In 2025,the global rare earth exploration and development sector achieved breakthroughs across multiple fronts.Projects advanced intensively across the Americas,Oceania,Africa,and Europe,with significant growth in res...In 2025,the global rare earth exploration and development sector achieved breakthroughs across multiple fronts.Projects advanced intensively across the Americas,Oceania,Africa,and Europe,with significant growth in resources,continuous emergence of new deposits,and strong impetus injected into the industry by technological innovation and policy support.The global rare earth resource supply pattern was further optimized (Table 1).1.Fruitful results in resource growth and new deposit discoveriesBrazil emerged as a core region for resource growth.The Colossus rare earth deposit saw a 150%increase in resources and announced its first reserve estimate.The Caldeira rare earth deposit’s resource estimate grew by 50%.The combined ore resources in the Caladão rare earth deposit’s Zones A and B reached 5.72×10~8 tonnes,with a total rare earth oxide(TREO) grade of 0.1506%,concurrently hosting 2.29×10~4tonnes of gallium metal resources.展开更多
Phosphorus (P) is an essential nutrient element that is critical for plant growth and ecosystem functionality.The soil P cycle plays multiple roles,such as sustaining plant growth and productivity,regulating nutrient ...Phosphorus (P) is an essential nutrient element that is critical for plant growth and ecosystem functionality.The soil P cycle plays multiple roles,such as sustaining plant growth and productivity,regulating nutrient balance within ecosystems,and enhancing ecosystem adaptability and resilience.This cycle is influenced by factors such as the restoration approach and microbial community dynamics.However,the extent to which the restoration approach alters the P cycle in karst ecosystems and the underlying microbial mechanisms remain poorly understood.The P-cycle multifunctionality index (P-cycle MFI) serves as a comprehensive indicator for evaluating soil P cycle function,and it provides insights into changes in the P cycle between different restoration approaches.To investigate the shifts in soil P-cycle MFI and microbial mechanisms between different restoration approaches,we analyzed soil available P (AP),total P (TP),microbial biomass P (MBP),and the activities of acid phosphatase (ACP) and alkaline phosphatase (ALP).These data were used to calculate the P-cycle MFI by averaging the Z-scores between two restoration approaches(artificial restoration of forest (AF) and natural restoration of forest (NF)) and a control (cropland,CP) at six subtropical karst ecosystem sites in China.We also determined the soil organic carbon (SOC),exchangeable calcium (Ca) and magnesium (Mg),pH,bulk density (BD),microbial biomass C (MBC),and microbial biomass nitrogen (MBN),as well as the community structure,relative abundance,diversity indices,and co-occurrence networks of phoD-harboring bacteria.The results showed that the community structure of phoD-harboring bacteria varied significantly among AF,NF,and CP and across different temperature gradients.These bacteria exhibited increasing complexity and tightness in co-occurrence networks from CP to AF and then to NF,along with the ACP and ALP activities,but not the TP and AP contents.The P-cycle MFI values were significantly higher in NF compared to AF and CP,and the variation was significantly explained by restoration approach,temperature,MBC,MBN,SOC,exchangeable Ca,BD,community structure of phoD-harboring bacteria,and exchangeable Mg.Furthermore,natural restoration had a more substantial impact on the P-cycle MFI than temperature by enhancing SOC,microbial biomass,the complexity and co-occurrence network tightness of the phoD-harboring bacterial community structure,and ACP and ALP activities,but it reduced soil BD.The rare genera of phoD-harboring bacteria significantly influenced the variation of soil P-cycle MFI compared to the dominant genera.This study highlights the importance of rare genera of phoD-harboring bacteria in driving soil P-cycle multifunctionality in karst ecosystems,with natural restoration being more effective than artificial methods for enhancing soil organic matter and microbial community complexity.展开更多
Ln@MOFs by anchoring rare metal ions(Ln) into metal-organic frameworks(MOFs) are proved to have great potential in the field of luminescent molecular thermometer.Nevertheless,the current research indicated that the po...Ln@MOFs by anchoring rare metal ions(Ln) into metal-organic frameworks(MOFs) are proved to have great potential in the field of luminescent molecular thermometer.Nevertheless,the current research indicated that the poor structural stability and low sensitivity hindered their application scope.In this work,a new MOF Zn-450 luminescent thermometer with multiple emission fluorescence characteristics was synthesized by the combination of 3,3,5,5-biphenyl tetracarboxylic acid(H_(4)L) and Zn^(2+) ion under solvothermal conditions.Interestingly,a high relative sensitivity of 1.43 % K^(-1) was found within 80-300 K based on Zn-450.Subsequently,two high-sensitivity luminescent Ln@MOFs(Ln = Eu and Tb) were further fabricated by doping rare earth ions into Zn-450 based on the post-synthesis strategy.Among them,the Eu@Zn-450 demonstrates various luminous behaviors while achieving an increased relative sensitivity of 1.63 % K^(-1).In addition,the continuously visible red,pink,and purple luminescent emissions at the same temperature range were observed,suggesting that the Eu@Zn-450 could be utilized as a luminescent colorimetric molecular thermometer.Importantly,this work can present new possibilities for the development of rare earth-doped luminescence and its temperature sensing properties.展开更多
Ion-adsorption rare earth ore(IAREO)is a crucial source of mid-heavy rare earths elements(M-HRE).Reverse osmosis technology is a promising technique for the pre-concentration of the leach solution from in-situ leachin...Ion-adsorption rare earth ore(IAREO)is a crucial source of mid-heavy rare earths elements(M-HRE).Reverse osmosis technology is a promising technique for the pre-concentration of the leach solution from in-situ leaching of IAREO.However,calcium sulfate scaling is inevitably formed in sulfate system,causing decreases in the flux and life time of membrane.Herein,to simulate the precipitation behavior of calcium sulfate in the leach solution of IAREO during reverse osmosis,a series of experiments was conducted in binary and quaternary supersaturated calcium sulfate solution systems.Experimental data show that the concentration of Ca^(2+)decreases with the increase of the concentration of Mg^(2+),and in-creases with the increase of the concentration of RE3+in both binary and quaternary systems.Whereas.the influence of Al^(3+)on the concentration of Ca^(2+)is different.This variation of the Ca^(2+)concentration is explained by thermodynamic analysis.The difference of association concentration for Mg^(2+),Al^(3+)and RE^(3+)with SO_(4)^(2-)in binary or quaternary system is the main reason.Finally,the influence and mechanisms of antiscalant on the precipitation behavior of calcium sulfate are discussed.X-ray diffraction(XRD),Zeta potential and scanning electron microscopy(SEM)analyses reveal that polyacrylic acid(PAA)effectively inhibits the crystal growth of calcium sulfate,and the precipitation time of calcium sulfate is prolonged,indicating that PPA is a potential inhibitor for calcium sulfate scaling during the process of reverse osmosis.展开更多
In order to highlight the achievements of China's rare earth industry over the past year with the support of national policy,and show that technological innovation has promoted the development of new high-quality ...In order to highlight the achievements of China's rare earth industry over the past year with the support of national policy,and show that technological innovation has promoted the development of new high-quality productive forces,expanded the application fields of rare earth elements and accelerated the progress of green and low-carbon transformation.展开更多
Aluminum is the main impurity of the weathered crust elution-deposited rare earth ore(WCED-REO).Efficient leaching of rare earths and low leaching of aluminum are of great importance for the leaching of the WCED-REO.T...Aluminum is the main impurity of the weathered crust elution-deposited rare earth ore(WCED-REO).Efficient leaching of rare earths and low leaching of aluminum are of great importance for the leaching of the WCED-REO.The effects of pH,MgSO_(4) concentration and Al^(3+)concentration of the leaching agent solution on the column leaching behaviors of WCED-REO using magnesium sulfate were investigated.Experimental data show that controlling the MgSO_(4) concentration to 0.15 mol/L,pH of the leaching agent solution to 2,the leaching amount of aluminum from the rare earth ore gradually decreases with the increase of Al^(3+)concentration in the leaching agent solution,indicating that Al^(3+)in the leaching agent solution may act as leaching agent to participate in the ion exchange of RE3+,but the leaching amounts of rare earths change insignificantly as the Al^(3+)concentration is increased.Increasing the MgSO_(4) concentration is beneficial to the leaching of aluminum,and when the Al^(3+)concentration is 0.04 mol/L(Al accumulation),the amount of Al^(3+)leached from the rare earth ore increased gradually with increasing the MgSO_(4) concentration.The pH of the leaching agent solution has a significant influence on the leaching of aluminum in the rare earth ore,and the leaching amount of aluminum from the rare earth ore increases gradually with decreasing the pH.When the Al^(3+)conce ntration is 0.04 mol/L(Al accumulation)and the pH of the leaching agent solution is above 2.0,the aluminum in the leaching agent solution can be back-adsorbed onto the rare earth ore,and the amount of the back-adsorbed Al^(3+)increases with increasing the pH of the leaching agent solution.The injection rate of the leaching agent solution has slight effect on the leaching behavior of rare earths and aluminum.In summary,leaching of Al^(3+)and consumption of MgSO_(4) can be reduced by regulating the accumulation of aluminum,MgSO_(4) concentration and pH.展开更多
State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.The la...State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.The laboratory was reconstructed based on former State Key Laboratory of Baiyun Obo Rare Earth Resources Researches and Comprehensive Utilization.展开更多
Modification of 6061 aluminum alloy was conducted through composite addition of cerium-rich rare earths and Al-Ti-B.Results show that the composite addition of Al-Ti-B and Ce/La element at a specific ratio notably pro...Modification of 6061 aluminum alloy was conducted through composite addition of cerium-rich rare earths and Al-Ti-B.Results show that the composite addition of Al-Ti-B and Ce/La element at a specific ratio notably promotes the refinement of the alloy's grains.Ce and La elements are combined with Si and other elements to form rare earth phases,improving the morphology and distribution of precipitates and mitigating the adverse effects ofβ-Fe phases on the microstructure and mechanical properties of alloy.However,excessive rare earth content poses challenges;it not only leads to a decrease in Mg-Si strengthening phase by binding with Si but also promotes the formation of larger or numerous rare earth phases that may act as initiation points for cracks,thereby impeding the improvement of the structure and performance of alloy.The composite addition of cerium-rich rare earths and Al-Ti-B not only preserves the strength of the alloy but also significantly enhances the plasticity of the 6061 as-cast alloy.At a composite addition ratio of Al-Ti-B:RE=2:1,the newly developed 6061-RE aluminum alloy exhibits increased average elongation by 50%and 45%in its as-cast and homogenized states,respectively,compared to the baseline 6061 alloy,facilitating subsequent deformation processing.After solution treatment at 540℃for 1 h and aging at 180℃for 5 h,the average ultimate tensile strength and yield strength of 6061-RE alloys reach 313.2 and 283.1 MPa,increased by 12.3%and 14.5%compared with those of the original alloy,respectively,and the average elongation is improved by 41%.展开更多
The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with t...The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with the advantage of being environmental-friendly.As one of the organic acids produced by biological metabolism,citric acid was used to leach REEs and explore the performance and process.The results demonstrate that citric acid exhibits higher leaching efficiency(96.00%)for REEs at a relatively low concentration of 0.01 mol/L compared with(NH_(4))_(2)SO_(4)(84.29%,0.1 mol/L)and MgSO_(4)(83.99%,0.1 mol/L).Citric acid shows a preference for leaching heavy rare earth elements,with 99%leaching efficiency in IAREO,which shows higher capacity than(NH_(4))_(2)SO_(4)and MgSO_(4)(as inorganic leaching agents).Kinetic analysis indicates that the leaching process of REEs with citric acid is controlled by both the internal diffusion kinetics and chemical reaction kinetics,which is different from inorganic leaching agents.Visual Minteq calculations confirm that RE-Citrate is the main constituent of the extract solution in the leaching process of the IAREO,thereby enhancing the leaching efficiency of REEs from the IAREO.It suggests that citric acid may be used as a promising organic leaching agent for the environmentalfriendly extraction of REEs from IAREO.展开更多
To achieve selective leaching of ion adsorption rare earth,it is necessary to thoroughly reveal the differences in the adsorption mechanisms of aluminum and rare earth elements.In this study,we investigated the adsorp...To achieve selective leaching of ion adsorption rare earth,it is necessary to thoroughly reveal the differences in the adsorption mechanisms of aluminum and rare earth elements.In this study,we investigated the adsorption processes of Dy and Al on the surface of K–homoionic kaolinite using batch experiments and sequential chemical extractions.The results revealed that the adsorption of Dy and Al,as well as the desorption of K,followed the Langmuir model.The maximum ion-exchangeable capacity of Dy was higher(9.39 mmol.kg^(-1))than that of Al(6.30 mmol.kg^(-1)).The ion exchange stoichiometry ratios of Dy–K and Al–K derived from the Langmuir model were2.0 and 2.6.The analysis of X-ray absorption fine structure(XAFS)and density functional theory(DFT)revealed that Dy and Al were adsorbed onto kaolinite as outer-sphere hydrated complexes via hydrogen bonds.Dy was adsorbed as[Dy(H_(2)O)_(10)]^(3+),and Al was adsorbed as[Al(OH)_(2)(H_(2)O)_(4)]^(+).In particular,the adsorption of Al resulted in protonation of the hydroxyl groups on the surface of the kaolinite.Based on the above insights,the higher ion exchange stoichiometry ratios are attributed to closer adsorption distances(6.04 A for Dy and 3.69 A for Al)and lower adsorption energies(-223.72 kJ.mol^(-1)for Dy and-268.33 kJ.mol^(-1)for Al).The maximum ionexchangeable capacity is related to the change of the surface electrical properties of kaolinite.The zeta potential was increased to-7.3 mV as the protonation resulted from aluminum adsorption,while Dy adsorption had a minor effect,maintaining a value of-17.5 m V.展开更多
Disclaimers:The International Energy Agency released Global Critical Minerals Outlook 2025 recently.The report presents the latest data and analysis on supply,demand,investment and more for key energy-related minerals...Disclaimers:The International Energy Agency released Global Critical Minerals Outlook 2025 recently.The report presents the latest data and analysis on supply,demand,investment and more for key energy-related minerals,including copper,lithium,nickel,cobalt,graphite and rare earth elements.It also made projections for how these markets will change over the next decade as the global energy transition picks up speed.The article"Outlook of global rare earth industry"is excerpted from the report and editted by the editorial office for reference.展开更多
This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage(AMD)streams to recover rare earth elements(REEs).A life cycle assessment(...This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage(AMD)streams to recover rare earth elements(REEs).A life cycle assessment(LCA)study was done to evaluate the environmental impacts of rare earth production from deleterious material in the form of highly contaminated leachate(HCL)and low-contaminated leachate(LCL).The results indicate that the main contributors to environmental categories that produce RE-hydroxide stages are NaOH and electricity.Also,oxalic acid,Na_(2)CO_(3),and hydrochloric acid significantly contribute to the production stage of individual rare earth oxides(REOs),including solvent extraction(SX)and precipitation steps.The HCL route has higher environmental impacts than LCL due to higher chemical/energy and H_(2)SO_(4)usage,so 468 and 292 kg of carbon dioxide are generated to produce1 t of individual REOs from HCL and LCL routes,respectively.Moreover,the carbon dioxide emitted from the process,including the RE-hydroxide production,SX,and REOs production,is less than 10 t CO_(2).A sensitivity analysis was also performed to assess the changeability of the environmental footprints of the main inputs in the SX process,as the main stage has a higher contribution to the whole process.This LCA study is the first step toward understanding the environmental influence of new processing methods to produce REEs from coal by-products through a developed pilot-scale process.展开更多
Rare earth elements were extracted using a sulfuric acid roasting-water leaching process.The effect of acid roasting on a new type of low-grade sedimentary rare earth ore found in Guizhou Province,China was analyzed u...Rare earth elements were extracted using a sulfuric acid roasting-water leaching process.The effect of acid roasting on a new type of low-grade sedimentary rare earth ore found in Guizhou Province,China was analyzed using X-ray diffraction and scanning electron microscopy.A systematic study was conducted on process parameters such as amount of acid,roasting temperature,roasting time,water leaching temperature,and leaching time.The results reveal that the total recove ry of rare earth elements reaches 81.37%,which is 3.1 times higher than that achieved through direct acid leaching,under the optimal conditions.In addition,the leaching rate of heavy rare earth elements reaches 72.53%.Rare earth elements and some other valuable metals are transformed into soluble sulfate through the local decomposition of clay minerals under the action of the sulfuric acid attack.The dissolution rates of aluminum,iron,and titanium ions are 34.94%,17.05%,and 62.77%,respectively.The precipitation rate of Ti reaches 99%,and the loss of rare earth ions in the solution is less than 1%.Meanwhile,the results of a leaching kinetics analysis indicate that the leaching process of rare ions is controlled by diffusion.Precious metal ions such as iron and aluminum in the leaching solution can reduce the adsorption of rare earth ions by kaolinite.This study efficiently recovered rare earth ions under conditions of low calcination te mperature and direct water leaching,resulting in reduced energy consumption of the extraction process and acidity of the leaching solution.These findings provide a solid foundation for the further separation and extraction of rare earth ions.展开更多
In this paper,a multi-stage leaching process for the weathered crust elution-deposited rare earth ore was proposed using MgSO_(4)as a leaching agent.The results indicate that with increasing the concentration of MgSO_...In this paper,a multi-stage leaching process for the weathered crust elution-deposited rare earth ore was proposed using MgSO_(4)as a leaching agent.The results indicate that with increasing the concentration of MgSO_(4)from 0.5 wt%-1.0 wt%to 2.0 wt%-4.0 wt%,the peak concentrations of rare earths increase from 1.87 to 3.59 to 5.49-10.21 g/L,and the collection periods of leach solution are sho rtened from 0.85 to 1.54 to 0.31-0.47(liquid-to-ore ratio).When the rare earth ore is leached with leaching agent solution with high initial pH(3.0-5.0),the rare earths and aluminum are predominantly leached by Mg^(2+)instead of H+.However,H+participate in the leaching process of rare earths and aluminum at lower initial pH(1.5-3.0)of the leaching agent solution.Especially,when the initial pH of leaching agent solution is 2.0,a large amount of aluminum is leached when the liquid-to-ore ratio is greater than 1.2.Based on the above insights,increasing the initial pH(3.0-5.0)of leaching agent solution in the injection stage using high-concentration MgSO_(4)(>1.0 wt%)can increase the peak concentration of rare earths in the leach solution and shorten the collection period.However,in the injection stage using low MgSO_(4)concentration(<1.0 wt%),an initial pH of leaching agent solution of 2.0 is selected to reduce the leaching amount of aluminum and the consumption of MgSO_(4).Comparing to the Leaching process using constant MgSO_(4)concentration(2.0 wt%,initial pH of 5.0),the leaching efficiency of rare earths using a multi-stage leaching process is approximately equal(about 94.6%)under optimal conditions.The leaching amount of aluminum is reduced by 16.9%.The consumption of MgSO_(4)is reduced by 67.1%.展开更多
Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl...Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl cellulose(PQ-10)was used as a novel green swelling inhibitor and percolation promoter and was mixed with conventional leaching agent ammonium sulfate((NH_(4))_(2)SO_(4))to form a composite leaching agent to study the performance and mechanism of swelling inhibition and percolation promotion.Adding PQ-10 can inhibit the hydration swelling of WREOs,promote the percolation effect of the leaching agent,improve the rare earth(RE)leaching efficiency,and reduce the im purity aluminum(Al)leaching efficiency.Compared with the conventional leaching agent 2 wt%(NH_(4))_(2)SO_(4),the percolation time is reduced by 50%by using the composite leaching agent(0.02 wt%PQ-10+2 wt%(NH_(4))_(2)SO_(4)).PQ-10 has positively charged quaternary ammonium groups and hydrophilic group hydroxyl groups,which makes it easy to adsorb on WREOs multiple sites through electrostatic interaction and hydrogen bonding,weakening the electrostatic repulsion between mineral particles,reducing the WREOs interlayer spacing,compressing the double electric layer thickness at the solid-liquid interface,weakening the mineral hydration swelling and increasing the percolation rate.The long carbon chains of the polymer entangle and link the fine mineral particles to agglomerate them,increasing their particle size and reduc ing their hydration dispersion,and preventing blockage of the pe rcolation pores caused by migration of the fine particles through the ore body with the solution.PQ-10 molecules also insert the mine ral interlayer and expulsion of the internal water,further inhibiting the swelling of WREOs.Adding PQ-10 reduces the surface tension of(NH_(4))_(2)SO_(4)solution,improving the spreading and spreading ability of the solution,reducing the adhesion work between molecules in the solid-liquid phase and the adhesion work reduction factor.It proves that PQ-10 promotes the percolation effect of the leaching process of WREOs.In addition,PQ-10 expands the leaching pore size and seepage channels,further improving the percolation rate.展开更多
The Mountain Pass mine is recognized as one of the world's primary sources of rare earth minerals.These rare earth minerals mainly consist of bastnaesite and a small amount of monazite phosphate,which cannot be de...The Mountain Pass mine is recognized as one of the world's primary sources of rare earth minerals.These rare earth minerals mainly consist of bastnaesite and a small amount of monazite phosphate,which cannot be decomposed and recovered through conventional oxidative roasting and hydrochloric acid leaching process.An efficient,clean,and economical process called the"combined method"was proposed for the utilization of the Mountain Pass mine to extract rare earths from Mountain Pass rare earth concentrate(MPREC).The main steps of this process include weak oxidation atmosphere roasting,step leaching of hydrochloric acid,solid-liquid separation,the monazite slag with sulfuric acid roasting water leaching,etc.In this paper,the roasting process of MPREC under a weak oxidation atmosphere was investigated.The study examines the thermal decomposition kinetics,phase transition process,and leaching behavior of MPREC in air/CO_(2)atmosphere.Results show that,the activation energy(Ea)for MPREC thermal decomposition in air and CO_(2)atmosphere are 146 and 320 kJ/mol,respectively.At temperature above 500℃in air or above 700℃in CO_(2)atmosphere,REOF are generated from bastnaesite through an in-situ reaction with CaO,which is decomposed from CaCO_(3),to form CaF_(2)and rare earth oxide(REO).Thus,F is regulated into solid phase.In an oxidizing atmosphere,the thermal decomposition of bastnaesite is accompanied by the rapid oxidation of Ce(Ⅲ).In co ntrast,the oxidation of Ce(Ⅲ)in a CO_(2)atmosphere is significantly inhibited.At 700℃,the oxidation rate of Ce in air is 74.09%,while in a CO_(2)atmosphere,it is only 33.83%.The hydrochloric acid leaching experiment shows that,the leaching rate of rare earth after roasting at 600℃under an air atmosphere reaches to 82.9%,and it reaches 87%after roasting at 800℃under a CO_(2)atmosphere.The reduction of Ce oxidation in a weak oxidizing atmosphere significantly improves the leaching rate of Ce.展开更多
2024 is a crucial year for fully implementing the spirit of the 20th National Congress of the Communist Party of China and a challenging year for deepening the implementation of the 14th Five-Year Plan.This year,the v...2024 is a crucial year for fully implementing the spirit of the 20th National Congress of the Communist Party of China and a challenging year for deepening the implementation of the 14th Five-Year Plan.This year,the vast number of rare earth technology workers made outstanding contributions to accelerating the construction of a technological powerhouse and achieving high-level technological self-reliance and self-improvement,facing the forefront of world science and technology,the main battlefield of the economy,primary national needs,and people's health.The rare earth technology industry had achieved fruitful results.展开更多
Ion-absorption deposits(IADs)of rare earth elements(REEs)constitute the main economic resources of the essential heavy rare earth elements(HREE).Nonetheless,the existing leaching methods for extracting REEs from IADs ...Ion-absorption deposits(IADs)of rare earth elements(REEs)constitute the main economic resources of the essential heavy rare earth elements(HREE).Nonetheless,the existing leaching methods for extracting REEs from IADs face limitations stemming from significant environmental consequences and a poor REE recovery rate.In a recent development,electrokinetic mining(EKM)has emerged as a novel technology for extracting REEs from ion-adsorption deposits,demonstrating the potential for environmentally friendly and efficient recovery of REEs from weathering crusts.However,the transport mechanism of REE in weathering crust soil in an applied electric field remains poorly understood,and the influence of the EKM process has yet to be studied.In this study,we systematically investigated the transport characteristics of REE in weathering crust soil under the influence of an electric field.We demonstrate that the transport of REE is simultaneous with the transport of water,H+,and OH-in the applied electric field,where the EKM process is influenced by the voltage gradient,initial soil water content,electrode numbers,and power-on time.Under the optimal EKM conditions,78,8%of REE is recovered from a 45 kg-scale weathering crust soil.Additionally,we identify the transport diversity between light REE(LREE)and HREE,which assists in the separation and pre-enrichment of LREE and HREE.Furthermore,we demonstrate that the mechanism for REE transport under an electric field involves a combination of electromigration,electroosmosis,and electrolysis working synergistically.This study provides new perspectives on the transport behavior and mechanism of REEs in weathering crust soil under an electric field.These findings pave the way for the practical implementation of EKM technology.展开更多
State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.
State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.The la...State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.The laboratory was reconstructed based on former State Key Laboratory of Baiyun Obo Rare Earth Resources Researches and Comprehensive Utilization.展开更多
文摘In 2025,the global rare earth exploration and development sector achieved breakthroughs across multiple fronts.Projects advanced intensively across the Americas,Oceania,Africa,and Europe,with significant growth in resources,continuous emergence of new deposits,and strong impetus injected into the industry by technological innovation and policy support.The global rare earth resource supply pattern was further optimized (Table 1).1.Fruitful results in resource growth and new deposit discoveriesBrazil emerged as a core region for resource growth.The Colossus rare earth deposit saw a 150%increase in resources and announced its first reserve estimate.The Caldeira rare earth deposit’s resource estimate grew by 50%.The combined ore resources in the Caladão rare earth deposit’s Zones A and B reached 5.72×10~8 tonnes,with a total rare earth oxide(TREO) grade of 0.1506%,concurrently hosting 2.29×10~4tonnes of gallium metal resources.
基金supported by the National Key Research and Development Program of China (2022YFF1300705)the Key Research and Development Project of Guangxi,China (Guike AB24010051)+1 种基金the National Natural Science Foundation of China (42261011,32271730 and U20A2011)the Central Public Welfare Research Institutes,Chinese Academy of Geological Sciences (2023020)。
文摘Phosphorus (P) is an essential nutrient element that is critical for plant growth and ecosystem functionality.The soil P cycle plays multiple roles,such as sustaining plant growth and productivity,regulating nutrient balance within ecosystems,and enhancing ecosystem adaptability and resilience.This cycle is influenced by factors such as the restoration approach and microbial community dynamics.However,the extent to which the restoration approach alters the P cycle in karst ecosystems and the underlying microbial mechanisms remain poorly understood.The P-cycle multifunctionality index (P-cycle MFI) serves as a comprehensive indicator for evaluating soil P cycle function,and it provides insights into changes in the P cycle between different restoration approaches.To investigate the shifts in soil P-cycle MFI and microbial mechanisms between different restoration approaches,we analyzed soil available P (AP),total P (TP),microbial biomass P (MBP),and the activities of acid phosphatase (ACP) and alkaline phosphatase (ALP).These data were used to calculate the P-cycle MFI by averaging the Z-scores between two restoration approaches(artificial restoration of forest (AF) and natural restoration of forest (NF)) and a control (cropland,CP) at six subtropical karst ecosystem sites in China.We also determined the soil organic carbon (SOC),exchangeable calcium (Ca) and magnesium (Mg),pH,bulk density (BD),microbial biomass C (MBC),and microbial biomass nitrogen (MBN),as well as the community structure,relative abundance,diversity indices,and co-occurrence networks of phoD-harboring bacteria.The results showed that the community structure of phoD-harboring bacteria varied significantly among AF,NF,and CP and across different temperature gradients.These bacteria exhibited increasing complexity and tightness in co-occurrence networks from CP to AF and then to NF,along with the ACP and ALP activities,but not the TP and AP contents.The P-cycle MFI values were significantly higher in NF compared to AF and CP,and the variation was significantly explained by restoration approach,temperature,MBC,MBN,SOC,exchangeable Ca,BD,community structure of phoD-harboring bacteria,and exchangeable Mg.Furthermore,natural restoration had a more substantial impact on the P-cycle MFI than temperature by enhancing SOC,microbial biomass,the complexity and co-occurrence network tightness of the phoD-harboring bacterial community structure,and ACP and ALP activities,but it reduced soil BD.The rare genera of phoD-harboring bacteria significantly influenced the variation of soil P-cycle MFI compared to the dominant genera.This study highlights the importance of rare genera of phoD-harboring bacteria in driving soil P-cycle multifunctionality in karst ecosystems,with natural restoration being more effective than artificial methods for enhancing soil organic matter and microbial community complexity.
基金supported by the National Natural Science Foundation of China (No.21801111)the Training Plan for Young Core Teachers in Higher Education of Henan Province (No.2021GGJS131)+1 种基金Natural Science Foundation of Henan Province (No.232300421232)the Heluo Young Talent Lifting Project (No.2023HLTJ02)。
文摘Ln@MOFs by anchoring rare metal ions(Ln) into metal-organic frameworks(MOFs) are proved to have great potential in the field of luminescent molecular thermometer.Nevertheless,the current research indicated that the poor structural stability and low sensitivity hindered their application scope.In this work,a new MOF Zn-450 luminescent thermometer with multiple emission fluorescence characteristics was synthesized by the combination of 3,3,5,5-biphenyl tetracarboxylic acid(H_(4)L) and Zn^(2+) ion under solvothermal conditions.Interestingly,a high relative sensitivity of 1.43 % K^(-1) was found within 80-300 K based on Zn-450.Subsequently,two high-sensitivity luminescent Ln@MOFs(Ln = Eu and Tb) were further fabricated by doping rare earth ions into Zn-450 based on the post-synthesis strategy.Among them,the Eu@Zn-450 demonstrates various luminous behaviors while achieving an increased relative sensitivity of 1.63 % K^(-1).In addition,the continuously visible red,pink,and purple luminescent emissions at the same temperature range were observed,suggesting that the Eu@Zn-450 could be utilized as a luminescent colorimetric molecular thermometer.Importantly,this work can present new possibilities for the development of rare earth-doped luminescence and its temperature sensing properties.
基金the Major Research Plan of the National Natural Science Foundation of China(91962211)the Key Research and Development Program of Guangxi Province(Guike-AB22080056)+1 种基金the Beijing Nova Program(20230484379)the Major Program of Qingyuan Innovation Laboratory(00122004)。
文摘Ion-adsorption rare earth ore(IAREO)is a crucial source of mid-heavy rare earths elements(M-HRE).Reverse osmosis technology is a promising technique for the pre-concentration of the leach solution from in-situ leaching of IAREO.However,calcium sulfate scaling is inevitably formed in sulfate system,causing decreases in the flux and life time of membrane.Herein,to simulate the precipitation behavior of calcium sulfate in the leach solution of IAREO during reverse osmosis,a series of experiments was conducted in binary and quaternary supersaturated calcium sulfate solution systems.Experimental data show that the concentration of Ca^(2+)decreases with the increase of the concentration of Mg^(2+),and in-creases with the increase of the concentration of RE3+in both binary and quaternary systems.Whereas.the influence of Al^(3+)on the concentration of Ca^(2+)is different.This variation of the Ca^(2+)concentration is explained by thermodynamic analysis.The difference of association concentration for Mg^(2+),Al^(3+)and RE^(3+)with SO_(4)^(2-)in binary or quaternary system is the main reason.Finally,the influence and mechanisms of antiscalant on the precipitation behavior of calcium sulfate are discussed.X-ray diffraction(XRD),Zeta potential and scanning electron microscopy(SEM)analyses reveal that polyacrylic acid(PAA)effectively inhibits the crystal growth of calcium sulfate,and the precipitation time of calcium sulfate is prolonged,indicating that PPA is a potential inhibitor for calcium sulfate scaling during the process of reverse osmosis.
文摘In order to highlight the achievements of China's rare earth industry over the past year with the support of national policy,and show that technological innovation has promoted the development of new high-quality productive forces,expanded the application fields of rare earth elements and accelerated the progress of green and low-carbon transformation.
基金Project supported by the Major Research Plan of the National Natural Science Foundation of China(91962211)the National Key Research and Development Program of China(2021YFC2902202)the Key Research and Development Program of Guangxi Province(Guike-AB22080056)。
文摘Aluminum is the main impurity of the weathered crust elution-deposited rare earth ore(WCED-REO).Efficient leaching of rare earths and low leaching of aluminum are of great importance for the leaching of the WCED-REO.The effects of pH,MgSO_(4) concentration and Al^(3+)concentration of the leaching agent solution on the column leaching behaviors of WCED-REO using magnesium sulfate were investigated.Experimental data show that controlling the MgSO_(4) concentration to 0.15 mol/L,pH of the leaching agent solution to 2,the leaching amount of aluminum from the rare earth ore gradually decreases with the increase of Al^(3+)concentration in the leaching agent solution,indicating that Al^(3+)in the leaching agent solution may act as leaching agent to participate in the ion exchange of RE3+,but the leaching amounts of rare earths change insignificantly as the Al^(3+)concentration is increased.Increasing the MgSO_(4) concentration is beneficial to the leaching of aluminum,and when the Al^(3+)concentration is 0.04 mol/L(Al accumulation),the amount of Al^(3+)leached from the rare earth ore increased gradually with increasing the MgSO_(4) concentration.The pH of the leaching agent solution has a significant influence on the leaching of aluminum in the rare earth ore,and the leaching amount of aluminum from the rare earth ore increases gradually with decreasing the pH.When the Al^(3+)conce ntration is 0.04 mol/L(Al accumulation)and the pH of the leaching agent solution is above 2.0,the aluminum in the leaching agent solution can be back-adsorbed onto the rare earth ore,and the amount of the back-adsorbed Al^(3+)increases with increasing the pH of the leaching agent solution.The injection rate of the leaching agent solution has slight effect on the leaching behavior of rare earths and aluminum.In summary,leaching of Al^(3+)and consumption of MgSO_(4) can be reduced by regulating the accumulation of aluminum,MgSO_(4) concentration and pH.
文摘State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.The laboratory was reconstructed based on former State Key Laboratory of Baiyun Obo Rare Earth Resources Researches and Comprehensive Utilization.
基金Subproject of Inner Mongolia Autonomous Region Key Research and Development and Achievement Transformation Plan Project(2023YFDZ0064,2023KJHZ0020,2022YFDZ0097)Natural Science Foundation of Inner Mongolia Autonomous Region of China(2022QN05040)+1 种基金Basic Research Funds for Directly Affiliated Universities in Inner Mongolia Autonomous Region(JY20220093)Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT24008)。
文摘Modification of 6061 aluminum alloy was conducted through composite addition of cerium-rich rare earths and Al-Ti-B.Results show that the composite addition of Al-Ti-B and Ce/La element at a specific ratio notably promotes the refinement of the alloy's grains.Ce and La elements are combined with Si and other elements to form rare earth phases,improving the morphology and distribution of precipitates and mitigating the adverse effects ofβ-Fe phases on the microstructure and mechanical properties of alloy.However,excessive rare earth content poses challenges;it not only leads to a decrease in Mg-Si strengthening phase by binding with Si but also promotes the formation of larger or numerous rare earth phases that may act as initiation points for cracks,thereby impeding the improvement of the structure and performance of alloy.The composite addition of cerium-rich rare earths and Al-Ti-B not only preserves the strength of the alloy but also significantly enhances the plasticity of the 6061 as-cast alloy.At a composite addition ratio of Al-Ti-B:RE=2:1,the newly developed 6061-RE aluminum alloy exhibits increased average elongation by 50%and 45%in its as-cast and homogenized states,respectively,compared to the baseline 6061 alloy,facilitating subsequent deformation processing.After solution treatment at 540℃for 1 h and aging at 180℃for 5 h,the average ultimate tensile strength and yield strength of 6061-RE alloys reach 313.2 and 283.1 MPa,increased by 12.3%and 14.5%compared with those of the original alloy,respectively,and the average elongation is improved by 41%.
基金Project supported by the Thousand Talents Program of Jiangxi Province,China(JXSQ2023201003)National Natural Science Foundation of China(42107254)+4 种基金Science and Technology Major Program of Ordos City(2022EEDSKJZDZX014-2)Technological Innovation Guidance Program of Jiangxi Province(20212BDH81029)Rare Earth Industry Fund(IAGM2020DB06)Selfdeployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055A01)the Key Research Program of the Chinese Academy of Sciences(ZDRW-CN-2021-3-3)。
文摘The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with the advantage of being environmental-friendly.As one of the organic acids produced by biological metabolism,citric acid was used to leach REEs and explore the performance and process.The results demonstrate that citric acid exhibits higher leaching efficiency(96.00%)for REEs at a relatively low concentration of 0.01 mol/L compared with(NH_(4))_(2)SO_(4)(84.29%,0.1 mol/L)and MgSO_(4)(83.99%,0.1 mol/L).Citric acid shows a preference for leaching heavy rare earth elements,with 99%leaching efficiency in IAREO,which shows higher capacity than(NH_(4))_(2)SO_(4)and MgSO_(4)(as inorganic leaching agents).Kinetic analysis indicates that the leaching process of REEs with citric acid is controlled by both the internal diffusion kinetics and chemical reaction kinetics,which is different from inorganic leaching agents.Visual Minteq calculations confirm that RE-Citrate is the main constituent of the extract solution in the leaching process of the IAREO,thereby enhancing the leaching efficiency of REEs from the IAREO.It suggests that citric acid may be used as a promising organic leaching agent for the environmentalfriendly extraction of REEs from IAREO.
基金financially supported by the National Key Research and Development Program of China(No.2021YFC2902203)the Key Research and Development Program of Guangxi Province(No.Guike-AB22080056)+2 种基金Beijing Nova Program(No.20230484379)the Science and Technology Innovation Fund of GRINM(No.2022PD0102)the Central Government Guides Local Science and Technology Development Fund Project(No.246Z4005G)。
文摘To achieve selective leaching of ion adsorption rare earth,it is necessary to thoroughly reveal the differences in the adsorption mechanisms of aluminum and rare earth elements.In this study,we investigated the adsorption processes of Dy and Al on the surface of K–homoionic kaolinite using batch experiments and sequential chemical extractions.The results revealed that the adsorption of Dy and Al,as well as the desorption of K,followed the Langmuir model.The maximum ion-exchangeable capacity of Dy was higher(9.39 mmol.kg^(-1))than that of Al(6.30 mmol.kg^(-1)).The ion exchange stoichiometry ratios of Dy–K and Al–K derived from the Langmuir model were2.0 and 2.6.The analysis of X-ray absorption fine structure(XAFS)and density functional theory(DFT)revealed that Dy and Al were adsorbed onto kaolinite as outer-sphere hydrated complexes via hydrogen bonds.Dy was adsorbed as[Dy(H_(2)O)_(10)]^(3+),and Al was adsorbed as[Al(OH)_(2)(H_(2)O)_(4)]^(+).In particular,the adsorption of Al resulted in protonation of the hydroxyl groups on the surface of the kaolinite.Based on the above insights,the higher ion exchange stoichiometry ratios are attributed to closer adsorption distances(6.04 A for Dy and 3.69 A for Al)and lower adsorption energies(-223.72 kJ.mol^(-1)for Dy and-268.33 kJ.mol^(-1)for Al).The maximum ionexchangeable capacity is related to the change of the surface electrical properties of kaolinite.The zeta potential was increased to-7.3 mV as the protonation resulted from aluminum adsorption,while Dy adsorption had a minor effect,maintaining a value of-17.5 m V.
文摘Disclaimers:The International Energy Agency released Global Critical Minerals Outlook 2025 recently.The report presents the latest data and analysis on supply,demand,investment and more for key energy-related minerals,including copper,lithium,nickel,cobalt,graphite and rare earth elements.It also made projections for how these markets will change over the next decade as the global energy transition picks up speed.The article"Outlook of global rare earth industry"is excerpted from the report and editted by the editorial office for reference.
文摘This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage(AMD)streams to recover rare earth elements(REEs).A life cycle assessment(LCA)study was done to evaluate the environmental impacts of rare earth production from deleterious material in the form of highly contaminated leachate(HCL)and low-contaminated leachate(LCL).The results indicate that the main contributors to environmental categories that produce RE-hydroxide stages are NaOH and electricity.Also,oxalic acid,Na_(2)CO_(3),and hydrochloric acid significantly contribute to the production stage of individual rare earth oxides(REOs),including solvent extraction(SX)and precipitation steps.The HCL route has higher environmental impacts than LCL due to higher chemical/energy and H_(2)SO_(4)usage,so 468 and 292 kg of carbon dioxide are generated to produce1 t of individual REOs from HCL and LCL routes,respectively.Moreover,the carbon dioxide emitted from the process,including the RE-hydroxide production,SX,and REOs production,is less than 10 t CO_(2).A sensitivity analysis was also performed to assess the changeability of the environmental footprints of the main inputs in the SX process,as the main stage has a higher contribution to the whole process.This LCA study is the first step toward understanding the environmental influence of new processing methods to produce REEs from coal by-products through a developed pilot-scale process.
基金supported by the Guizhou Provincial Science and Technology Program ([2022]ZD006)。
文摘Rare earth elements were extracted using a sulfuric acid roasting-water leaching process.The effect of acid roasting on a new type of low-grade sedimentary rare earth ore found in Guizhou Province,China was analyzed using X-ray diffraction and scanning electron microscopy.A systematic study was conducted on process parameters such as amount of acid,roasting temperature,roasting time,water leaching temperature,and leaching time.The results reveal that the total recove ry of rare earth elements reaches 81.37%,which is 3.1 times higher than that achieved through direct acid leaching,under the optimal conditions.In addition,the leaching rate of heavy rare earth elements reaches 72.53%.Rare earth elements and some other valuable metals are transformed into soluble sulfate through the local decomposition of clay minerals under the action of the sulfuric acid attack.The dissolution rates of aluminum,iron,and titanium ions are 34.94%,17.05%,and 62.77%,respectively.The precipitation rate of Ti reaches 99%,and the loss of rare earth ions in the solution is less than 1%.Meanwhile,the results of a leaching kinetics analysis indicate that the leaching process of rare ions is controlled by diffusion.Precious metal ions such as iron and aluminum in the leaching solution can reduce the adsorption of rare earth ions by kaolinite.This study efficiently recovered rare earth ions under conditions of low calcination te mperature and direct water leaching,resulting in reduced energy consumption of the extraction process and acidity of the leaching solution.These findings provide a solid foundation for the further separation and extraction of rare earth ions.
基金Project supported by the Major Research Plan of the National Natural Science Foundation of China(91962211)the National Key Research and Development Program of China(2021YFC2902202)+2 种基金the Science and Technology Innovation Fund of GRINM(2022PD0102)the Major Program of Qingyuan Innovation Laboratory(00122004)the Beijing Nova Program(20230484379)。
文摘In this paper,a multi-stage leaching process for the weathered crust elution-deposited rare earth ore was proposed using MgSO_(4)as a leaching agent.The results indicate that with increasing the concentration of MgSO_(4)from 0.5 wt%-1.0 wt%to 2.0 wt%-4.0 wt%,the peak concentrations of rare earths increase from 1.87 to 3.59 to 5.49-10.21 g/L,and the collection periods of leach solution are sho rtened from 0.85 to 1.54 to 0.31-0.47(liquid-to-ore ratio).When the rare earth ore is leached with leaching agent solution with high initial pH(3.0-5.0),the rare earths and aluminum are predominantly leached by Mg^(2+)instead of H+.However,H+participate in the leaching process of rare earths and aluminum at lower initial pH(1.5-3.0)of the leaching agent solution.Especially,when the initial pH of leaching agent solution is 2.0,a large amount of aluminum is leached when the liquid-to-ore ratio is greater than 1.2.Based on the above insights,increasing the initial pH(3.0-5.0)of leaching agent solution in the injection stage using high-concentration MgSO_(4)(>1.0 wt%)can increase the peak concentration of rare earths in the leach solution and shorten the collection period.However,in the injection stage using low MgSO_(4)concentration(<1.0 wt%),an initial pH of leaching agent solution of 2.0 is selected to reduce the leaching amount of aluminum and the consumption of MgSO_(4).Comparing to the Leaching process using constant MgSO_(4)concentration(2.0 wt%,initial pH of 5.0),the leaching efficiency of rare earths using a multi-stage leaching process is approximately equal(about 94.6%)under optimal conditions.The leaching amount of aluminum is reduced by 16.9%.The consumption of MgSO_(4)is reduced by 67.1%.
基金Project supported by the National Natural Science Foundation of China(U2002215)。
文摘Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl cellulose(PQ-10)was used as a novel green swelling inhibitor and percolation promoter and was mixed with conventional leaching agent ammonium sulfate((NH_(4))_(2)SO_(4))to form a composite leaching agent to study the performance and mechanism of swelling inhibition and percolation promotion.Adding PQ-10 can inhibit the hydration swelling of WREOs,promote the percolation effect of the leaching agent,improve the rare earth(RE)leaching efficiency,and reduce the im purity aluminum(Al)leaching efficiency.Compared with the conventional leaching agent 2 wt%(NH_(4))_(2)SO_(4),the percolation time is reduced by 50%by using the composite leaching agent(0.02 wt%PQ-10+2 wt%(NH_(4))_(2)SO_(4)).PQ-10 has positively charged quaternary ammonium groups and hydrophilic group hydroxyl groups,which makes it easy to adsorb on WREOs multiple sites through electrostatic interaction and hydrogen bonding,weakening the electrostatic repulsion between mineral particles,reducing the WREOs interlayer spacing,compressing the double electric layer thickness at the solid-liquid interface,weakening the mineral hydration swelling and increasing the percolation rate.The long carbon chains of the polymer entangle and link the fine mineral particles to agglomerate them,increasing their particle size and reduc ing their hydration dispersion,and preventing blockage of the pe rcolation pores caused by migration of the fine particles through the ore body with the solution.PQ-10 molecules also insert the mine ral interlayer and expulsion of the internal water,further inhibiting the swelling of WREOs.Adding PQ-10 reduces the surface tension of(NH_(4))_(2)SO_(4)solution,improving the spreading and spreading ability of the solution,reducing the adhesion work between molecules in the solid-liquid phase and the adhesion work reduction factor.It proves that PQ-10 promotes the percolation effect of the leaching process of WREOs.In addition,PQ-10 expands the leaching pore size and seepage channels,further improving the percolation rate.
基金supported by the National Key Research and Development Program of China(2020YFC1909104)National Natural Science Foundation of China(52274355)Major Science and Technology Project of Inner Mongolia Autonomous Region(2021ZD0016)。
文摘The Mountain Pass mine is recognized as one of the world's primary sources of rare earth minerals.These rare earth minerals mainly consist of bastnaesite and a small amount of monazite phosphate,which cannot be decomposed and recovered through conventional oxidative roasting and hydrochloric acid leaching process.An efficient,clean,and economical process called the"combined method"was proposed for the utilization of the Mountain Pass mine to extract rare earths from Mountain Pass rare earth concentrate(MPREC).The main steps of this process include weak oxidation atmosphere roasting,step leaching of hydrochloric acid,solid-liquid separation,the monazite slag with sulfuric acid roasting water leaching,etc.In this paper,the roasting process of MPREC under a weak oxidation atmosphere was investigated.The study examines the thermal decomposition kinetics,phase transition process,and leaching behavior of MPREC in air/CO_(2)atmosphere.Results show that,the activation energy(Ea)for MPREC thermal decomposition in air and CO_(2)atmosphere are 146 and 320 kJ/mol,respectively.At temperature above 500℃in air or above 700℃in CO_(2)atmosphere,REOF are generated from bastnaesite through an in-situ reaction with CaO,which is decomposed from CaCO_(3),to form CaF_(2)and rare earth oxide(REO).Thus,F is regulated into solid phase.In an oxidizing atmosphere,the thermal decomposition of bastnaesite is accompanied by the rapid oxidation of Ce(Ⅲ).In co ntrast,the oxidation of Ce(Ⅲ)in a CO_(2)atmosphere is significantly inhibited.At 700℃,the oxidation rate of Ce in air is 74.09%,while in a CO_(2)atmosphere,it is only 33.83%.The hydrochloric acid leaching experiment shows that,the leaching rate of rare earth after roasting at 600℃under an air atmosphere reaches to 82.9%,and it reaches 87%after roasting at 800℃under a CO_(2)atmosphere.The reduction of Ce oxidation in a weak oxidizing atmosphere significantly improves the leaching rate of Ce.
文摘2024 is a crucial year for fully implementing the spirit of the 20th National Congress of the Communist Party of China and a challenging year for deepening the implementation of the 14th Five-Year Plan.This year,the vast number of rare earth technology workers made outstanding contributions to accelerating the construction of a technological powerhouse and achieving high-level technological self-reliance and self-improvement,facing the forefront of world science and technology,the main battlefield of the economy,primary national needs,and people's health.The rare earth technology industry had achieved fruitful results.
基金Projects supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0430205)Guangdong Major Project of Basic and Applied Basic Research(2019B030302013)+2 种基金National Natural Science Foundation of China(42102037,42272158)Guangdong Basic and Applied Basic Research Foundation(2023A1515012927)Science and Technology Planning of Guangdong Province,China(2023B1212060048)。
文摘Ion-absorption deposits(IADs)of rare earth elements(REEs)constitute the main economic resources of the essential heavy rare earth elements(HREE).Nonetheless,the existing leaching methods for extracting REEs from IADs face limitations stemming from significant environmental consequences and a poor REE recovery rate.In a recent development,electrokinetic mining(EKM)has emerged as a novel technology for extracting REEs from ion-adsorption deposits,demonstrating the potential for environmentally friendly and efficient recovery of REEs from weathering crusts.However,the transport mechanism of REE in weathering crust soil in an applied electric field remains poorly understood,and the influence of the EKM process has yet to be studied.In this study,we systematically investigated the transport characteristics of REE in weathering crust soil under the influence of an electric field.We demonstrate that the transport of REE is simultaneous with the transport of water,H+,and OH-in the applied electric field,where the EKM process is influenced by the voltage gradient,initial soil water content,electrode numbers,and power-on time.Under the optimal EKM conditions,78,8%of REE is recovered from a 45 kg-scale weathering crust soil.Additionally,we identify the transport diversity between light REE(LREE)and HREE,which assists in the separation and pre-enrichment of LREE and HREE.Furthermore,we demonstrate that the mechanism for REE transport under an electric field involves a combination of electromigration,electroosmosis,and electrolysis working synergistically.This study provides new perspectives on the transport behavior and mechanism of REEs in weathering crust soil under an electric field.These findings pave the way for the practical implementation of EKM technology.
文摘State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.
文摘State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization was approved by the Ministry of Science and Technology to be one of the national key laboratories in November 2022.The laboratory was reconstructed based on former State Key Laboratory of Baiyun Obo Rare Earth Resources Researches and Comprehensive Utilization.
