Preparation of Nd(III) carbonate by precipitation stripping of Nd(III)-loaded VA10

The preparation of fine particles of Nd(III) carbonate from kerosene solution, from which Nd(III) was extracted with versatic acid 10 (VA10) by a precipitation stripping technique using an aqueous NH₃-(NH₄)₂CO₃ solution as stripping medium, was studied. In preliminary experiments, we were unable to recover simple Nd(III) carbonate from Nd(III)-loaded VA10 by CO₂ gas bubbling, when water, (NH₄)₂CO₃, NH₄HCO₃, NaHCO₃, or NA₂CO₃ solution saturated with CO₂ was used as the stripping solution. To obtain simple Nd(III) carbonate, it is necessary to use more than the stoichiometric amount of NH₃ compared to VA10 and about 10 times as much (NH₄)₂CO₃ as Nd(III). The solution mixture of NH₃-(NH₄)₂)CO₃ acts as a pH buffer, an adductor for VA10, and a CO ₃ ²⁻ ion source. Although it was concluded that the precipitates are Nd₂(CO₃)₃·xH₂O (x⊧4), their X-ray pattern does not coincide with that quoted by JCPDS. By heating these precipitates, cubic Nd₂O₃ was obtained at 823 K, while, at 973 K, hexagonal Nd₂O₃ was formed. Since the stripping solution consisting of NH₃-(NH₄)₂CO₃ was highly alkaline, VA10 was also stripped in the aqueous phase. To use a closed-circuit system for the precipitation stripping of Nd(III) carbonate from Nd(III)-loaded VA10, it is important to regenerate VA10 in the organic phase. For this purpose, evaporation of NH₃ by air bubbling was studied. By bubbling air into a stripping solution warmed at 333 K, almost all the VA10 can be transferred to the organic phase.     

Extraction of rare earth ions from phosphate leach solution using emulsion liquid membrane in concentrated nitric acid medium

It is very significant to recover rare earths (REs) from wet-process phosphoric acid, in terms of extraction rate and selectivity, the current carrier di(2-ethlhexly) phosphate (D2EHPA) out there is still inferior. Based on this question, our team modified D2EHPA to synthesize new extractants. This paper presents a comprehensive study on the extraction of rare earth ions (RE³⁺) from phosphate leach solution using emulsion liquid membrane (ELM) in concentrated nitric acid medium. The ELM system is made up of (RO)₂P(O)OPh-COOH as carrier, polyisocrotyl succinimide (T154) as surfactant, sulfonated kerosene as diluent, phosphoric acid (H₃PO₄) as stripping solution. Different chemical parameters such as type and concentration of carrier, surfactant, stripping solution, volume ratio of oil phase to internal phase, and volume ratio of emulsion ratio to external phase were analyzed. The extraction of RE³⁺ was evaluated by the yield of extraction. In addition, the demulsification process was also investigated. The proposed method of ELM using (RO)₂P(O)OPh-COOH as carrier can be expected to provide an efficient, simplify operation, and facilitated method for extracting RE³⁺.     

Solvent extraction-separation of La(III), Eu(III) and Er(III) ions from aqueous chloride medium using carbamoyl-carboxylic acid extractants

N,N-dibutyldiglycol amic acid(HLI) and N,N-dioctyldiglycol amic acid(HLII) were synthesized and characterized by conventional spectroscopic methods. These molecules were examined as extractants for extraction-separation of La(III), Eu(III) and Er(III), as representative ions of light, middle and heavy rare earths, from aqueous chloride solutions. The analysis of the extraction equilibria revealed that the extracted species of lanthanum and europium ions by both of the extractants had a 1:3 metal to ligand ratio. It was suggested that erbium ions were extracted into the organic phase via the formation of Er(LI or II)2Cl complexes. The effect of the organic diluents on the extraction-separation efficiency of the studied rare earths by HLI and HLII was investigated by comparing the results obtained in dichloromethane and carbon tetrachloride. Regardless to the diluent used, the order of selectivity presented by the investigated extractants was Er(III)Eu(III)La(III). It is noteworthy that, a significant enhancement in separation of the studied rare earths by the extractants was achieved in their competitive extraction experiments with respect to that obtained in single component extraction experiments. Applicability of the extractants for the removal of rare earth ions from spent Ni-MH batteries was tested by removal of La(III), Eu(III) and Er(III) ions from simulated leach solution of such batteries.     

电解控制酸度萃取法研究HEH(EHP)从氯化稀土溶液中萃取La(Ⅲ)、Ce(Ⅲ)、Pr(Ⅲ)和Nd(Ⅲ)

首次提出电解控制酸度萃取法,探讨了该法萃取反应机理。并用该法研究了HEH(EHP)从氯化稀土混合溶液中萃取La( )、Ce( )、Pr( )和Nd( )过程中各元素在HEH(EHP)—酸性萃取体系中的分离系数(β)、萃取速率(r)和电流效率(η1)等的变化规律。     

Theoretical elucidation of rare earth extraction and separation by diglycolamides from crystal structures and DFT simulations

Diglycolamides(DGAs) show excellent application prospects for the extraction and separation of rare earth metals from highly radioactive liquid wastes and rare earth ores.The extraction ability of DGAs for rare earth ions in nitrate or chloride media increases with increasing atomic number of the rare earth metal.To understand the origin of this phenomenon,three binuclear crystals [Ln(TEDGA)3][Ln(NO_3)_6] of N,N,N',N'-tetraethyldiglycolamide(TEDGA) with rare earth ions La(Ⅲ),Pr(Ⅲ) and Eu(III) were prepared and characterized crystallographically.The three complexes belong to the triclinic crystal system,P-1 space group.The bond lengths of Ln-O_(amide) are significantly shorter than those of Ln-O_(ether) in the same crystal.The Ln-O_(amide) and Ln-O_(enher) bond lengths gradually decrease with increasing atomic number of the rare earth ion.The dihedral angle formed by TEDGA and metal ions through the tridentate coordination gradually increases with increasing metal ion atomic number,tending toward the formation of sizeable planar coordination structures for the most massive rare earth ions.The structures of the compounds formed by the extractant and metal ion were optimized by means of DFT simulations.We find that the interaction between TEDGA and the rare earth ion is dominated by electrostatic interaction by analyzing binding energy,WBIs,Mulliken charge,natural electron configurations,and molecular orbital interaction.The covalent component of the Ln-O bonds of the complexes increases with increasing metal atomic number.The observed increase in extraction and separation capacity of diglycolamides for rare earth ions with increasing atomic number might be due to the formation of two fivemember rings by one tridentate ligand.The rare earth ions with large atomic numbers tend to form planar structures with large dihedral angles with DGA ligands.     

Comparative studies on Y(III) and Dy(III) extraction from hydrochloric and nitric acids by Cyanex 572 as a novel extractant

Extraction of Y(III) and Dy(III) from hydrochloric and nitric acids by Cy-572 in kerosene was studied. The factors affecting the extraction were separately investigated. The stoichiometry of the extracted species was deduced on the basis of slope analysis method. Evaluation of extraction equilibrium and stripping investigation was studied as well as saponification effect of Cy-572. The composition of the extracted metal species in the organic phase was found to be $\overline{{[\text{MA}}_3·{\left(\text{HA}\right)}_3]}$ for Y(III) or Dy(III) in both media. 1.0 mol/L HCl is the best stripping agent for each metal ion from the studied acidic media in one step. Saponified Cy-572 does not exhibit any selectivity towards the extraction of Y(III) or Dy(III) from both HCl and HNO₃ solutions. Based on the obtained results, the data were compared and the separation feasibility between lanthanides and Y(III) in the two media was discussed.     

水热法合成BaNd_xFe_（12－x）O_（19）铁氧体的研究

本文利用水热法合成了六角形磁铅石结构的ＢａＮｄｘＦｅ（１２－ｘ）Ｏ（１９）铁氧体，用Ｘ射线衍射仪、透射电子显微镜和振动样品磁强计等仪器对粉末的结构、形貌和磁学性能进行了研究，并讨论了Ｎｄ（３＋）对钡铁氧体磁学性能的影响。结果表明，Ｎｄ（３＋）可以明显提高ＢａＦｅ（１２）Ｏ（１９）粉末的矫顽力。     

Evaluation of toxicity profiles of rare earth elements salts (lanthanides)

The presented study aims to extend the knowledge of toxicological profile of rare earth elements salts(REEs).The basal toxicity test performed comprised assessment of cytotoxicity(3 T3 Balb/c Neutral Red Uptake Test)that allows for calculation of LD50(rats)on the basis of the concentration which leads to a50%reduction in cell growth(IC50).Environmental toxicity was addressed by the Tubifex tubifex(T.t.)express test.The in vitro skin irritation(OECD TG 439)and skin corrosion tests(OECD TG 431)utilizing the 3 D in vitro reconstructed human epidermal model EpiDerm(MatTek IVSL,SK)were used for assessment of skin irritation and corrosion potential hazard of REEs.Mutagenic effects were determined using the bacterial reverse mutation assay(Ames Test)on 5 Salmonella typhimurium strains with and without metabolic activation(OECD TG 471).Endocrine disruption was evaluated by means of a yeastbased assay YES/YAS(Xenometrix,CH).Skin sensitization was assessed using the LuSens assay,based on a genetically modified human keratinocyte cell line(OECD TG 442 D).The tested REEs have no potential of mutagenicity or skin sensitization,exhibit very weak endocrine disruption potential and only exceptional local irritation/corrosion effects for thulium(Ⅲ)chloride anhydrous,but have acute and chronic toxic effects on the aquatic environment.     

Luminescence of halophosphate solid-solution Ca5(PO4)3(F0.8Cl0.2):Eu2+,Mn2+ for WLED

Solid-solution based luminescent materials have been widely explored due to their tunable optical properties in recent years. In this work, instead of more common cation-substitution approach, we investigated the luminescence properties of Eu~(2+) and Mn~(2+) co-doped halophosphate solid solution Ca_5(PO_4)_3(F_(0.8)Cl_(0.2)) via anion substitution synthesized by high temperature solid state reaction method.The formation of the solid solution was confirmed by X-ray diffraction(XRD) characterization, which indicates that the introduction of certain proportion of Cl~-will not make significant change on the Ca_5(PO_4)_3F lattice. We also studied the energy transfer from Eu~(2+) to Mn~(2+) in the host so as to obtain white light emission via adjusting the doping concentrations of Eu~(2+) and Mn~(2+). The white light emission was achieved through combination of Eu~(2+) blue emission and Mn~(2+) red-orange emission with appropriate proportions. The results suggest that Ca_5(PO_4)_3(F_(0.8)Cl_(0.2)):0.01Eu~(2+),0.18 Mn~(2+) could be a potential WLED phosphor working under ultraviolet excitation.     

Studies on the Fractionation and Availability of Added Soluble Rare Earth Elements in Soil

ＳｔｕｄｉｅｓｏｎｔｈｅＦｒａｃｔｉｏｎａｔｉｏｎａｎｄＡｖａｉｌａｂｉｌｉｔｙｏｆＡｄｄｅｄＳｏｌｕｂｌｅＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｓｉｎＳｏｉｌＣｈｅｎＺｈａｏｘｉ（ＥａｓｔＣｈｉｎａＩｎｓｔｉｔｕｔｅｏｆＭｅｔａｌｌｕｒｇｙ，Ｍａａｎｓｈ...     

Calculation of RECl_3-CaCl_2-LiCl Phase Diagrams(RE=La, Ce, Pr, Nd)

ＣａｌｃｕｌａｔｉｏｎｏｆＲＥＣｌ_３－ＣａＣｌ_２－ＬｉＣｌＰｈａｓｅＤｉａｇｒａｍｓ（ＲＥ＝Ｌａ，Ｃｅ，Ｐｒ，Ｎｄ）ＱｉａｏＺｈｉ－Ｙｕ（乔芝郁）；ＸｉｎｇＸｉａｎ－Ｒａｎ（邢献然），ＤｕａｎＳｈｕ－Ｚｈｅｎ（段淑贞）（ＤｅｐａｒｔｍｅｎｔｏｆＰｈ...     

稀土镧对钢中残余元素的固定作用

采用Ｍｉｅｄｅｍａ二元生成热模型,从热力这证明了稀土镧和多种残余元素反应是完全可能的。采用ＳＥＭ及ＴＥＭ手段研究了稀土尖不同锡含量的钢中形成夹杂的情况。镧放钢中较低含量的锡（０．０４５％）作用生成简化合物。证实了用移土金属减轻低氧、低硫钢中残余元素钢性能危害的可行性。     

Compilation of Q－data and Simulation of Q－spectra in Rare Earth Elements Analysis by Using ICP－AES

ＣｏｍｐｉｌａｔｉｏｎｏｆＱ－ｄａｔａａｎｄＳｉｍｕｌａｔｉｏｎｏｆＱ－ｓｐｅｃｔｒａｉｎＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｓＡｎａｌｙｓｉｓｂｙＵｓｉｎｇＩＣＰ－ＡＥＳＨｕｏＤｅｎｇ－Ｗｅｉ（霍登伟），ＹｉｎＸｉａｎｇ－Ｌｉａｎ（尹香莲），ＺｈａｏＧ...     

Behavior of sulfate in preparation of single light rare earth carbonate by Mg(HCO_3)_2 precipitation method

The precipitation of the water-leaching solution of Baotou mixed rare earth(RE) concentrate roasted with sulfuric acid using ammonium bicarbonate for producing RE carbonate produces a mass of ammonia-nitrogen wastewater because of the relatively low solubility of rare earth sulfate.To solve the serious problem of ammonia-nitrogen pollution,new precipitators need to be developed urgently so as to meet the requirements of environmental protection and impurities content of the product(SO_4~(2-)1.8 wt% in RE carbonates products).In this paper,we studied the effects of feeding modes on the behavior of SO_4~(2-) during the preparation of light RE carbonate(RE=La,Ce,Pr,Nd) from their sulfate solutions using Mg(HCO_3)_2 as a precipitant.The results indicate that the contents of SO_4~(2+) in the La and Ce precipitates using positive feeding mode exceed 16 wt% because of the formation of La2(CO_3)_(2.15)(-SO_4)_(0.85)·4 H_2 O and Ce2(CO_3)_(2.15)(SO_4)_(0.85)·3 H_2 O,while those of the Pr and Nd precipitates are 4 wt%-5 wt%since they exist in the form of n-carbonate.The precipitates prepared using synchronous feeding mode are all RE carbonate with only 4 wt%-5 wt% of SO_4~(2-) enclosed in the precipitation.The content of SO_4~(2-) in the RE carbonate obtained using reverse feeding mode is the lowest.Among them,the content of SO_4~(2-) in La precipitate is only 1.40 wt%.Both synchronous and reverse feeding modes can effectively reduce the content of SO_4~(2-)in RE carbonate,which provides theoretical guidance for the preparation of qualified light RE carbonate products by Mg(HCO_3)_2 precipitation method.     

Gold stripping by hydro-alcoholic solutions from activated carbon: Experimental results and data analysis by a semi-empirical model

The aim of this work was to study gold stripping from activated carbon using a range of different alcohols (isopropanol, ethanol and ethylene glycol). The experimental work was carried out on a laboratory scale, using activated coconut carbon, at 40 to 80 °C and up to 8 h extraction time. Isopropanol was the most rapid eluent with > 98% Au eluted after 1 h at 80 °C, ethylene glycol had a similar extraction after 2 h, ethanol was the least effective with 5 h required for > 95% extraction. Interestingly, 77% Au extraction was obtained at 40 °C using ethylene glycol.     

金属钕及镨中钕,镨和钐的ICP测定

采用ＩＣＰ发射光谱研究了稀土钕和镨样品中钕、镨和钐三个元素的分析。通过采用内参比法补偿非光谱干扰、Ｋ系数法和逐步逼近法扣除光谱干扰,测定了稀土主含量、次含量和杂质,主含量的变异系数小于０．５％,次含量的变异系数小于４％。将本方法同Ｘ荧光光谱法对比,结果吻合很好。     

Ce（Ⅲ） Salt Induced Changes of Superficial Microstructure in Freshwater Pearls

The transition of the superficial microstmcture of freshwater pearls induced by Ce was investigated by means of scanning electron microscopy. The pearls were cultured in freshwater containing 0 （control group ）, 0.5, 1, and 1.5 mg·L^-1 of a Ce additive. X-ray photoelectron spectroscopy （XPS） measurement showed that the concentration of Ce absorbed in the superficial microstmcture of pearls was positively correlated to the additive Ce. At the same time, the surface microstmcture of pearls changed greatly with Ce concentration, the shape of the blocks changed from spindly to perfect regular hexagonal sheets and finally to round discs. The glossiness of the pearls changed correspondingly with the microstmcture, pearls possessing the regular hexagonal blocks having the highest glossiness. Therefore, the REE Ce exerted a significant influence on the microstructure and glossiness of freshwater pearls. An appropriate quantity of Ce may improve the glossiness of pearls.     

The Characteristics of Adsorption and Desorption of Rare Earth Elements by the Main Types of Soils of China

The adsorption-desorption behavior of the mixed rare earth elements(RE)on the main types ofsoils of China,kaolinite and synthetic oxides was studied.The isothermal adsorption of RE was fitted toLangmuir.Freundlich and Temkin equations.The main factors determining the RE adsorption capacity ofthe soils are the type of clay mineral and the content of amorphous iron oxide in the soils.The above two fac-tors and the pH of soil determine the RE adsorption ability of the soils.The soil and synthetic iron,manga-nese oxides strongly adsorb RE specifically.     

偕胺肟基纤维对Sm(Ⅲ)、Nd(Ⅲ)、Pr(Ⅲ)的吸附与富集

以偕胺肟基纤维 (用 L 表示 )为吸附剂 ,对 Sm( )、Nd )、Pr( )进行螯合吸附 ,再将螯合后的纤维进行解吸 ,使稀土离子得到富集。通过实验确定出最佳吸附条件为 :温度 5 0℃、时间 30～ 6 0 m in、p H3～ 4 ;最佳解吸条件为 :0 .0 2～ 0 .0 8m ol· L- 1 HCl、室温、30～ 6 0 min。纤维 L 对 Sm( )、Nd( )、Pr( )三种离子的一次吸附的最大量分别为 2 .99、2 .86、4 .11mg· g- 1 (被吸附离子的初始浓度 C0 =0 .0 0 1mol· L- 1 )。L 对三种离子均可进行三次以上累积吸附。     

Effect of RE Elements on the Morphology of Carbides and the Impact Fatigue Properties of the Low Cr White Cast Iron

An apparatus of zone melting unidirectional solidification with a steep temperature gradient andan impact fatigue tester were used.The effect of RE elements on the morphology of carbides and the impactfatigue properties of the low Cr white cast iron were investigated.Experimental results showed that the modi-fying effect of RE elements was remarkable on the M3C carbides.With the addition of RE elements in thelow Cr iron,a lot of plate-like carbides were transformed into lath-like and rod-like ones.The higher thecontent of RE elements was,the more was the fraction of the lath-like and rod-like carbides.In the low Crwhite cast iron,the RE modifying agent can efficiently increase the impact fatigue resistance and decrease thecrack growth rate and delay the time of incipient cracking.With the increase of the content of RE elements inthe low Cr cast iron,the impact fatigue resistance increased greatly and the crack growth rate decreased rap-idly.