Wet Air Oxidation and Kinetics of Cerium(III) of Rare Earth Hydroxides

Zou, Dan; Chen, Ji; Cui, Hongmin; Liu, Yu; Li, Deqian

doi:10.1021/ie502241t

Cited by 22 publications

(12 citation statements)

References 24 publications

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“…Moreover, only 18% of the cerium was dissolved. Indeed, Ce(III) is prone to oxidation when in contact with air even in the presence of strongly chelating agents (Deblonde et al, 2013;Zou et al, 2014). Consequently, it is very likely that CePO 4(s) is partly converted into Ce(OH) 4(s) during the alkaline conversion, which prevents its dissolution in dilute HCl in the next step of the process.…”

Section: Purification Of Phosphate Ree Concentratementioning

confidence: 99%

Recovery of yttrium and lanthanides from sulfate solutions with high concentration of iron and low rare earth content

Beltrami¹,

Deblonde²,

Bélair³

et al. 2015

Hydrometallurgy

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To overcome the low recovery, generally obtained for the heavy and middle rare earth elements (HREE and MREE) by sodium double sulfate precipitation, the recovery of the MREE and HREE as phosphate salts was investigated. High recovery yields (≥95%) were obtained even for sulfate solutions containing low concentrations of REE and a high concentration of iron(II). The influence of many industry-relevant parameters (temperature, pH, stoichiometric excess of phosphate, aluminum contamination, residence time) is discussed in order to optimize the REE recovery and to minimize the precipitation of iron. The developed process was also validated in continuous operation at a pilot scale. Finally, the REE phosphate concentrate could be converted into REE hydroxides which allows its dissolution into diluted HCl. Taking into account the phosphate precipitation, the conversion into hydroxides and the dissolution in HCl (aq) , high recovery yields were obtained for Y, Gd and La (68%, 77% and 86% respectively). The results show that it is possible to economically obtain purified REE solutions starting from industrial solutions which are usually discarded.

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Section: Purification Of Phosphate Ree Concentratementioning

confidence: 99%

Recovery of yttrium and lanthanides from sulfate solutions with high concentration of iron and low rare earth content

Beltrami¹,

Deblonde²,

Bélair³

et al. 2015

Hydrometallurgy

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“…In the rare earth industry, mixed rare earth minerals, bastnaesite, monazite, ion-absorbed rare earth ore and xenotime are generally used as feedstock to produce rare earth products [2]. The mixed rare earth mines in Bayan Obo are some of the most critical rare earth mines in China and in the world because of their large reserves and output [3]. Mixed rare earth concentrates (MREC) commonly used in industry are composed of bastnaesite and monazite in a range from 7:3 to 8:2, containing 50-65% rare earth oxide (REO), 7-10% fluorine and some other impurie elements [4,5].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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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.

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“…Rare earth (RE) elements exist in a variety of minerals, some of which, such as bastnaesite, monazite, and Bayan Obo mixed rare earth ores, are of great significance and commercial value [1][2][3]. As for the rare earth resources in the world, bastnaesite deposits in China and the United States account for the largest proportion.…”

Section: Introductionmentioning

confidence: 99%

“…Monazite deposits in Australia, Brazil, China, India, Malaysia, South Africa, Sri Lanka, Thailand, and the United States are the second largest deposits [4][5][6][7][8]. The Bayan Obo mixed rare earth ores, which is mainly composed of bastnaesite and monazite, is the largest light rare earth resource in the world [3,9]. The Bayan Obo deposit is actually the tailings of the iron ore processing scheme of Fe-RE-Nb deposit [10,11].…”

Section: Introductionmentioning

confidence: 99%

Extraction and Recovery of Cerium from Rare Earth Ore by Solvent Extraction

Li¹,

Chen²,

Zou³

2019

Cerium Oxide - Applications and Attributes

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Rare earth elements are widely found in many minerals, some of which, such as bastnaesite, monazite, and xenotime, are of great commercial value. Cerium (Ce) is the rare earth element with the highest content in light rare earth ore. Solvent extraction is the most effective and efficient method to recover and separate Ce from other light rare earth elements. After acid leaching of rare earth minerals, leaching solution was obtained, and cerium oxide of products of high purity was obtained by extraction and stripping. It is well known that Ce(IV) can be easily separated from the other RE(III) by adopting the traditional solvent extraction. Based on this principle, the clean process of oxidation roasting and Ce(IV) separation for Sichuan bastnaesite was developed. And then, a preliminary flow sheet of two-step oxidation and extraction of Ce(IV) for Bayan Obo mixed rare earth ores was further proposed.

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Wet Air Oxidation and Kinetics of Cerium(III) of Rare Earth Hydroxides

Cited by 22 publications

References 24 publications

Recovery of yttrium and lanthanides from sulfate solutions with high concentration of iron and low rare earth content

Recovery of yttrium and lanthanides from sulfate solutions with high concentration of iron and low rare earth content

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

Extraction and Recovery of Cerium from Rare Earth Ore by Solvent Extraction

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