Journal of Rare Earths最新文献

{"title":"Ce-modified USY zeolite catalysts for catalytic oxidation of chlorinated VOCs: Effect of the location of CeO2 and its synergistic effect with USY zeolite","authors":"","doi":"10.1016/j.jre.2023.12.012","DOIUrl":"10.1016/j.jre.2023.12.012","url":null,"abstract":"<div><div>The catalytic behavior of a catalyst for chlorine-containing volatile organic compounds (CVOCs) oxidation largely depends on the synergistic interaction between the oxidizing and acidic sites. In the present work, two catalysts with different distributions of CeO₂ on the inner and outer surfaces of 4.0Ce-USY-ex and 4.0Ce-USY-dp (USY zeolite) were prepared respectively by ion exchange and deposition methods, with a purpose of finding out how the location of the oxidation sites (CeO₂) influence its synergistic effect with the acidic sites of zeolite. The results show that 4.0Ce-USY-ex is much more active for catalytic degradation of 1,2-dichloroethane (DCE), while 4.0Ce-USY-dp catalyst exhibit higher catalytic degradation activity for other structured CVOCs (dichloromethane (DCM), trichloroethylene (TCE), chlorobenzene (CB)). CeO₂ in 4.0Ce-USY-ex catalyst mainly disperses in the pore channels of USY zeolite, and there are many strong acid centers on the surface, which is conducive to the dechlorination conversion of CVOCs. However, CeO₂ in 4.0Ce-USY-dp catalyst is mainly distributed on the outer surface of USY and has strong oxidation ability, which contributes to the deep oxidation of CVOCs. Moreover, the presence of a large number of strong acid centers on the catalyst surface of 4.0Ce-USY-ex catalysts leads to severe accumulation of surface carbon species and significantly decreases its stability towards DCE. However, a large number of active oxygen species on the surface of 4.0Ce-USY-dp and CeO₂ catalysts are beneficial to the deep oxidation of DCE, reducing the formation of surface carbon and thus improving the stability of the catalyst. Thus, the influence of the location of the oxidation sites on its synergistic effect with the acidic sites was established in the present work, which could provide some new ideas for the rational design of CVOCs degradation catalyst with appropriate distribution of active sites.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"42 11","pages":"Pages 2068-2077"},"PeriodicalIF":5.2,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139095207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Promotional effect of stannum on Pd/CeO2 catalysts for CO and C3H6 co-oxidation","authors":"Congwei Liu, Jie Li, Meng Wang, Jieying Cai, Miaomiao Liu, Yulong Shan, Yan Zhang, Wenpo Shan","doi":"10.1016/j.jre.2023.12.014","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.014","url":null,"abstract":"<p>The successful control of hydrocarbon and CO emissions from low-temperature diesel exhausts requires the use of highly active co-oxidation catalysts. In this study, Sn was used to enhance the catalytic performance of Pd/CeO₂ in CO and C₃H₆ co-oxidation conditions. CeO₂ with added stannum (Sn) was prepared as a support using the co-precipitation method, and Pd was loaded onto the support using the impregnation method. After Sn addition (the optimal Ce/Sn ratio is 0.75:0.25), the <em>T</em>₅₀ values of CO and C₃H₆ are reduced by 20 and 32 °C, respectively. A series of characterization methods indicates that the addition of Sn to the support greatly enhances its lattice oxygen mobility and increases the proportion of PdO. During the co-oxidation process, stronger lattice oxygen mobility allows CO to react faster through the Mars–van Krevelen mechanism, weakening the competition with C₃H₆ for O₂. A higher PdO content enhances the C₃H₆ oxidation capability. Moreover, CO can more readily reduce PdO than Pd²⁺ in solid solution with the support, which consequently further enhances co-oxidation activity. Therefore, the addition of Sn is a simple and effective strategy for enhancing the performance of Pd/CeO₂ catalysts in CO and C₃H₆ co-oxidation reactions. Furthermore, the promotional effect of CO achieved in this study contributes to a deeper understanding of the interactions that occur during the co-oxidation of C₃H₆ and CO.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"131 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139067213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoluminescence upgradation of La2MgTiO6:2%Dy3+ perovskite with monovalent (Li+), divalent (Ba2+, Sr2+) and trivalent (Bi3+, Sm3+) cation sensitization","authors":"V.P. Veena, K. Arun, C.K. Shilpa, S.V. Jasira, K.M. Nissamudeen","doi":"10.1016/j.jre.2023.12.013","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.013","url":null,"abstract":"<p>Nano phosphors of 2 % Dy³⁺ (wt%) doped La₂MgTiO₆ and monovalent/divalent/trivalent co-doped La_1.98Dy_0.02MgTiO₆:<em>x</em>%A^<em>y</em>+ (A^<em>y</em>+: Li⁺, Ba²⁺, Sr²⁺, Bi³⁺, and Sm³⁺; 0 ≤ <em>x</em> ≤ 2 wt%) were synthesized by combustion method. From the XRD data, it is deduced that an increase in the valency of co-dopant increases the crystallinity of the double perovskite orthorhombic nanocrystal structure. With an increase in co-dopant size, an elevation in optical bandgap is visible with the highest bandgap of 3.835 eV for Bi³⁺. The photo-absorption is monotonically broadened for Sr²⁺, Sm³⁺, and Li⁺ around 200–450 nm. Under 351 nm, Dy³⁺ triggered lattice shows major characteristic emission peaks at 480 nm (⁴F_9/2 → ⁶H_15/2), 574 nm (⁴F_9/2 → ⁶H_13/2), and 670 nm (⁴F_9/2 → ⁶H_11/2), leading to near white light emission with CIE coordinates (0.341, 0.376). Upon co-doping, the PL intensity is significantly increased with maximum emission for trivalent Sm³⁺, followed by divalent Sr²⁺ and monovalent Li ⁺ respectively. With increasing excitation wavelength, Sr²⁺ shows a dominated output and it is found that divalent Sr²⁺ is a potential co-dopant that could enhance luminescence intensity up to 6 times with a Sr²⁺ → Dy³⁺ energy transfer efficiency of 86 %. It is specified that the CIE coordinates of Li⁺ co-doped samples show ideal white emission with color coordinates (0.333, 0.336). The concluding outcomes signify the noblest rare earth Sm³⁺ co-doping and thus Sm³⁺ → Dy³⁺ energy transfer mechanism is discussed in detail.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"44 5 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139067211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunable and wideband high-performance rare earth-doped Ni-Mg-Cu-Zn nano ferrite-based meta-absorbers for C-band application","authors":"Majid Niaz Akhtar, Magbool Alelyani, Fatimah Mohammed A. Alzahrani, Abdullah Almohammedi, Sabih Qamar, M.A. Baqir, M. Irfan, Muhammad Azhar Khan, Kheir S. Albarkaty, Z.A. Alrowaili, M.S. Al-Buriahi","doi":"10.1016/j.jre.2023.12.007","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.007","url":null,"abstract":"<p>Due to advanced technology, electromagnet interference and dissipation problems in the electronic and portable devices at GHz range are increasing daily. Magnetic absorbing materials with outstanding electromagnetic properties, wide bandwidth, and strong absorption are highly desirable. The present investigation deals with the preparation of Ni-Mg-Cu-Zn (NMCZ) substituted nano ferrites with composition of Ni_0.3Mg_0.2Cu_0.3Zn_0.2X_0.02Fe_1.98O₄ (X = Nd, Ho, Pr, Gd, Yb). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), a vibratory sample magnetometer (VSM), and a Vector network analyzer (VNA) were used to investigate these rare earth-doped nanocrystalline ferrites' features. XRD reveals the single spinel phase structure in all Ni-Mg-Cu-Zn ferrites. FTIR spectroscopy shows the presence of tetrahedral and octahedral bands of spinel ferrites. FESEM images reveal the lowest agglomeration for the Ho-doped NMCZ nano-spinel ferrites sample. TEM images show the hexagon shapes of the Yb- and Nd-doped NMCZ ferrites. Pr-doped NMCZ ferrites show more coercivity than other rare earth metals substituted NMCZ nanocrystalline ferrites. VSM analysis was used to calculate the magnetic features like initial permeability, magnetic anisotropy constant, remanence, coercivity, and magnetic moment. High-frequency switching field distributions (SFD) analyses were also investigated. Magnetodielectric characteristics such as losses, permittivity, modulus, <em>Q</em>, ac conductivity, and impedance of the Nd-, Ho-, Pr-, Gd-, Yb-doped Ni-Mg-Cu-Zn ferrites were evaluated. The minimum reflection loss (–57.3 dB) is found at 1.4 GHz for Pr-doped Ni-Mg-Cu-Zn ferrite absorber. However, the reflection loss (RL) of –53.9 dB at 2.9 GHz is observed for Ho-doped Ni-Mg-Cu-Zn ferrite absorber. Soft magnetization, low coercivity, outstanding magnetodielectric, and absorption properties of the Nd-, Ho-, Pr-, Gd- and Yb-doped Ni-Mg-Cu-Zn ferrites are suitable candidates for absorption in telecommunication, defense, and technological industries.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"27 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139022449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure and electrochemical hydrogen storage properties of nanosized doped La2Ti2O7 solid solutions","authors":"Guofang Zhang, Xu Jianyi, Sun Shilong, Li Yiming, Liu Zhuocheng, Guo Ruihua, Yang Zhiyong, Bai Lu, Zhang Yanghuan","doi":"10.1016/j.jre.2023.12.011","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.011","url":null,"abstract":"<p>Hydrothermal-sintering method was employed to obtain pure and Li, Co, Mn, Cu and Zn doped La₂Ti₂O₇ solid solutions. The substitution sites of doping ions are discussed. X-ray diffraction (XRD) results indicate that the doped ions were incorporated into the lattice of La₂Ti₂O₇ successfully. Transmission electron microscopy (TEM) measurements prove that the doped ions with smaller radius induce the contraction of lattice. The results of UV and photoluminescence (PL) tests show that the doped ions cause the red-shift of band gap energies and enhance the concentrations of oxygen vacancies and defects. The electrochemical hydrogen storage properties of the samples were measured at 303 and 333 K, respectively. The discharge capacities of the doped samples keep growing by increasing the cycle number at 333 K. Meanwhile, the doped samples possess better kinetic performances than the pure La₂Ti₂O₇. Among the samples, the Mn, Co and Li ions doped samples exhibit better electrochemical hydrogen storage properties. The hydrogen storage properties are closely related with the characteristics of doped ions, crystallite sizes, the content of the oxygen vacancies and defects in the lattice of La₂Ti₂O₇.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"1 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139022451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solvent extraction of scandium from leaching solution of red mud roasted with ammonium sulfate using D2EHPA/TBP","authors":"","doi":"10.1016/j.jre.2023.12.010","DOIUrl":"10.1016/j.jre.2023.12.010","url":null,"abstract":"<div><div>Red mud is an important secondary resource for scandium production. The red mud leaching solution containing scandium in this study was derived from environmentally friendly ammonium sulfate roasting and water leaching process. A synergistic extraction with a mixture of di(2-ethylhexyl) phosphate acid (D2EHPA) and tributyl phosphate (TBP) for recovery of scandium from red mud leaching solution is proposed. The effects of D2EHPA concentration, H₂SO₄ concentration, rare earth elements, dosage of TBP, phase ratio (A/O), contact time and H₂O₂ concentration on scandium extraction were investigated. The results show that more than 99% scandium is extracted under the optimal conditions while Fe, Al, Ti, Ca and rare earth elements (Ce, Y, La, Nd, Er, etc.) are hardly extracted. The stripping efficiency of Sc reaches above 92.37% under the optimal stripping conditions of 5 mol/L NaOH with an A/O of 1 at 90 °C for 30 min. The proposed technology could provide an effective method for extraction of scandium from red mud leaching solution.</div></div>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"42 10","pages":"Pages 1943-1949"},"PeriodicalIF":5.2,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138741710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Creation of an oxygen-enriched environment during synthesis as an effective way to improve luminescent properties of Y2O3:Eu3+☆","authors":"Aleksandr A. Nashivochnikov, Anton I. Kostyukov, Mariana I. Rakhmanova, Lidiya S. Kibis, Svetlana V. Cherepanova, Evgenii A. Suprun","doi":"10.1016/j.jre.2023.12.008","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.008","url":null,"abstract":"<p>The growing demand for luminescent nanomaterials intended for various applications increases the necessity to develop and improve approaches to the creation of highly efficient nanosized phosphors. In current study, an approach to enhancing the efficiency of red luminescence of monoclinic Y₂O₃:Eu³⁺ with the particle size of ∼20 nm by creating the oxygen-enriched environment during the gas-phase synthesis was developed. To investigate the effect of oxygen amount during the synthesis on characteristics of the phosphor, a series of nanostructured Y₂O₃:Eu³⁺ with the addition of 0–40 vol% O₂ to the main buffer gas Ar was synthesized by laser vaporization. It is shown that the amount of added O₂ exerts virtually no effect on the phase composition and particle size, but significantly improves the luminescent characteristics of Y₂O₃:Eu³⁺. Thus, the addition of 30 vol% O₂ leads to virtually a 20-fold growth in the photoluminescence (PL) intensity caused by ⁵D₀→⁷F_0–4 transitions in Eu³⁺ and an increase in the absolute PL quantum yield from 3% to 53% (<em>λ</em>_ex = 395 nm) compared to the sample synthesized without O₂. The addition of oxygen also improves the emission color coordinates from (0.571, 0.320) to (0.630, 0.322) due to the removal of a considerable fraction of oxygen vacancies. The synthesized nanopowders are shown to be highly stable: upon storage under ambient conditions for two years. Quantum yield (QY) of the samples decreases by less than 2%. It is expected that the key features underlying the proposed approach will be useful for various methods used to synthesize oxide nanophosphors.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"6 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138741646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-dose X-ray induced long afterglow NIR luminescence from Cr3+ doped Zn1–xCdxGa2O4 spinel solid solutions","authors":"Tingting Zhao, Wenzhi Sun, Shuya Wang, Wei Meng, Chunqing Fu, Xiaoyan Fu, Hongwu Zhang","doi":"10.1016/j.jre.2023.12.006","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.006","url":null,"abstract":"<p>The low-dose X-ray induced long afterglow near infrared (NIR) luminescence from Cr³⁺ doped Zn_{1–<em>x</em>}Cd_<em>x</em>Ga₂O₄ spinel solid solutions was investigated. The structure analysis shows the good formation of Zn_{1–<em>x</em>}Cd_<em>x</em>Ga₂O₄ spinel solid solutions, which possesses a cubic spinel structure with <em>Fd</em>3<em>m</em> space group. The formation of Zn_{1–<em>x</em>}Cd_<em>x</em>Ga₂O₄ spinel solid solutions induces the obvious increase of long afterglow near infrared luminescence excited by low-dose X-ray. When the content of doped Cd²⁺ reaches 0.1, the low-dose X-ray induced long afterglow NIR luminescence is the maximum. More importantly, only 5 s X-ray irradiation can induce more than 6 h NIR afterglow emission, of which the afterglow luminescent intensity is still 5 times stronger than the background intensity after 6 h. The thermoluminescent results show that under the 5 s exposure of X-ray, the trap density of Zn_0.9Cd_0.1Ga₂O₄:Cr³⁺ is much higher than that of ZnGa₂O₄:Cr³⁺. The replacement of Cd²⁺ ions with large radius at Zn²⁺ sites causes the increase of defects and dislocations, which results in the obvious increase of trap concentrations. And the addition of high-<em>z</em> number elements Cd²⁺ would enhance the X-ray absorption of the solid solutions, which thus can be easily excited by low-dose X-ray. Zn_0.9Cd_0.1Ga₂O₄:1%Cr³⁺ solid solution is a potential candidate of low-dose X-ray induced long afterglow luminescent materials.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"34 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138741594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review on micro-mechanism of forming emulsification during rare earth extraction by acidic extractants","authors":"Jie Liu, Yuxiu Zhao, Zhirong Wang, Minghui Jia, Wenxiang Xia, Guizhi Wu, Wenda Guo, Ru’an Chi, Kun Huang","doi":"10.1016/j.jre.2023.12.009","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.009","url":null,"abstract":"<p>Solvent extraction is the main method used to separate and purify rare earth elements. In the process of rare earth extraction, emulsions often form due to the instability of the aqueous and organic phases or improper operating conditions. Once emulsification occurs, it would not only lead to low rare earth recovery rates, small product quantities, high production costs and the loss of extractant and rare earth resources, but also result in serious environmental pollution. Therefore, it is very important to study the microscopic mechanism for emulsification and establish new methods to prevent emulsification from the source. In this paper, possible factors resulting in emulsification, such as the compositions and properties of the organic and aqueous phases, the operating conditions of the rare earth extractions are reviewed. The micro-mechanisms of emulsification are summarized based on the microscopic structures present in the bulk phase, aggregation of the extractants at the organic-aqueous interface, spectral characterizations and computational simulations.</p><p>On this basis, new formation mechanisms are proposed for emulsification. Preliminary explorations were employed to verify the correctness of these new viewpoints. Finally, future directions for studies of the emulsification micro-mechanism are proposed. This study provides a theoretical basis for further understanding the micro-mechanisms of interfacial instability resulting in emulsification in the process of rare earth extractions.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"218 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138741709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement of weathered crust elution-deposited rare earth ores leaching process with the addition of PQ-10","authors":"Aoyang Sha, Huifang Yang, Zhengyan He, Zhigao Xu, Chenjie Wu, Wu Ming, Ru'an Chi","doi":"10.1016/j.jre.2023.12.005","DOIUrl":"https://doi.org/10.1016/j.jre.2023.12.005","url":null,"abstract":"<p>To solve the problems of the long development period, low mass transfer efficiency and high impurity content in the <em>in-situ</em> leaching process of weathered crust elution-deposited rare earth ores (WCE-DREO), cationic hydroxyethyl cellulose (PQ-10) was composited with conventional leaching agent ammonium sulfate ((NH₄)₂SO₄) to form a novel composite leaching agent. The effects of PQ-10 concentration, leaching temperature and leaching flow rate of the composite leaching agent on the leaching kinetics and mass transfer processes of rare earth (RE) and aluminum (Al) were investigated. Compared to the single leaching agent (NH₄)₂SO₄, the composite leaching agent (2 wt% (NH₄)₂SO₄+0.02 wt% PQ-10) can reduce the RE leaching equilibrium time from 465 to 130 min and increase the RE leaching efficiency and decrease the Al leaching efficiency. It also facilitates the leaching process of WCE-DREO by increasing the peak concentrations of RE and Al, reducing the theoretical tower plate height (HETP) and improving the leaching mass transfer efficiency. It is indicated that PQ-10 can promote the leaching of WCE-DREO. The leaching process of the composite leaching system conforms to the diffusion kinetic control model. When the PQ-10 concentration is in the range of 0.005 wt%<strong>–</strong>0.020 wt%, the reaction orders of RE and Al are 0.73 and 0.54, respectively, which shows a positive effect on the leaching velocity; when the PQ-10 concentration is in the range of 0.030 wt%<strong>–</strong>0.060 wt%, the reaction orders of RE and Al are <strong>–</strong>1.16 and <strong>–</strong>0.75, respectively, which show a negative effect on the leaching velocity. In the range of 10<strong>–</strong>50 °C, the apparent activation energies of RE and Al are 15.02 and 17.31 kJ/mol, respectively, and the higher the leaching temperature, the smaller the HETP and the higher the leaching velocity and mass transfer efficiency. The increase in leaching flow rate contributes to the increase in the longitudinal diffusion velocity of the leaching agent within WCE-DREO, causing a shorter time for RE and Al to reach leaching equilibrium. In addition, the flow rate and HETP are consistent with the Van Deemter equation. At a flow rate of 0.8 mL/min, HETP was minimized and the optimal mass transfer efficiencies is achieved for RE and Al.</p>","PeriodicalId":16940,"journal":{"name":"Journal of Rare Earths","volume":"104 1","pages":""},"PeriodicalIF":4.9,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}