DIRECT DETERMINATION OF NEODYMIUM AND ERBIUM IN RARE EARTH MIXTURE BY DERIVATIVE SPECTROPHOTOMETRY

The absorption spectra of 4f electron transitions of the complexes of neodymium and erbium with 8-hydroxyquinoline-5-sulphonic acid in the presence of diethylamine and ethanol have been measured by normal and third-derivative spectrophotometry. Their molar absorptivities are 70.7 l.mol^(-1).cm^(-1) for Nd and 62.5 l.mol^(-1).cm^(-1) for Er. They are 7.6 times and 14.9 times greater than those of corresponding chlorides, respectively. Use of the third-derivative spectra both eliminates the interference of Ce(Ⅳ) and increases the sensitivity for Nd and Er. Beer,s Law was obeyed from 0-10 ug/ml of Nd and Er. The method has been applied to the determination of neodymium and erbium in rare earth mixtures.

Investigation of Polyacrylate Anion-Exchangers for Separation of Rare Earth Element Complexes with EDTA

The rare earth complexes with EDTA, Ln(edta), show an unusual sequence of affinity for the anion exchangers. The sorption and chromatographic separation of Y 3+ for Nd 3+ complexes with EDTA was studied by using the strongly basic gel and macroporous polyacrylate anion exchangers, Amberlite IRA 458 and Amberlite 958, and the weakly basic gel polyacrylate anion exchanger, Amberlite IRA 68. The investigations on sorption and separation of rare earth complexes with EDTA on the polyacrylate anion exchangers applied mainly in the environment protection so far indicate that they can be applied in anionexchange separation of lanthanide complexes with aminopolycarboxylic acids. It was shown that the weakly basic polyacrylate gel anion exchanger Amberlite IRA 68 is the most effective in purification of Y 3+ from Nd 3+ in comparison with the strongly basic anion exchangers of this type.

Removing Al from Rare Earth Chloride Solution by Method of Extraction

Using long-chain fatty acid as extractant, the process of removing the impurity element aluminum in the solution of praseodymium-neodymium chloride and the influence of extracting conditions were studied. The results show that the amount of aluminum can be decreased from 728 to 14 mg·L -1 that is the 98% of total in the solution of praseodymium-neodymium chloride by one-stage extraction under the condition as follows: the concentration of rare earth is 100～200 g·L -1, the organic phase is 20% fatty acid -10% isooctanol -70% kerosene (V/V), saponification number is 20% with dense ammonia, and the extracting equilibrium time is 5～15 min. Under the same conditions, the extraction ratio of aluminum in the system of fatty acid is 3～5 times of that in naphthene acid. The fatty acid extractant is distinctly better than naphthene acid.

Gasoline Sensor Based on Rare Earth-Doped Indium Oxide with Low Power Consumption

Nanocrystalline indium oxide powders were prepared by microemulsion and then Y2O3 and Nd2O3 doped In2O3 were synthesized separately by impregnation and chemical co-deposition. The structure and morphology were characterized by XRD and TEM, respectively. Gas sensing properties were tested at static state. The results show that homogeneous indium oxide nanopowder with main grain size of 20 nm can be obtained from microemulsion after sintered at 600 ℃ for 1 h. Pure indium oxide gas sensor has higher sensitivity to gasoline than that to ethanol, HCHO, C6H6, NH3, C4H10, but the selectivity is not as well as sensitivity.

Separation of Scandium and Rare Earths with the Method of PSO-Extraction Chromatography

Separation of scandium and rare earths was investigated by using a new extraction chromatography which PSO was used as a stationary phase,while HCl-NH_4SCN solution as a mobile phase.The separation conditions were studied.In this system, the separation factor(β_(Nd)^(Sc))can reach up to 1.3×10~4.The method can be applied to the purposes of separation,purification and analysis of microquantity of Sc in the mixed rare earth.

Synthesis and Characterization of Rare Earth Complexes with Phthalanilic Acids and Amino Acids

The complexes with the general formula REP3A· H2O [P = 2- (COO ) C6H4CONHC6H4X, X=2-CI, 4-Br; A=Gly, Ala, Leu; RE=Pr3+, Nd3+] were synthesized and characlerized by elemental analysis, IR and reflectance electronic spectra and TG methods. The results show that rare earth ion in each complex is coordinated by three oxygen atoms. One is from the amido and the other two from the hydroxyl in the carboxylate and the amino acid respectively, and each complex contains one coordinate water molecule. Condon parameters Fk, Lande parameters(4f), Nephelanxetic ratio(β), percentage convalency parameter(δ) and bonding parameter(b ) of the chelates were calculated from the reflectance electronic spectra, indicating certain covalent character in the metalligand bond. The apparent decompose activation energies were evaluated and the decompose mechanism were discussed.

用新型钕系催化剂体系催化合成超高顺式-1,4-聚丁二烯橡胶

采用由改性新癸酸钕[(m-Nd(vers)_(3))]为主催化剂、三异丁基铝为助催化剂和氯源组成的催化体系研究了丁二烯的聚合反应行为,考察了三异丁基铝用量、氯源结构、聚合反应温度、催化剂用量等因素对丁二烯聚合活性、顺式-1,4-结构选择性和聚合物分子量及其分布的影响。结果表明,使用m-Nd(vers)3/三异丁基铝/倍半乙基氯化铝体系催化丁二烯聚合可得到具有较高催化活性、超高顺式-1,4-结构(最高摩尔分数可达99.2%)、高分子量(数均相对分子质量为1.19×10^(5)~4.12×10^(5))和窄分子量分布(多分散性指数小于2.5)的聚丁二烯。

Effect of Neodymium on Physiological Activities in Oilseed Rape during Calcium Starvation

It was reported that rare earth elements promote plant growth and other physiological activities. Since the ion radius of Nd3+ is very close to that of Ca2+, the interaction between Nd and Ca might be one of the important mechanisms to be understand. Seedlings treated with 3 Umol·T, -1 Nd(NO3)3 in Ca2+ -deficient solution, and the effect of Nd on their membrane damage in oilseed rape(Brassica napus L.) was studied. It shows that the symptom of Ca-starvation is relieved and the peroxidation process in rape is inhibited. It indicates that adding Nd can lower relative permeability of the root and MDA content in leaves and increase CAT, POD, and SOD activities in rape. Likewise, the Nd addition to Hoagland solution shags similar result. The interpretation is that the effect is a consequence of substitution of Nd function for some Ca function through interacting with cellular membrane.

Effects of Carbonate on Exchangeability and Bioavailability of Exogenous Neodymium in Soil

The effects of carbonate on the exchangeability and the bioavailability of exogenous neodymium in soil were studied by Nd-147 isotopic tracer method. Exchangeable Nd was extracted by I mol(.)L(-1) NaAc (pH8.2) in the experiment. The results indicate that whether carbonate exists in soil or not, beyond 99% of exogenous Nd is adsorbed by soil. Low-concentration carbonate (0.8 similar to 1.6 g(.)kg(-1)) can reduce exchangeable Nd concentration in soil, while high-concentration carbonate (4.0 g(.)kg(-1)) impacts little on the exchangeable Nd concentration. In addition, carbonate of 0.8 similar to 1.6 g(.)kg(-1) in soil can inhibit wheat seedlings to absorb Nd. However, when the carbonate concentration rises to 4.0 g(.)kg(-1) the inhibition will become indistinct.

Study on F-F Transitions of Powdered Neodymium Compounds by Photoacoustic Spectroscopy

Photoacoustic (PA) spectra of powdered neodymium oxide (Nd 2O 3 (A type)), neodymium hydrated chloride (NdCl 3·6H 2O) and neodymium fluoride (NdF 3) were reported. PA band shifts as compared to their positions in aqueous Nd 3+ are used to calculate the nephelauxetic parameters of the compounds. The variation of these parameters and correlation with the nature of metal ligand bonding were discussed. A novel method is introduced to determine the relative values of oscillator strengths and Judd Ofelt parameters of powdered samples using PA spectroscopy. It is found that a linear correlation exists between relative values of τ 2 and oscillator strengths of hypersensitive transitions of the title compounds. It is hopetul that the new method of PA technique may serve for the Judd Ofelt quantitative analysis of powdered rare earth compounds.

Study on Polymerization of 4-Vinylpyridine by Neodymium Complex Catalyst

Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyridine was investigated. The results show that different kinds of ligand in the rare earth complex have an effect on the catalytic activity of the complex. The catalytic activity of the rare earth complex is higher than that of simple rare earth chloride. The catalytic activity of polymer-supported catalyst is higher than those of the similar small molecular system.

Reducing Greenhouse Gas Emission from the Neodymium Oxide Electrolysis. Part II: Basics of a Process Control Avoiding PFC Emission

The neodymium electrolysis produces unnecessary high emission of CF4 and C2F6. These perfluorocarbons (PFCs) are potent greenhouse gases and are not filtered or destroyed in the off-gas. A process control in analogy to the aluminum electrolysis can reduce the PFC emission to a great extend and keep the process in a green process window. Therefore, a theoretical analysis is done of the cell voltage of the industrial neodymium electrolysis in dependence on the neodymium oxide concentration in the electrolyte. The analysis shows the different contributions to the cell voltage focusing on the impact of the anodic overvoltage on the cell voltage, by which the electrolysis process can be controlled. The model of the cell voltage is evaluated by laboratory neodymium electrolysis with a similar setup as the industrial cell. The relation of the oxide concentration, the anodic current density and the cell voltage with the cell resistance are measured. The continuous off-gas measurements show the gas concentration and PFC emissions. The effect of Nd2O3 feeding on the galvanostatic electrolysis is analyzed as well. Based on the results a process control strategy is proposed similar to the aluminum electrolysis strategy. The green process window is in a narrow oxide concentration range, making a continuous and precise oxide feeding essential.

Photoacoustic Spectral Analysis of f-f Transitions of Neodymium Compounds with TFA and HFA

The photoacoustic(PA) spectra of neodymium oxide, Nd 2O 3(A type), and trisfluoroacetylactone(TFA) and hexafluoroacetylactone(HFA) neodymium complexes, Nd(TFA) 3·2H 2O and Nd(HFA) 3·2H 2O, are reported. The nephelauxetic ratio β , bonding parameter b 1/2 , and Sinha parameter δ were calculated based on their PA spectra. The variation of these parameters and correlation of them with the nature of metal ligand bonding were discussed. The intensity analysis of PA bands of f f transitions of neodymium ion was carried out by calculating the intensity branching vector and the environmental effects on the f f transitions of neodymium ion were discussed also. The branching vectors of f f transition of Nd(TFA) 3·2H 2O and Nd(HFA) 3·2H 2O are similar, which indicates the perturbation of the two ligand fields is similar. As the oscillator strength of the hypersensitive transition increases, the branching vector exhibits a corresponding increase. The PA spectra provide a new tool for the study of the interaction between Ln 3+ ions and the environment.

Effects of Neodymium Application Mode on Resistance to Fusarium Wilts in Cucumbers

The effects of neodymium application mode on the disease index, PAL, POD and PPO activity, content of lignin and generation rate of ·O2^- in cucumbers were investigated by pot experiment. The results suggest that the disease index decreases after spraying Nd^3＋. Relative protection effects of at-the-same-time-group, induced-group and therapy-group are 7.51%, 27.14% and 11.51%. The PAL activity of Nd ＋ Fo treatment in at-the-same-time-group, induced-group and therapy-group increases by 9.86%, 48.57% and 4.97% respectively compared with that of Fo treatment. The POD activity decreases by 27.52%, 35.87% and 7.67%. The PPO activity increases by 5.75%, 36.58% and 52.19%. The ·O2^- generation rate decreases by 9.49%, 28.08% and 25. 21%.

Synthesis and Crystal Structure of a Neodymium Ionic Associate [Nd(dmso)_7Cl][Bph_4]_2

The title compound, [Nd(dmso) 7Cl][Bph 4] 2(dmso=dimethylsulfoxide, Bph 4=tetraphenylboron anion) was synthesized in organic solvent acetone/EtOH and the structure was determined by single crystal X ray diffraction. The crystal is triclinic with space group P 1, and the crystal data are as follows: a =1 2554(1) nm, b = 1 2799(1) nm, c =2 4598(3) nm; α =93 53(1)°, β =104 50(1)°, γ =112 77(1)°, V =3 4722(6) nm 3, Z =2, M r=1365 01, D c=1 306 g·cm -3 . The crystal is composed of a big cation [Nd(dmso) 7Cl] 2+ and two big anions [BPh 4] -. The Nd 3+ is coordinated by a chlorine atom and seven oxygen atoms from seven dimethylsulfoxides forming a distorted square antiprism coordination polyhedron,while the BPh - 4 anion is charge equilibrium ion.

Thermochemical Study on Coordination Complex of Neodymium Trichloroacetic Acid with 8-Hydroxyquinoline

Two coordinate reactions, NdCl 3·6H 2O(s) +3CCl 3COOH(s)( or TCA) =Nd(TCA) 3·3H 2O(s) +3HCl(g) +3H 2O(l) and Nd(TCA) 3·3H 2O(s) +2C 9H 7NO(s)= Nd(TCA)(C 9H 6NO) 2 (s) +2CCl 3COOH(s) +3H 2O(l), were studied by the classical solution calorimetry at 298.15K. The molar dissolution enthalpies of the reactants and the products in certain solvent (the first reaction in 1 mol·L -1 HCl, the second in a mixed solution consisting of absolute ethyl alcohol, dimethyl sulfoxide and 4 mol·L -1 HCl ) were measured by using an isoperibol calorimeter at 298.15K . From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(TCA) 3·3H 2O,s,298.15K] and [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] are determined as Δ fH m °[Nd(TCA) 3·3H 2O,s,298.15K]= -3053.3 kJ·mol -1 and Δ fH m° [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] = -1355.6 kJ·mol -1 .

Electronic Structure and Chemical Bonding of a Tetranuclear Neodymium Complex Nd_4O(OR)_4(NR'_2)_6

The nonrelativistic DV-X_α-SCC method was used to study the electronic structure and chemi- cal bonding of tetranuclear neodymium complex Nd_4O(OR)_4(NR′_2)_6,with emphasis on the bonding charac- ter of the central μ_4-O atom and the four Nd atoms.The results of calculation show that the μ_4-O atom uses its sp^3 valence orbitals to contribute four O-Nd bonding MOs with character of multicenter bond apparent- ly.The Mulliken population analysis shows that the overlap population between Nd atoms is almost equal to zero,therefore there is no direct metal-metal bond between Nd atoms.The coordination number of Nd in the complex is discussed briefly.

Synthesis and Catalytic Activities of Polymer-Supported Neodymium Complexes——Polymers Containing Thiol and Sulphoxide

The neodymium complexes with crosslinked polystyrene containing -CH2SH and -CH2SOCH3 groups, P-CH2SH . NdCl3 and P-CH2SOCH3. NdCl3, were prepared. P-CH2SH . NdCl3 shows no catalytic activity for butadiene polymerization, while P-CH2SOCH3. NdCl3 can catalyze the polymerization of butadiene. The content of cis-1,4-polybutadiene is more than 95%.

Corrosion Resistance of Ceramic Materials in Metallic Neodymium and NdF_3-LiF-Nd_2O_3 System

Corrosion resistant properties of Si3N4-SiC and TiB2 at high temperature were studied. The experiments were carried out in metallic neodymium and NdF3-LiF-Nd2O3 system, respectively. Corrosion temperature was 1100 ℃ and the holding time of corrosion experiments was 24 h. Corrosion products were analyzed by XRD and SEM, and corrosion behavior and corrosion mechanism of the experiments were studied. The results showed that Si3N4-SiC was corroded seriously in the above-mentioned two systems. A few of compounds were found on the surface of Si3N4-SiC, and surface structure of the Si3N4-SiC samples was loosened. The corrosion resistance of TiB2 was better than that of Si3N4-SiC. Oxidation resistance of TiB2 at high temperature should be enhanced.

Extraction of Neodymium by Emulsion-Liquid-Membrane within Hollow-Fiber-contactor and Its Mass Transfer Properties

A non-dispersive extraction technique, using an emulsion liquid membrane within a hollow-fiber-contactor for the extraction and enrichment of Nd^3＋ from the dilute feed aqueous, was applied. The emulsion system is consisted of span80 [ sorbitian monooleate], paraffin oil, D2EHPA [ 2-（ 2-ethylhexyl- phosphonic acid）], kerosene as well as HCl solution. The extraction under various conditions such as the span80 concentrations, the flow rate of aqueous, the extraction time and HCl concentrations in receiving phase were studied. Results show that the lower the flow rates of aqueous are, the higher the extraction percentage and enrichment-fold are, and the extraction percentage increases with the increasing of HCl concentrations. When the initial Nd^3＋ concentration in feed is maintained at 1000 mg· L^-1 and the emulsion is recycled with 70 times by a counter-flow,