Kinetics and mechanism of the reduction-dissolution of cerium oxide catalyzed by fluoride ions in hydrochloric acid solution

Lemont, Florent; Barbier, A

doi:10.1016/j.hydromet.2018.12.009

Cited by 9 publications

(7 citation statements)

References 15 publications

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“…Despite that, it is well known that the dissolution of cerium oxide in aqueous solutions is hindered by the great stability of the crystalline network, the same that endures the cyclic formation of oxygen vacancies and cerium reduction. 22 However, nanoceria around 2–3 nm is very close to the calculated thermodynamically stable crystal size 23 facilitating NP dissolution. This process accelerates as pH decreases.…”

Section: Resultssupporting

confidence: 58%

“…Therefore, if Ce 3+ ions and the corresponding oxygen vacancies are not recycled back to Ce 4+ and oxygen absorbed, the increasing concentration of these oxygen vacancies in the NP will lead to cation repulsion and the NP to irreversible disintegrate. Despite that, it is well known that the dissolution of cerium oxide in aqueous solutions is hindered by the great stability of the crystalline network, the same that endures the cyclic formation of oxygen vacancies and cerium reduction 22 . However, nanoceria around 2-3 nm is very close to the calculated thermodynamically stable crystal size 23 Please do not adjust margins Please do not adjust margins facilitating NP dissolution.…”

Section: Please Do Not Adjust Marginsmentioning

confidence: 99%

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Nanoceria dissolution at acidic pH by breaking off the catalytic loop

et al. 2022

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Section: Resultssupporting

confidence: 58%

Section: Please Do Not Adjust Marginsmentioning

confidence: 99%

Nanoceria dissolution at acidic pH by breaking off the catalytic loop

et al. 2022

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“…Thus, the determination of 141 Pr was hindered by the spectral interference due to the presence of hydride polyatomic ions 140 Ce 1 H and a "tail" of the neighboring intense peak of 140 Ce. The determination of 159 Tb was difficult because of the presence of hydroxide interferences with the 142 Ce 16 O 1 H matrix element.…”

Section: Resultsmentioning

confidence: 99%

“…The described procedure of sample decomposition is suitable for cerium oxide samples not subjected to preliminary heat treatment (calcination). The HF concentration in the studied solution, considering the dilution factors, was 0.025 and 0.012% for ICP-OES and ICP-MS analysis, respectively, which corresponds to its catalytic amounts [16]. These concentrations are low enough not to affect the analytical characteristics of the methods used to determine the target impurity elements in cerium oxide.…”

Section: Methodsmentioning

confidence: 96%

Analysis of Cerium Oxide by Mass Spectrometry and Optical Emission Spectrometry with Inductively Coupled Plasma

2021

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Procedures are developed for the multielement analysis of high-purity cerium oxide for the manufacture of phosphors and optical materials using inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The "robust" settings of the mass spectrometer are given suitable to determine Fe, Ni, Cr, Co, Cu, V, Mn, and rare-earth metals in cerium oxide (nebulizer gas flow, liquid flow, plasma sampling depth, the extract lens voltage), lowering the matrix effect and, therefore, enabling the use of more concentrated solutions for analysis. The effect of the matrix element in the direct analysis of cerium oxide by ICP-OES is estimated. The combination of mass spectral and atomic emission methods has some advantages, expands the range of elements to be determined, and increases the reliability of the analysis. In particular, the use of ICP-OES makes it possible to determine low concentrations of terbium in cerium oxide (the limit of determination for terbium by ICP-OES is 1 × 10 -4 wt %) and decreases the limits of determination for Fe and Pr by a factor of 4-5 compared to ICP-MS. The limits of determination of the target components (Fe, Ni, Cr, Co, Cu, V, Mn, and rare-earth metals) in cerium oxide by ICP-MS and ICP-OES are in the range of n × 10 -6 -n × 10 -4 wt %.

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“…It has an impact on the subsequent extraction process of rare earth elements. Many studies have shown that it is difficult to leach Ce(IV) by dilute hydrochloric acid alone, which reduces the leaching rate of rare earth elements. While Ce(IV) is reduced to Ce(III) in the hydrochloric acid leaching solution, the stable complex ion [CeF x ] 4– x causes the conversion of Cl – to Cl 2 .…”

Section: Introductionmentioning

confidence: 99%

Decomposition Process of Nonoxidative Microwave Radiation Roasting of a Mixed Rare Earth Concentrate with Sodium Carbonate

Tian

Guan

et al. 2021

ACS Omega

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This article introduces an efficient decomposition process that uses sodium carbonate (Na 2 CO 3 ) and activated carbon (C) as additives to decompose Bayan Obo mixed rare earth concentrate (hereinafter to be referred to as RE concentrate) by nonoxidative microwave radiation roasting. The roasting temperature, holding time, and contents of Na 2 CO 3 and activated carbon are investigated. The optimum process parameters for decomposition are 800 °C and 30 min. The ratio of m(Na 2 CO 3 )/m(RE concentrate) is 0.5, and the ratio of m(C)/m (ER concentrate and Na 2 CO 3 ) is 0.2 based on experimental data. Under the above conditions, the decomposition rate (shortened to DR) of RE concentrate is 98.58%, and the removal rates (shortened to CRs) of fluorine (F) and phosphorus (P) reached 80.35 and 46.75%, respectively. These rates are higher than traditional oxidation roasting under the same conditions. The three reasons for the result are the unique microwave heating characteristics, the overall efficient reaction of the mixture (RE concentrate, Na 2 CO 3 , and activated carbon), and the high nonoxidation rate of cerium. For these reasons and large experimental data, the reaction rate of the mixture is improved, and the efficiency of dilute hydrochloric acid for leaching rare earth elements is enhanced. In this article, the valence of rare earth elements in the roasted ore is all in the form of trivalence. Importantly, this nonoxidative roasted product can avoid the generation of chlorine in hydrochloric acid leaching. Moreover, such a short holding time is scarce in traditional roasting. When the mixture was roasted by utilizing microwave heating, the sinter phenomenon of the roasted product was avoided at high-temperature roasting. Finally, the surface morphology of RE concentrate at different conditions was observed by scanning electron microscopy (SEM) analysis, which can be used to compare the specific differences of roasting methods. According to these results, this process is beneficial for the decomposition of RE concentrate in terms of Na 2 CO 3 roasting and is helpful for improving the clean and green technology method of hydrometallurgy.

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Kinetics and mechanism of the reduction-dissolution of cerium oxide catalyzed by fluoride ions in hydrochloric acid solution

Cited by 9 publications

References 15 publications

Nanoceria dissolution at acidic pH by breaking off the catalytic loop

Nanoceria dissolution at acidic pH by breaking off the catalytic loop

Analysis of Cerium Oxide by Mass Spectrometry and Optical Emission Spectrometry with Inductively Coupled Plasma

Decomposition Process of Nonoxidative Microwave Radiation Roasting of a Mixed Rare Earth Concentrate with Sodium Carbonate

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