铌铪合金中钨钽铪钛锆的X射线荧光光谱分析

铌铪合金中各元素的分析,目前多采用化学法分析,手续繁琐,周期长,费时费力.为了满足生产上的需要,用X射线荧光光谱法对该合金中钨、钽、铪、钛、锆等元素进行了分析试验,其精密度和准确度均能满足分析要求,而且方法简便、准确、实用.1 试验部分1.1 试验条件及检测原理用西门子公司SRS300型X射线荧光光谱仪,端窗铑靶X射线管,真空光路.为了消除试样的不均匀性,采用样品转动方式.其余测量条件见表1.     

锆铪催化添加剂对PX液相氧化过程的影响

向对二甲苯(PX)催化氧化体系加入锆铪离子可有效地加速该反应过程．对锆铪离子与Co-Mn-Br催化剂体系的协同催化机理作了简要阐述，并对添加不同浓度下锆铪离子的催化作用进行了动力学实验．考察了添加锆和铪离子对主反应和燃烧副反应的影响，获得了锆铪离子添加剂对PX氧化过程的影响规律．研究发现，在实验所考察的温度与催化剂组成条件下，添加锆铪离子对反应过程中不同阶段的加速效果各不相同．且两种离子对燃烧副反应过程也有不同程度的加速作用．     

氩元素概念的形成和发展与化学思想的演进

19世纪末英国化学家瑞利和拉姆塞发现了氩元素,开启了发现稀有气体元素的历程,开辟了发现元素周期表中的零族元素之门。20世纪20年代氩元素同位素的发现使人们形成了对氩元素的概念的现代认知,同时英国化学家莫斯莱提出原子序数概念,揭示了元素在周期表中位置排列的实质,同氩同位素的发现相结合,解决了氩在周期表中的位置排列问题。20世纪上半叶原子结构和化学键理论的提出阻碍了氩化合物的发现。21世纪初,氟氩化氢的发现使人们对氩的“惰性”有了全新的认识,改称氩为稀有气体元素,并对化学键理论的发展起到促进作用。总之,氩元素概念的形成和发展对于元素周期律的完善和发展以及人们对原子结构和化学键理论的认识都起到了极为重要的桥梁作用。     

立体化学刚性的七配位环戊二烯基三(二苄基二硫代氨基甲酸)钛、锆、铪配合物的合成和性质

二烷基二硫代氨基甲酸基作为良好的双齿配体较易与过渡金属生成高配位的配合物,含有环戊二烯基的高配位钛、锆、铪配合物的研究相继出现^[1-5],这类七配位、18-电子构型的配合物是立体化学刚性,具有独特的光谱性质和结构行为。选择钛、锆和铪二茂二氯化物与三当量的二苄基二硫代氨基甲酸钠反应合成了五种未见报道的七配位配合物,讨论了产物的光谱性质和配位结构。     

锆元素概念的形成和发展

1789年,普鲁士分析化学家克拉普罗特提出黄锆石中含有一种新土质,并将其命名为“锆土”,锆元素假说正式形成。随后,锆的原子重量的测定以及锆元素在元素表中位置的确定,促进了锆元素假说的发展。1914年,荷兰工程师勒利和汉布格首次制得纯度较高的金属锆,这使得锆元素假说得以证实,锆元素概念正式形成。从1924年至2020年,锆同位素的发现使人们对锆元素有了新认识,促使了现代锆元素概念的形成。锆元素概念的形成和发展的过程既是元素的发现史,也是化学思想和化学方法的演进史。     

电感耦合等离子体质谱(ICP-MS)法测定锆钛矿中的铪

锆钛矿组成成分复杂,存在耐高温的锆、钛化合物,不易分解,且铪以类质同象进入锆矿物,导致锆钛矿中的铪含量不均,因此完全分解锆钛矿并准确测定其中含量不同的铪成为一个难题。本文建立了碳酸钠-硼砂高温熔融,以178Hf为分析同位素及50 ng/mL185Re为内标,使用电感耦合等离子体质谱法（ICP-MS）测定锆钛矿中铪的新方法,可准确锆钛矿中含量不均的铪。实验研究了锆钛矿成分及其熔融方法,结果表明碳酸钠-硼砂高温熔融效果最好,可完全溶解耐高温难分解的锆钛矿,当碳酸钠-硼砂质量配比为2:1时熔融效果最佳。电感耦合等离子体质谱法具有检出限低、灵敏度高、线性范围宽等优势,可用于测定锆钛矿中含量不均的铪,ICP-MS蠕动泵转速为45 rpm、雾化流量为1.06 L/min时雾化效率最优。在选定的实验条件下,HfO2质谱强度与其质量浓度在0.01～250 ng/mL范围内呈良好的线性关系,相关系数为0.9997,背景等效浓度为0.029 ng/mL,方法检出限为0.0032 ng/mL。按实验方法对中国国家标准物质中的HfO2进行测定,测定值与认定值一致,相对标准偏差在1.6%~3.2%之间。按实验方法对锆钛矿样品中的HfO2进行测定并进行加标回收率实验,测定结果的相对标准偏差（RSDs,n=9）在0.9～3.4%之间,加标回收率在96%～106%之间,满足国家地质矿产行业标准DZ/T 0130—2006的要求。     

分光光度法同时测定多元素的研究(Ⅱ)——以CPA-矩阵法计算混合体系中微量锆和铪

本文将m-NPF+CTMAB体系用于锆、铪混合物中微量锆、铪的同时测定。确定了同时测定锆,铪的最佳实验条件。通过使用CPA-矩阵法计算解决了混合体系中锆、铪分量的测定;对光度分析中应用CPA-矩阵法的关键——选择适宜的测定波长问题作了进一步讨论,提出了“相关波长”和“相关组份”的概念。     

新试剂7—（2,4,6—三羟基苯偶氮）—8—羟基喹啉—5—磺酸光度法同时测定微量锆和

本研究了新试剂７－（２，４，６－三羟基苯偶氮）－８－羟基喹啉－５－磺酸与锆、铪的显色反应。酸性条件下锆、铪均可形成Ｍ－ＴＨＢＡＱＳ－ＣＴＭＡＢ三元络合物，ε＾Ｚｒ５１５ｎｍ＝３．２７×１０＾４，ε＾Ｈｆ５１５ｎｍ＝３．８×１０＾４，适量Ｈ２Ｏ２使锆络合物吸光度显降低，据此实际了锆铬的同时测定。     

立体化学刚性的七配位环戊二烯基三(二苄基二硫代氨基甲酸)钛、锆、铪配合物的合成和性质

二烷基二硫代氨基甲酸基作为良好的双齿配体较易与过渡金属生成高配位的配合物,含有环戊二烯基的高配位钛、锆、铪配合物的研究相继出现,这类七配位、18-电子构型的配合物是立体化学刚性,具有独特的光谱性质和结构行为。选择钛、锆和铪二茂二氯化物与三当量的二苄基二硫代氨基甲酸钠反应合成了五种未见报道的七配位配合物,讨论了产物的光谱性质和配位结构。     

锆和铪的色谱分离

介绍了用二甲基硅酮作固定相的毛细管气相色谱法分离三氟乙酰丙酮合锆和三氟乙酰丙酮合铪的混合物及乙酰丙酮合锆和乙酰丙酮合铪的混合物。用Ｃ＿（１８）键合固定相的反相高效液相色谱法分离上述β－二酮合锆和铪的混合物;讨论了色谱分离中的问题。     

Separation of zirconium and hafnium from early actinides and rare earth elements with eichrom’s pb resin in HCl

The separation of zirconium and hafnium isotopes from the early actinides and rare earth elements (REE) with Eichrom’s Pb resin has been studied. Batch studies were performed to characterize the behavior of actinium, thorium, zirconium, hafnium, lutetium, and yttrium on Pb resin from HCl solutions (0.001 M to 11 M). The early actinides and REE had no affinity for the resin at any concentration of HCl, but zirconium and hafnium showed a moderate uptake at high concentrations of HCl with a maximum extraction at 11 M HCl. Several column separations were tested, including with only tracer isotopes and with mass. Rapid, simple separations of zirconium from actinium, thorium, protactinium, and the REE with high yields and low elution volumes are presented with applications for tracer isotope production and fission product separations. The resin is less suitable for hafnium separations as hafnium tends to bleed off the resin even at high concentrations of HCl.

     

Thermodynamics of oxidation of zirconium and hafnium borides

Gibbs thermodynamic potentials of oxidation of zirconium and hafnium diborides with molecular and atomic oxygen and nitrogen monoxide were calculated for a temperature range of 20–2500°C. Oxidation of zirconium and hafnium borides with atomic oxygen was found to be the most expected reaction. The probability of oxidation is lower for zirconium boride than that for hafnium boride.     

Inorganic ion-exchangers for the removal of zirconium,hafnium and niobium radioisotopes from aqueous solutions

Studies were made on the uptake of zirconium, hafnium and niobium isotopes onto zeolites and amorphous zirconium phosphate. Ion exchange capacities and distribution coefficients were determined and the influence of pH examined. Kinetic experiments were made to determine the rates of uptake of the radioisotopes on the exchangers and to measure the leaching of isotopes from preloaded exchangers by synthetic sea water, simulated pond water and distilled water.     

X-ray determination of traces of hafnium in zirconium metal or traces of zirconium in hafnium metal after separation by ion exchange

A method is proposed for the determination of traces of hafnium in zirconium metal or zirconium in hafnium metal. The trace metals are first separated from the matrix metals on an ion-exchange column and then determined by X-ray analysis.     

A simple method for the preparation of pure hafnium

The separation of zirconium and hafnium by fractional precipitation as pyrophosphate¹ has been extended for the preparation of pure hafnium. The favourable uptake of hafnium, in spite of the decreasing tendency of partition factor when hafnium concentration is high, is maintained for all concentration of hafnium (relative to zirconium). Particularly significant is the fact that at very high concentrations of hafnium (at≈84%) the uptake of zirconium sharply falls. So pure hafnium can be prepared from natural zirconium by a simple process of eight or nine stages of fractional precipitations as pyrophosphate. This process yields reactor grade zirconium on the one side and pure hafnium on the other side.     

Determination of zirconium and hafnium with xylenol orange and methylthymol blue

Both Xylenol Orange and Methylthymol Blue are highly selective and sensitive reagents for zirconium and hafnium forming intensely red complexes in an acidic medium. The factors affecting the color formation have been studied. The properties of the complexes have been determined and compared. In general, zirconium forms a more stable complex with the two dyes than hafnium, and Xylenol Orange forms a stronger complex with either zirconium or hafnium than Methylthymol Blue. Hydrogen peroxide can completely mask the zirconium complexes of either dye but only slightly affects the hafnium complex of Xylenol Orange. Zirconium and hafnium can both be determined without separation using peroxide as a masking agent and sulfate as a demasking agent. A bleaching reaction was observed when small amounts of hafnium were added to the red zirconium complex of Methylthymol Blue in 2.4 N perchloric acid or a small amount of zirconium was added to the red hafnium complex of Methylthymol Blue solution at pH 2 to 3.     

1921年诺贝尔化学奖获得者——索迪

在探索微观元素的过程中,同位素与放射性元素位移定律的发现无疑具有里程碑式的意义。同位素的发现修正了道尔顿原子学说,元素位移规律的发现使放射化学成为一门独立的学科,为此1921年的诺贝尔化学奖授予了同位素与元素位移定律的发现者—弗雷德里克.索迪,2011年恰逢索迪逝世55周年,特写此文来纪念他对现代放射化学与核物理学做出的贡献。     

A photoplate calibration technique applied to the determination of hafnium in zirconium by SSMS

A photoplate calibration procedure is suggested for spark source mass spectrometry /SSMS/ with photoplate detection. The technique uses the Churchill two-line method applied to the two stable isotopes of copper. The calibration curve thus obtained is split into fragments and each fragment is approximated by a polynomial. The method was applied for the quantitative determination of Hf as impurity in zirconium sponge obtained from a pilot plant dedicated to the depletion of the hafnium content in zirconium by fractional crystallization.     

Insight into the electronic structure, optical properties, and redox behavior of the hybrid phthalocyaninoclathrochelates from experimental and density functional theory approaches

An insight into the electronic structure of several hafnium(IV), zirconium(IV), and lutetium(III) phthalocyaninoclathrochelates has been discussed on the basis of experimental UV-vis, MCD, electro- and spectroelectrochemical data as well as density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. On the basis of UV-vis and MCD spectroscopy as well as theoretical predictions, it was concluded that the electronic structure of the phthalocyninoclathrochelates can be described in the first approximation as a superposition of the weakly interacting phthalocyanine and clathrochelate substituents. Spectroelectrochemical data and DFT calculations clearly confirm that the highest occupied molecular orbital (HOMO) in all tested complexes is localized on the phthalocyanine ligand. X-ray crystallography on zirconium(IV) and earlier reported hafnium(IV) phthalocyaninoclathrochelate complexes revealed a slightly distorted phthalocyanine conformation with seven-coordinated metal center positioned ～1 ? above macrocyclic cavity. The geometry of the encapsulated iron(II) ion in the clathrochelate fragment was found to be between trigonal-prismatic and trigonal-antiprismatic.     

A rapid procedure for the simultaneous determination of zirconium and hafnium in high-temperature alloys by means of a spectrophotometric masking approach

Data are presented for a refined spectrophotometric procedure for the simultaneous determination of zirconium and hafnium based on the combined effects of hydrogen peroxide, sodium sulphate, and excess of zirconium ion on the hafnium and zirconium complexes with Xylenol Orange in 0.2M perchloric acid. Isolation procedures for the hafnium/zirconium content of complex high-temperature alloys which result in an ionic substrate compatible with the spectrophotometric masking method were devised.