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Separation of La(Ⅲ),Ce(Ⅳ)and Ca(Ⅱ)from bastnaesite using acidic phosphonic chitosan and rotating disk membrane

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Journal of Rare Earths 2024年第5期42卷 995-1000,I0007页

作者： Dandan Lu Wenhui Li Linlin Fan Yunren Qiu School of Chemistry and Chemical Engineering Central South UniversityChangsha410083China

The separation of rare earths is difficult due to their similar properties and the complex characteristics of associated vein o ***-ultrafiltration(CUF)and shear induced o rderly dissociation coupling with ultrafiltration(SIODUF)were used to separate metal ions(M,M=La(Ⅲ),Ce(Ⅳ)and Ca(Ⅱ))from simulated bastnaesite leaching solution using acidic phosphonic chitosan(aPCS)and rotating disk *** of simultaneous removal of metallic ions was investigated by CUF,and suitable conditions were obtained for C/M 10.0(mass ratio of complexant to metal ions)and pH *** shear stabilities of aPCS-M complexes were explored at different pH values and the results show that the complexes can dissociate at a certain rotational speed,the critical *** critical s hear rates of aPCS-La,aPCS-Ce and aPCS-Ca complexes at pH 5.0 were calculated as 1.42×10^(5).1.69×10^(5) and 9.75×10^(4) s^(-1),*** order of complexes shear stability is aPCS-Ca aPCS-La<*** high selective separation of M and regeneration of aPCS were achieved by SIODUF in the light of the difference of aPCSM complexes shear *** separation coefficientsβLa/Ce andβCa/La reach 31.2 and 53.9,respectively.

关键词： bastnaesite Rare earths Complexation-ultrafiltration Acidic phosphonic chitosan Rotating disk membrane

Thermal decomposition mechanism and kinetics of bastnaesite in suspension roasting process:A comparative study in N_(2) and air atmospheres

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Journal of Rare Earths 2024年第9期42卷 1809-1816,I0006页

作者： Wenbo Li Jijia Chen Shaokai Cheng Junyan Sun Xiaolong Zhang School of Resources and Civil Engineering Northeastern UniversityShenyang110819China National-Local Joint Engineering Research Center of High-Efficient Exploitation Technology for Refractory Iron Ore Resources Shenyang110819China

To investigate the thermal decomposition behavior and reaction kinetics of bastnaesite in suspension roasting,the gas and solid products of bastnaesite roasted in N2 and air atmospheres were examined using a gas analyzer,X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive spectrometry(EDS).Subsequently,the kinetic parameters of bastnaesite in the suspension roasting process were derived and calculated using the isothermal *** results show that the decomposition product of bastnaesite in N_(2) is ***,once the roasting temperature exceeds 600℃,CO is generated in addition to CO_(2),and all the XRD diffraction peaks of CeOF are shifted to the right,indicating that CO_(2) can oxidize CeOF and lead to the transformation of Ce(Ⅲ) into Ce(Ⅳ).When roasted in air,the decomposition product CeOF can be completely converted to CeF3 and Ce_7O_(12) as it easily ***,the reaction rate of bastnaesite in air is higher than that of N_(2),and the starting reaction temperature is lower than that of N_(2).A large number of irregular cracks and holes appear on the surface of solid-phase products following suspension roasting,which are due to the thermal decomposition of bastnaesite that produces CO_(2) as well as the reconstruction of the lattice of the solid-phase *** reaction kinetic model of bastnaesite roasted in N_(2)(temperature range 600-750℃) and air(temperatu re range 500-575℃) confo rms to the A_(3/2) model with the mechanism function G(α)=-ln(1-α)^(2/3),and the reaction activation energy is 59.78 kj/mol and lnA is 1.65 s^(-1) in N_(2) *** air,the reaction activation energy is 100.30 kj/mol and lnA is 9.63 s^(-1).

关键词： Rare earths bastnaesite Suspension roasting Thermal decomposition mechanism Reaction kinetics

Synergistic depression mechanism of Ca^(2+) ions and sodium silicate on bastnaesite flotation

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Journal of Rare Earths 2022年第6期40卷 988-995,I0006页

作者： Zhao Cao Zeyu Cheng Jieliang Wang Yongdan Cao Institute of Mining Engineering Inner Mongolia University of Science and TechnologyBaotou 014010China State Key Laboratory of Mineral Processing Beijing 100160China Inner Mongolia Key Laboratory of Mining Engineering Baotou 014010China

bastnaesite is an important rare earth mineral and is usually beneficiated by *** silicate is commonly used to depress calcium-bearing gangue minerals,however it can also depress bastnaesite when Ca^(2+) ions exist in the *** this study,the effect of Ca^(2+) ions and sodium silicate individually or in combination on bastnaesite flotation was studied through micro-flotation,zeta potential,fluorescence spectroscopy and X-ray photoelectron spectroscopy(XPS) ***-flotation results show that the combination of Ca^(2+) ions and sodium silicate depresses bastnaesite more severely due to their synergistic *** potential results show that the combination renders the surface potential of bastnaesite negatively shifted more *** spectroscopy shows that the combination decreases the surface hydrophobicity of bastnaesite more *** shows that the combination increases the adsorption of sodium silicate on bastnaesite by forming hydrophilic Ca-SiO_(3) precipitate,which causes more serious depression on bastnaesite flotation.

关键词： bastnaesite Flotation Sodium silicate Ca^(2+)ions Synergistic depression Rare earths

Defluorination of bastnaesite by steam roasting process

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Journal of Rare Earths 2022年第12期40卷 1963-1968,I0006页

作者： Shuchen Sun Ying Yang Ganfeng Tu Faxin Xiao School of Metallurgy Northeastern UniversityShenyang 110819China College of Chemical Engineering Shenyang University of Chemical TechnologyShenyang 110142China

The bastnaesite was defluorinated by steam roasting process,and fluorine was removed in the form of hydrogen fluoride to realize the separation from rare *** effects of particle size of raw material,roasting temperature and time on defluorination rate of bastnaesite were *** suitable conditions of steam roasting process are that the particle size of raw material is less than 74μm,the roasting temperature is 1000℃and the roasting time is 4 *** defluorination rate of bastnaesite is close to 100%under above these *** the temperature rises to 1000℃,the voids on the surface of the particles increase obviously,and there is a developed network of voids,which indicates that the fluorine oxides in bastnaesite react fully with the saturated water vapor at this stage,and a large amount of fluorine escapes in the form of hydrogen fluoride from the surface and inside of the mineral.X-ray diffraction results show that there are only rare-earth oxides in the form of Ce_(0.33)La_(0.33)Ca_(0.33)O_(1.5)and Ce_(7)O_(12)in the *** results of energy spectra and chemical analysis show that the fluorine in the baking sand was basically completely removed.

关键词： bastnaesite Roasting Steam decomposition Defluorination reaction Defluorination rate Rare earths

Flotation and adsorption of novel Gemini decyl-bishydroxamic acid on bastnaesite:Experiments and density functional theory calculations

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International Journal of Mining Science and Technology 2023年第10期33卷 1193-1202页

作者： Longhua Xu Chang Liu Jiushuai Deng Donghui Wang Kai Xue Yan Wang Jinping Meng Jiongtian Liu School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of EducationSouthwest University of Science and TechnologyMianyang 621010China School of Chemical&Environmental Engineering China University of Mining&Technology-BeijingBeijing 100083China State Key Laboratory of Mineral Processing Beijing 100160China

Rare earth element is an important strategic metal,but the supply of high purity rare earth ores is growing slowly,which is in sharp contradiction with the rapidly growing *** flotation has been confirmed to be an effective method to separate bastnaesite from its gangue ***,the traditional collectors are facing serious problems in flotation separation of minerals,requiring the addition of excess depressant and regulator in the flotation ***,we proposed and synthesized novel Gemini hydroxamic acids Octyl-bishydroxamic acid(OTBHA),Decyl-bishydroxamic acid(DCBHA)and Dodecyl-bishydroxamic acid(DDBHA)as the collectors in bastnaesite-barite flotation *** effect of different carbon chain lengths on the molecular properties were explored by density functional theory(DFT)*** possessed a stronger reactivity compared with OCBHA and *** flotation results verified the consistency of the computational calculation about the performance prediction of Gemini hydroxamic *** with OCBHA and DDBHA,DCBHA displayed superior collecting affinity toward bastnaesite,and did not float *** potential results showed that the presence of DCBHA increased the potential of bastnaesite,while it had almost no effect on barite,indicating DCBHA had a stronger affinity for ***,Fourier transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)analyses indicated that the adsorption mechanism was due to two hydroxamate groups of DCBHA co-anchored on bastnaesite surface by forming five-membered hydroxamic―(O―O)―Ce *** addition,atomic force microscopy(AFM)clearly observed that DCBHA uniformly aggregated on bastnaesite surface,which increased surface contact angle and improved the hydrophobicity of bastnaesite.

关键词： Gemini-hydroxamic acid bastnaesite DFT Flotation Adsorption mechanism

Direct search for primordial ^(244)Pu in Bayan Obo bastnaesite

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Chinese Chemical Letters 2022年第7期33卷 3522-3526页

作者： Yang Wu Xiongxin Dai Shan Xing Maoyi Luo Marcus Christl Hans-Arno Synal Shaochun Hou China Institute for Radiation Protection Taiyuan 030006China Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions Suzhou 215006China Laboratory of Ion Beam Physics ETH ZurichZurich 8093Switzerland Baotou Research Institute of Rare Earths Baotou 014030China

The abundances of heavy elements produced in r-process nucleosynthesis in the early solar system need experimental verification.^(244)Pu could be the heaviest primordial nuclide produced before the formation of the Earth still being detectable *** recent attempts failed to confirm the discovery of ^(244)Pu signals at a concentration of 1.0×10^(-18)g/g in bastnaesite reported by Hoffman et *** this study,the total primordial ^(244)Pu in 450 g bastnaesite sample from Bayan Obo ore (China) was measured using ultrasensitive compact accelerator mass spectrometry (AMS).As no ^(244)Pu signal was detected,an upper limit for the ^(244)Pu in our bastnaesite sample was estimated to be 2.1×10^(-20)g/g at 99%confidence level.

关键词： ^(244)Pu Initial abundance ratio of^(244)Pu/^(238)U AMS measurement Pu radiochemistry analysis bastnaesite

Surface chemistry considerations of gangue dissolved species in the bastnaesite flotation system

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Fundamental Research 2022年第5期2卷 748-756页

作者： Longhua Xu Zhoujie Wang Kaiqian Shu Houqin Wu Yuehua Hu Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of Education Southwest University of Science and TechnologyMianyang 621010SichuanChina State Key Laboratory for Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang 621010SichuanChina School of Resources Processing and Bioengineering Central South UniversityChangsha 410012HunanChina

Inefficient flotation of bastnaesite remains a challenge in the production of rare earth *** study aimed to investigate the dissolution and adsorption behaviour of species that are commonly released into bastnaesite flotation pulp from Ca/Ba-bearing gangue *** influence and corresponding mechanisms on the bastnaesite mineral surface and collectors,namely sodium oleate(NaOL),were evaluated experimentally based on micro-flotation,zeta potentials,in situ attenuated total reflection Fourier transform infrared spectroscopy(ATRFTIR),and X-Ray photoelectron spectroscopy(XPS)*** flotation recovery of bastnaesite significantly decreased from ~95% to ~25%,~15%,~80%,~25% when exposed to calcite,fluorite,barite,and mixed dissolved species,*** zeta potential of bastnaesite was pH sensitive,indicating that H^(+) and OH^(−)determine the surface potential of *** chemistry analyses revealed that the presence of the dissolved species differed at various pH *** situ ATR-FTIR demonstrated the different effects of the dissolved species from calcite,fluorite,and barite on collector *** former two dissolved species mainly depressed the chemisorption of the NaOL monomers(RCOO^(-)),whereas calcite also affected the physical adsorption of the oleic acid molecular dimer(RCOOH·RCOO^(-)).Moreover,the barite dissolved species only affected the physical adsorption of the NaOL *** results of XPS analysis revealed that dissolved species from these three gangues could pre-adsorbed onto bastnaesite and affected the interaction with the *** functional theory calculations were employed to provide further theoretical insights into the interactions between the dissolved species from calcite,fluorite,and barite and NaOL.

关键词： bastnaesite Dissolved species Flotation Adsorption Calcite

Decomposition process of bastnaesite concentrate in NaOH-CaO-H2O system

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Journal of Rare Earths 2019年第7期37卷 760-766页

作者： Jiang Liu Ting’an Zhang Zhihe Dou Yan Liu Guozhi Lv Key Laboratory of Ecological Metallurgy of Multi-Metal Intergrown Ores of Ministry of Education School of Metallurgy Northeastern University

A novel process of calcification-leaching for bastnaesite concentrate(REFCO3) was proposed. The prior calcification was carried out in the system of NaOH-CaO-H2O and the lgC-pH pattern for Ce-F-Ca-C-H2O system was drawn. The thermodynamics result indicates that decomposition for bastnaesite requires certain alkaline condition, but excessive alkalinity also causes decomposition of CaF2. XRD and SEM-EDS analyses on the calcification-leaching process reveal that bastnaesite first decomposes into RE(OH)3 and CaF2. Then, by HCl leaching rare earths were extracted,while CaF2 was left in the leaching residue. In addition, effects of temperature, time, NaOH and CaO on the calcification were investigated. The results show that the leaching rate of rare earths(REs)reaches 72.5 wt%, at the same time 99.2 wt% of F is left in leaching residue with 20 wt% NaOH and 38 wt% CaO at 493 K for 180 min.

关键词： bastnaesite concentrate Calcification process Thermodynamics Fluorine Rare earths

A comparative investigation into floatability of bastnaesite with three di/trialkyl phosphate surfactants

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Journal of Rare Earths 2021年第11期39卷 1442-1449,I0005页

作者： Hongli Fan Xianglin Yang Jing Qi Guangyi Liu Jingqin Qin College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China

Flotation separation and recovery of rare earth minerals(REM) have returned to an important position due to the growing strategy demand for rare earth elements(REE).In this paper,a comparative investigation into the floatability of bastnaesite((Ce,La)FCO3) was conducted by using three di/trialkyl phosphate collectors,di(2-ethylhexyl) phosphate(DEHPA),dibutyl phosphate(DBP) and tributyl phosphate(TBP).The density functional theory(DFT) computation recommends that the chemical activity of the three phosphate collectors is in order of DEHPA≥ DBP >> TBP,and their hydrophobization assuggested by the IgP(oil-water partition coefficient) value is in the order of DEHPA> TBP> *** micro-flotation indicates that the preferable pH values for flotation of bastnaesite with the three phosphate collectors are 7.0-8.0,and DEHPA achieves much higher flotation recovery of bastnaesite,followed by DBP,and then TBP,which coincides with their reactivity and hydrophobicity,the two prerequisites for froth *** contact angle,zeta potential,Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS) deduce that DEHPA likely reacts with the Ce(Ⅲ)atoms of bastnaesite interface through its O atom(s) of the P(=O)-O-group to generate the Ce-O-P bonds,and its two 2-ethylhexyl groups orient outside for attaching bubbles,resulting in flotation enrichment of ***,this investigation offers a novel strategy for developing collectors in selective beneficiation of REM.

关键词： di(2-ethylhexyl)phosphoric acid bastnaesite Flotation Mechanism Activity Rare earths