Luminescence properties of rare earth complexes bonded to novel mesoporous spherical hybrid materials

YVO₄:Eu³⁺phosphors have been widely used in optoelectronic integration fields of its chemical and thermal stability.However,the excitation spectrum band of VO₄^3- is too narrow for high-efficiency luminescence,restricting its further development.Herein,flower-like and linear-like YVO₄:Eu³⁺ hollow mesoporous spheres were synthesized and connected with Eu organic ligand,to obtain a new hybrid luminescent material.The characterization...     

Recent progress on lanthanide complexes/clay minerals hybrid luminescent materials

The unique luminescent performance of lanthanide complexes/clay minerals hybrid materials has been fascinating many researchers for recent decades.It not only retains the excellent luminescent characteristics of lanthanide complexes but also improves the poor stability of the complexes.In this article,we introduce the luminescence mechanism of lanthanide complexes and point out the necessity of their combination with clay minerals.After the analysis of the structure and interlayer environment di...     

Hierarchical porous cellulose/lanthanide hybrid materials as luminescent sensor

Photoluminescent hybrid materials containing carboxymethyl cellulose and lanthanide ions (Eu³⁺, Tb³⁺) were prepared by a facile method under ambient conditions. Lanthanide ions were covalently grafted to the cellulose framework through coordination with the carboxylic groups of the cellulose. Hybrid materials were fabricated as hydrogel and aerogel. As shown by SEM and pore parameters, aerogel materials which were obtained by supercritical CO₂ drying show hierarchical porous structure. The photoluminescence spectrum of the hybrid materials shows the characteristic red emission of Eu³⁺ ion and green emission of Tb³⁺. Further luminescent investigations reveal that these hybrid materials can detect Fe³⁺ with relative selectivity and high sensitivity, which suggests that the hybrid materials could be a promising luminescent probe for selectively sensing Fe³⁺ ion.     

Growth and optical properties of ytterbium and rare earth ions codoped CaF_2-SrF_2 eutectic solid-solution(RE=Y~(3+),Gd~(3+),La~(3+))

Ytterbium and rare earth ions(RE=Y,Gd,La)codoped CaF₂-SrF₂single crystals(3 at%Yb,6 at%RE:CaF₂-SrF₂)were fabricated by temperature gradient technology(TGT).All the space groups remain the same Fm3m as that of Yb:CaF₂-SrF₂.The lattice parameter a,unit cell volume V,as well as bond length of Ca/Sr-F and F-F increase in the sequence of rare-earth ions radius Y³⁺3+3+.The segregation coefficients of Yb ions are 0.87 in Yb,La:CaF₂-SrF₂and Yb,Gd:CaF₂-SrF₂,which are larger than 0.85 in Yb,Y:CaF₂-SrF₂and 0.80 in Yb:CaF₂-SrF₂.Absorption spectra in the range of 200 and 400 nm were analysed with Yb²⁺contents.The absorption and emission cross-sections in the range of 900-1100 nm were determined together with fluorescence lifetime.The saturation pump density/Sat,minimum pump density/m in and gain cross-section were analysed.Yb,La:CaF₂-SrF₂has a relatively higher optical parameter(δem×t,0.52×10²⁰cm²·ms),lower Isat(3.68 kW/cm²)and^min(0.50 kW/cm²)at 1038 nm indicating the potential application in high power laser.Low phonon energy of CaF₂-SrF₂is 302 cm^-1which is located between those of CaF₂and SrF₂as measured by Raman spectra.It is believed that ytterbium and rare earth ions(RE=Y³⁺,Cd³⁺,La³⁺)codoped CaF₂-SrF₂eutectic solid-solution is promising for high-power and wavelength-tunable solid-state lasers.     

Luminescent characterization of rare earth Dy3+ ion doped TiO2 prepared by simple chemical co-precipitation method

Pure and rare-earth ion (Dy³⁺) doped TiO₂ nanomaterials were prepared through a chemical co-precipitation method. The chemical composition, microstructure and optical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy and photoluminescence (PL). XPS analysis reveals that Dy³⁺ ions are preferentially occupied in the TiO₂ crystallite lattices. Both the XRD and TEM analyses confirm that both the pure and Dy doped TiO₂ are in pure anatase phase and in nano size range, respectively. Also it is found that the maximum solubility limit for Dy³⁺ ions is found to be 0.4% in TiO₂ matrix, above which it occupies interstitials and/or crystallite surface of TiO₂ nanocrystals. From the UV-Vis spectroscopy studies it is found that Dy doping induces blue shift in TiO₂. From the PL analysis it is found that doping Dy³⁺ improves the luminescence behavior in comparison with the pure TiO₂ nanoparticles. Overall, doping very low concentrations of Dy³⁺ greatly alters the structural morphology and directly increases the luminescence behavior of TiO₂ suitable for advanced optoelectronic applications.     

Local structure and luminescent properties of lead phosphate glasses containing rare earth ions

Local structure and luminescent properties of lead phosphate glasses containing rare earth ions were studied.Optically active ions such as Eu3+,Dy3+,Tb3+ and Er3+ were chosen as dopants.The local structure was verified using X-ray diffraction and Fourier transform in-frared(FT-IR) spectroscopy.The visible luminescence bands recorded for the studied samples corresponded to 5D0→7FJ(J=0÷4) transitions of Eu3+,4F9/2→6HJ/2(J=11÷15) transitions of Dy3+,5D3→7FJ’(J’=1÷6) and 5D4-7FJ(J=3÷6) transitions of Tb3+,and 4S3/2→4I15/2 transitions of Er3+.     

Recent progress in luminescent materials based on lanthanide complexes intercalated synthetic clays

Interest in lanthanide complexes in the synthetic clays remains growing considerably during the last decades because of the attractive features of the individuals. Synthetic clays like Laponite^® and Aminoclay show great potentials in building up the luminescent hybrid materials due to their obvious advantages such as high purity, high dispersibility (or solubility) in water to yield translucent gels and clear aqueous solution. Additionally, their strong adsorption capacity for non-polar molecules or complexes is favorable to the formation of water-soluble and aqueous processable luminescent materials. This feature article summarizes the latest developments in the design and preparation of highly luminescent organic-inorganic hybrid materials with excellent aqueous process ability based on lanthanide complexes intercalated synthetic clays.     

Effects of contaminant metal ions on precipitation recovery of rare earth elements using oxalic acid

Solution equilibrium calculations were performed in this study to understand the impact of contaminant metal ions on the precipitation efficiency of selected ra...     

我国稀土抛光粉材料的生产及应用

本文综述了我国稀土抛光粉材料的主要发展状况。其内容包括稀土抛光粉的生产原料、生产工艺与装备、生产能力及产量、品种和质量、产品的应用及市场,并针对目前存在的一些问题,提出了对策建议。     

A novel polystyrene-poly(hydroxamic acid) interpenetrating polymer network and its adsorption towards rare earth ions

A novel polystyrene-poly(hydroxamic acid)interpenetrating network resin(PS-PHA IPNs)was successfully synthesized by suspension polymerization and interpenetrating network technology.The effects of various experimental parameters,including pH,contact time and initial concentrations of rare earth ions on the adsorption capacity were discussed in detail.Under the condition of pH 4.0(La³⁺),1.0(Ce³⁺)and 3.0(Y³⁺),respectively,PS-PHA IPNs can reach equilibrium adsorption in 6 h and get maximum adsorption capacities(1.08,1.43 and 1.36 mmol/g).The adsorption process of PS-PHA IPNs for La(Ⅲ),Ce(Ⅲ)and Y(Ⅲ)ions can be described by liquid membrane diffusion,particle diffusion and chemical reaction.The adsorption process is a spontaneous and endothermic process and can be better simulated by Langmuir adsorption isotherm.The studies of SEM-EDS indicate that rare earth ions are adsorbed on the surface of PS-PHA IPNs.Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)analysis further prove that rare earth ions are chemisorbed on the surface of PS-PHA IPNs.These results reveal that the as-prepared PS-PHA IPNs is a promising adsorbent for adsorption of rare earth ions due to their higher adsorption capacity than other adsorbents.     

废旧氢镍电池负极材料中稀土的资源化利用

设计了综合回收氢镍电池负极材料中稀土元素并同时回收镍、钴的湿法冶金流程.该流程回收的主要步骤包括：硫酸浸出负极,使大部分稀土以硫酸稀土的形式与镍、钴分离,硫酸稀土经碱转化为氢氧化稀土;进入浸出液的稀土,用P507+煤油萃取使其与镍、钴分离,并同时将锌、锰等杂质与镍、钴分离;用HCl反萃稀土,反萃液与氢氧化稀土中和得到氯化稀土.稀土的综合回收率为98.4%,镍、钴的综合回收率为98.5%.     

稀土永磁材料的生产应用及市场

介绍了近几年来我国稀土永磁材料的生产技术、品种、质量和产量发展状况;永磁品应用的新领域动向;在激烈竞争中磁品国内外市场贸易情报。目前我国已成为全球稀土永磁材料生产、应用和市场发展中心!根据永磁品发展中存在的问题,讨论了一些议题并提出了建议。     

Research progress of rare earth composite shielding materials

With the rapid development of nuclear technology,nuclear protection has received extensive attention.As an important strategic resource,rare earth plays an important role in the field of nuclear shielding materials.In this review,the shielding principles of rare earth materials are first introduced.According to the type of matrix,the characteristics and current research status of metal-based,inorganic nonmetallic-based and polymer-based rare earth shielding materials are reviewed.Meanwhile,the f...     

Dissolved rare earth elements estimation of ion-absorption rare earth ores using reflectance spectroscopy in south Jiangxi province,China

Ion-absorption rare earth ores are an important mineral resource in China. Nowadays, the unauthorized mining has become a serious problem, resulting in severe water pollution and the wastage of rare earth elements (REEs). Being able to estimate the concentration of dissolved REEs in water bodies near mines is essential for tackling this environmental problem. Conventionally, quantitative analyses of the contents of dissolved REEs are performed using laboratory-based techniques, which can be time consuming and costly. Spectral reflectance is a rapid and cost-effective means of characterizing the chemical compositions of light-absorbing materials. In this study, reflectance spectroscopy was performed on dissolved REEs, and the correlation between their reflectance characteristics and REE content was determined. A total of 50 aqueous media samples collected in south Jiangxi Province and 25 laboratory-produced aqueous media samples were tested, and their reflectance spectra and REE contents were measured using reflectance spectroscopy and inductively coupled plasma mass spectrometry, respectively. Next, the reflectance, differential reflectance, and absorption depth were analysed based on the REE content. Six diagnostic absorption features related to REEs are recognised in the visible and near-infrared wavelength regions, along with several smaller peaks. It indicates that the results of the absorption depth analysis are in accordance with the absorption spectra characteristics of the REEs, with the R² value being higher than 0.97. The intensity of each of the six absorption bands exhibits a linear correlation to the total REE content. Therefore, linear regression models can be derived for estimating the total concentration of REEs in aqueous media samples. What's more, the detection limit for REEs is determined to be about 30 μg/L. Thus, it can be concluded that reflectance spectroscopy is a suitable technique for estimating the concentration of dissolved REEs.     

Research progress of rare earth separation methods and technologies

Strategical elements,such as rare earth elements,play a crucial role in the industry,especially in producing high-tech materials.Major global industries have developed a strong dependence on rare earth materials.Every year,there are innovations in industries such as modern technology,green energy,or communications technology,which need more strategic metals to improve investment profitability.This article reviews advances in rare earth separation methods and techniques to guide and recommend the...     

Element migration and phase distribution characteristics during crystallization of rare earth phase in rare earth slag

The crystallization experiment of molten rare earth (RE) slag under different cooling rates was carried out. The characteristics of element migration and phase distribution during RE phase crystallization were studied by using different equipment. The experimental results show that there are two RE phases in the RE slag, namely (Ca, Ce, La)₅(SiO₄)₆F and (Ca,Ce,La,Mg)₃(Ti,Al,Nb)₂O₇. During the cooling crystallization process of molten RE slag, Ca and P elements in the RE phase of (Ca,Ce,La)₅(SiO₄)₆F migrate from inside to outside, and finally gather at the outer edge of the phase to form phase Ca₃(PO₄)₂. The RE phase (Ca,Ce,La)₅(SiO₄)₆F is distributed inside the furnace-cooled slag, and the RE phase (Ca,Ce,La,Mg)₃(Ti,Al,Nb)₂O₇ is distributed in the surface layer of the furnace-cooled slag. And based on the phase distribution characteristics, the central hollowing method is proposed to realize the preliminary enrichment of valuable elements Ti, Nb and RE in RE slag.     

A review of the recycling of rare earth metals

Although rare earth metals are more abundant than their name would indicate, disruptions of their supplychain have occurred recently, and it is no surprise thatthe US Department of Energy (DOE) and the European Union (EU) Commission have listed several of them as critical for their role as materials essential for a clean society. This paper briefly reviews the major uses for rare earth metals and identifies the potential sources of scrap for recycling. The paper then describes the various processes developed to recycle rare earth-containing scraps, such as spent Ni-metal hydride (MH) batteries, magnets, catalysts, polishing powders and phosphors, with case studies taken from industrial practice and research work. The success of recycling efforts depends not only on adequate technical advancements but also requires the overcoming of non-technical challenges comprising, among others, logistics (collection, transportation), and an appropriate political and legal framework.     

Optical and electrical conductivity properties of rare earth elements (Sm,Y, La,Er) co-doped CeO2

In this research, un-doped CeO₂ and Ce_0.85La_0.10M_0.05O₂ (M: Sm, Er, Y) compounds were synthesized by hydrothermal method and the multi-functional properties are reported. Oxygen defects were created with the additives of rare earth ions. The electrical and luminescence behaviors of the synthesized compounds were investigated in accord with the types of additives. The synthesized products were characterized by X-ray diffraction (XRD) analysis, Brunauer–Emmett–Teller (BET) measurement, UV–vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy and electrochemical impedance spectroscopic (EIS). All synthesized compounds are found to be nano-structured and have cubic phase. The total conductivity of all samples was calculated. Hence, the total conductivity of un-doped CeO₂, Ce_0.85La_0.10Y_0.05O₂, Ce_0.85La_0.10Er_0.05O₂ and Ce_0.85La_0.10Sm_0.05O₂ is found to be 2.07 × 10^?10, 5.70 × 10^?4, 1.0 × 10^?3 and 0.0747 S/cm, respectively. Also, bandgap energy (E_g) of these samples calculated from UV visible absorption spectra is discussed, and the optical results show variation between 3.2 and 2.15 eV. Additionally, the luminescence properties of the compounds were investigated and different emissions occur depending on the additive type. Accordingly, photoluminescent emission spectra of Ce_0.85La_0.10Y_0.05O₂, Ce_0.85La_0.10Er_0.05O₂ and Ce_0.85La_0.10Sm_0.05O₂ phosphors indicate that these phosphors have red, green and orange-red colors, respectively.     

Process mineralogy of Weishan rare earth ore by MLA

Mineral liberation analyser (MLA) was applied to quantitatively analyze the rare earth ore from Weishan in Shandong. Mineralogy parameters, such as mineral composition, occurrence states of rare earth elements (REEs) and valuable elements, mineral embedded grain size distribution, mineral association and liberation, are obtained. Results show that the contents of REEs and other valuable elements mainly contained in the ore were La 1.02 wt%, Ce 4.29 wt%, Pr 0.34 wt%, Nd 0.84 wt%, Sr 3.4 wt% and Ba 26.53 wt%, respectively. The REEs mainly occur in bastnaesite and carbocernaite in the form of independent mineral and the contents of bastnaesite and carbocernaite in the ore were 5.96 wt% and 12.30 wt%, respectively. 67.34% of strontium occurs in carbocernaite and the rest occurs in celestobarite and strontianite mineral. 92.71% of barium occurs in barite. Liberation of main rare-earth minerals such as bastnaesite and carbocernaite is more than 80% when the grinding fineness is 78.42% passing 74 μm. The research results could be employed to provide detailed basic theoretical data for further improvement of the beneficiation process flow and the processing index of rare earth ore, the recycling of other valuable minerals and the comprehensive utilization of tailings.     

稀土掺杂Sr2MgSi2O7长余辉发光材料的研究进展

硅酸镁锶(Sr2MgSi2O7)作为目前常用的一种长余辉发光材料基质,性能稳定,耐酸碱性能良好。本文介绍了长余辉发光材料的发光原理,综述了近年来Sr2MgSi2O7长余辉发光材料的主要制备方法以及稀土掺杂Sr2MgSi2O7材料的研究进展,并对该材料的发展做出了展望。制备Sr2MgSi2O7长余辉发光材料的方法主要包括高温固相法,溶胶-凝胶法,化学沉淀法和燃烧合成法,其中最常用的为高温固相法。通过掺杂稀土离子可以形成具有不同发光特性的长余辉发光材料。稀土掺杂Sr2MgSi2O7材料作为一种储能、节能的长余辉发光材料,展现出了广阔的发展和应用前景。