DIBK-TBP体系萃取分离锆铪(英文)

采用 DIBK 和 TBP 混合萃取剂在硫氰酸盐介质中对锆铪进行萃取分离,考察 TBP 的加入量、水相酸度、料液中锆铪浓度、盐析剂加入量、萃取温度和萃取时间等因素对锆铪分离的影响。结果表明:DIBK-TBP 体系优先萃取铪;在优化工艺条件下,即 20%的 TBP、水相酸度 3.0 mol/L、硫酸铵加入量 0.8～1.25 mol/L、室温、萃取时间 10 min,锆铪的分离系数可达到 9.3。     

PSO与TBP二元中性体系对Au(Ⅲ)的协同萃取

研究石油亚砜(PSO)与磷酸三丁酯(TBP)组成的二元中性体系(B-B体系)在HCl介质中对Au(Ⅱ)的萃取行为,发现其中有明显的协同萃取效应.用斜率法及红外、紫外光谱法确定协萃配合物的组成为H_3O~+·2PSO·TBP·AuCl_4~-.还讨论了协萃反应的机理.     

用TBP萃取分离和的工艺研究

研究了以碱熔-盐酸法代替碳氯法制备氧氯化锆溶液,用TBP(磷酸三丁酯)萃取分离锆、铪的工艺。研究结果表明:碱熔-盐酸法制备氧氯化锆,通过提纯可以获得低硅的氧氯化锆溶液,用TBP萃取不产生乳化,两相分离清楚。经小试、中试和扩大连续运转试验,证实了分离效果好、萃取过程不产生乳化、工艺操作稳定、回收率高,可获得原子能级的氧化锆和氧化铪。用TBP萃取分离锆和铪可应用于工业生产。     

纯紫外级氧化铪研发成功

由北京有色金属研究总院承担的纯紫外级二氧化铪材料研究成功并进入批量生产和实际应用。北京有色金属研究总院是最早从事我国锆铪分离工艺的知名研究院，该院进行了多种锆铪分离方法，如重结晶法、离子交换法、硝酸-盐酸体系(TBP)萃取法、改进的硫酸体系(N235)萃取法和火法分离(岐化)法等。其中TBP和N235萃取方法已先后在上海、遵义、锦州、北京的企业实现了工厂化生产，为发展我国核工业提供了合格的大批量锆铪产品。     

用TBP萃取分离锆和铪的工艺研究

研究了以碱熔-盐酸法代替碳氯法制备氧氯化锆溶液，用TBP(磷酸三丁酯)萃取分离锆、铪的工艺。研究结果表明：碱熔-盐酸法制备氧氯化锆，通过提纯可以获得低硅的氧氯化锆溶液，用TBP萃取不产生乳化，两相分离清楚。经小试、中试和扩大连续运转试验，证实了分离效果好、萃取过程不产生乳化、工艺操作稳定、回收率高，可获得原子能级的氧化锆和氧化铪。用TBP萃取分离锆和铪可应用于工业生产。     

磷酸三丁酯从氯化物介质中萃取Zn与Cd的机理研究SCIEI

研究了磷酸三丁酯(TBP)从氯化钠稀盐酸溶液中萃取Zn和Cd,用多种物理化学方法确定了萃合物的组成。实验结果表明,TBP从氯化钠的稀盐酸溶液中萃取Zn,Cd,其有机相络合物的形式分别可能为ZnCl_2·2TBP和CdCl_2·2TBP。对于Cd,在较低的酸度条件下,有机相中就出现氯镉酸(HCdCl_3)的共萃取,随着溶液酸度增加,有机相萃合物中H_2CdCl_4占主导地位。而对于Zn,只有当溶液酸度达到一定值时([HCl]>0.1mol/L),有机相萃合物中才出现氯锌酸(HZnCl_3)的形式。此外,对萃取机理及温度效应也进行了讨论。     

石油亚砜Ⅱ（2）萃Pd（Ⅱ）机理的研究

研究在盐酸介质中石油亚砜Ⅱ(2)萃Pd(Ⅱ)的机理,并分析水相中影响(Ⅱ)萃取的主要因素及其原因,考察不同盐酸浓度下亚砜的萃合方式,盐酸浓度的萃钯(Ⅱ)实验曲线及其对贵金属萃取分离的意义,还测定了萃合物组成.     

不对称亚砜BSO萃取钯的性能及机理研究

研究了不对称亚砜BSO从盐酸介质中萃取钯的性能和机理,结果表明:待萃液Pd(Ⅱ)浓度为1.0g.L-1,HCl浓度为0.1mol.L-1,用0.3mol.L-1BSO-煤油按相比1:1混合萃取Pd(Ⅱ),经过5min的萃取振荡时间,萃取率可达99.8%。通过斜率法和红外光谱分析表明,在低酸度([H+]≤0.3mol.L-1)下,亚砜主要以中性溶剂络合萃取机理萃取钯,萃合物组成为[PdCl2.2BSO](0);在高酸度(1.0≤[H+]≤4.0mol.L-1)下,亚砜以离子缔合萃取机理萃取钯,萃合物组成可能为[H+.hH2O.(BSO)2]2.[PdCl42-](0)。     

己基苯并咪唑硫醚树脂固相萃取钯

合成萃取剂己基苯并咪唑硫醚(HBMS),对其分子结构进行分析,并将其制备成HBMS树脂,研究该树脂萃取钯的性能;考察H+浓度对萃取钯的影响。结果表明:在低酸度条件下,利用HBMS树脂可实现铂、钯的分离。紫外-可见吸收光谱、红外吸收光谱研究结果表明:盐酸介质中HBMS树脂萃取Pd(Ⅱ)的机理为配位取代。萃合物的晶体结构表明:培养出的HBMS-Pd(Ⅱ)萃合物单晶中的HBMS通过苯并咪唑基上的氮原子与Pd(Ⅱ)直接配位,萃合物以钯原子为中心呈完全对称平面正方型构型,萃合物的组成为nPd(Ⅱ):nHBMS=1:2。     

用甲基异丁基酮萃取分离锆铪的工艺评价

简要评述了用甲基异丁基酮（MIBK）萃取分离锆铪方法的基本原理、分离工艺和条件、萃取设备。指出，MIBK在硫氰酸体系中萃取分离锆铪分离效果好，技术成熟，可进行规模生产。MIBK法的主要缺点是必须用有毒的SCN作稀释剂，工艺复杂而冗长，操作不易控制，劳动强度大，收率低。MIBK在水中有较大的溶解度，废液不易处理，给工艺操作和环境带来极大困难。     

Equilibrium and kinetic data of adsorption and separation for zirconium and hafnium onto MIBK extraction resin

The equilibrium and kinetics of methyl isobutyl ketone (MIBK) extraction resin for adsorption and separation of zirconium and hafnium were studied under the different conditions of acidity, initial total concentrations of zirconium and hafnium and temperature. The equilibrium data of both zirconium and hafnium are found to follow the Freundlich adsorption isotherm, and the Freundlich isotherm constants (K_F) are 3.53 and 0.64 mg/g, respectively. The equilibrium data of zirconium also fit the Langmuir adsorption isotherm, and the saturation adsorption capacity (Q_max) and the Langmuir isotherm constant (K_L) are 75.93 mg/g and ?0.012 7 L/g, respectively. The obtained kinetic data of both zirconium and hafnium are found to fit the HO pseudo-second-order kinetic model, and the rate constants of pseudo-second-order equation (k₂) are ?0.019 and 0.41 g/(mg·min), respectively. Column tests show that the MIBK extraction resin could be used as efficient adsorbent material for separating hafnium from zirconium.     

High temperature interaction behavior at liquid metal-ceramic interfaces

Liquid metal/ceramic interaction experiments were undertaken at elevated temperatures with the purpose of developing reusable crucibles for melting reactive metals. The metals used in this work included zirconium (Zr), Zr-8 wt.% stainless steel, and stainless steel containing 15 wt.% Zr. The ceramic substrates include yttria, Zr carbide, and hafnium (Hf) carbide. The metal-ceramic samples were placed on top of a tungsten (W) dish. These experiments were conducted with the temperature increasing at a controlled rate until reaching set points above 2000 °C; the systems were held at the peak temperature for about five min and then cooled. The atmosphere in the furnace was argon (Ar). An outside video recording system was used to monitor the changes on heating up and cooling down. All samples underwent a post-test metallurgical examination. Pure Zr was found to react with yttria, resulting in oxygen (O) evolution at the liquid metal-ceramic interface. In addition, dissolved O was observed in the as-cooled Zr metal. Yttrium (Y) was also present in the Zr metal, but it had segregated to the grain boundaries on cooling. Despite the normal expectations for reactive wetting, no transition interface was developed, but the Zr metal was tightly bound to yttria ceramic. Similar reactions occurred between the yttria and the Zr-stainless steel alloys. Two other ceramic samples were Zr carbide and Hf carbide; both carbide substrates were wetted readily by the molten Zr, which flowed easily to the sides of the substrates. The molten Zr caused a very limited dissolution of the Zr carbide, and it reacted more strongly with the Hf carbide. These reactive wetting results are relevant to the design of interfaces and the development of reactive filler metals for the fabrication of high temperature components through metal-ceramic joining. Parameters that have a marked impact on this interface reaction include the thermodynamic stability of the substrate, the properties of the modified interface, the temperature-dependent solubility limits of the liquids and solid phases, and the high-temperature stoichiometry of the ceramic.     

Zur Korrosion des Hafnium – Oxide und Hydride

Corrosion of hafnium – oxides and hydrides Investigations concerning the growth and behaviour of hafnium as well as electrode kinetics have been performed on hafnium (Goodfellow and Material Research Company) in various electrolytes (acidic, alkaline and Cl^?-containing solutions). Conventional electrochemical methods and impedance spectroscopy were applied. Corrosion rates derived from electrochemical measurements were found to be significantly higher than the published data obtained from the loss weight observed usually over long of time. – The DK was evaluated to be 11.5. – SIMS profiles indicate that the oxide layer in not uniform, due to the nonstoichiometry of the Hf oxide at 22°C. The layer shows a very low n-conductivity – quasi insulator behaviour; the Mott-Schottky-plot leads to the flat band potential U = ? 10 mV. The initial oxide layer was determined by capacity measurements to 2.7 nm. Cl₂-evolution begins at U = 0.5 V in 0.5 M NaCl solution. In the cathodic potential region hydrogen is generated at Hf oxide at U = ? 1.69 ? 0.058 V. With respect to the hydrogen induced cracking of Hf the behaviour of hydrogen in Hf was investigated using the nuclear physics ¹⁵N-method. After cathodic polarisation hydrogen is absorbed by hafnium and the hydride HfH_1.6 is formed. The hydrogen diffusion coefficient is determined to D_20° = 3.8 × 10^?11 cm²s^?1. At 385°C hydrogen is released from HfH_1.6. The results are discussed and compared to those found for titanium and zirconium.     

Synergistic Extraction of Rhenium(VII) and Molybdenum(VI) with Mixtures of Bis-(3,5-dimethylhexyl-4-methylhexyl) Amine and Tributylphosphate

The extraction of rhenium(VII) and molybdenum(VI) from chloride media by mixtures of bis-(3,5-dimethylhexyl-4-methylhexyl) amine N298 and tributylphosphate (TBP) was studied in the present paper. The mixtures had higher synergistic effects on Re(VII) than that of Mo(VI), and the maximal synergistic factor was obtained at a ratio of N298 to TBP of 1 to 9. Re(VII) was extracted as (R₂NH₂Cl)₃·HReO₄·B, whereas Mo(VI) was extracted as (R₂NH₂Cl)_1/2·H₂MoO₄·1/4B by the mixtures, instead of (R₂NH₂Cl)₃·HReO₄ and (R₂NH₂Cl)₃·H₂MoO₄ by N298 alone. Furthermore, the formation constants and extraction mechanism were determined. The possibility of separating rhenium and molybdenum ions by the mixtures according to its synergistic effects and extraction ability was investigated.     

锆及锆合金中微量铝的测定

本文介绍在硫酸介质中,先用钽试剂-氯仿萃取分离除去锆以及钛、铁、铪等;再在pH=8.5左右,用苯萃取铝-钽试剂配合物,用稀盐酸反萃取;最后在pH=5.5—6时用铬天青S比色以测定铝的方法,确定了其测定条件。本方法准确性好,灵敏度高,测定范围为0.0025%—0.035%。     

Critical assessment and thermodynamic calculation of the ternary system C-Hf-Zr (Carbon-Zirconium-Hafnium)

Based on an assessment of the available experimental thermochemical and phase diagram information available, the phase equilibria of the C-Hf-Zr system were calculated. The G of the individual phases was described with thermodynamic models. The liquid phase was described as a substitutional solution using the Redlich-Kister formalism for excess G. Graphite was treated as a stoichiometric phase. The solid solutions of carbon in α(Hf,Zr) and β(Hf,Zr), as well as the non-stoichiometric phase (Hf,Zr)C_1?x, were represented as interstitial solid solutions using the compound energy model with two sublattices. The parameters in the models were determined by computerized optimization using selected experimental data. A detailed comparison was made between calculation and experimental data.     

Ir–Hf–Zr ternary refractory superalloys for ultra-high temperatures—Phase and microstructural constitution

A phase and microstructural evaluation of Ir–Hf–Zr ternary alloys with a composition below 30 mol% (Hf + Zr) was conducted by microstructural observation using scanning electron microscopy (SEM), composition analysis using electron probe microscopy analysis (EPMA), and phase identification using X-ray diffraction analysis (XRD). Partial isothermal sections of the Ir–Hf–Zr ternary system close to the Ir corner at 1800 °C and 2000 °C were determined. Research revealed that the f.c.c. and L1₂–Ir₃(Hf, Zr) two-phase regions, which are shown in the Ir–Hf and Ir–Zr binary systems, were connected from the Ir–Hf side to Ir–Zr side in the Ir–Hf–Zr ternary system at Hf + Zr contents of less than 25 mol%. The L1₂–Ir₃Hf and L1₂–Ir₃Zr phases were fully soluble with each other. An Ir₃(Hf, Zr)/Ir(Hf, Zr) two-phase structure was found in the Ir–15Hf–15Zr alloy with the Hf + Zr contents of 30 mol%. The potential of the Ir–Hf–Zr ternary alloys as ultra-high-temperature structural materials is discussed from the viewpoints of the microstructure and the lattice misfit between the f.c.c. and the L1₂ phases.