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When considering resource shortages and environmental pressures, salvaging valuable metals from the cathode materials of spent lithium-ion batteries (LIBs) is a very promising strategy to realize the green and sustainable development of batteries. The reductive acid leaching of valuable metals from cathode materials using methanol as a reducing agent was studied. The results show that the leaching efficiencies of Co and Li are 99% under optimal leaching conditions. The leaching kinetics of cathode materials in a H

Inexpensive electrolyte systems and readily available rare-earth (RE) precursors are necessary for the facile recovery of RE metals at the lowest temperature, which will allow the sustainable devel...

The density, conductivity, and viscosity of the 1,3-dimethyl-2-imidazolinone and lithium nitrate (DMI– LiNO3) solvated ionic liquid were measured as a function of temperature. Additionally, the electrochemical mechanism and electrodeposition of neodymium from the DMI–LiNO3 solvated ionic liquid were investigated. Cyclic voltammetry results indicate that the electrochemical reduction of Nd(III) is irreversible and proceeds via one-step with three-electron transfer, which is controlled by diffusion with a diffusion coefficient of 5.08×10−8 cm2/s. Energy- dispersive X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at −4 V (vs Ag) using the DMI–LiNO3–Nd(CF3SO3)3 solvated ionic liquid contains metallic neodymium.

This study aims to design and implement an efficient cooling system to reduce the shutdown pot's cooling time in the smelter's delining room. This cooling process requirement is a result of the usual delay between the cut-down of a pot and the start of the pot demolition process that would have to be left to cool down from a temperature of about 960 °C to a temperature with which the delining team can physically handle it. As the cooling process is currently carried out in a free convection environment, the process takes five to nine days, causing the pot to spend a significant amount of time in the repair room. On the other hand, environmental regulation does not allow aluminum smelting plants to leave the hot pot in the open air; it has to be in a room enclosure. In developing a cooling technique that reduces the pot's cooling time and flue gas releases after shutting down, it is essential to ensure that the mechanical integrity of the potshell is maintained. To this effect, this study was kicked off by experimental studies to deduce the effect of various cooling parameters on the potshell material's microstructure and mechanical properties. Subsequently, 3D Finite Element Heat Transfer (FEHT) models of the DX technology pot were developed. On-site measurements were carried out on the DX pot at the plant and used to validate the models and validate the cooling techniques' effectiveness and their efficiency in reducing energy consumption. The models developed are useful in working out suitable and sustainable heat transfer mechanisms for efficient potline management to achieve acceptably low social and environmental impacts.

Urea/1-ethyl-3-methylimidazolium chloride (urea-EMIC) was developed to electrodeposit Cu from Cu2O at room temperature. Density, viscosity and conductivity of this urea-EMIC system were obtained. The cyclic voltammograms illustrated that the electroreduction of copper ion (Cu(I) ion) involves a quasi-reversible and one-step single electron transfer process. Chronoamperometric studies showed that the copper electrodeposition proceeds a three-dimensional (3D) progressive model. With an increase in temperature, on voltammograms the onset potentials for copper ion reduction shifted anodically and the diffusion coefficient determined using chronoamperometry increased from 5.40 × 10−11 m2 s−1 at 333 K to 1.02 × 10−10 m2 s−1 at 363 K. Also, potentiostatic electrolysis was conducted on tungsten substrates at − 0.65 V (vs. Ag) and 363 K. Then spherical metallic copper electrodeposits were obtained.

Samples of (LiF−CaF2)eut−xSmF3(−xGdF3) (x=0.03−0.50) were prepared by spontaneous cooling as well by very fast cooling (using the rapid solidification processing (RSP) method) which provide two types of sample morphology: riffle-like and sphere-like fragments. All types of samples were studied by XRD, optical absorption and fluorescence spectroscopy. The presence of LiF stabilises the cubic cell dimension, and the content of lanthanide fluorides presents influence on phases formed, as well as the crystallinity of the system, in both the spontaneously and rapidly-cooled systems. The photoluminescence properties of the investigated systems are dependent on the lanthanide fluoride content. The intensity of the emission bands, corresponding to the Sm3+ ion, reaches the maximum when the Sm content is x(SmF3)=0.03. An even stronger dependence is observed of optical properties on the morphology of the samples, i.e. whether the samples are spontaneously cooled or processed by the RSP method followed by mechanical grinding. Mechanical grinding enhances the luminescent properties and leads to higher emission intensities. It is also shown that the photoluminescent spectroscopy is suitable for detection/approval of lowered local symmetry via significant splitting of spectral bands.

To electrochemically extract Pb from PbO at room temperature, a new electrolyte, urea−1-ethyl-3- methylimidazolium fluoride (urea−[EMIM]F), was synthesized to dissolve PbO. Afterwards, the electrochemical behavior of Pb in this electrolyte was studied. The density, viscosity and conductivity of this electrolyte were investigated before electroextraction. The electrochemical behavior of Pb in the urea−[EMIM]F system was recorded via cyclic voltammograms, chronoamperometry and potentiostatic electrolysis. The results illustrate that Pb can be electrochemically extracted from PbO in this system at room temperature and that Pb reduction involves a quasireversible process and follows a one-step and two-electron transfer process. The reduction of Pb proceeds with a three-dimensional (3D) progressive model. With an increase in temperature, the onset potentials for Pb reduction shift anodically. The diffusion coefficient of Pb(II) is determined to be 6.88×10−10 cm2/s at 353 K. Additionally, spherical Pb particles are obtained after electrodeposition in the urea−[EMIM]F system via potentiostatic electrolysis.

A three-dimensional numerical model has been developed to quantify the predominant phenomena roles on dynamics alumina particles between an electrolytic bath and the vicinity of gas bubbles. At the particle scale, the bath, regarded as turbulent flow, was modeled by a steady plane shear flow and solved using a lattice Boltzmann method. The coupling between the fluid and particle phases is carried out using an immersed boundary method to tackle the interface. This numerical scheme resolves the hydrodynamic perturbation induced by the alumina particles, and hence their interactions are described by Lagrangian particle tracking. The hydrodynamic effects combined with mechanical and thermal responses on the computation of the fluid system's stress intensity factors were investigated. An excellent convergence and accuracy were achieved for the transport and interaction of the alumina particle model.

The conversion of CO2 into carbon materials and oxygen gas has great significance for reducing the greenhouse gas concentrations of Earth and realizing in situ utilization of Mars’ atmosphere. In this work, LiF-Li2O melts containing CO2 were electrolyzed using a Ni cathode and Pt anode at 850°C. Carbon materials with different morphologies were deposited on the cathode and oxygen evolution was detected in anode gas. The products were characterized by Raman spectroscopy, x-ray diffraction, scanning electron microscopy and gas chromatography. The results demonstrated that CO2 was firstly captured and converted into the carbonate in LiF-Li2O melts, and subsequently electrolyzed. The morphologies of the carbon material obtained on the cathode were dependent on the electrolysis potentials. The rate of CO2 and O2 production in the anode gas was related to the reaction process, current density, and potentials. Electrochemical decomposition of CO2 into carbon materials and oxygen gas in a fluoride melt was proved to be feasible.

A facile procedure is reported for the synthesis of various 2-bromo-1-phenyl-5,6-dihydro-3H,7aH-benzo[b]pyrrolo[2,1-c][1,4]oxazin-3-ones via a radical bromination-induced ipso cyclization–ortho cyclization sequence of N-arylpropiolamides in the presence of TBAB and oxone. The radical cyclization sequence involves a radical bromo α-addition into the alkyne, ipso-cyclization, and ortho-trapping of the spirocyclic intermediate.

A model was built to simulate liquid aluminum leakage during the casting process, including transient trough flow, orifice outflow, and spread, to prevent the explosion. A comparison between the simulation data and the theoretical calculation results verifies that the model has remarkable adaptability and high accuracy. Although the height of liquid aluminum in the mixing furnace and outlet radius are changed, the molten aluminum will not leak during the casting process. The aluminum in the trough moves forward in a wave-like motion and causes a leakage. The spread of the leaked aluminum resembles a long strip on the ground. The leakage amount and spread area of liquid aluminum increase with increasing the height of liquid aluminum in the mixing furnace.

China is short of high grade bauxite for the production of smelting grade alumina. With the massive exploitation of potassium containing bauxite in China, the produced Bayer alumina contains a non-negligible content of potassium oxide. When this kinde of alumina is used as the raw material for aluminum electrolysis, the potassium would cause multiple effects to the cell performance. In this paper, the potassium concentrations of fresh alumina, secondary alumina, aluminum fluoride, anode, electrolyte, anode cover, cathode block, carbon lining, silicon carbide block and product aluminum et al. in 160 kA and 200 kA prebaked aluminum reduction cells were tested and a potassium balance model was preliminarily given. Initial results showed that most of the potassium was brought into the cell by the potassium containing impurities in the fresh alumina. The only effective way for potassium removal from the cell was through the carbon residue though nearly 80 wt% of the potassium would stay and enrich in different positions of the cell.

To investigate the electrochemical reduction mechanism of Ta(V) in ethylene carbonate and aluminum chloride (EC−AlCl3) solvate ionic liquid, cyclic voltammetry experiments were conducted on a tungsten working electrode. Four reduction peaks were observed in the cyclic voltammogram of the EC−AlCl3−TaCl5 ionic liquid. The reduction peaks at −0.55, −0.72, and −1.12 V (vs Al) were related to the reduction of Ta(V) to tantalum metal by three stages including the formation of Ta(IV) and Ta(III) complex ions. The reduction of Ta(III) to tantalum metal was an irreversible diffusion-controlled reaction with a diffusion coefficient of 3.7×10−7 cm2/s at 323 K, and the diffusion activation energy was 77 kJ/mol. Moreover, the cathode products at 323 K were characterized by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The results showed that tantalum metal and tantalum oxides were obtained by potentiostatic electrodeposition at −0.8 V for 2 h.

The molten mixtures of alkali metal fluorides and aluminum fluoride are applied as aluminum electrolytes or brazing fluxes. However, the presence of Al2F7− in such molten systems is disputed. In the present study, MF–AlF3 (M = K, Cs) systems with molar ratios

Cobalt chloride and neodymium chloride were dissolved in the urea and choline chloride deep eutectic solvents (DESs), and the electrochemical mechanisms of Co-Nd alloy codeposition were investigated under ambient conditions. Results from cyclic voltammetry indicated that the deposition of metallic Co on the tungsten electrode proceeds by an apparent two-electron transfer irreversible process at − 1.02 V (vs Ag). It is impossible to deposit pure Nd in urea and choline chloride DESs, whereas Co-Nd alloys can be codeposited from electrolytes with both Co(II) and Nd(III) ions. Furthermore, chronoamperometric experiments demonstrated that the electrochemical deposition of metallic Co can be considered as a three-dimensional (3-D) progressive nucleation process, while Co-Nd alloys were formed by instantaneous nucleation with diffusion-controlled growth. The average value of the diffusion coefficient of Co(II) ions in the urea and choline chloride DESs containing 3.8 × 10−5 mol/cm3 CoCl2 at 373 K was calculated to be 1.98 × 10−7 cm2/s. Moreover, analysis by scanning electron microscopy and energy dispersive X-ray spectroscopy suggested that a flat and uniform film consisting of Co (96.26 wt pct) and Nd (3.74 wt pct) was prepared by electrodeposition on a Cu substrate.

Four types of flowerlike manganese dioxide in nano scale was synthesized via a liquid phase method in KMnO4-H2SO4 solution and Cu particles, wherein the effect of Cu particles was investigated in detail. The obtained manganese dioxide powder was characterized by XRD, SEM and TEM, and the supercapacity properties of MnO2 electrode materials were measured. The results showed that doping carbon black can benefit to better dispersion of copper particles, resulting in generated smaller size of Cu particles, and the morphology of MnO2 nanoparticles was dominated by that of Cu particles. The study of MnO2 synthesis by different sources of Cu particles showed that the size of MnO2 particles decreased significantly with freshly prepared fine copper powder compared with using commercial Cu powder, and the size of MnO2 particles can be further reduced to 120 nm by prepared Cu particles with smaller size. Therefore, it was suggested that the copper particles served as not only the reductant and but also the nuclei centre for the growth of MnO2 particles in synthesis process MnO2, and that is the reason how copper particles worked on the growth of flower-like MnO2 and electrochemical property. In the part of investigation for electrochemical property, the calculated results of b values indicated that the electrode materials have pseudo capacitance property, and the highest specific capacitance of 197.2 F g-1 at 2 mV s-1 and 148 F/g at 1 A/g were obtained for MCE electrode materials (MnO2 was synthesized with freshly prepared copper particles, where carbon black was used and dispersed in ethanol before preparation of Cu particles). The values of charge transfer resistance in all types of MnO2 materials electrodes were smaller than 0.08 Ω. The cycling retention of MCE material electrode is still kept as 93.8% after 1000 cycles.

Copper and copper-zinc alloys were electrochemical prepared from Cu2O-ZnO mixed oxides in urea and 1-butyl-3-methylimidazolium chloride deep eutectic solvent at 383 K. The electrochemical reduction and nucleation mechanism of copper and copper-zinc alloys were investigated by cyclic voltammetry and chronoamperometry. Cyclic voltammetry showed that copper species [Cu2ClO·urea]− was reduced to copper at − 0.68 V (vs. Ag), while zinc species [ZnClO·urea]− was reduced to zinc and formed copper-zinc alloy at − 1.8 V (vs. Ag). Chronoamperometry indicated that copper particles were electrodeposited by progressive nucleation with diffusion-controlled growth process in urea-BMIC-Cu2O solutions, and the average diffusion coefficient of copper complex ions was determined to be 2.79 × 10−8 cm2 s−1. On contrast, the electrodeposition of copper-zinc alloy proceeded via combination of 3D instantaneous and progressive nucleation. On the other hand, copper and copper-zinc alloys were electroplated on to a stainless steel substrate and characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy.

To develop Martian soil simulant, basalts of the Chahar volcanic group in Wulanchabu, Inner Mongolia, China were selected as the simulant initial materials, which were ground and sorted to a predetermined particle size ratio, and small amounts of magnetite and hematite were added. The main phases of NEU Mars-1 simulant were plagioclase, augite and olivine. The glass transition and crystallization temperatures of NEU Mars-1 were 547.8 and 795.7 °C, respectively. The complex dielectric constant, magnetic conductivity (0.99–1.045), and dielectric loss tangent angles (0.0025–0.030) of NEU Mars-1 were all stable in the frequency range of 2–18 GHz. Mossbauer spectroscopy results showed that the mass ratio of Fe2+ to Fe3+ in the simulant was 77.6:22.4. The NEU Mars-1 Martian soil simulant demonstrated particle size ratio, chemical composition, phase composition, thermal stability, and dielectric property similar to Martian soil, and can be used as the substitute material to extract oxygen and metals with in-situ resource utilization technologies.

Amorphous chromium (III) oxide (Cr2O3) nanoparticles were synthesized by a solution plasma discharge procedure in CrCl3 aqueous solution. X–ray diffraction, Fourier transform infrared spectroscopy, and thermal analysis were conducted to analyze the nanoparticles. Nanoscale Cr2O3 with good magnetic properties can be employed in information storage and spintronics. Therefore, the magnetic properties of the product were measured to assess their potential application. The results showed that the obtained Cr2O3 product was amorphous with a sheet-like morphology, in which small nanoparticles were attached to each other and wrapped by the water layer. Transmission electron microscopy results indicated that the covered particles produced in the CrCl3 solution were spherical with a mean diameter of 50 nm. The sheet-like morphology was converted into thinner slices when discharge electrolysis was conducted in the solution containing H2SO4. The amorphous phase could be transferred to nanocrystalline Cr2O3 with an average grain size of 100 nm after calcination at 600 °C. The Cr2O3 particles obtained in the H2SO4 solution became more uniform after heat treatment. The results of the magnetic property measurement showed that the Verwey transition and blocking temperatures of the produced Cr2O3 nanoparticles were 16 K and 66 K, respectively, and the separation of the zero-field-cooled curve and field-cooled curve occurred at 300 K. The magnetic properties of the nanoparticles were shown to be irreversible due to hysteresis. The formation process of amorphous Cr2O3 was proposed as 2Cr + 3H2O → Cr2O3 + 3H2 and 4Cr3+ + 6OH− + 6e– → 2Cr2O3 + 3H2.

The corrosion behavior of Fe-Ni alloys in molten 45KF-50AlF3-5Al2O3 (wt.%) at 700 °C was characterized in this study. After oxygen evolution, all of the Fe-Ni alloys formed a passivation film consisting of an outer Fe2O3 layer, an intermediate Fe3O4 layer, and an inner FeO layer. Because of the outward diffusions of nickel ions, a NiO layer formed in the passivation film when the 43Fe-57Ni alloy was passivated by O2. A solid-state reaction between Fe2O3 and NiO led to the formation of NiFe2O4 in the passivation film, which greatly promoted its corrosion resistance to the molten fluoride salts.

The fabrication of hybrid materials, such as SnO2-C, applicable in advanced energy storage systems, often suffers from lack of simplicity, scalability, cost effectiveness and/or sustainability. Therefore, the development of simpler and more efficient technologies for the sustainable production of energy materials with decent performance is highly desirable. In the current investigation, a hybrid nanostructured powder comprising of natural graphite flakes decorated with SnO2 single crystalline nanorods (NG-SnO2) was synthesized by a facile, rapid and cost effective one-step molten salt method, and characterized by a variety of techniques including X-ray diffraction, Raman spectroscopy, thermal analysis and electron microscopy. A perfect connection was identified between SnO2 nanorods and few-layers graphite on the surface of flakes. This hybrid material exhibited an excellent electrochemical performance as the anode material for Li-ion batteries, delivering a reversible capacity of 495 mAhg−1 after 500 cycles. The few-layered graphite substrate could successfully promote the electron transfer kinetics and also buffers the mechanical stress caused by the lithiation-delithiation of perfectly attached SnO2 nanorods during the battery cycling. The molten salt process discussed here provides a cost-effective and scalable strategy for rapid preparation of the hybrid nanostructured anode material, utilizing the low cost and abundant natural graphite.

A highly stable solvate ionic liquid comprising a 2:1 (mol/mol) mixture of ethylene carbonate (EC) and AlCl3 was used for near room-temperature electrochemical codeposition of an Al-Nd alloy using chlorides as precursors. This liquid is low-cost, easy to prepare, and has high electrochemical stability. The ionic structure was analyzed by 27Al nuclear magnetic resonance; Raman spectroscopy and the dissolution phenomenon was studied by ultraviolet-visible spectroscopy. The dissolution mechanism of NdCl3 in this solvate ionic liquid was derived as 3[AlCl2(EC)n]+ + 2NdCl3 ⇆ 2Nd(III) + 3[AlCl4]− + 3nEC. Cyclic voltammetry was used to explore the electrochemical behavior of Nd- and Al-containing species, revealing that the reduction of Al and Nd are both one-step electron-gaining processes. X-ray diffraction confirmed that an Al-Nd alloy can be obtained in the form of thermally stable Al2Nd by potentiostatic electrolysis at high cathode overpotential (− 3.5 V vs. Al). Although the deposited alloy layer is not dense, Al-containing solvate ILs have immense potential in green electrometallurgy because of their higher tunability and similar properties to ILs.

Two kinds of lunar soil simulants, including Northeastern University-1a (NEU-1a) with low titanium content and Northeastern University-1b (NEU-1b) with high titanium content, were prepared at Northeastern University using volcanic cinder and basalt sampled from Huinan County, China. The preparation and characterization of the prepared lunar simulants are described. The results show that Northeastern University-1 (NEU-1) series lunar soil simulants have typical rock characteristics, and they are comprised of anorthite, pyroxenite, and olivine. The grain compositions of both NEU-1a and NEU-1b lunar soil simulants fall in the range of standard real lunar soil grain compositions. TiO2 contents in NEU-1a and NEU-1b lunar soil simulants are 2.87% and 6.5% by mass, respectively. The glass transformation, crystallization, and melting temperatures of NEU-1a are 628°C, 800°C, and 1140°C, while the glass crystallization and glass melting temperatures of NEU-1b are 800°C and 1070°C, respectively. NEU-1 lunar soil simulants are paramagnetic polar materials that can meet the requirements for laboratory studies on in situ lunar resource utilization.

The transient electrochemical behavior of the Yb (III) ion (Yb3+) on the surface of a Ni working electrode in a (LiF–CaF2)eut.–Yb2O3 molten salt system was analyzed using a three-electrode system with a reversible (Ni2+/Ni) internal reference electrode and Pt external reference electrode. The (Ni2+/Ni) internal reference electrode exhibited good stability and reliability, and provided results that were consistent with those of the Pt external reference electrode. The (Ni2+/Ni) electrode also had a wider measurement window for analysis of the electrochemical process than that of the Ni working electrode. Cyclic voltammetry, square wave voltammetry, chronopotentiometry, and chronoamperometry were used to analyze the Yb3+ ion in the (LiF–CaF2)eut.–Yb2O3 (0.03 mol%) system. It was confirmed that the Yb3+ ion was reduced according to Yb3+ + e → Yb2+ and Yb2+ + 2e → Yb, and the electrode reaction process was quasi-reversible and controlled by diffusion. Moreover, the Yb3+ ion alloyed with the Ni electrode to form a Ni–Yb alloy.

A facile procedure is reported for the synthesis of various 2-bromo-1-phenyl-5,6-dihydro-3H,7aH-benzo[b]pyrrolo[2,1-c][1,4]oxazin-3-ones via a radical bromination-induced ipso cyclization-ortho cyclization sequence of N-arylpropiolamides in the presence of TBAB and oxone. The radical cyclization sequence involves a radical bromo α-addition into the alkyne, ipso-cyclization, and ortho-trapping of the spirocyclic intermediate.

The electrochemical behavior of Zr(IV) at molybdenum and nickel electrodes was investigated by cyclic voltammetry, square-wave voltammetry, chronoamperometry, and chronopotentiometry at 1023 K to investigate the mechanism through which zirconium was electrochemically reduced. The number of electrons transferred in the two-step reduction of Zr(IV) at a molybdenum electrode in molten NaCl–KCl was calculated from the square-wave voltammetry results. Zr(IV) reduction to Zr(0) was found to be a two-step reaction described by the equations Zr(IV)+2e−→Zr(II) and Zr(II)+2e−→Zr(0). The diffusion coefficient for the transfer of Zr(IV) to the molybdenum electrode in molten NaCl–KCl was calculated from the chronoamperometry results. The phase and structure of the product of Zr(IV) reduction at a nickel electrode were determined by X-ray diffractometry and by scanning electron microscopy with energy dispersive X-ray spectroscopy, and a NiZr intermetallic compound was found.

Spiky polycrystalline SnO2 balls assembled from pyramid-shaped SnO2 nanocrystals with surface oxygen vacancies were synthesized by a simple and facile in-situ molten salt oxidation method using SnCl2 as the tin source and graphite as the surface reductant. In this method, perfect SnO2 nanocrystals are first formed on the surface of graphite particles at 500 °C. By increasing the processing temperature to 700 °C, the formation of surface oxygen vacancy defects was confirmed, supported by various characterisation methods including Raman and XPS spectroscopy. A sharp increase in the bulk electrical conductivity of the samples was detected by exceeding the onset temperature corresponding to the formation of oxygen deficient SnO2 crystals, at which the conductivity of the sample significantly outperformed that of commercial SnO2 nanoparticles. The formation of oxygen vacancies on SnO2 crystals is thermodynamically studied, and suggested to occur by surface carbon reduction of the crystals at sufficiently high temperatures. The enhanced electrical conductivity of oxygen deficient SnO2 crystals can lead to a wider application of tin oxides in advanced electrical applications.

The molten Li2O–LiCl system is an important molten salt for CO2 capture and electrochemical transformation. In this study, the solubility of CO2 in Li2O–LiCl with 4–8 wt % concentration of Li2O was...