| 1 | Solubilization behaviors of interfacial lutetium-extractant complex in a solvent extraction system显示文摘Knowledge of the solubilization behaviors of rare-earth-extractant complex is mandatory for full comprehension of interfacial phenomenon and intermediate state of rare earth(RE) ion transport from water to oil during solvent extraction. The lutetium with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester(P507) extraction system was explored as a case study for the solubilization behaviors in this paper. With a quantitative analysis of a white crud obtained in the practical process, the results demonstrate that the insoluble REL_3(L = the anion of P507) complex enriches at the oil/water interface and forms the network polymers. Besides, with the increase of RE loading ratios in the oil phase, the interfacial tension increases while the free ligand in the bulk phase decreases, which results in the flocculation of REL_3 complex and the formation of polymers at the interface. Furthermore,the properties of the oil phase and the interface reveal that the free ligand can solubilize the REL_3 complex along with the transfer of water from microemulsion to aqueous phase. In addition, the change of aqueous acidity can regulate the solubilization behaviors of the interfacial complex to improve RE extraction efficiency. These fundamental studies will hopefully provide new insights into the solubilization of metal-extractant complex and a technical guidance to the transfer of RE from water to oil. | Wenrou Su Ji Chen Yu Jing Chuanying Liu Yuefeng Deng Maohua Yang | 2018 | Journal of Rare Earths2018，36，5： | 1 |
| 2 | In-situ measurement of mineral phase transition and kinetics in roasting process of Bayan Obo mixed rare earth concentrate by sodium carbonate显示文摘In this study,the Bayan Obo rare earth concentrates mixed with Na_(2)CO_(3)were used for roasting research.The phase change process of each firing stage was analyzed.The kinetic mechanism model of the continuous heating process was calculated.This study aims to recover valuable elements and optimize the production process to provide a certain theoretical basis.Using X-ray diffraction(XRD),Fourier infrared spectroscopy,scanning electron microscopy with energy dispersive spectrometry,the reaction process and the existence of mineral phases were analyzed.The variable temperature XRD and thermogravimetric method were used to calculate the roasting kinetics.The phase transition results show that carbonate-like substances first decompose into fine mineral particles,and CaO,MgO,and SiO_(2)react to form silicates,causing hardening.Further,REPO_(4)and NaF can directly generate CeF_(3) and CeF_(4)at high temperatures,and a part of CeF_(4)and NaF forms a solid solution substance Na_(3)CeF_(7).Rare earth oxides calcined at a high temperature of 750℃were separated to produce Ce_(0.6)Nd_(0.4)O_(1.8),Ce_(4)O_(7),and LaPrO_(3+x).Then,BaSO_(4),Na_(2)CO_(3),and Fe_(2)O_(3)react to form barium ferrite BaFe_(12)O_(19);the kinetic calculation results show that during the continuous heating process,the apparent activation energy E reaches the minimum in the entire reaction stage in the temperature range of 440-524℃,and the reaction order n reaches the maximum,which indicates that the decomposition product REFO significantly impacts the reaction system and reduces the activation energy.The mechanism function is F(α)=[-In(1-α)]^(1/3).The reaction order n reaches the minimum in the temperature range of 680-757℃,and the apparent activation energy E is large.The difficulty of the reaction increases during the final stage.The reaction mechanism function is F(α)=[1-(1-α)^(1/3)]^(2).Observing the entire reaction stage,the step of controlling the reaction rate changes from random nucleation to three-dimensional diffusion(spherical symmetry). | Peng Zu Jie Li Jingxuan Wu Wenhao Zhang Jiawei Lin Shiwen Yi Wenrou Su | 2022 | Journal of Rare Earths2022，40，7： | 0 |
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