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The phase formation of neodymium tungstate Nd2WO6 from mechanically activated oxides was studied in a wide temperature range: 25–1600°C. Conditions for the formation of various polymorphic modifications were determined: low-temperature orthorhombic β-Nd2WO6 and δ-Nd2WO6 (P212121 (no. 19)); high-temperature monoclinic Nd2WO6 (C12/c1 (no. 15)). Optical absorption spectra were studied for polymorphic ceramics with a nominal composition of Nd2WO6. Differences in the spectra of δ-Nd2WO6 and monoclinic Nd2WO6 were detected. Both modifications (δ-Nd2WO6 and monoclinic Nd2WO6) showed proton conductivity with activation energies of 1.05 and 1.06 eV, respectively. For the Ca-containing solid solution with a monoclinic structure (Nd Cax)2WO (x = 0.01), whose overall conductivity increases compared to that of pure monoclinic Nd2WO6, hole conductivity predominates in air. [ABSTRACT FROM AUTHOR]

Using mechanical activation of an oxide mixture containing 0.2 wt% hexagonal boron nitride, followed by high-temperature firing (1400–1500 °C), we prepared single-phase (La 0.2 Nd 0.2 Ho 0.2 Lu 0.2 Y 0.2) 2 ZrO 5 ceramic, a high-entropy oxide (HEO) analog of Gd 2 ZrO 5 , whereas we failed to obtain single-phase Gd 2 ZrO 5 under similar conditions: the material consisted of two phases, with the fluorite and bixbyite structures, like in the case of conventional synthesis or coprecipitation in previous work. Thus, the use of the HEOs allowed us to obtain a phase-pure compound with the fluorite structure at a markedly lower synthesis temperature. An important role was played by 0.2 wt% hyperstoichiometric hexagonal BN additions, which ensured considerable amorphization of the starting oxides. The start powders and resulting ceramics were studied by X-ray diffraction, SEM analyses and conductivity was measured by impedance spectroscopy method in dry and wet air. The highest proton conductivity, ∼2.5 × 10−5 S/cm at 630 °C, was offered by the (La 0.2 Nd 0.2 Ho 0.2 Lu 0.2 Y 0.2) 2 ZrO 5 HEO ceramic. The use of HEO analogs of various compounds can be helpful for not only assessing thermodynamic properties of ceramics (reduction in synthesis and polymorphic transformation temperatures), but also preparing proton conductors when it is necessary to enhance hydrating properties of the cation sublattice. [ABSTRACT FROM AUTHOR]

The use of thermite to aid spacecraft demise during atmospheric re-entry has been investigated in the ESA-TRP SPADEXO project. An experimental campaign in DLR's L2K arc-heated wind tunnel facility was dedicated to explore the Thermite-for-Demise concept. Steel mock-ups of a ball bearing unit, partially filled with thermite, were placed in L2K. The breadboards were then exposed to an air flux simulating the typical conditions that characterize spacecraft re-entry. In this paper, the key results of the tests are presented. The dispersion of a mechanically activated fraction of thermite proved to be effective in controlling the overall charge ignition temperature. Thermite-induced demise was experimentally verified in the wind tunnel. The SCARAB software was extended and used to rebuild the retrieved thermal data. The results of the simulations were in good agreement in both predicting the ignition timing and the effects of the thermite charge on the sample. • Thermite-induced demise was verified in hypersonic wind tunnel conditions. • Mechanical activation can tune thermite passive ignition in space-like environment. • Numerical models can describe and foresee thermite-induced demise. [ABSTRACT FROM AUTHOR]

Zeolitic carrier materials offer ion release and uptake functionality for a wide range of applications. The release kinetics are controlled by the mobility of the target species within the zeolite framework and at its surface. Here, we achieve control over the release dynamics and the quantity of released Co2+ ions from a faujasitic zeolite through mechanical amorphization of the zeolite framework. We identify a two‐step reaction mechanism in which ion release and reintegration compete on short and intermediate timescales. The competition between these two processes is governed by the degree of amorphization, with a timescale ranging from a few minutes to several days. [ABSTRACT FROM AUTHOR]

This review summarizes the effects of mechanical impact on crystal lattices of some inorganic substances (Si, S, NaCl, KCl, CaO2, BaO2, YBa2Cu3O7–x, hematite α-Fe2O3, ordinary glass Na2O ∙ CaO ∙ 6SiO2) in a centrifugal mill. It was found that powder particles subjected to short-term impact-shear loading are deformed and reduced in size, and have structural damage after grinding in the mill. Examination of disordered compound particles showed that the resulting activated states have a certain amount of energy. Intensive mechanical activation in a centrifugal mill leads to an excess enthalpy and a change in the properties for all studied compounds. The results obtained can be used in exploratory studies of substances and materials using various mechanochemical reactors. [ABSTRACT FROM AUTHOR]

This research was focused on the influence of manganese (Mn) incorporation at Sr and/or Ti sites on the microstructure, relative dielectric permittivity and specific magnetization of strontium titanate (SrTiO 3) ceramics. A solid-state method was used for the preparation of mechanically activated (10, 30 and 120 min) Mn-doped SrTiO 3 ceramics with various manganese dioxide (MnO 2) weight percentages (1.5, 3 and 6 wt%). Rietveld's analysis showed that the mean crystallite size in doped-activated SrTiO 3 ceramics is smaller than in undoped ceramics, which is a consequence of additional crystal structure distortion due to ion substitution. Changes in the Raman spectra indicated dopant incorporation in the SrTiO 3 lattice. The microstructural analysis pointed out a decrease in the mean grain size with increasing dopant concentration and time of activation. The highest values of permittivity and magnetization were observed for Mn-doped SrTiO 3 ceramic mechanically activated for 120 min. Based on all the above, the optimal electrical and magnetic properties of SrTiO 3 ceramics can be achieved by the appropriate choice of mechanical activation time and dopant concentration. [ABSTRACT FROM AUTHOR]

The results of structural studies and assessment of the bending strength of a VKNA-4U alloy based on nickel aluminide are presented. It is for the first time that this alloy was produced by spark plasma sintering of mechanically activated powders of the starting components. The mechanical activation of the powders lasted for 1.5, 3.5, and 5 min. X‑ray diffraction analysis was performed to determine the optimal duration (3 min 30 sec) of mechanical activation for this alloy. To obtain a dense low-defect workpiece, the VKNA-4U alloy was sintered at a heating temperature of 1100 °C, a pressure of 40 MPa, and a holding time of 5 min. This material has higher ultimate bending strength at room temperature (σbend = 1215 ± 65 MPa) than the strength of Ni3Al intermetallic compound produced in similar conditions and microhardness 690 ± 25 HV. [ABSTRACT FROM AUTHOR]

The authors study compacted materials obtained using different periods of the mechanical activation of mixtures whose compositions correspond to alloys of grades VKNA-1V and VKNA-4U, with subsequent electric spark sintering. The maximum strengths of the compacted materials are reached after 3.5 min of mechanical activation: 1200 MPa for VKNA-1V and 1100 MPa for VKNA-4U. [ABSTRACT FROM AUTHOR]

Basic oxygen furnace slag (BOFS) is a high-volume waste resulting from the production of steel from pig iron. Due to its high free lime content, BOFS is difficult to recycle and/or include into conventional cement systems. Alkali-activation technology offers a pathway to transform industrial wastes such as BOFS into low-carbon cements. Alternative precursors for cement systems are needed as the reliance on commonly used materials like ground granulated blast furnace slag (GGBFS) is becoming unsustainable due to decreasing availability. This study investigates alkali-activated cements incorporating 20 and 30 wt.% of naturally weathered BOFS as a replacement for GGBFS, in both sodium silicate- and sodium carbonate-activated systems. A fraction of BOFS subject to mechanical activation is compared against the untreated BOFS in the 20 wt.% systems. It is observed that in naturally weathered BOFS, a significant portion of the free-lime is found to convert to portlandite, which accelerates alkali-activation kinetics. In sodium silicate-activated systems, the high pH of the activator results in incomplete reaction of the portlandite present in BOFS. The sodium carbonate-activated system shows near complete conversion of portlandite, causing an acceleration in the kinetics of reaction, setting, and hardening. These findings confirm the viability of sodium carbonate activated GGBFS-based systems with only a minor loss in strength properties. BOFS can be utilised as a valuable cement additive for the production of sustainable alkali-activated cements utilising sodium carbonate as a less carbon-intensive activator solution than the more commonly used sodium silicate. Mechanical activation of BOFS offers further optimisation potential for alkali-activation. [ABSTRACT FROM AUTHOR]

Silico-manganese (SiMn) slag is a byproduct of SiMn alloy production process, which has been blended with a clinker to produce Portland slag cement. The influence of mechanical activation (in vibratory mill) on the heat of hydration, physical properties, and structural changes is elucidated and compared with a ball-milled control sample. Calorimetric studies have shown the variation in hydraulic behaviour with the addition of mechanically activated slag. However, reducing peak maxima and appearing later with an increase of fineness is not directly related to its reactivity. Still, it is due to the decrease in the water-to-binder ratio subcutaneously. Typical cement hydration phases such as CH, CSH, and CAH (throughout the study cement abbreviations are used such as C = CaO, A = Al2O3, S = SiO2, H = H2O, etc.) are identified by XRD analysis and further detected by EDX analysis. Formation of dense gel with well-connected matrix attributes higher compressive strength development with an increase of milling time. [ABSTRACT FROM AUTHOR]

Purpose: To solve the problem of poor activity, large accumulation and low utilization rate of lithium slag,a technical study on the preparation of alkali-activated cementitious materials with lithium slag as the main raw material and mineral powder as silicon-aluminum corrective material was proposed. Method;The influence of various influencing factors on the compressive strength of cementitious materials was explored by orthogonal experiments to obtain the optimal raw material ratio; the optimal activation conditions of lithium slag were obtained by mechanical activation and thermal activation, and the microstructure of lithium slag-based cementitious materials was characterized by XRD and SKM. Result; The results show that when the lithium slag is mechanically activated for 60 min utes and thermally activated at 650 *C for 1 hour with a content of 60%,a water glass modulus of 1,a water glass content of 12%,a liquid-solid ratio of 0. 4,a curing temperature of 20 *C,and a stirring time of 10 minutes,the 28-day strength of the cementitious material can reach 45. 52 MPa;the main hydration products of the cementitious material are sodium zeolite,C-S-H gel,leucite,etc. The gel fills the pores,increases the density,and improves the performance of the cementitious material. Significance;It provides a new idea for the comprehensive utilization of lithium slag. [ABSTRACT FROM AUTHOR]

This paper is one of the first studies focusing on phase and microstructure formation mechanisms during reactive sintering of AlxCoCrFeNi (x = 0.3, 1) high entropy alloys (HEAs). The alloys have been prepared by mechanical activation followed by spark plasma sintering (SPS). Both powders are subjected to gluing to the milling vials and the phenomenon intensifies with Al content, resulting in a more important mechanical alloying delay for the equiatomic composition. The temperature influence on phase and microstructure formation was investigated by SPS from 550 to 1100 °C. Al0.3CoCrFeNi reactive sintering led to a face-centered cubic (FCC) solid solution with a grain size around hundreds of nanometers with nanometric intergranular B2 precipitates which content and size reduced with the temperature increase. Grain growth was observed at prior particle boundaries due to dynamic recrystallization, a phenomenon that can be controlled through modification of the milling and sintering steps, leading thus to tailored grain sizes. For the AlCoCrFeNi composition, temperature increase favors secondary FCC formation and leads to sigma phase precipitation. A dual homogeneous-heterogeneous microstructure is obtained due to the important gluing leading to insufficient milling. The dynamic recrystallization at prior particle boundaries promotes also body-centered cubic (BCC) to FCC phase transition. Therefore, the proposed reactive sintering route allows to obtain, for the equiatomic composition, alloys exhibiting very fine microstructures, with higher FCC fraction content than by conventional metallurgy processes.

K-feldspar represents an important natural resource of potassium and aluminum. Within the framework of this study, the K-feldspar was mechanically activated in a planetary ball mill under different conditions planned according to 43 Taguchi orthogonal array experimental design. As outputs, specific surface area (SBET), median particle size (d50), amorphization degree of mineral phases , and Al recovery were used. It was found that the initial d50 value of 293 μm could be reduced to 6.7 μm and the SBET value of 4.7 m2/g could be increased up to 32.5 m2/g upon milling. Both microcline KAl3SiO8, and albite NaAl3SiO8 could be almost completely amorphized, whereas quartz SiO2 still maintained some crystallinity even under the most intensive conditions. Increasing SBET and decreasing the d50 values did not lead to a significant improvement in Al leach recovery, whereas a clear relationship between the amorphization of microcline and the recovered aluminum was found. Analysis of Variance (ANOVA) showed that increasing ball-to-powder ratio is the most beneficial for the improvement in Al recovery. In situ powder X-ray diffraction monitoring performed in an oscillation ball mill under synchrotron irradiation has shown very rapid amorphization of microcline phase at the beginning. However, amorphization of microcline was only partial after two hours of the treatment in this mill, apart from almost complete process in the planetary ball mill. In the end, regressions for the calculation of Al recovery by knowing the values of input parameters were calculated. In general, by just using mechanical activation without the subsequent roasting process that is commonly used to boost metal recoveries, it was possible to quantitatively recover aluminum from K-feldspar.

This is an article in the field of mining engineering. In this article, SEM-EDS, XRD, FT-IR, laser particle size analysis and other means were used to characterize the mechanical activation of boron and magnesium ore powder. The results show that the crystal structure of boraxite changes at the action of mechanical force from the regular and orderly crystal structure to the disorder of the amorphous structure. The particle size distribution of the ore powder is greatly affected by the mechanical force. At the experimental conditions of 200 r/min speed of the ball mill and the ratio of ball to material of 10∶1, the optimal activation time is 6 h, when the particle size of 90% of the ore powder is less than 21.5 μm. The activity of ascharite is related to the number of active bonds after activation. In a certain activation time, the activity of ascharite increases with increasing activation time, but the agglomeration of mineral powder particles at the action of van der Waals force for a long activation time leads to a decrease in activity. The mechanical activation pretreatment can reduce the dependence on sulfuric acid concentration and temperature in the leaching reaction of ascharite, and significantly improve the leaching rate of elements in ascharite. The experiments show that the leaching rate of ascharite after activation for 6 h is 50% higher than that of the raw ascharite under the condition of reaction temperature 25 ℃ and sulfuric acid concentration 1.48 mol/L. And amorphous SiO2 can be prepared at friendly conditions. The apparent activation energy decreases from 23.54 kJ/mol to 9.41 kJ/mol after activation. The diffusion of the solid product layer during the leaching process is the limiting link which affects the reaction of ascharite with sulfuric acid.

The study of the cementitious material activity of industrial solid wastes is a key issue in the comprehensive utilization of its green building materials. In this study, mechanical activation was used to prepare cementitious materials from vanadium-titanium iron ore tailings (VTIOT) as the main raw materials, and the effects of grinding time, the key parameter, on the grinding characteristics of VTIOT, the mechanical properties of the VTIOT cementitious material, and the hydration mechanism were investigated by means of surface area analysis, particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), alkali leaching, mechanical testing, hydration heat analysis, and thermogravimetric analysis (TGA). The results show that: the grinding time and specific surface area of VTIOT exhibit a linear correlation. Prolonging the grinding time, the fractal dimension of the particles gradually increases. The activity of Si4+ and Al3+ elements increases rapidly, reaching a Si4+ and Al3+ content of 96 mg·L−1 at 90 min of grinding. With a VTIOT mixing amount of 30 %, a mortar paste ratio of 1:3, and a water cement ratio of 0.5, the 50 min ground VTIOT mortar demonstrates 7 d and 28 d compressive strengths of 29 MPa and 38.7 MPa, corresponding to the highest values of the activity index, measured at 71.4 % and 75.2 %, respectively. Under standard curing conditions, the hydration products of cementitious materials at 7 d are ettringite (AFt), calcium silicate hydrate (C-S-H), alumina, ferric oxide, monsulfate (AFm), calcium hydroxide (Ca(OH)2), and calcium silica (CS). In the hydration process of 7 d, the exothermic peak and exothermic amount of the 50 min VTIOT cementitious materials are greater than those observed for other grinding times, but lower than those of pure reference cement.

Abstract In this study, we explore the mechanical treatment of two metal–organic frameworks (MOFs), HKUST-1 and MOF-76, applying various milling methods to assess their impact on stability, porosity, and CO2 adsorption capacity. The effects of different mechanical grinding techniques, such as high-energy ball milling and hand grinding, on these MOFs were compared. The impact of milling time, milling speed and ball size during high-energy ball milling was assessed via the Design of Experiments methodology, namely using a 33 Taguchi orthogonal array. The results highlight a marked improvement in CO2 adsorption capacity for HKUST-1 through hand milling, increasing from an initial 25.70 wt.% (5.84 mmol g-1) to 41.37 wt.% (9.40 mmol g-1), marking a significant 38% increase. In contrast, high-energy ball milling seems to worsen this property, diminishing the CO2 adsorption abilities of the materials. Notably, MOF-76 shows resistance to hand grinding, closely resembling the original sample’s performance. Hand grinding also proved to be well reproducible. These findings clarify the complex effects of mechanical milling on MOF materials, emphasising the necessity of choosing the proper processing techniques to enhance their stability, texture, and performance in CO2 capture and storage applications.

In order to obtain a green and efficient preparation process for carboxymethyl porous starch, carboxymethyl porous starch was prepared by mechanical activation solid phase etherification method, where enzymatically hydrolyzed porous cassava starch was used as raw material, sodium chloroacetate as etherifying agent, and sodium hydroxide as catalyst. Single-factor experiments were conducted to explore the effects of various factors on the degree of substitution (DS) of carboxymethyl porous starch, and the application of carboxymethyl porous starch in soy sauce was discussed. The results showed that the optimal process conditions for the preparation of carboxymethyl porous starch by mechanical activation and solid phase synthesis method were as follows: The molar ratio of porous starch to sodium chloroacetate was 1:1, the mass fraction of sodium hydroxide was 18.8%, the ball milling time was 1.5 h, and the reaction temperature was 50℃. Under these conditions, the highest DS of carboxymethyl porous starch obtained was up to 0.2532. Furthermore, the carboxymethylation reaction of porous starch was confirmed by infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). With the increase of DS of carboxymethyl porous starch, its cold water solubility, water absorption, and adsorption of lemon yellow increased. When DS was 0.2532, the cold water solubility of carboxymethyl porous starch reached 64.94%, the water absorption rate reached 180.73%, and the adsorption amount of lemon yellow reached 2.5086 mg·g−1. The powder soy sauce prepared by carboxymethyl porous starch has better solubility, lower moisture absorption, and higher content of amino acid nitrogen, and is closer to the original soy sauce compared to those prepared by cassava starch and porous starch. Therefore, the mechanical activation and solid phase etherification method can effectively prepare carboxymethyl porous starch, which is simple to operate, environmentally friendly, and highly substitutive, providing a scientific basis for the development and utilization of porous starch.

The study of the cementitious material activity of industrial solid wastes is a key issue in the comprehensive utilization of its green building materials. In this study, mechanical activation was used to prepare cementitious materials from vanadium-titanium iron ore tailings (VTIOT) as the main raw materials, and the effects of grinding time, the key parameter, on the grinding characteristics of VTIOT, the mechanical properties of the VTIOT cementitious material, and the hydration mechanism were investigated by means of surface area analysis, particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), alkali leaching, mechanical testing, hydration heat analysis, and thermogravimetric analysis (TGA). The results show that: the grinding time and specific surface area of VTIOT exhibit a linear correlation. Prolonging the grinding time, the fractal dimension of the particles gradually increases. The activity of Si4+ and Al3+ elements increases rapidly, reaching a Si4+ and Al3+ content of 96 mg·L−1 at 90 min of grinding. With a VTIOT mixing amount of 30 %, a mortar paste ratio of 1:3, and a water cement ratio of 0.5, the 50 min ground VTIOT mortar demonstrates 7 d and 28 d compressive strengths of 29 MPa and 38.7 MPa, corresponding to the highest values of the activity index, measured at 71.4 % and 75.2 %, respectively. Under standard curing conditions, the hydration products of cementitious materials at 7 d are ettringite (AFt), calcium silicate hydrate (C-S-H), alumina, ferric oxide, monsulfate (AFm), calcium hydroxide (Ca(OH) 2), and calcium silica (CS). In the hydration process of 7 d, the exothermic peak and exothermic amount of the 50 min VTIOT cementitious materials are greater than those observed for other grinding times, but lower than those of pure reference cement. [ABSTRACT FROM AUTHOR]

Summary: The synthesis of octenyl succinic anhydride‐modified starch was achieved through a fluidised bed activated by jet milling with graded revolution rates of 1200, 1800, 2400, 3000, and 3600 rpm. This study investigated the changes in the structural, physicochemical, and application properties of modified starch after jet milling. The results showed that modified starch can be synthesised using a one‐step jet milling process. The degree of substitution increased with a decrease in the starch particle size, resulting in a rough granule morphology. Structural analysis revealed that crystalline areas were destroyed in the modified starches. In the Fourier‐infrared spectrum, typical peaks appeared at 1724 and 1573 cm−1 upon introduction of the octenyl succinic anhydride group, whereas a new sodium peak appeared in the XPS spectrogram. The 1H‐NMR spectrum indicated that the esterification reaction mainly occurred on OH2 groups. The emulsification properties of the modified starch were significantly enhanced and increased with the crushing strength. The octenyl succinic anhydride‐modified starch has potential as a wall material for microcapsules, with good embedding rate and thermal stability. This novel synthesis method represents an innovative method for the synthesis of OSA‐starches. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract—The technology of preparation of cladding materials based on mechanically activated cullet modified with sodium and potassium hydroxides has been developed. The phase composition and macro- and microstructure of the cladding materials are studied. The structure of the composite modified with potassium hydroxide is found to consist of needle-shaped and columnar crystals in the interporous space, while lamellar crystals are formed in the NaOH-modified composite. The physicomechanical properties of the cladding materials are studied. [ABSTRACT FROM AUTHOR]

The influence of mechanical activation (MA) of the (100 – x)(Ti + C) + x(Ti + 2B) system on the characteristics of combustion of samples with different macrostructures—pressed compacts with a relative density of 0.53–0.6 and bulk density granules 0.6–1.6 mm in size—is studied. It is found that MA of powders leads to a gradual decrease in the combustion rate of pressed samples as the Ti + 2B content in the mixtures increases (a descending dependence), while an increase in the Ti + 2B content in compacts of nonactivated powders leads to an increase in the combustion rate (an ascending dependence). The obtained results contradict the theoretical ideas about the influence of MA on the combustion process, according to which the combustion rate should increase. One of the important factors influencing the change in the combustion rate is the release of impurity gases (IGs). For the first time, the influence of MA on the combustion patterns of granular mixtures is experimentally determined. It is found that the burning rates of granular mixtures are higher than those of powder mixtures for all the compositions studied. It is shown that granulated mixtures from an activated powder have a combustion rate that is on average 3 times higher than granules from a nonactivated powder, and the dependence of the combustion rate on the mass content of Ti + 2B has a local minimum, which is probably related to the peculiarities of the MA process. [ABSTRACT FROM AUTHOR]

Although sodium‐ion batteries (SIBs) offer promising low‐cost alternatives to lithium‐ion batteries (LIBs), several challenges need to be overcome for their widespread adoption. A primary concern is the optimization of carbon anodes. Graphite, vital to the commercial viability of LIBs, has a limited capacity for sodium ions. Numerous alternatives to graphite are explored, particularly focusing on disordered carbons, including hard carbon. However, compared with graphite, most of these materials underperform in LIBs. Furthermore, the reaction mechanism between carbon and sodium ions remains ambiguous owing to the structural diversity of disordered carbon. A straightforward mechanical approach is introduced to enhance the sodium ion storage capacity of graphite, supported by comprehensive analytical techniques. Mechanically activated graphite delivers a notable reversible capacity of 290.5 mAh·g−1 at a current density of 10 mA·g−1. Moreover, it maintains a capacity of 157.7 mAh·g−1 even at a current density of 1 A·g−1, benefiting from the defect‐rich structure achieved by mechanical activation. Soft X‐ray analysis revealed that this defect‐rich carbon employs a sodium‐ion storage mechanism distinct from that of hard carbon. This leads to an unexpected reversible reaction on the solid electrolyte surface. These insights pave the way for innovative design approaches for carbon electrodes in SIB anodes. [ABSTRACT FROM AUTHOR]

This study investigates the sintering mechanism of commercially pure Magnesium (Mg) using the Field Assisted Sintering Technique (FAST). Powder morphologies are in a vast variety of spherical to flake, as well as nano to fine grain as in powder size and mechanically milled (MM) between 0-108 hours. The MM'ed Mg particles were sintered by FAST with at 350-425°C for 5-20min. Relative densities (93-99%) and compressive strength up to 369MPa were obtained from FAST'ed Mg samples depending on MM durations and particle geometries which significantly influenced the sintering mechanism. SEM and XRD analysis identified four distinct bonding and sintering mechanisms influenced by particle geometry, residual stress, and microstructure developed through mechanical milling. The combination of mechanical milling and FAST exhibited significant effects on the microstructural and mechanical properties of Mg powders, with the Mg36 sample displaying promising strength and hardness. [ABSTRACT FROM AUTHOR]

The objective of this study is to perform a comparative analysis of the impact of incorporating alkaline earth metal carbonates (MCO3, where M–Mg, Ca, Sr, Ba) into low-calcium fly ash (FA) on the geopolymerization processes and the resultant properties of composite geopolymers. Mechanical activation was employed to enhance the reactivity of the mixtures. The reactivity of the mechanically activated (FA + alkaline earth carbonate) blends towards NaOH solution was experimentally studied using XRD analysis and FTIR spectroscopy. In agreement with thermodynamic calculations, MgCO3 demonstrated the most active interaction with the alkaline solution, whereas strontium and barium carbonates exhibited little to no chemical interaction, and calcite was situated in the transition region. As the calcite content in the mixture with FA increased, the compressive strength of the geopolymers continuously improved. The addition of Mg, Sr, and Ba carbonates to the FA did not enhance the strength of geopolymers. However, the strength of geopolymers based on these blends was comparable with that of geopolymers based on 100% FA. The strength of geopolymers synthesized from the 100% FA and from the (90% FA + 10% MCO3) blends, mechanically activated for 180 s, at the age of 180 days was 11.0 MPa (0% carbonate), 11.1 MPa (10% MgCO3), 36.5 MPa (10% CaCO3), 13.6 MPa (10% SrCO3), and 12.4 MPa (10% BaCO3) MPa, respectively. The influence of carbonate additives on the properties of the composite geopolymers was examined, highlighting filler, dilution, and chemical effects. The latter determined the unique position of calcite among the carbonates of alkaline earth metals. [ABSTRACT FROM AUTHOR]

Coal mining causes surface subsidence, resulting in the loss of phosphorus from the soil surface and affecting crop growth. To provide a basis for the reclamation of soils in coal mining subsidence areas, using the Suntuan mine area in Huaibei City as an example, indoor soil cultivation experiments were conducted to investigate the effects of applying different types of phosphate rock powders (mechanically activated and nonmechanically activated), active minerals (zeolite, kaolin, bentonite) and phosphorus solubilizing microorganisms (Pseudomonas fluorescens, Aspergillus niger) on soil pH, available phosphorous content, and the conversion of soil phosphorus fractions. The results showed that the combined action of phosphate rock powder and phosphorus solubilizing bacteria could significantly improve the soil acidic environment. The application of phosphate rock powder, active minerals, and phosphorus solubilizing microorganisms can promote the release of available phosphorous in soil, and Aspergillus niger has a better effect than Pseudomonas fluorescens. Soil content of H2O-P, NaOH-Pi, NaHCO3-Pi, and HCl-P increased, NaOH-Po decreased, and some treatment groups had reduced Residual-P content. Together, phosphate rock powders, active minerals, and phosphorus solubilizing microorganisms can mitigate soil acidification, promote soil phosphorus release, result in the transformation of soil phosphorus fractions, and improve phosphate fertilizer utilization. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The mining industry generates vast quantities of mine tailings on an annual basis. However, due to their limited economic value, a significant portion of these tailings are deposited close to mining sites, often underwater. The principal environmental apprehensions associated with mine tailings revolve around their elevated levels of heavy metals and sulfidic minerals. The oxidation of these sulfidic minerals can lead to the formation of acid mine drainage, which in turn releases heavy metals into nearby water systems. The effective management of tailing dams requires substantial financial investments for their construction and meticulous control. Consequently, a pressing need exists for stable, sustainable, and economically viable management approaches. One promising method for addressing mine tailings is through alkali activation, a technique that serves as a stabilization process. This approach yields robust, concrete-like structures by utilizing raw materials abundant in aluminum and silicon, which conveniently constitute the primary components of mining residues. This comprehensive review outlines the research on utilizing alkali activation for mine tailings. It delves into the reactivity and chemical attributes of diverse minerals. Numerous mine tailings exhibit an inadequate level of reactivity under alkaline conditions, so various pre-treatment methodologies and their impacts on mineralogy are meticulously explored. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Extraction of molybdenum (Mo) from jordisite is difficult due to the amorphous state of MoS2. In this study, mechanical activation was employed to pretreat this type of ore with a low Mo content of 0.26%, and then molybdenum and uranium were both extracted from the milled ore using sulfuric acid. The effects of milling time, oxidant, and optimal leaching conditions were investigated in the laboratory. The results show that the mechanical activation will reduce the particle size and increase the specific surface area of the ore under certain milling conditions. Mechanical activation without oxidants in a hypoxia environment is not conductive to the recovery of molybdenum. When the oxidant of MnO2 is added during the milling process, the Mo recovery will increase greatly. The effect of mechanical activation on U recovery is not so obvious. The phenomenon of agglomerate will occur during the milling process, which will reduce Mo recovery seriously, especially when the milling time is more than 120 min. The Mo and U recovery can reach 84.52% and 61.39%, respectively, after optimization of sulfuric acid leaching process conditions. [ABSTRACT FROM AUTHOR]

Mechanically activated strontium titanate (SrTiO3) powders with various manganese dioxide (MnO2) doping levels (1.5, 3 and 6 wt%) were prepared by solid state method. Due to the possibility of manganese ion incorporation in SrTiO3 at Ti4+ and/or Sr2+ sites a detailed analysis of the influence of dopants on the microstructure, morphology and optical properties of perovskite oxide was conducted. The investigation showed that manganese was incorporated into the lattice and surface layers of SrTiO3 particles with the presence of manganese segregation and inhomogeneities. Optical measurements indicated a shift of the absorption edge to higher values of wavelengths where the lowest value of the band gap (3.10 eV) was for the longest activation time (120 min) and the highest weight percentage of dopant (6 wt%). In the case of lower concentration (1.5 wt%), there was a significant relative contribution of the substitution of Sr2+ ions by Mn2+ ions, while the substitution of Ti4+ ions by Mn4+ ions dominated samples with an increased concentration. [ABSTRACT FROM AUTHOR]

The results of a study of the influence of fluoroplastic F-42 on the properties of an elastomeric material based on nitrile butadiene rubber BNKS-18AMN are presented. To increase the interaction with the elastomeric matrix, the F-42 method of preliminary mechanical activation was used. It has been shown that modified vulcanizates are characterized by increased oil, wear and frost resistance while maintaining the level of elastic-strength characteristics and relative residual compression strain. [ABSTRACT FROM AUTHOR]

Heavy metal pollution such as cadmium and arsenic in water seriously threatens human health and safety, and the removal of Cd/As combined pollution is more difficult. In this work, the performance of mechanically activated calcite composite FeSO4 to remove Cd/As combined pollution was investigated by Cd/As combined pollution removal test in water. It was found that mechanically activated calcite can significantly improve the removal efficiency of Cd/As combined pollution in water. The results showed that the removal rate of Cd and As can reach 99% in 30 min by activated calcite composite FeSO4. The removal mechanism of Cd/As combined pollution in water by activated calcite and FeSO4 was studied by SEM-EDS, XPS, and XRD. The results showed that the crystallinity and dissolution activity of calcite were changed by mechanical activation, and the hydrolysis of calcite to produce CO32- and OH- was enhanced. OH- promoted the formation of a stable iron oxide bound precipitate of FeSO4 with arsenic, and CO32- binded with cadmium to form a stable precipitate of cadmium carbonate.

The utilization of vanadium titano-magnetite concentrate (VTM) for pellet preparation poses challenges in terms of low consolidation strength and high energy consumption during the thermal process. The effect and function mechanism of high-pressure grinding roll (HPGR) pretreatment on the preparation of VTM pellets were investigated. The results indicate that HPGR pretreatment increased the strength of the pellets prepared by VTM and decreased the thermal processing temperature and time. The main reason can be attributed to the reduced particle size of VTM, accompanied by an increase in specific surface area, iron-bearing mineral liberation, and improved interfacial hydrophilicity and particle ballability. Moreover, HPGR pretreatment reduced the crystallite size of VTM and increased lattice microstrain and amorphousness, leading to a 13.21 kJ/mol improvement in the mechanical energy storage of titanomagnetite. The increased specific surface area was a crucial factor in strengthening the preparation of VTM pellets, which increased the contacting points participated in interface physicochemical reactions. The enhanced hydrophilicity and ballability were beneficial to improving the strength of green pellets, while the increased strength of roasted pellets was primarily attributed to the iron-containing mineral liberation and crystal mechanical activation, which promoted the oxidation of iron-bearing minerals and the microcrystalline diffusion and connection. Compared with the untreated VTM, the compressive strength of roasted pellets increased from 2168 N P−1 (Newton per pellet) to 2813 N P−1 when the roller pressure intensity was 12 MPa, and the proper roasting temperature could be reduced by more than 50 °C.

A number of industries require materials with a low coefficient of linear thermal expansion (CLTE), in particular, in the production of satellite spherical antennas. The latter are formed from composites containing carbon fibers and synthetic resins. The composition is cured by heating up to 180 °C. This leads to a thermal expansion of the mold and a change in the geometric characteristics of the product. Therefore, specific requirements are imposed on the materials for making molds. The high cost of special materials used for molds determines the need to search for other materials with a low CLTE. Wood is a possible solution to this problem. Its CLTE along the fibers is less than that of the vast majority of materials, and is approximately 3 ‧ 10-6 K–1, which is comparable to special materials. However, the expansion of wood across the fibers is much higher than the longitudinal one, which excludes the use of solid wood. Anisotropy can be reduced by creating a composite in which the fibers are uniformly oriented in all structural directions, bringing the value of wood expansion across the fibers closer to the value of expansion along the fibers. The traditional approach to producing wood composites, based on the use of synthetic adhesives, fails to achieve a noticeable reduction in thermal expansion due to the high CLTE of adhesives The use of boards made of hydrodynamically activated wood particles without binders is promising. Three series of experiments have been carried out: with varying the density of the boards, preliminary thermal modification of the original wood and the use of alkali during hydrodynamic processing. The thermal expansion study has been carried out using the NETZSCH DIL-402 C induction dilatometer in dynamic mode with a heating rate of 2 K/min. It has been established that thermal expansion increases with increasing density.The average CLTE at a density of 950 kg/m3 is 12 ‧10–6 K–1 and at a density of 1,100 kg/m3 it is 17‧10–6 K–1. At a comparable density, the thermal expansion of boards without binders is significantly lower than that of fiberboards (MDF). Preliminary thermal modification of wood does not significantly affect the CLTE of the boards. The use of alkali in the hydrodynamic treatment also has no effect.

This paper investigates the preparation of spherical molybdenum-copper (Mo-Cu) composites through the utilization of plasma spheroidization1 of molybdenum powder, followed by ‘Carbon thermal pre-reduction + Hydrogen deep reduction2’ processes. The properties of these composites are analyzed. By adjusting the mass ratio of molybdenum to copper and employing mechanical activation during high-temperature sintering, Mo and Cu are dispersed more uniformly, resulting in improved fluidity and a reduced tendency to agglomerate in x% Mo-Cu (x = 20, 40, 60, 80) composites. Experimental results demonstrate that compared to original powder Mo-Cu composites, the prepared spherical Mo-Cu composites exhibit uniform elemental distribution, regular arrangement, and reduced porosity. Among these, the 60% Mo (spherical)-Cu composites show the best dispersion and superior performance. At the optimal sintering temperature of 1250°C, the thermal conductivity of the sintered product increased from 137 Wm−1K−1 to 148 Wm−1K−1, the electrical conductivity increased from 18.9 MS/m to 21.8 MS/m, and the Vickers hardness increased from 177 HV to 209 HV. [ABSTRACT FROM AUTHOR]

The mechanisms of high-speed sintering of tungsten and W+5wt%Ni nanopowders obtained by high-energy ball milling (HEBM) have been studied. The phase composition, microstructure parameters, hardness and fracture resistance of the obtained samples were investigated. It is shown that the samples have high relative density, small grain size and increased hardness. It is established that the formation of strong intermetallic phases MexWyCz and MexWy, as well as MeO oxides occurs at SPS of mechanically activated nanopowders. The simultaneous increase in the content of intermetallic phases and reduction of the grain size leads to a non-monotone character of the dependence of the SPS activation energy on the HEBM time. It is shown that the main mechanism of SPS of tungsten W+5wt%Ni nanopowders is Coble creep. [ABSTRACT FROM AUTHOR]

There is a huge reservation of loess in the Shanxi mining area in China, which has great potential for preparing supplementary cementitious materials. Loess was modified via mechanical and thermal activation, and the pozzolanic activity was evaluated using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Moreover, the workability of grouting materials prepared using modified loess was assessed. The experimental results revealed that the number of ultrafine particles gradually increased with the grinding time, enhancing the grouting performance. The coordination number of Al decreased upon the breakage of the Al–O–Si bond post-calcination at 400 °C, 550 °C, 700 °C, and 850 °C. Moreover, the breaking of the Si–O covalent bond produced Si-phases, and the pozzolanic activity of loess increased. Furthermore, the modified loess was hydrated with different cement proportions. With increasing grinding time, the overall setting time increased until the longest time of 14.5 h and the fluidity of the slurry decreased until the lowest fluidity of 9.7 cm. However, the fluidity and setting time decreased with increasing calcination temperature. The lowest values were 12.03 cm and 10.05 h. With the increase in pozzolanic activity, more ettringite was produced via hydration, which enhanced the mechanical properties. The maximum strength of the hydrated loess after grinding for 20 min reached 16.5 MPa. The strength of the hydrated loess calcined at 850 °C reached 21 MPa. These experimental findings provide theoretical support for the practical application of loess in grouting. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• An effective method was applied for the synergistic recovery of valuable elements. • High leaching efficiencies of REEs, Co, and B in the spent NdFeB magnets. • Mechanically induced lattice strain enhancing activity of NdFeB magnets. • The new process reduced the activation energy as well as the roasting temperature. The efficient and sustainable recovery of rare earth resources from spent NdFeB magnets has received considerable and increasing attention. However, the currently prevalent NdFeB magnets recovery techniques focus only on the recovery for rare earth elements (REEs), some of which also recover cobalt (Co) or boron (B). Herein, a simple mechanochemical strategy was proposed to recover REE, Co, and B from spent NdFeB magnets by mixing the NdFeB magnets powder and FeCl 3 6H 2 O through the grinding-roasting-water leaching technological route. The results indicated high leaching efficiencies of 98.94 % for REEs, 99.99 % for Co, and 93.36 % for B from the NdFeB magnets. Additionally, iron remains in the leaching residue as iron oxide (96.73 wt %), achieving the complete separation of REEs, Co, B, and Fe. This mechanochemical based technology offers a green and efficient recovery process, facilitating more effective synergistic recovery of valuable elements from spent NdFeB magnets. [ABSTRACT FROM AUTHOR]

The objective of this work is an attempt to introduce into scientific practice the method of "mechanochemical recrystallization" in solid-phase systems with small additives of a liquid solvent. Dimethyl sulfoxide (DMSO), a universal bipolar aprotic solvent, has been used as the additive. As an example, the mechanical activation of reaction AgNO3 + NH4I + z NH4NO3 (diluent) + yS + xDMSO = AgI + yS* + (z+1)NH4NO3 + xDMSO has been studied, where z ≈ 5, y ≈ 1, and x 1 are molar fractions. The formation of sulfur (S*) and silver iodide (AgI) nanoparticles has been revealed, and/or S*/AgI nanocomposites with controlled contents of the components have been synthesized. The use of NH4NO3, which is a non-target product of the mechanosynthesis, as a diluent leads to the stabilization of nanoparticle sizes. The nanoparticles are formed in the medium of DMSO due to the conventional recrystallization (continuous process of dissolution–crystallization of sulfur) or the reactional recrystallization (process of dissolution of AgNO3 and NH4I followed by their interaction with the AgI crystallization) rather than the direct mechanical activation. The former and latter mechanisms are realized when obtaining S* and AgI, respectively. The target products (S*, AgI, and S*/AgI) are purified from water-soluble components (NH4NO3, DMSO) by washing in an ultrasonic bath. The proposed technical solution of the problem has been realized in planetary ball mills with different milling tools. [ABSTRACT FROM AUTHOR]

This paper mainly introduced the principle of mechanical activation, the application of mechanical activation in slow-release fertilizer, effect factors of mechanical activation on the characteristics of fertilizer, and the green evaluation methods of mechanical activation were reviewed.And the future research direction of mechanical activation was prospected, in order to provide reference for the realization of green production and efficient application of mechanical activation in fertilizer. [ABSTRACT FROM AUTHOR]