Synthesis of cerium orthophosphates with monazite and rhabdophane structure from phosphoric acid solutions in the presence of hydrogen peroxide

It has been proposed to conduct the synthesis of cerium(III) orthophosphates by reacting cerium(IV) compounds with hydrogen peroxide in the presence of concentrated orthophosphoric acid at ambient temperature. It has been shown that the reaction of H₂O₂ with CeO₂ suspensions in H₃PO₄ medium produces CePO₄ · xH₂O (rhabdophane structure), while that with CeO₂ solutions in concentrated H₃PO₄ results in CePO₄ (monazite structure).     

微波消解-电感耦合等离子体质谱法检测土壤中16种稀土元素

建立了微波消解-电感耦合等离子体质谱法(ICP-MS)测定土壤样品中16种稀土元素的分析方法。样品经硝酸-过氧化氢-氢氟酸消解,直接用ICP-MS测定试液中16种稀土元素。研究了ng/mL水平的Ba氧化物及轻稀土氧化物对重稀土元素的干扰程度,其中Ba和Pr的氧化物干扰较严重,不过此类干扰可通过Method编辑干扰方程得以校正。测定土壤标准物质GBW07446及GBW07451,结果与标准物质证书值一致。     

微波溶样ICP-MS直接测定茶叶中15种痕量稀土元素

本文报道用ＨＮＯ３－Ｈ２Ｏ２微波溶样，不经分离富集，用标准加入ＩＣＰ－ＭＳ法，直接测定茶叶中１５种痕量稀土元素．对微波溶样和等离子体质谱测定条件进行了优化选择．在最佳实验条件下，用本法测定了国家一级茶叶标准物质ＧＢＷ０７６０５中的单一稀土元素，测得值与标准值很好吻合     

Separation and gravimetric determination of niobium,tantalum and titanium by precipitation with n-benzoyl-n-phenylhydroxylamine

A method is described for the separation and gravimetric determination of niobium, tantalum and titanium by precipitation with N-benzoyl-N-phenylhydroxylamine. Titanium is kept in solution with EDTA and hydrogen peroxide, and the earth acids are precipitated in 1N sulphuric acid Niobium and tantalum are separated and determined by a modification of the method of MAJUMDAR AND MUKHERJEE. All three metals are finally precipitated with N-benzoyl-N-phenyl-hydroxylamine. In the analysis of complex materials niobium, tantalum and titanium are separated from other constituents by a double precipitation with N-benzoyl-N-phenylhydroxylamine in the presence of EDTA and tartaric acid     

The determination of zirconium in its binary alloys with niobium and tantalum

A procedure is presented for the determination of zirconium in the presence of niobium or tantalum. The bulk of the niobium or tantalum is first removed by extracting with hexone from a 10M hyclrofluoric acid, 6M sulphuric acid solution of the sample. The zirconium is then. separated from any unextractcd earth, acid element by precipitation with ammonium hydroxide followed by the addition of hydrogen peroxide. Under these conditions, both the niobium and tantalum form soluble peroxy complexes whereas the zirconium is completely precipitated from solution. After the separation of the precipitate by filtration, it is re-dissolved in hydrochloric acid and the zirconium concentration is finally determined by titration with ethylenediaminetetraacetic acid.     

噻吩在稀土离子改性Y型分子筛上吸附与催化转化研究

以NaY、HY、液相Ce离子交换改性Y分子筛(L-CeY)和稀土离子改性超稳Y分子筛(HRSY-3)为研究对象,运用XRD、N₂吸附、NH₃-TPD和Py-FTIR表征样品的物化性能;采用原位红外光谱技术与程序升温脱附-同步质谱检测联用技术(TPD-MS)研究噻吩在活性中心上的吸附及催化转化行为.结果表明,稀土离子改性不改变分子筛晶体的基本结构但改变其精细结构,并形成一定的介孔,同时降低分子筛强酸位的强度,并生成与稀土离子物种有关的弱L酸位.REY与HY均可通过B酸中心的质子化作用活化噻吩,而稀土离子物种促进氢转移反应及低聚反应的进行,进而利于噻吩裂化反应的进行.     

环烷酸类载体液膜体系对金属离子传输机理的研究

本文先在大块液膜体系中以环已烷甲酸为载体,通过正交设计,系统地研究了各种因素对希土离子输送作用的影响规律。比较了相同条件下RE~(3+)(希土)同Na~+,NH_4~+、Ca~(2+)和Fe~(3+)等离子的输送作用。发现在适当条件下,无皂化的羧酸载体对RE~(3+)离子具有良好的输送效果,同时证实,羧酸输送RE~(3+)离子是通过三个H~+离子与一个RE~(3+)离子的交换,而当载体皂化时,皂化的载体直接与接收相H~+离子发生交换,从而降低了羧酸对RE~(3+)离子的输送和分离效果。 在大块液膜研究的基础上,建立了一个以无皂化的环烷酸为载体的乳状液膜体系,从模拟离子矿的硫酸铵浸出液中萃取希土,通过正交试验确定了最优的液膜萃取条件,希土萃取率达96％以上,富集度30～40倍。     

稀土和磷改性对裂化催化剂反应性能的影响

我们采用稀土以及稀土和磷两种方式对Y型沸石表面进行修饰，NH3-TPD测试表明稀土和磷复合改性Y沸石(P—RE—USY)的酸性分布更集中在中强酸范围．在固定床和提升管装置上评价了含有P—RE-USY沸石催化剂的反应性能．经过稀土和磷复合改性，增强了沸石孔道的酸性中心，而表面活性中心在磷和稀土相互作用的改性中得以减少和弱化．这种修饰作用引导更多的烃分子进入沸石孔道中进行反应，减少了烃分子通过表面反应形成大量烯烃分子的几率．同时，由于烯烃的降低不完全来自二次氢转移反应的饱和过程，所以，适度降低二次反应有效地减少了中间馏分油的裂解，提高了柴油收率．     

电感耦合等离子体原子发射光谱法(ICP-AES)测定稀土镁合金中钆

试样用盐酸、过氧化氢溶解,建立了电感耦合等离子体原子发射光谱法测定稀土镁合金中钆的分析方法。实验过程中优化了仪器的工作条件,选定钆测定的最佳分析谱线,采用标准工作曲线法完成钆的测定。实验结果表明,方法测定具有较高的精密度和准确度,相对标准偏差(RSD)小于0.89%(n=10)。钆含量在0~100μg/mL(非最高量)的范围内有很好的线性关系,其相关系数大于0.9996。方法用于大量稀土镁合金生产炉前配料与成品试样中钆含量的测定,完全满足工业化生产的检测要求。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定镧玻璃废粉中稀土元素总量及配分量

建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定镧玻璃废粉中稀土元素总量和配分量的分析方法。样品经碱熔融后分离硅、铝等元素及钠盐,用硝酸和高氯酸破坏滤纸和溶解沉淀,用ICP-AES法测定稀土元素总量和配分量。讨论了溶解样品条件、共存元素干扰等影响测定的各种因素。实际样品的稀土总量与草酸盐重量法测定结果一致,配分量与X-射线荧光光谱(XRF)法、电感耦合等离子体质谱(ICP-MS)法测定结果一致。RSD(n=11)在0.15%~1.1%,加标回收率为97%~105%。测定范围为:La_2O_3/REO(80%~98%);CeO_2/REO(2%~20%);REO(16%~70%)。方法能快速准确地测定镧玻璃废粉中稀土元素总量及配分量。     

稀土N-苯基邻氨基苯甲酸-1,10-邻菲咯啉二元、三元配合物的合成、表征及其光物理性质

合成了几种新型的稀土(钆,铕,铽)的N-苯基邻氨基苯甲酸-1,10-邻菲咯啉的二元、三元配合物.以元素分析、红外光谱和紫外光谱进行了表征,确定了组成.同时以低温磷光光谱确定了配体的三重态能级为24330cm^-1,研究了配体与稀土离子的能级匹配.详细讨论了配合物的光物理性质如发光性能和配体与稀土离子之间以及有机配体之间的分子内能量传递机制,结果发现,铽的N-苯基邻氨基苯甲酸-1,10-邻菲咯啉配合物的发光性能良好.     

焊条药皮中稀土氧化物向焊缝中过渡机制的研究

通过向焊条药皮中加入稀土氧化物的方法，研究了在焊条药皮中加入不同种类、不同含量的稀土氧化物对焊缝金属低温冲击韧性、显微组织以及扩散氢含量的影响。实验表明，在焊条药皮中添加适量的稀土氧化物可以细化焊缝组织、增加针状铁素体的含量、提高焊缝金属的低温冲击韧性和降低焊缝中扩散氢含量，这是一种经济有效的向熔池中过渡稀土元素的方法，可以在焊接材料中发挥稀土元素的特殊作用。从焊接冶金的角度出发，深入研究了焊条药皮中稀土氧化物向熔池中过渡稀土元素的机理、规律及其影响因素。研究表明，焊条药皮中的稀土氧化物在熔滴的高温阶段可以分解出稀土活性原子并过渡到熔池中，参与焊接冶金反应，对焊接熔池起到进一步脱硫去氧的作用。     

Synthesis of Fluoro-Contained Bisazo Chromotropic Acid Derivants and studies on Their Color Reactions with Rare Earth Elements

In this paper, a series of f1uoro-contained bisazo chromotropic acid derivants has been designed and synthesized. They are easily soluble in water, alcohol and acetone but insoluble in benzene, ether and chloroform. Some regularities of the effects of their molecular structure on the color reaction have also been studied. The result shows that in this series of reagents, DCF-chlorophosphonazo and DBF-chlorophosphonazo are excellent color reagents for the determination of the total amount of rare earth elements. The molar absor-ptivities of light and heavy rare earth elements are approach to each other. The tolerant quantity of Bi (Ⅲ) and Pb (Ⅱ) , Sn(Ⅳ) are larger than that of the other arsenazo or chlorophosphonazo type of color reagents. We also discover that p-fluorochlorophosphonazo can form β-type complexes with heavy rare earth elements, and p -fluoro-carboxyazo with light rare earth elements. If the reaction time is controlled, p -fluoro-carboxyao can form β-type complex only with La, and the     

八极杆碰撞/反应池(ORS)-电感耦合等离子体质谱(ICP-MS)法测定复杂矿物中的稀土元素

对未知复杂矿物样品采用扫描电子显微镜-能谱法解析样品,确定基本成分后选择合适的样品前处理方法。实验中采用过氧化钠熔融法熔解样品,用水浸出,硝酸酸化后制备待测样品溶液。以Rh为内标,用八极杆碰撞/反应池(ORS)-电感耦合等离子体质谱(ICP-MS)法测定了复杂样品中的稀土元素。多次测定同一混合标准溶液结果的相对标准偏差(RSD,n=11)小于4%,加标回收率为90%~110%。方法适用于未知复杂矿物中稀土元素的测定。     

稀土PVC稳定剂的作用机制研究

稀土化合物可以作为聚氯乙烯稳定剂，硬脂酸稀土是稀土复合稳定剂的重要成分。本文通过研究PVC与硬脂酸镧及其它硬脂酸盐作用前后的红外光谱，探讨了硬脂酸盐对PVC的热稳定作用机制，发现了稀土化合物对PVC的特殊稳定机制，即改变PVC的构象和抑制脱氯化氢的作用，并对稀土稳定剂独特的协同作用做出了解释。     

微波消解-电感耦合等离子体质谱(ICP-MS)法测定板栗中的矿物元素及稀土元素

为了准确测定板栗中矿物元素和稀土元素的含量水平,采用冷冻干燥方式预处理样品,选用硝酸和过氧化氢体系微波消解样品,结合电感耦合等离子体质谱技术,建立了板栗中钠(Na)、钾(K)、镁(Mg)、锰(Mn)、铁(Fe)、钒(V)、钴(Co)等19种矿物元素及镧(La)、铈(Ce)、镨(Pr)、钕(Nd)、钐(Sm)、铕(Eu)、钆(Gd)、铽(Tb)、镝(Dy)、钬(Ho)、铒(Er)、铥(Tm)、镱(Yb)、镥(Lu)、钇(Y)等15种稀土元素的同时分析测定方法。方法检出限为0.0027~0.78μg/L,相对标准偏差为1.4%~6.3%。通过国家标准物质GBW10019苹果的准确度实验验证,测定结果均在标准证书值范围内。实验结果表明,方法适用于板栗中矿物元素及稀土元素的同时测定。     

Anion-exchange behaviour of various metals on DEAE-cellulose in mixed acetic acid-nitric acid media

A number of nitrato complexes of metals have been found to be adsorbed on DEAE-cellulose from mixed acetic acid-nitric acid media, although none can be adsorbed from aqueous nitric acid solutions. The distribution coefficients of Sc, Mo, La, Sm, W, Re, Bi, Th and U are given as functions of acetic acid and nitric acid concentrations (sometimes in the presence of hydrogen peroxide to prevent hydrolytic precipitation). For 25 other metals column adsorption behaviour is described for a 90% acetic acid-10% 7.6M nitric acid mixture. Favourable differences in the distribution coefficients allow useful separations such as FeMoW and USmMoBiTh, to be achieved.     

我国现行主要稀土矿分解流程的经济技术指标分析

对我国主要稀土矿分解方式进行了阐述，着重讨论了离子吸附型稀土矿、氟碳铈矿和包头白云鄂博矿的典型前处理方式的经济技术指标，对目前最常用前处理方法的投资、生产单耗、成本进行了统计和分析。离子吸附型稀土矿赋存状态奇特，富含高价值中重稀土，但品位低、分布广，多以离子交换的方式开采，环境保护面临的突出问题是植被恢复和废水达标排放；北方矿以轻稀土为主，价值相对较低，原矿品位高，分布集中，露天开采后多以重、磁、浮选工艺选出精矿，然后用煅烧和酸浸结合的工艺进行冶炼，废水和废气以及废渣是环境保护的主题。这些不同稀土矿前处理工艺的特点、发展历史以生产消耗等情况，既可作为稀土生产的投资参考，也可作为稀土企业挖潜改造、提高生产管理水平和环境保护水平的重要依据。     

Aliphatic peptidyl hydroperoxides as a source of secondary oxidation in hydroxyl radical protein footprinting

Hydroxyl radical footprinting is a technique for studying protein structure and binding that entails oxidizing a protein system of interest with diffusing hydroxyl radicals, and then measuring the amount of oxidation of each amino acid. One important issue in hydroxyl radical footprinting is limiting amino acid oxidation by secondary oxidants to prevent uncontrolled oxidation, which can cause amino acids to appear more solvent accessible than they really are. Previous work suggested that hydrogen peroxide was the major secondary oxidant of concern in hydroxyl radical footprinting experiments; however, even after elimination of all hydrogen peroxide, some secondary oxidation was still detected. Evidence is presented for the formation of peptidyl hydroperoxides as the most abundant product upon oxidation of aliphatic amino acids. Both reverse phase liquid chromatography and catalase treatment were shown to be ineffective at eliminating peptidyl hydroperoxides. The ability of these peptidyl hydroperoxides to directly oxidize methionine is demonstrated, suggesting the value of methionine amide as an in situ protectant. Hydroxyl radical footprinting protocols require the use of an organic sulfide or similar peroxide scavenger in addition to removal of hydrogen peroxide to successfully eradicate all secondary oxidizing species and prevent uncontrolled oxidation of sulfur-containing residues.     

离子型钴铁氧体磁流体的稀土改性与机理研究

Rare earth composite cobalt ferrite ionic magnetic fluids were prepared by precipitation in the presence of Tri-sodium citrate. The sample phase, structure and particle sizes were determined by X-ray diffraction transmission and electron microscopy. It is clear that the particles appear as variously sized balls, Cobalt ferrite with sizes of 12-15 nm, Dysprosium cobalt ferrite and Yttrium cobalt ferrite with sizes of 6-8 nm. By adding rare earth ions, the average diameter of the magnetic nanoparticles was decreased. The decrease in diameter was explained using a micro-model of rare earth modification. The effect of rare earth ion modification on the saturation magnetization and magnetic induction of magnetic fluids was carried out using a Gouy magnetic balance and a spectrophotometer. The result shows that saturation magnetization and magnetic induction can be improved by adding Dy3+. By adding Y3+, magnetic induction was increased. However, the saturation magnetization then decreased. A theory of the mechanism of rare earth ion modification is discussed in detail.