In this review, we describe the creation of a large database of thermoelectric materials prepared by abstracting information from over 100 publications. The database has over 18 000 data points from multiple classes of compounds, whose relevant properties have been measured at several temperatures. Appropriate visualization of the data immediately allows certain insights to be gained with regard to the property space of plausible thermoelectric materials. Of particular note is that any candidate material needs to display an electrical resistivity value that is close to 1 mΩ cm at 300 K, that is, samples should be significantly more conductive than the Mott minimum metallic conductivity. The Herfindahl–Hirschman index, a commonly accepted measure of market concentration, has been calculated from geological data (known elemental reserves) and geopolitical data (elemental production) for much of the periodic table. The visualization strategy employed here allows rapid sorting of thermoelectric compositions w...

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Data-Driven Review of Thermoelectric Materials: Performance and Resource Considerations

Phytoextraction is an in situ technique that can be applied to minerals and mining wastes using hyperaccumulator plants to purposely bio-concentrate high levels of metals or metalloids into their shoots in order to remove them from the substrate, while achieving monetary gain. Phytoextraction can be applied to a limited number of elements depending on the existence of hyperaccumulator plants with suitable characteristics. Although phytoextraction has been trialled in experimental settings, it requires testing at field scale to assess commercial broad-scale potential. The novelty and purported environmental benefits of phytoextraction have attracted substantial scientific inquiry. The main limitation of phytoextraction with hyperaccumulators is the number of suitable plants with a high accumulation capacity for a target element. We outline the main considerations for applying phytoextraction using selected elemental case studies in which key characteristics of the element, hyperaccumulation and economic considerations are evaluated. The metals cobalt, cadmium, thallium and rhenium and the metalloids arsenic and selenium are present in many types of minerals wastes, especially base metal mining tailings, at concentrations amenable for economic phytoextraction. Phytoextraction should focus on the most toxic elements (arsenic, cadmium, and thallium) or especially valuable elements (selenium, cobalt, and rhenium). The value proposition is in the clean-up of contaminated land in the case of toxic elements, whereas it is in the ‘bio-ore’ generated by the process in the case of valuable elements.

https://link.springer.com/content/pdf/10.1007/s11104-020-04487-3.pdf

Phytoextraction of high value elements and contaminants from mining and mineral wastes: opportunities and limitations

Rhenium (Re)-Me alloys (where Me = Ni, Fe, or Co) were deposited galvanostatically. The plating bath consisted of ammonium perrhenate, nickel or cobalt sulfamate, or iron sulfate, citric acid, and magnesium sulfamate. The effects of bath chemistry and deposition time on faradaic efficiency (FE), Re content, and partial deposition currents were determined. Rhenium contents as high as 93 atom % or FE values as high as 96% were attained in different solutions. The results are discussed, with emphasis on routes to increase the FE and Re content in the coating. The possible role of the second metal in the electrodeposition of Re is presented. A plausible mechanism by which addition of Ni, Fe, or Co to the solution enhances the rate of the deposition of Re is through a unique type of electroless deposition, in which the reducing agent is Me 0 formed in situ.

Electrodeposition of Alloys of Rhenium with Iron-Group Metals from Aqueous Solutions

A variety of processing technologies exist for recovery from both primary and secondary sources of rhenium. Currently, there are no known primary rhenium deposits; thus, the method in which primary rhenium is produced is dependent on the commodity of which it is a byproduct, e.g., copper, molybdenum, uranium, etc. In addition, focus on the recovery of rhenium from secondary sources, such as alloy scraps and catalysts, is continually growing. This paper presents a review of both primary and secondary processing technologies for the recovery of rhenium.

Extractive metallurgy of rhenium: a review

Rhenium-185/187 solid-state nuclear magnetic resonance (SSNMR) experiments using NaReO4 and NH4ReO4 powders provide unambiguous evidence for the existence of high-order quadrupole-induced effects (HOQIE) in SSNMR spectra. Fine structure, not predicted by second-order perturbation theory, has been observed in the 185/187Re SSNMR spectrum of NaReO4 at 11.75 T, where the ratio of the Larmor frequency (ν0) to the quadrupole frequency (νQ) is ∼2.6. This is the first experimental observation that under static conditions, HOQIE can directly manifest in SSNMR powder patterns as additional fine structure. Using NMR simulation software which includes the quadrupole interaction (QI) exactly, extremely large 185/187Re nuclear quadrupole coupling constants (CQ) are accurately determined. QI parameters are confirmed independently using solid-state 185/187Re nuclear quadrupole resonance (NQR). We explain the spectral origin of the HOQIE and provide general guidelines that may be used to assess when HOQIE may impact the interpretation of the SSNMR powder pattern of any spin-5/2 nucleus in a large, axially symmetric electric field gradient (EFG). We also quantify the errors incurred when modeling SSNMR spectra for any spin-5/2 nucleus within an axial EFG using second-order perturbation theory. Lastly, we measure rhenium chemical shifts in the solid state for the first time.

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Definitive solid-state 185/187Re NMR spectral evidence for and analysis of the origin of high-order quadrupole-induced effects for I = 5/2

On the basis of publications of recent years, the contemporary state of the world market for rhenium and the economics of production and trends of development of rhenium-containing products are reviewed

A. V. Naumov

Papers

Rhythms of rhenium