reaction time on the COD and color removal rate were investigated. The results showed that ozonation was an effective method for advanced treatment of biochemical treated coking wastewater. The increasing of initial pH value, ozone concentration, reaction temperature, and reaction time has enhanced the removal rate of COD and color. Meanwhile, the results also revealed that the maximal COD and color removal rate of 69.65% and 92.27% could be reached under the optimal conditions of the initial pH value is 10.5, ozone concentration is 150 mg/L, reaction temperature is 298 K, and reaction time is 30 min.

Formation constants of trivalent lanthanide metal ions and hydrazone β-diketones in 75% dioxane – water solvent

1988 ◽  
Vol 66 (9) ◽  
pp. 2362-2366 ◽  
Author(s):  
Basheir A. El-Shetary ◽  
Shaker L. Stefan ◽  
Mohamed S. Abdel-Moez ◽  
Mahmoud M. Mashaly
Keyword(s):  
Rare Earth ◽  
Ion Exchange ◽  
Rare Earths ◽  
Ionization Constant ◽  
Formation Constants ◽  
Organic Ligands ◽  
Ph Titration ◽  
Water Solvent ◽  
Trivalent Lanthanide ◽  
Lanthanide Metal

A new series of hydrazone β-diketone organic ligands were prepared: 3-(2-acetylphenylhydrazone)pentane-2,4-dione (2-APHA), 2-(2-acetylphenylhydrazone)-1-phenyl-1,3-butane dione (2-APHB), 2-(2-acetylphenylhydrazone)-1,3-diphenyl-1,3-propane dione (2-APHDB), 3-(2-acetylphenylhydrazone) 1,1,1-trifluoropentane-2,4-dione (2-APHTA) and 2-(2-acetyl-phenylhydrazone)-5,5-dimethyl-1,3-cyclohexane dione (2-APHDm). The step formation constants of their 1:1 and 1:2 rare-earth complexes were determined at 30 °C by pH titration in 75% (v/v) dioxane–water solvent. The ionization constant of ligands were also measured. A curious odd–even stability differential was apparent in the (2-APHDm) ligand with the heavier rare earths Gd–Lu. The differential was apparent in both log K1 and log β values and may be sufficient to cause reversal of the usual ion-exchange elution sequence.

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.

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