High-purity Metal Research Articles

Metals Recovery from Spent Lithium-Ion Batteries: Synthesis and Physicochemical Properties of New Extractants for Solvent Extraction Processes

Cobalt, nickel, lithium and manganese are strategic metals from many applications including alloys manufacturing, electrode materials for lithium-ion batteries (LIBs), etc. Their recovery from spent materials is a good opportunity from economical and geopolitical viewpoints. Indeed, these metals are expensive and recycling will reduce considerably their supply risks in the forthcoming years due to likely emergence of electric vehicles. Therefore, recovery of cobalt, nickel manganese and lithium from LiBs is strategic and development of efficient and economic processes is coming to the fore. Several research activities were carried out to recycle strategic metals from spent batteries by different methods such as pyrometallurgy, hydrometallurgy and biohydrometallurgy. Pyrometallurgical processes are however energy intensive and release gases like sulfur dioxide and carbon dioxide which are harmful to the environment. In recent past, metallurgical industry has been searching for hydrometallurgical processes due to some advantages such as possibility of treating low-grade resources, easier control of wastes and lower energy consumption. Hydrometallurgical processes are based on physical separation, leaching, purification, precipitation and in some cases electrowining. The demand for high purity metals and recent trends towards environmentally friendly technologies have focused more attention onto solvent extraction because this technology is mature and permits to achieve high extraction efficiency at low operating costs. Although extractant molecules are at the center of concern to achieve high efficiency and high selectivity of metal recovery in hydrometallurgical recycling processes, only few teams focus their research on the synthesis of new extractants. In this paper, extraction properties of new extracting agents for the recovery of cobalt, nickel, manganese and lithium will be presented after a brief overview of challenges and drawbacks in the development of lithium-ion batteries recycling processes. Extraction equilibria and relationships between their chemical structures and their extraction properties will be discussed. A flow sheet will be then deduced from experimental data provided in this paper to recover lithium, cobalt, nickel and manganese from spent cathodes contained in LiBs. A. Chagnes, B. Pospiech, "A brief review on hydrometallurgical technologies for recycling spent lithium-ion batteries”, Journal of Chemical Technology and Biotechnology 88, 1191-1199 (2013).A. Chagnes, J. Swiatowska (Ed), “Lithium Process Chemistry: Resources, Extractions, Batteries and Recycling”, http://dx.doi.org/10.1016/B978-0-12-801417-2.00005-0, ISBN 978-0-12-801417-2, Elsevier (2015).

Simulation of the processes that occur in a high-frequency VChI 11-60/1,76 induction plant for melting of metals and the conservation of radioactive wastes

High-frequency induction plants are widely used to melt high-purity refractory metals and to conserve radioactive wastes in a glassy mass. The regimes of operation of such a plant are simulated, and the optimum conditions of stable energy transfer to a melting crucible are revealed.

Specific features of determinations of the composition of high-purity lanthanide crystal hydrates

Problem of the determination of the composition of high-purity rare-earth metal salts is discussed. Prospects of the application of direct chemical methods to the determination of the water content of crystal hydrates of rare-earth metal salts used in the GET 173-2013 State Primary Standard of Mass Fraction and Mass (Molar) Concentration of Water in Solid and Liquid Substances and Materials are studied.

Recycling of silicon metal powder from industrial powder waste streams

Most industries today have waste or side streams that are deposited or sold as bi-products. Industries that are cutting and grinding silicon metal, such as the photovoltaic and semi-conductor industry, are depositing valuable metal powder materials. ReSiTec has worked on research projects for several years and developed new technology for recycling and purification of valuable metal powders. The focus has been silicon metal powder from cutting and grinding production. The process has been developed to collect fine particles, with a size range of 0–150 μm, from highly diluted waste water. Furthermore, known separation and classification techniques for metal powder processing have been adapted with the purpose of purifying and upgrading silicon metal powder from waste to new products. The tests performed were successful and the results showed an increase in purity level from 50% to >99% metallic silicon and an acceptable yield. It is believed that this new technology can be suitable for similar types of industrial metal powder waste streams. Today, ReSiTec is supporting the process industry with R&D services and is producing more than 500 tons per year of recycled, high-purity silicon metal powder.

Solid state synthesis and structural characterization of zinc titanates

Zinc titanate composite materials were synthesized via solid state sintering process using high-purity metal oxide powders (purity ∼99.99%). The titanium incorporation into ZnO matrix was investigated by X-ray diffraction which revealed the coexistence of spinel Zn2TiO4 and hexagonal ZnTiO3 with the ZnO wurtzite structures. No reflection peaks of rutile TiO2 phase were detected. The IR spectroscopy and Raman scattering spectroscopy were used to characterize the structural and chemical properties of the ZnO/TiO2 composites. The IR bands and vibrational modes of all crystalline phases were detected. The effect of TiO2 doping rates (x = 3, 5 and 7 wt%) on bands shifting, Raman intensity and structural quality was discussed.

Interplanar coupling-dependent magnetoresistivity in high-purity layered metals.

The magnetic field-induced changes in the conductivity of metals are the subject of intense interest, both for revealing new phenomena and as a valuable tool for determining their Fermi surface. Here we report a hitherto unobserved magnetoresistive effect in ultra-clean layered metals, namely a negative longitudinal magnetoresistance that is capable of overcoming their very pronounced orbital one. This effect is correlated with the interlayer coupling disappearing for fields applied along the so-called Yamaji angles where the interlayer coupling vanishes. Therefore, it is intrinsically associated with the Fermi points in the field-induced quasi-one-dimensional electronic dispersion, implying that it results from the axial anomaly among these Fermi points. In its original formulation, the anomaly is predicted to violate separate number conservation laws for left- and right-handed chiral (for example, Weyl) fermions. Its observation in PdCoO2, PtCoO2 and Sr2RuO4 suggests that the anomaly affects the transport of clean conductors, in particular near the quantum limit.

Alkaline Earth Metal Zirconate Perovskites MZrO3 (M=Ba(2+), Sr(2+), Ca(2+)) Derived from Molecular Precursors and Doped with Eu(3+) Ions.

The effect of alkaline earth metal alkoxides on the protonation of zirconocene dichloride was investigated. This approach enabled the design of compounds with preset molecular structures for generating high-purity binary metal oxide perovskites MZrO3 (M=Ba(2+), Sr(2+), Ca(2+)). Single-source molecular precursors [Ba4 Zr2 (μ6 -O)(μ3 ,η(2)-OR)8 (OR)2(η(2) -HOR)2 (HOR)2 Cl4], [Sr4 Zr2 (μ6 -O)(μ3 ,η(2)-OR)8 (OR)2 (HOR)4 Cl4], [Ca4 Zr2 (μ6-O)(μ3 ,η(2)-OR)8 (OR)2 Cl4], and [Ca6 Zr2 (μ2 ,η(2)-OR)12 (μ-Cl)2 (η(2) -HOR)4 Cl6 ]⋅8 CH2 Cl2 were prepared via elimination of the cyclopentadienyl ring from Cp2 ZrCl2 as CpH in the presence of M(OR)2 and alcohol ROH (ROH=CH3OCH2 CH2OH) as a source of protons. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. The compounds were then thermally decomposed to MCl2 /MZrO3 mixtures. Leaching of MCl2 from the raw powder with deionized water produced highly pure perovskite-like oxide particles of 40-80 nm in size. Luminescence studies on Eu(3+)-doped MZrO3 revealed that the perovskites are attractive host lattices for potential applications in display technology.

Effect of impurity scattering on superconductivity in K2Cr3As3

Impurity scattering in a superconductor may serve as an important probe for the nature of superconducting pairing state. Here we report the impurity effect on superconducting transition temperature $T_\mathrm{c}$ in the newly discovered Cr-based superconductor K$_2$Cr$_3$As$_3$. The resistivity measurements show that the crystals prepared using high-purity Cr metal ($\geq$99.99\%) have an electron mean free path much larger than the superconducting coherence length. For the crystals prepared using impure Cr that contains various \emph{nonmagnetic} impurities, however, the $T_\mathrm{c}$ decreases significantly, in accordance with the generalized Abrikosov-Gor'kov pair-breaking theory. This finding supports a non-$s$-wave superconductivity in K$_2$Cr$_3$As$_3$.

Solution Layer Deposition: A Technique for the Growth of Ultra‐Pure Manganese Oxides on Silica at Room Temperature

With the ever increasing miniaturization in microelectronic devices, new deposition techniques are required to form high-purity metal oxide layers. Herein, we report a liquid route to specifically produce thin and conformal amorphous manganese oxide layers on silicon substrate, which can be transformed into a manganese silicate layer. The undesired insertion of carbon into the functional layers is avoided through a solution metal-organic chemistry approach named Solution Layer Deposition (SLD). The growth of a pure manganese oxide film by SLD takes place through the decoordination of ligands from a metal-organic complex in mild conditions, and coordination of the resulting metal atoms on a silica surface. The mechanism of this chemical liquid route has been elucidated by solid-state (29) Si MAS NMR, XPS, SIMS, and HRTEM.

Tensile Properties of High-purity Ca Metal

Tensile Properties of High-purity Ca Metal

Hardness Inhomogeneity and Microstructure Stability in Aluminum-copper Alloys Processed by Equal Channel Angular Pressing

Three alloys; Al- 2Cu, Al- 2Cu- 0.5Ag and Al-2Cu- 0.5Mg (composition in wt.%) were casted from high purity metals into rods of 14 mm diameter and 80 mm long, using chill casting. Samples of 11 mm diameter and 70 mm long were machined, solution treated and overaged at 350℃ and then subjected to equal channel angular pressing (ECAP) processing, for one pass and two passes (route A) at room temperature. The microhardness of ECAP processed specimens was measured along a diametral direction from the top to bottom surface at room temperature (RT). The results indicate homogeneous deformation with hardness values fluctuating around mean value with standard error of ± 5 HV. The thermal stability and recovery process of ECAP processed samples, were investigated by isochronal aging in the temperature range of 200-375℃ for half an hour. Hardness values were compared and showed gradual decrease with increasing aging temperature for one-pass ECAP processed samples. For two-pass processed samples hardness tends to increase, after initial decrease, with increasing annealing temperature above 300℃. Mechanical testing showed high increase in tensile properties with number of passes as compared to overaged samples. Two-pass samples exhibited high tensile strength, high strain hardening and high ductility.

Fabrication of novel cryomill for synthesis of high purity metallic nanoparticles.

The successful preparation of free standing metal nanoparticles with high purity in bulk quantity is the pre-requisite for any potential application. This is possible by using ball milling at cryogenic temperature. However, the most of ball mills available in the market do not allow preparing high purity metal nanoparticles by this route. In addition, it is not possible to carry out in situ measurements of process parameters as well as diagnostic of the process. In the present investigation, we present a detailed study on the fabrication of a cryomill, which is capable of avoiding contaminations in the product. It also provides in situ measurements and diagnostic of the low temperature milling process. Online monitoring of the milling temperature and observation of ball motion are the important aspects in the newly designed mill. The nanoparticles prepared using this fabricated mill have been found to be free standing and also free from contaminations.

Local states of iron ions in Bi0.815Eu0.085La0.1FeO3 perovskite

Multiferroic Bi0.815Eu0.085La0.1FeO3 with rhombohedral structure is synthesized using the solid state method from high-purity metal oxides in air. The hyperfine magnetic fields and quadrupole and isomer shifts on 57Fe nuclei are investigated at temperatures of 87, 295, and 600–700 K by Mossbauer spectroscopy. Three nonequivalent magnetic trivalent high-spin states of iron ions exist in this perovskite at 295 and 87 K. It is also established that there is no spatial spin-modulated structure in Bi0.815Eu0.085La0.1FeO3.

Borohydride Electro-Oxidation on Ni-Based Electrocatalysts: Investigation of Electrocatalytic Activity and Hydrolysis Process

Direct borohydride fuel cells (DBFCs) or borohydride batteries are promising devices since they present high energy density and involve easy handling and storage of the fuel (1). Sodium borohydride can be used directly or dissolved in an alkaline electrolyte (2), which enable the use of non-noble metals as catalysts. However, the development of such devices is hampered by the low efficiency BH4 - electro-oxidation, because of the parallel occurrence of BH4 - hydrolysis, leading to borates and hydrogen evolution (3). Therefore, the development of electrocatalysts that allow minimization of the hydrogen release is of paramount importance for improving the viability of such electrochemical systems. In this context, this work aims at investigating the electrocatalytic activity and the extent of BH4 - hydrolysis at different nickel-based materials (Ni powder, NiO/C and LaNi4.7Sn0.2Cu0.1). The NiO/C catalysts were prepared by a thermal decomposition method (4, 5) with 33 wt.% and 66 wt.% of metal on Vulcan carbon (XC-72R). The metal hydride alloy was prepared from high-purity metals by the arc melting technique under an inert gas atmosphere. The electrochemical cell used was jacketed to control de reaction temperature at 25°C. The working electrode was prepared depositing 10 mg of an ink composed by 50 mg of catalyst, 50 mg of carbon, 0.984 mL of water, 0.200 mL of iso-propanol and 0.516 mL of Nafion (5 – 10 % of water), on carbon paper (Toray). To improve the overall conductivity and the catalyst adhesion, the composites were hot-pressed for 5 min at 5 bar and 125oC. An Hg/HgO electrode was used as a reference electrode and Au wire served as counter electrode. Before and after the electrochemical tests, the electrocatalysts were characterized by XRD, XPS and TEM. Cyclic voltammetry (CVs) was performed in 1 M NaOH electrolyte in the absence and in the presence of 0.5 M sodium borohydride. Differential electrochemical mass spectrometry (DEMS) has been employed to evaluate the hydrogen formation during the borohydride oxidation. CV results with the electrocatalysts composed by nickel powder and carbon-supported nickel nanoparticles have shown high BH4 - oxidation currents, with an onset potential located at ca. -0,4V vs Hg/HgO. Chronoamperometric results presented a stable current profile. Furthermore, the results have shown that the exposition of the electrode to 0.5 M borohydride solution leads to significant hydrolysis. Interesting, for pure nickel particles (nickel powder), the hydrogen release resulting from BH4 - hydrolysis ceased after 3 hours, when the electrode was polarized above the BOR on set potential. On the other hand, the results for LaNi4.7Sn0.2Cu0.1 have shown that the hydrogen release initiates only after several hours of BH4 - oxidation, but it suffered deactivation during prolonged polarization measurements. These results for the pure Ni catalysts evidence that the surface phase produced during the BOR, becomes inactive for the BH4 - hydrolysis, but remained active for the BOR. This would increase the overall faradaic efficiency. For the alloyed material, the occurrence of a segregation phenomenon of the Ni atoms to the surface may initiate the catalysis of the hydrolysis process.

Structure, texture, and properties of superconductive electrolytic niobium coatings on nickel and copper substrates

Structure, texture, chemical purity, and other characteristics of superconductive niobium coatings prepared via electrochemical deposition onto nickel and copper substrates in (LiF + NaF + KF)eut + 5 wt % K2NbF7 molten salt are studied. It is shown that, when depositing the coatings onto nickel, the intermediate layer of Ni3Nb and NiNb intermetallides is formed at the substrate-coating interface, which inhibits the diffusion of nickel in niobium. The nickel concentration in niobium coatings above this layer is (2–7) × 10−2 wt %. In coatings deposited onto the copper substrate the copper content does not exceed 1.5 × 10−4 wt %, and from the viewpoint of the amount of impurities, niobium is considered as a high purity metal. The dynamics of structure modifications in niobium coatings and changes in microdeformations and dislocation density in the deposited metal are explored depending on the current density at the cathode.

Magnetic and Catalytic Properties of Cu x Fe1−x Fe2O4 Nanoparticles

This study reports the simple and efficicent synthesis of copper-doped magnetite (Cu x Fe 1−x Fe 2 O 4 (x= 0, 0.2, 0.4, 0.6, 0.8, and 1.0)) magnetic recyclable nanocatalysts (MRCs) by polyol method using high purity metal acetylacetonitrates in ethyleneglycol. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and vibrating sample magnetometer (VSM) techniques, and their catalytic activities were followed by UV-Vis spectroscopy. XRD powder diffraction analysis proved the presence of single product for all samples. The size of the particles in the range of 7–11 nm. The effect of copper doping ratio (x) on the magnetic properties of the synthesized products was discussed with the help of variation in saturation magnetization (M s) and coercivity (H c) by vibrating sample magnetometer (VSM). It was found out that the saturation magnetization of samples is decreased with increasing the copper doping ratio. On the contrary to this observation, catalytic properties of the samples are increasing with the increase of the copper doping ratio. All products presented catalytic activity for the color degradation of methyl orange in the presence of NaBH 4.

Ordered silicon microwire arrays grown from substrates patterned using imprint lithography and electrodeposition.

Silicon microwires grown by the vapor-liquid-solid process have attracted a great deal of interest as potential light absorbers for solar energy conversion. However, the research-scale techniques that have been demonstrated to produce ordered arrays of micro and nanowires may not be optimal for use as high-throughput processes needed for large-scale manufacturing. Herein we demonstrate the use of microimprint lithography to fabricate patterned templates for the confinement of an electrodeposited Cu catalyst for the vapor-liquid-solid (VLS) growth of Si microwires. A reusable polydimethylsiloxane stamp was used to pattern holes in silica sol-gels on silicon substrates, and the Cu catalyst was electrodeposited into the holes. Ordered arrays of crystalline p-type Si microwires were grown across the sol-gel-patterned substrates with materials quality and performance comparable to microwires fabricated with high-purity metal catalysts and cleanroom processing.

Physical and electromagnetic properties of nanosized Gd substituted Mg–Mn ferrites by solution combustion method

Nanosized powders of Gd substituted Mg–Mn ferrites synthesized by solution combustion method using high purity metal nitrates are presented. These powders were calcined, compacted and sintered at 1250°C. The powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The effect of Gd substitution on phase formation, microstructure and bulk density was also studied. Gd2O3 facilitates the formation of a secondary phase on the grain boundary which suppresses abnormal grain growth. The bulk density was found to decrease from 4.26 to 3.38g/cm3 with an increase of Gd substitution, but the electrical resistivity was increased. Ferrite with a low dielectric constant in the range of 6–12 was observed and there was no maximum dielectric loss in the frequency range measured to 1GHz. A decrease in saturation magnetization was also observed by a small fraction of Gd substitution. Correlation between magnetic properties and physical properties were discussed.

Mass Attenuation Coefficients of Binderless and Polylactic Acid Added Oil Palm Trunk Particleboard in the Diagnostic Energy Range

Two types of oil palm trunk particleboards namely binderless and polylactic acid (PLA) added board were manufactured with a target density of 1.0 g/cm 3 . The mass attenuation coefficients of the binderless and PLA added particleboards were determined by using X-ray fluorescence (XRF) photons emanating from high purity metal plates. The energies of the XRF emitted from those metal plates were in the range of 16.59 keV– 25.26 keV. The experimental values of the mass attenuation coefficients of the binderless particleboards and the XCOM calculated values for water are comparable. These results suggest that binderless particleboards have the potential to be a phantom material at diagnostic photon energies.

Optical modulation characteristics of VO2 thin film due to electric field induced phase transition in the FTO/VO2/FTO structure

VO2 thin films have been studied for their semiconductor-metal reversible transition from the monoclinic to the rutile structure, where the electrical and optical properties undergo a drastic change by increasing the temperature or by applying a voltage. VO2 film is becoming a promising material for optical switch, optical storage, optical modulator, smart window, and micro-bolometer. The preparation procedures of the FTO/VO2/FTO structure in detail are as follows: First, the F-doped SnO2 conductive glass (FTO) substrates are cleaned sequentially in acetone, ethanol, and deionized water for 10 min using an ultrasonic cleaning equipment at a frequency of 20 kHz. When the FTO substrates was cleaned, they are dried with nitrogen. Second, the dried FTO substrates are placed in the chamber of a DC magnetron sputtering system equipped with a high-purity metal target of V (99.9%). After argon (99.999%) of 80 sccm flux was discharged with the current of 2 A and the voltage of 400 V for 2 min, the vanadium films are deposited on the FTO substrates. Third, the prepared vanadium films are annealed for different annealing time in an atmosphere composed of different proportions of nitrogen-oxygen. Then another layer thickness of 350 nm of FTO conductive film is deposited on the VO2 thin film by using the plasma enhanced chemical vapor deposition method. Finally, different sizes of the FTO/VO2/FTO structure are prepared by using photolithography and chemical etching processes. The effect of different annealing time and different proportions of nitrogen-oxygen atmosphere on the VO2 thin films has been studied. X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and spectrophotometer are then used to test and analyze the crystal structure, surface morphology, surface roughness, the relative content of the surface elements, and transmittance of the VO2/FTO composite films. Results show that a relatively single component VO2 thin film can be obtained under the optimum condition. The current abrupt change can be seen at the threshold voltage when the FTO/VO2/FTO structure is applied to voltage on both the transparent conductive films of the VO2 thin film. The threshold voltage is 1.7 V when the contact area is 3 mm×mm, and the threshold voltage increases as the contact area increases. When the contact area is 6 mm × 6 mm, the threshold voltage of the thin film phase transition is 4.3 V; when the contact area is 8 mm × 8 mm, the threshold voltage of the thin film phase transition is 9.3 V. Compared with the no voltage situation, the infrared transmittance difference of the FTO/VO2/FTO structure under the effect of voltage is up to 28% before and after the transition. The structure remains stable with a strong electrochromic capacity when it is applied with voltage repeatedly. This brings about many new opportunities for optoelectronic devices and industrial production.