In order to remediate heavy metal ions from waste water, Al2O3-SiO2 composite aerogels are prepared via a sol—gel and an organic solvent sublimation drying method. Various characterisation techniques have been employed including X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscope (SEM), Energy-dispersion X-ray spectroscopy (EDX), Brunauer—Emmett—Teller

We investigated the effect of nanosized NbC precipitates on hydrogen-induced cracking (HIC) of high-strength low-alloy steel by conducting slow-strain-rate tensile tests (SSRT) and performing continuous hydrogen charging and fracture analysis. The results reveal that the HIC resistance of Nb-bearing steel is obviously superior to that of Nb-free steel, with the fractured Nb-bearing steel in the SSRT

The demand for Li-ion batteries (LIBs) for vehicles is increasing. However, LIBs use valuable rare metals, such as Co and Li, as well as environmentally toxic reagents. LIBs are also necessary to utilize for a long period and to recycle useful materials. The reduction, reuse, and recycle (3R) of spent LIBs is an important consideration in constructing a circular economy. In this paper, a flowsheet

Computational simulations and high-temperature measurements of velocities near the surface of a mold were carried out by using the rod deflection method to study the effects of various operating parameters on the flow field in slab continuous casting (CC) molds with narrow widths for the production of automobile exposed panels. Reasonable agreement between the calculated results and measured subsurface

Natural magnetite formed by the isomorphism substitutions of transition metals, including Fe, Ti, Co, etc., was activated by mechanical grinding followed by H2 reduction. The temperature-programmed reduction of hydrogen (H2-TPR) and temperature-programmed surface reaction of carbon dioxide (CO2-TPSR) were carried out to investigate the processes of oxygen loss and CO2 reduction. The samples were characterized

Open cell steel foams were successfully fabricated through the powder metallurgy route using urea granules as the water leachable space holder in the present study. The influence of different amounts of phosphorus (0, 0.5wt%, 1wt%, 2wt%, and 4wt%) was investigated on the cell morphology, porosity, microstructure of cell walls, and mechanical properties of steel foams. The cell morphology and microstructure

Manganese was leached from a low-grade manganese ore (LGMO) using banana peel as the reductant in a dilute sulfuric acid medium. The effects of banana peel amount, H2SO4 concentration, reaction temperature, and time on Mn leaching from the complex LGMO were studied. A leaching efficiency of ∼98% was achieved at a leaching time of 2 h, banana peel amount of 4 g, leaching temperature of 120°C, manganese

A new method for separating and recovering tin from a low-grade tin middling with high Si content and low Fe content by roasting with anthracite coal was researched by studying the reaction mechanism and performing an industrial test, in which the Sn was sulfurized into SnS(g) and then collected using a dust collector. The Fe-Sn alloy may be formed at roasting temperatures above 950°C, and like the

A high-voltage pulsed discharge (HVPD) pretreatment was used to strengthen the leaching effect of Carlin-type gold ore containing arsenic. Optimal results of the pretreatment experiments were obtained at the following operating conditions: a spherical gap spacing of 20 mm, pulse number of 100, and voltage of 30 kV. The leaching rate of gold was increased by 15.65% via the HVPD pretreatment. The mass

The hot ductility of an Fe-0.3C-9Mn-2Al medium Mn steel was investigated using a Gleeble3800 thermo-mechanical simulator. Hot tensile tests were conducted at different temperatures (600–1300°C) under a constant strain rate of 4 × 10−3 s−1. The fracture behavior and mechanism of hot ductility evolution were discussed. Results showed that the hot ductility decreased as the temperature was decreased from

The trouble-free and efficient operation of paste thickeners requires an optimal design and the cooperation of each component. When underflow discharging is suspended, alleviating the vast torque that the remaining solids within the thickeners may place on rakes mainly lies in the circulation unit. The mechanism of this unit was analyzed, and a mathematical model was developed to describe the changes

The effect of Cr/Mn segregation on the abnormal banded structure of high carbon bearing steel was studied by reheating and hot rolling. With the use of an optical microscope, scanning electron microscope, transmission electron microscope, and electron probe microanalyzer, the segregation characteristics of alloying elements in cast billet and their relationship with hot-rolled plate banded structure

Selective laser melting (SLM) technology plays an important role in the preparation of porous titanium (Ti) implants with complex structures and precise sizes. Unfortunately, the processing characteristics of this technology, which include rapid melting and solidification, lead to products with high residual stress. Herein, an in situ method was developed to restrain the residual stress and improve

Monoclinic SrAl2Si2O8 ceramics for Sr immobilization were prepared by a liquid-phase sintering method. The sintering temperature, mineral phase composition, microstructure, flexural strength, bulk density, and Sr ion leaching characteristics of the SrAl2Si2O8 ceramics were investigated. A crystalline monoclinic SrAl2Si2O8 phase formed through liquid-phase sintering at 1223 K. The introduction of four

We report the electrochemical performance of Ni(OH)2 on a gas diffusion layer (GDL). The Ni(OH)2 working electrode was successfully prepared via a simple method, and its electrochemical performance in 1 M NaOH electrolyte was investigated. The electrochemical results showed that the Ni(OH)2/GDL provided the maximum specific capacitance value (418.11 F·g−1) at 1 A·g−1. Furthermore, the Ni(OH)2 electrode

A numerical study of stress distribution and fatigue behavior in terms of the effect of voids adjacent to inclusions was conducted with finite element modeling simulations under different assumptions. Fatigue mechanisms were also analyzed accordingly. The results showed that the effects of inclusions on fatigue life will distinctly decrease if the mechanical properties are close to those of the steel

The formation mechanism of the bonding between compound cast Al/Ti bimetal during a heat treatment regime was investigated. Commercially pure Al was cast and melt on a Ti bar in a steel tube, followed by heat treatment on the compound cast Ti/Al bimetal for different periods of time once the Al melt was solidified. No bonding was observed between the two metals after the initial casting, which can

Climate changes that occur as a result of global warming caused by increasing amounts of greenhouse gases (GHGs) released into the atmosphere are an alarming issue. Controlling greenhouse gas emissions is critically important for the current and future status of mining activities. The mining industry is one of the significant contributors of greenhouse gases. In essence, anthropogenic greenhouse gases

Four types of meager and meager-lean coal and one type of high-quality anthracite were selected based on the safety requirements for blast furnace coal injection and domestic coal quality to conduct microstructure and component analyses. The analyses of the organic and inorganic macerals and the chemical compositions of the selected coal samples indicate that the four types of meager and meager-lean

Continuous-drive rotary friction welding was performed to join cylindrical specimens of carbon steel (EN24) and nickel-based superalloy (IN718), and the microstructures of three distinct weld zones—the weld interface (WI)/thermo-mechanically affected zone (TMAZ), the heat-affected zone (HAZ), and the base metal—were examined. The joint was observed to be free of defects but featured uneven flash formation

Electroslag remelting (ESR) gives a combination of liquid metal refining and solidification structure control. One of the typical aspects of liquid metal refining during ESR for the advanced steel and alloy production is desulfurization. It involves two patterns, i.e., slag-metal reaction and gas-slag reaction (gasifying desulfurization). In this paper, the advances in desulfurization practices of

Sn3O4, a common two-dimensional semiconductor photocatalyst, can absorb visible light. However, owing to its rapid recombination of photogenerated electron-hole pairs, its absorption is not sufficient for practical application. In this work, a Sn nanoparticle/Sn3O4−x nanosheet heterostructure was prepared by in situ reduction of Sn3O4 under a H2 atmosphere. The Schottky junctions formed between Sn

Two types of ultralow carbon steel weld metals (with and without added Cu-Nb) were prepared using gas metal arc welding (GMAW) to investigate the correlation between the microstructure and mechanical properties of weld metals. The results of microstructure characterization showed that the weld metal without Cu-Nb was mainly composed of acicular ferrite (AF), lath bainite (LB), and granular bainite

Nanosheets with mesopores on the surface have been prepared using molybdenum trioxide (α-MoO3). The effect of mesopores on the performance of the electrode remains elusive. The MoO3 nanosheets obtained in this study exhibited great battery performance, including good capacity, prolonged recycling life cycles, and excellent rate performance; e.g., 780 mAh/g when charged under a super high current-density

In this study, we used the stop-action technique to experimentally investigate the material flow and microstructural evolution of al-clad 2A12-T4 aluminum alloy during refill friction stir spot welding. There are two material flow components, i.e., the inward- or outward-directed spiral flow on the horizontal plane and the upward- or downward-directed flow on the vertical plane. In the plunge stage

With the wide application of coating materials in aerospace and other fields, their safety under fatigue conditions in service is important. However, research on the fatigue properties of ceramic hard coatings started late, and a unified standard is yet to be established to evaluate the fatigue life of hard coating-ductile substrate systems. Studies also present different opinions on whether coatings

The oxidation of oxygen ions and the generation of an anode effect at a low oxygen content of 150 mg/kg were discussed in this paper. Cyclic voltammetry and square-wave voltammetry tests were conducted to explore the anodic processes of LiF–NdF3 melt after a lengthy period of pre-electrolysis purification at 1000°C (during which the oxygen content reduced from 413 to 150 mg/kg). The oxidation process

To evaluate the feasibility of recovering Pb and Zn sulfides and Ag-containing minerals from Zn leaching residue by the process of reduction roasting followed by flotation, the reaction behaviors of Pb and Zn sulfates during this process were investigated. Chemical analysis showed that the transformation ratios of PbSO4 and ZnSO4 could reach 65.51% and 52.12%, respectively, after reduction roasting

Zinc acetate is used as a raw material to synthesize the desired ZnO in hot solvent by controlling the amount of citric acid (CA) added. Notably, the amount of CA added has a significant relationship with the control of the morphology of ZnO. Spherical ZnO wrapped in nanosheets is synthesized through the secondary crystallization of Zn2+. The optical properties of the ZnO sample are tested through

The original version of this article unfortunately contained a mistake. The affiliation of the authors was incorrect. The correct version is given below: Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, Iran

Electrorefining effectively separates metals from their corresponding alloys. To obtain Nd from Cu6Nd alloy, cyclic voltammetry and square wave voltammetry were used to investigate the reduction behavior of Nd3+ and the anode dissolution behavior of Cu6Nd in the NaCl–KCl–0.5mol%NdCl3 melt at 1023 K. According to the analysis of the electrochemical behavior, the cell voltage was determined to be between

A new concept for producing highly pure Ti metal powder from ilmenite (FeTiO3) is proposed in this article. Titanium nitride (TiN) or titanium oxycarbonitride (TiOxCyNz) could be synthesized in the first step via the simultaneous carbothermal reduction and nitridation (CTRN) of FeTiO3 to remove oxygen roughly. To separate oxygen completely, high-quality TiS2 samples were then synthesized from TiN and

The Ca–Pb electrode couple is considered to be one of the least expensive (∼36 $/(kW h)) among various optional materials for liquid–metal batteries (LMBs). The electrochemical properties of Ca–Pb alloy in a Ca∣LiCl–NaCl–CaCl2∣Pb cell were investigated in this paper. The electrode potential maintained a linear relationship in the current density range of 50–200 mA cm-2, which indicates that the alloying

Pyrolysis of the Ta2O5/melamine mixture in molten chlorides is herein demonstrated as a facile and controllable method to nitridize and functionalize Ta2O5. The influence of the stoichiometry and composition of Ta2O5/melamine in molten salts on the nitridation process is rationalized to ensure the controllable preparation of Ta3N5 and Ta3N5/TaON. The characterization results, including scanning electron

The low O2− diffusion rate in the electro-deoxidation of titanium containing compounds by either the OS process or the FFC process leads to a low reaction speed and a low current efficiency. In this study, Ca3Ti2O7 was used as a precursor to improve the reduction speed of titanium. Because of the greater number of “diffusion channels” created in cathode as Ca2+ liberates from Ca3Ti2O7 precursor in

Sm extraction from a LiCl-KCl melt was carried out by forming alloys on various electrodes, including Al, Ni, Cu, and liquid Zn, and the electrochemical behaviors of the resultant metal products were investigated using different electrochemical techniques. While Sm metal deposition via the conventional two-step reaction process was not noted on the inert electrode, underpotential deposition was observed

Tailings from the vanadium extraction process are discarded each year as waste, which contain approximately 30wt% of Fe. In our previous work, we extracted Fe and Mn from vanadium slag, and Fe and Mn existed in the form of FeCl2 and MnCl2 after chlorination by NH4Cl to achieve effective and green usage of waste containing Fe and Mn. In this work, square wave voltammetry (SWV) and cyclic voltammetry

Aluminum storage systems with graphite cathode have been greatly promoting the development of state-of-the-art rechargeable aluminum batteries over the last five years; this is due to the ultra-stable cycling, high capacity, and good safety of the systems. This study discussed the change of electrochemical behaviors caused by the structural difference between flake graphite and expandable graphite

Molten salt is an excellent medium for chemical reaction, energy transfer, and storage. Molten salt innovative technologies should be developed to recover metals from secondary resources and reserve metals from primary natural sources. Among these technologies, molten salt electrolysis is an economic and environment-friendly method to extract metals from waste materials. From the perspective of molten

The cathodic reduction mechanism of Hf(IV) ions in a fused NaCl–KCl–NaF–K2HfF6 salt system was studied in various NaF concentrations at 1073 K to obtain a purified dendritic Hf metal. The results of cyclic voltammetry and square wave voltammetry indicated that the reduction process comprised two steps of Hf(IV) → Hf(II) and Hf(II) → Hf at low NaF concentrations (0 < molar ratio of [F−Hf4+] ≤ 17.39)

Molten salts play multiple important roles in the electrolysis of solid metal compounds, particularly oxides and sulfides, for the extraction of metals or alloys. Some of these roles are positive in assisting the extraction of metals, such as dissolving the oxide or sulfide anions, and transporting them to the anode for discharging, and offering the high temperature to lower the kinetic barrier to

Solid oxide membrane-assisted electrolytic reduction of solid Cr2O3 to Cr in molten CaCl2 was performed using a sintered porous Cr2O3 cathode paired with an yttria-stabilized zirconia (YSZ) tube anode containing carbon-saturated liquid copper alloy. Analyses of the reduction mechanism, ion migration behavior, and effects of cathode pellet porosity and particle size on the electrolysis products and

Carbon nanofiber (CNF) is considered a promising material due to its excellent physical and chemical properties. This paper proposes a novel way to transform CO2 into heteroatom-doped CNFs, with the introduction of Fe, Co, and Ni as catalysts. When the electrolyte containing NiO, Co2O3, and Fe2O3 was employed, sulfur-doped CNFs in various diameters were obtained. With the introduction of Fe catalyst

Graphite materials are widely used as electrode materials for electrochemical energy storage. N-doping is an effective method for enhancing the electrochemical properties of graphite. A novel one-step N-doping method for complete and compact carbon paper was proposed for molten salt electrolysis in the LiCl-KCl-Li3N system. The results show that the degree of graphitization of carbon paper can be improved

The Fe-Ni36 alloy was prepared via the one-step electrolysis of a mixed oxides precursor in a molten Na2CO3-K2CO3 eutectic melt at 750°C, where porous Fe2O3-NiO pellets served as the cathode and the Ni10Cu11Fe alloy was an inert anode. During the electrolysis, NiO was preferentially electro-reduced to Ni, then Fe2O3 was reduced and simultaneously alloyed with nickel to form the Fe-Ni36 alloy. Different

Magnesium (Mg) alloys, as the lightest metal engineering materials, have broad application prospects. However, the strength and ductility of traditional Mg alloys are still relativity low and difficult to improve simultaneously. Refining grain size via the deformation process based on the grain boundary strengthening and the transition of deformation mechanisms is one of the feasible strategies to

Nano-sized silicon carbide (SiC: 0wt%, 1wt%, 2wt%, 4wt%, and 8wt%) reinforced copper (Cu) matrix nanocomposites were manufactured, pressed, and sintered at 775 and 875°C in an argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy were performed to characterize the microstructural evolution. The density, thermal expansion, mechanical, and electrical properties were studied. XRD

The effects of picosecond Nd:YAG laser irradiation on chemical and morphological surface characteristics of the commercially pure titanium and Ti-13Nb-13Zr alloy in air and argon atmospheres were studied under different laser output energy values. During the interaction of laser irradiation with the investigated materials, a part of the energy was absorbed on the target surface, influencing surface

This review aims to discuss the application and development of three-dimensional printing (3DP) technology in the field of rock mechanics and the mechanical behaviors of 3D-printed specimens on the basis of various available printing materials. This review begins with a brief description of the concepts and principles associated with 3DP, and then systematically elaborates the five major applications

The original version of this article unfortunately contained a mistake. In the Table 1, the values of volume are not correct.

To further clarify the dewatering performance and torque evolution during the tailings thickening process, a self-made rake was connected to a rheometer to monitor the shear stress and torque. The dewatering performance of the total tailings was greatly improved to a solid mass fraction of 75.33% in 240 min. The dewatering process could be divided into three stages: the rapid torque growth period,

To simulate the wear and corrosion behavior of high-strength EH47 hull steel in a complicated marine environment in which seawater, sea ice, and sea sand coexist, accelerated wear and corrosion tests were performed in a laboratory setting using a tribometer. The effect of large loads on the behavior of abrasion and corrosion in a 3.5wt% NaCl solution with ice and sand to simulate a marine environment

An improved method of (NH4)2SO4 roasting followed by water leaching to utilize zinc oxidized ores was studied. The operating parameters were obtained by investigating the effects of the molar ratio of (NH4)2SO4 to zinc, roasting temperature, and holding time on zinc extraction. The roasting process followed the chemical reaction control mechanism with the apparent activation energy value of 41.74 kJ·mol−1

The specific distribution characteristics of inclusions along with the sliver defect were analyzed in detail to explain the formation mechanism of the sliver defect on the automobile exposed panel surface. A quantitative electrolysis method was used to compare and evaluate the three-dimensional morphology, size, composition, quantity, and distribution of inclusions in the defect and non-defect zone

The microwave-assisted reduction behaviours of two low-grade iron ores having a similar Fe content of 49wt% but distinctly different mineralogical and liberation characteristics were studied. Their performances in terms of the iron grade and recovery as obtained from statistically designed microwave (MW) roasting followed by low-intensity magnetic separation (LIMS) experiments were compared. At respective

Crystalline rare-earth (RE) carbonates having large particle size were prepared from the lixivium of weathered crust elution-deposited rare-earth ores using the precipitation method with ammonium bicarbonate as the precipitant. Their chemical composition was studied using elemental and thermogravimetric analyses (TGA), and their structure and morphology were characterized using Fourier transform infrared

This study documents laboratory-scale observation of the interactions between the Ni-based superalloy FGH4096 and refractories. Three different crucibles were tested—MgO, Al2O3, and MgO-spinel. We studied the variations in the compositions of the inclusions and the alloy-crucible interface with the reaction time using scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and

The influence of welding speed on the joint microstructures of an austenitic stainless steel (ASS) produced by friction stir welding (FSW) was investigated. The FSW process was conducted using a rotational speed of 400 r/min and welding speeds of 50 and 150 mm/min. The study was carried out using electron backscattered diffraction (EBSD) technique in different regions of the resultant stir zones (SZs)

Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide (MgO). The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically investigated. Scanning electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize

The effect of three heat processes with different calcium contents on the evolution of inclusions during the ladle furnace refining process of AISI 321 stainless steel was investigated. The size, morphology, and composition of the inclusions were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. After the addition of aluminum and titanium, the primary oxide in the AISI