Application of Polyelectrolyte‐Enhanced Ultrafiltration for Rhenium Recovery from Aqueous Solutions

Polyelectrolyte‐enhanced ultrafiltration was investigated for rhenium(VII) recovery from aqueous solutions by using polyquaternium‐6 (PQ6) as a complexing agent. The effects of the operating parameters on the permeate flux (J) and the rhenium rejection coefficient (R) were studied. In the process of concentration, J declines slowly and R is about 1. The concentrated solution was used for the decomplexation. It takes 10 min to achieve the decomplexation equilibrium at a chloride ion concentration of 100 mg L^–1. The decomplexation percentage reaches 45.6 %. In the diafiltration process, rhenium is extracted effectively, and the purification of the regenerated PQ6 is satisfactory. The regenerated PQ6 was used to bind rhenium(VII). The binding capacity of the regenerated PQ6 is close to that of fresh PQ6.     

Chemical vapor deposition of rhenium on a gourd shaped graphite substrate

Chemical vapor deposition (CVD) of rhenium coatings on a gourd shaped graphite substrate is studied. Effects of deposition temperature, chlorine flow rate, total pressure and chlorination temperature on deposition rate, yield, morphology and texture of rhenium coating are investigated, respectively. Uniform rhenium coatings have been obtained by using proper combination of deposition conditions at an acceptable deposition rate and yield. The rhenium coatings consist of two sub-layers, i.e., an inner nucleation layer of fine equiaxed grains and an outer layer comprising oriented columnar grains. Although different surface morphologies have been observed, the grains of rhenium coatings are all <002> oriented. The tendency of the preferred orientation <002> is more significant with decreasing surface roughness of the coating.     

Mechanisms of Rhenium on Wettability and Interactions Between Nickel-Base Superalloy Melt and Al2O3-Based Ceramic Material

A systematic study on the wettability and interactions between superalloy melts with various Re contents and Al₂O₃-based ceramic moulds was presented in this paper. It was found that the increase of Re content inhibited the interfacial reactions to some extent. With regard to the 0, 1.5 and 3Re alloys, a double reaction layer containing Al₂O₃ and HfO₂ was formed at the interface, but the thickness of reaction layer decreased with the increase of Re content. However, only Al₂O₃ phase was detected at the interface when the content of Re was 6 wt%, and the interface reaction was the weakest and the thickness of reaction layer was the thinnest. The wetting angle of the alloy/ceramic system increased as the level of Re increased. Moreover, the formation of viscous sand at the interface mainly depended on the change of wetting angle of the system.     

Towards near-IR emissive rhenium tricarbonyl complexes: Synthesis and characterisation of unusual 2,2′-biquinoline complexes

Diethyl-2,2′-biquinoline-4,4′-dicarboxylate (debq) reacts with pentacarbonylbromorhenium in toluene to give fac-[Re(CO)₃(debq)Br]; subsequent reaction with AgOTf in MeCN affords the cationic complex fac-[Re(CO)₃(debq)(MeCN)]OTf. X-ray crystallographic data on fac-[Re(CO)₃(debq)Br] show that the debq ligand is coordinated in a bidentate fashion at an angle of 32° from the equatorial plane of the complex: DFT calculations confirm this as the lowest energy conformation. fac-[Re(CO)₃(debq)Br] and fac-[Re(CO)₃(debq)(MeCN)]OTf both possess ¹MLCT absorptions in the visible region, the former most red-shifted to ca. 465 nm. Both complexes demonstrated unusual luminescent properties: in solution, emission appears to be dominated by ligand-centred processes, whereas only ³MLCT emission, tailing into the near-IR, was observed in the solid state at 671 (τ = 59 ns) and 711 nm (τ = 19 ns) for fac-[Re(CO)₃(debq)(MeCN)]OTf and fac-[Re(CO)₃(debq)Br], respectively. However, the debq ligand is not labile in these complexes, which are robust to competing ligands and coordinating solvents.     

Chloroform Aided Extraction Spectrophotometric Determination of Rhenium Using Thiocyanate Complexing Agent

A new technique is developed for quantitative determination of rhenium in aqueous media containing molybdenum, iron and copper ions. The method seems easier and more accurate than the traditional ones. It consists of the formation of rhenium thiocyanate complex, which is extracted with chloroform at the presence of hydrochloric acid. This complex is a highly visible light absorbent that can easily be detected with the aid of a spectrophotometer. The maximum absorbance (λmax) observed for this complex was in the visible range of 430-435 nm. The experimental results showed that in a concentration range from 0.5-8 mg/L, the absorbance behavior of the rhenium thiocyanate complex is followed to the Beer-Lambert law.     

液膜法提取高纯铼

用TBP[（C4H9O）3PO]、异戌醇[（CH3）2CH（CH2）2OH]、L113B、液体石蜡、磺化煤油和NH4NO3水溶液等液膜体系提取（富集）铼。实验结果表明,在选择条件下,铼的提取（富集）率在99.4%以上,提取（富集）的ReO4^-经过处理后,金属铼的纯度在99.9%以上。     

超声氧化消解法从含铼离子液体中分离回收铼

以质量分数35%的过氧化氢水溶液及冰醋酸为氧化剂,采用超声氧化消解的方法从含铼离子液体中分离回收铼。当高铼酸盐离子液体为2.5mmol时,超声氧化消解含铼离子液体的适宜条件为质量分数35%的H2O2水溶液为25mmol、冰醋酸为15mmol时,50℃条件下超声氧化24h,使用氨水将溶液pH调至9～10。经回收得到铼化合物的最佳回收率为69.07%。实验结果表明,经以上过程得到铼产品为高铼酸铵,粗产品纯度为99%。     

Thermodynamic re-assessment of the Re–X (X=Al,Co, Cr,Ta) binary systems

Rhenium was one of important alloying elements in the Ni-based superalloys. Based on the molar Gibbs energy of the pure Re updated in SGTE Pure 5 database, the Re–X(X=Al, Co, Cr, Ta) systems were re-optimized by means of CALPHAD (CALculation of PHAse Diagrams) technique. In the present work, the phases liquid, fcc, bcc and hcp were described using a substitutional solution model. The phases AlRe, Al₃Re, Al₆Re, Al₁₂Re, AlRe₂ and Al₁₁Re₄ in the Re–Al system were described as stochiometric compound. The Al₄Re_H and Al₄Re_L instead of Al₄Re were evaluated in the present work. The phases σ in the Re–Cr and Re–Ta systems and χ in the Re–Ta system were modeled as (X, Re)₁₀(X, Re)₂₀ (X=Cr or Ta) and Re₂₄(Re, Ta)₁₀(Re, Ta)₂₄, respectively. A set of self-consistent thermodynamic parameters of the Re–X systems were obtained and the optimized results were in good agreement with the experimental data.     

氧化镧—钼的粉末粒度与显微组织结构

在钼的氧化物中添加硝酸镧,经还原后能够获得含有Ｌａ２Ｏ３－Ｍｏ的细颗粒粉末,制取的金属坯条断面具有晶粒发亮的显微组织结构,晶粒界面相成分存在Ｌａ５ＭｏＯ１４和Ｌａ４ＭｏＯ９的复合氧化物,这种金属钼坯条经加工成钼材,其再结晶温度显著提高,具有良好的综合力学性能。     

Predicting the performance of tungsten in a fusion environment: a literature review

Tungsten has been proposed for use in the divertor of future fusion devices. In this environment, it will be exposed to high heat fluxes, neutron damage and hydrogen and helium implantation. This review covers previous experimental and modelling work to establish our ability to predict the performance of tungsten in a fusion environment. Surrogates for high-energy neutrons have been used to predict the change in mechanical properties of tungsten, including fission neutron and self-ion exposure. These studies are critically analysed, with a focus on the difference in results from neutron and ion studies. Further studies to improve our ability to predict the performance of tungsten are proposed as a critical part of the path towards a working fusion reactor.

This review was submitted as part of the 2016 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged