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The magnetite oxidation process involves magnetite surface adsorption and O2 dissociation, and the presence of impurity elements such as silicon inevitably affects the magnetite surface adsorption process. To explore and analyze the surface adsorption and oxidation behaviors of silicon‐doped Fe3O4, thermogravimetric experiments and density functional theory methods are used to investigate the physicochemical properties of this material during magnetite oxidation. The results of experiments show that with the increase of SiO2 content, the peaks of the oxidation reaction gradually migrate to the high‐temperature region, the initial oxidation temperature of the mineral increases, and the average oxidation rate decreases. The results of calculations show that when the surface system is doped with Si atoms, the relaxation time of the adsorption and dissociation of oxygen on the surface is prolonged, and the presence of Si isomerization tends to stabilize the crystal lattice structure, reduce the migration of ions, and decrease the mineral's oxidizing properties. [ABSTRACT FROM AUTHOR]

The present study deals with fabricating and characterizing glass fiber reinforced epoxy composites with heavy mineral filler (magnetite particles) for potential low-energy radiation shielding applications. The composite materials were fabricated by the hand layup method. Glass/epoxy composite was used as control sample, and radiation shielding composites were manufactured by mixing 20 and 30% (by weight) magnetite particles with epoxy resin. It was revealed that the tensile properties of the magnetite-modified composites were increased, and the composites containing 30% filler exhibited maximum improvement than the control ones. Further assessment of the composite samples was performed by DMA (Dynamic Mechanical Analysis), TGA (Thermogravimetric Analysis), FTIR (Fourier-Transform Infrared) spectroscopy, water uptake (%), and SEM (Scanning Electron Microscopy) testing. The radiation shielding ability of the control and filler-modified composites was assessed by using a gamma (γ) radiation source (60Co). Then, the shielding efficiency was characterized by radiation-reduced intensity (%), LAC (Linear Attenuation Coefficient), MAC (Mass Attenuation Coefficient), HVL (Half Value Layer), TVL (Tenth Value Layer), and SVL (Sixteenth Value Layer). It was revealed that the 30% magnetite filler content composite experienced relatively good attenuation performance against γ-ray than other studied composites. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles can boost methane production via direct interspecies electron transfer. However, the combined effect of inoculum and particle characteristics on magnetite's methanogenesis stimulation is poorly understood. Here, the influence of inoculum type, particle size, and particle concentration on the ability of magnetite to accelerate methanogenesis was studied in batch anaerobic digestion experiments. Fresh and degassed mesophilic digester sludge was used as inoculum, representing methanogenic communities in the exponential or stationary growth and endogenous decay phases, respectively. Three magnetite particle size ranges, small (50–150 nm), medium (168–490 nm), and large (800 nm–4.5 μm), at two different concentrations (2 and 7 mM) were used. With degassed sludge, the effect of magnetite on the methane production rate was weak and depended on the particle size and concentration. Only magnetite of medium size at both 2 and 7 mM significantly increased the methane production rate by 12% compared to the control with no magnetite. The lag phase was reduced by 17% compared to the control, only with 2 mM of both small and medium size magnetite. Conversely, adding magnetite into fresh sludge significantly increased the methane production rate by an average of 32% while simultaneously decreasing the lag phase by 15%–40%, as compared to the control, independently of the magnetite's size and concentration. The stimulation of methane production depends on magnetite and inoculum characteristics. [ABSTRACT FROM AUTHOR]

The current body of research on microwave-assisted grinding of vanadium-titanium magnetite (VTM) predominantly focuses on the analysis of changes in particle size and dissociation degree of the grinding products. Nonetheless, the microwave heating mechanism of the ore remains inadequately explored. In this study, the dielectric property of VTM with different particle sizes were measured at a frequency of 2.45 GHz and temperatures ranging from ambient to 800 °C. The results indicate that the dielectric constants (ε′) and dielectric loss factors (ε″) of VTM increase with temperature. The loss tangent coefficients (tan δ) initially increase and then decrease, reaching a maximum value of 0.44 at approximately 500 °C. The values of dielectric property parameters increase as the particle size decreases. By calculating the penetration depth equation, it can be determined that the optimal particle size for uniform heating in microwave of VTM is approximately 15 ∼ 30 mm. The heating rate of the ore in the microwave field is divided into two stages. Initially, the heating rate is very fast due to the ore being a strong magnetic mineral. However, when the ore temperature reaches 500 °C, the tan δ of the ore decreases, leading to a decrease in the heating rate. [ABSTRACT FROM AUTHOR]

In this paper, cordierite ceramics with high far-infrared emission properties are synthesized by a high-temperature solid-phase method using molybdenum tailings and vanadium-titanium magnetite tailings. The microstructure, physical properties and far-infrared emission mechanism of ceramics are investigated. The results show that the ceramics synthesized with 10 wt% molybdenum tailings and 30 wt% vanadium-titanium magnetite tailings have a flexural strength of 67 MPa, a bulk density of 2.531 g/cm3 and a maximum far-infrared emissivity of 0.958 when the sintering temperature is 1200 °C. The crystal phase of the ceramic are 21.4 % cordierite and 58.7 % magnesia-alumina spinel. In the sintering process, the Fe3+ in vanadium-titanium magnetite tailings doped into the cordierite to substitute the Mg2+, which has the similar ionic radius with Fe3+, to form a substitutional solute. Ionic substitution causes the lattice parameters of cordierite larger, reducing the symmetry of the lattice vibrations and leading to lattice distortion. In addition, the composition of a large amount of magnesia-aluminum spinel is attributed to the far-infrared emission properties of ceramics. [ABSTRACT FROM AUTHOR]

In this paper, CO is used as reductant in the process of copper slag cleaning, which can reduce the Fe3O4 content and improve the settling environment of copper in slag. The results showed that the Fe3O4 content and converter slag viscosity decrease with the increase in reduction temperature and time. The system temperature and reduction time have important effects on the CO utilization ratio. According to the variation of Fe3O4 reduction degree, the kinetic of the reduction process between CO and Fe3O4 at 1250–1350 °C was studied. It was found that the [ - ln 1 - X ] 2 3 = k t accords with the kinetic equation of cleaning process of copper slag by CO. The apparent activation energy of reaction process was 313 kJ/mol, and the reaction rate was controlled by the interface chemical reaction. [ABSTRACT FROM AUTHOR]

Cancer is a global issue and hence various efforts are being made. Iron oxide is considered a significant biochemical agent in the biomedical arena for cancer treatment. Marine macroalgae-mediated iron oxides especially, magnetite (Fe3O4) nanoparticles (NPs) are a prospective alternative to diagnose and treat cancer owing to their fluorescent and magnetic properties. We intend to appraise the usability of the aqueous extract of Rosenvingea intricata (R. intricata) in Fe3O4 NPs synthesis and to study their cytotoxic effects against human hepatocarcinoma (Hep3B) and pancreatic (PANC1) cancer cells. In the present study, R. intricata were collected from the coastal region of South Andaman, India. Aqueous extracts of R. intricata were utilized to synthesize Fe3O4 NPs via the co-precipitation method. Phycosynthesized Fe3O4 NPs exhibited wide peak at 400–600 nm from ultraviolet–visible diffused reflectance spectroscopic analysis which validated the formation of NPs. Band edge emission peak at 660 nm in fluorescent spectra confirmed the quantum confinement in Fe3O4 NPs. Fourier transform infrared spectroscopy confirmed the role of R. intricata as a capping and reducing agent with functional groups such as O–H, C–H, C=O, N=O, C=C, C–O, C–N, and C–S arising from amino acids, polysaccharides, aliphatic hydrocarbons, esters, amides, lignins, alkanes, aliphatic amines, and sulfates. Physicochemical properties such as crystallite size (14.36 nm), hydrodynamic size (84.6 nm), irregular morphology, elemental composition, particle size (125 nm), crystallinity, and saturation magnetization (0.90007 emu/g) were obtained from x-ray diffractometer, dynamic light scattering, scanning electron microscopy, energy dispersive x-ray spectrometer, high-resolution transmission electron microscopy, selected area electron diffraction and vibrating sample magnetometer techniques, respectively. The cell viability showed dose-dependent cytotoxic effects and enhanced the apoptosis against Hep3B and PANC1 cancer cells. R. intricata extract capped Fe3O4 NPs could be the most appropriate and effective nanomaterial for cancer treatment and management. [ABSTRACT FROM AUTHOR]

Wastewater is discharged in large amounts from different industries; thus, wastewater treatment is currently one of the main concerns, advanced oxidation is a promising technique for wastewater treatment. This research aims to synthesize magnetite nanoparticles and study their application in wastewater treatment via adsorption and advanced oxidation processes. Magnetite nanoparticles were synthesized via coprecipitation technique between ferric and ferrous sulfate at a molar ratio of 2:1. The prepared sample was characterized using FTIR, XRD, TEM, BET surface area, zeta potential, VSM, and UV‒visible spectroscopy. XRD confirmed the formation of a single face-centered cubic (FCC) spinel structure of Fe3O4. TEM revealed an average particle size of 29.2 nm and a BET surface area of 70.1 m2 g−1. UV‒visible spectroscopy revealed that the UV–visible peak of the sample was obtained at 410 nm. VSM confirmed the attraction of the sample to a magnet with a magnetization of 60 (emu/g). The removal efficiency of methylene blue was studied using adsorption and advanced oxidation methods. For adsorption, the studied parameters were dye concentration 2–10 ppm, 3–10 pH, and 50:300 mg Fe3O4/L. For advanced oxidation, peroxide was used with nanomagnetite as a catalyst, and the studied parameters were pH 2–11, magnetite dose 20–200 PPM, and peroxide dose 500–2000 PPM. The removal efficiency by adsorption reached 95.11% by adding 50 mg of Fe3O4/L and 10 ppm dye conc at 6.5 pH; on the other hand, in advanced oxidation, it reached 98.5% by adding 110 PPM magnetite and 2000 ppm H2O2 at pH 11. The magnetite nanoparticles were reused for ten cycles of advanced oxidation, for a 10% reduction in removal efficiency at the tenth cycle. [ABSTRACT FROM AUTHOR]

AbstractIron oxide nanoparticles (IONPs) have been extensively explored in biomedicine, bio-sensing, hyperthermia, and drug/gene delivery, attributed to their versatile and tunable properties. However, owing to its numerous applications, the functionalization of IONPs with appropriate materials is in demand. To achieve optimal functionalization of IONPs, polydopamine (PDA) was utilized due to its ability to provide a superior functionalized surface, near-infrared light absorption, and adhesive nature to customize desired functionalized IONPs. This notion of involving PDA led to the successful synthesis of magnetite-PDA nanoparticles, where PDA is surface-coated on magnetite (Fe3O4@PDA). The Fe3O4@PDA nanoparticles were characterized using techniques like TEM, FESEM, PXRD, XPS, VSM, and FTIR, suggesting PDA’s successful attachment with magnetite crystal structure retention. Human serum albumin (HSA), the predominant protein in blood plasma, interacts with the delivered nanoparticles. Therefore, we have employed various spectroscopic techniques, along with cytotoxicity, to inspect the effect of Fe3O4@PDA NPs on the stability and structure of HSA. The structural alterations were examined using circular dichroism (CD) and synchronous fluorescence spectroscopy (SFS). It has been observed that there are no structural perturbations in the secondary structure of the HSA protein after interaction with Fe3O4@PDA. Studies using steady-state fluorescence revealed that the inherent fluorescence intensities of HSA were suppressed after interaction with Fe3O4@PDA. In addition, temperature-dependent fluorescence measurements suggested that the type of quenching consists of both static and dynamic quenching simultaneously. A cytotoxicity study in Drosophila melanogaster larvae revealed no cytotoxic effects but did show a minor genotoxic effect only at higher concentrations. [ABSTRACT FROM AUTHOR]

The surface chemistry of pyrrhotites from intact particles directly collected from asteroid (162173) Ryugu was investigated by micro-Raman spectroscopy. The Raman peak characteristic to pyrrhotite was observed at around 115 cm−1 in Ryugu pyrrhotites, similar to freshly cleaved surfaces of terrestrial pyrrhotites. Additional Raman bands centered at around 220, 275, and 313 cm−1 with broadened features were also detected from the Ryugu pyrrhotites. The set of Raman bands at 220 and 275 cm−1 was assigned to typical Fe-S stretching vibrations of ν 2 (225 cm−1) and ν 1 (275 cm−1). These bands are not clearly observed in bulk crystals of pyrrhotite but appear in its nanoparticulate phase. These bands are ordinarily seen in amorphous monosulfides that formed under low oxygen fugacity (f O 2) conditions in nature, indicating that the structural alteration of pyrrhotite surfaces occurred heterogeneously on the nanoscale under low f O 2 conditions. Further, the Raman band at 313 cm−1 was attributed to a characteristic tetrahedral bonding of Fe(III) in the lattice of FeII 1-3x FeIII 1-2x S, followed by the local breakdown of the crystal lattice structures from planar bonding with Fe(II). In addition, some areas of the Ryugu pyrrhotite grains showed corroded structures with iridescence. Furthermore, assemblages of magnetite particles were also preferentially observed on small areas of the likely-dissolved pyrrhotite crystals in phyllosilicate matrices. These characteristic features in the Raman spectra and in corroded structures of Ryugu pyrrhotites record changes in the local environmental conditions via aqueous alteration. The corrosion of pyrrhotite crystals followed by the preferential formation of magnetite particles by asteroidal water is the likely product of dissolution of Fe(II) from the pyrrhotite surface and its oxidative precipitation in microchemical environments on the Ryugu parent body. [ABSTRACT FROM AUTHOR]

Chiton articulatus is a species of mollusk living in the tropical Pacific intertidal rocky shores of Mexico. This species feeds on solid waste organic sources, including hard crustose algae that grow on rocky substrates, by grazing on them with its radula, a flexible chitinous membrane lined with mineralized major lateral teeth. In this study, the composition, morphology, and resulting mechanics of the mature teeth of this species, which have yet to be examined, are revealed. The results show the presence of multiphasic mature teeth, each consisting of aligned hard magnetite nanoparticles on the leading edge of the tooth underneath which are magnetite lamellae, followed by goethite, lepidocrocite, and eventually hydroxyapatite near the trailing edge. This multiregional structure demonstrates a gradation in hardness as well as different microstructural features integrated with tough interfaces. The combination of these microstructural and phase arrangements results in an abrasion‐resistant tough structure with a self‐sharpening ability. The results of this work will help contribute to developing new bioinspired designs while also helping to understand the evolution and feeding habits of these intriguing invertebrates. [ABSTRACT FROM AUTHOR]

Superparamagnetic nanoparticles (SPMNPs) have attracted considerable attention in biomedicine, particularly magnetic hyperthermia for cancer treatment. However, the development of efficient and eco-friendly methods for synthesizing SPMNPs remains a challenge. This study reports on a green synthesis approach for SPMNPs using pomegranate peel extract as a stabilizing agent. The effects of various synthesis parameters, including the type of precipitating agent (NH3 and NaOH), N2 gas, extract volume, and pH, were systematically investigated with regard to the size, morphology, and magnetic properties of the nanoparticles. The results showed that reducing the volume of the extract increased the saturation magnetization of the nanoparticles. N2 gas was found to be essential in preventing the oxidation of the nanoparticles. The type of precipitating agent also affected the size and magnetization of the nanoparticles, with NaOH leading to the synthesis of SPMNPs with higher magnetization (~4 times) compared to NH3. Additionally, nanoparticles synthesized at pH 10 exhibited higher magnetization than those synthesized at pH 8 and 12. In conclusion, the optimized synthesis conditions significantly affected the magnetization and stability of SPMNPs. These nanoparticles are suitable for use in magnetic nanofluid hyperthermia applications. [ABSTRACT FROM AUTHOR]

George Barrow's maps (1893, 1912) of the metamorphic zones named after him in the south‐eastern Scottish Highlands, show a prominent staurolite zone running from the west of Glen Clova to the North Sea coast near Stonehaven in the east. Pelitic mica schists throughout this zone commonly show principal mineral assemblages of staurolite+biotite+garnet+muscovite +quartz (St + Bt + Grt), with sodic plagioclase, ilmenite and sometimes magnetite as common accessories; these schists have bulk compositions corresponding with those of common Dalradian metasediments. However, the mineral assemblages on the low‐ and high‐grade margins of the staurolite zone show evidence of changes from west to east. Lower grade assemblages near Stonehaven include chloritoid+biotite, which has not been found further west in the classic ‘Barrovian’ sequence; whilst the higher grade assemblages near Stonehaven lack kyanite, which is widely seen further west. The Stonehaven area has been suggested to have under gone metamorphism at lower pressure (P) than the classic region of the ‘Glens’ inland to the west.This paper describes the occurrence at middle grade in the broad staurolite zone, of unusual bulk rock compositions showing high ratios of Fe2O3/(Fe2O3 + FeO) and MgO/(MgO + FeO) (abbreviated to M/FM). The high M/FM assemblages are distinct from those of the common St‐Bt‐Grt schists. The high ratios of ferric to ferrous iron are thought to result from original sedimentary protolith compositions, that led to metamorphism at relatively high conditions of oxygen fugacity (ƒo2), and resulted in the formation of haematite‐bearing assemblages, rather than ones carrying accessory ilmenite and magnetite as in the common St + Bt + Grt rocks.In the west (Glen Lethnot), the haematite‐bearing pelites show the occurrence of kyanite at a distinctly lower grade than the common (haematite‐free) pelites, and a transition from staurolite‐biotite (St + Bt) through staurolite–kyanite‐biotite (St + Ky + Bt) to kyanite‐biotite (Ky‐Bt) assemblages occurs with increasing abundance of haematite and higher bulk M/FM values. In all bulk compositions, the upgrade formation of kyanite may be associated with the movement of the St + Ky + Bt assemblage to lower M/FM bulk compositions with increasing temperature (T). The difference in the temperature of lowest‐grade kyanite formation in haematite‐rich schists, compared with that in common haematite‐free schists may approach 50°C.In the east (Stonehaven section), the haematite‐bearing assemblages are much rarer than in Glen Lethnot, but those found so far are very distinctive in showing large porphyroblasts of probable cordierite (typically altered to chlorite and sericite). Occasional assemblages of andalusite‐cordierite‐biotite (And‐Crd‐Bt) also occur in the haematite‐bearing rocks and confirm lower pressures of metamorphism near Stonehaven than those seen further west in Glens Clova, Lethnot and Esk. [ABSTRACT FROM AUTHOR]

This work discusses the synthesis of magnetite nanoparticles using microfluidic method. The main characteristics of the resulting nanoparticles were investigated, including chemical composition, size distribution, saturation mass magnetization, and coercive force. To assess the possibility of using nanoparticles for medical and biological purposes, the hemolytic activity of a suspension of magnetite nanoparticles was studied. [ABSTRACT FROM AUTHOR]

A new composite was synthesized by modifying CoFe2O4/MCM-41 particles with N-phenyl anthranilic acid (PA) followed by treatment with Ni (II) particles. The prepared material was denoted as CoFe2O4/MCM-41/PA/Ni. This composite has fantastic properties like high stability, excellent magnetic performance, and remarkable catalytic activity. The catalyst was characterized by different analyses This MCM-41 silica is like a protective layer around the magnetite particles. This coating process gives the particles some interesting properties. This composite consisted of a mesoporous structure with a surface area of 342.9 m2/g, mean pore size of 5.57 nm, and pore volume of 0.4772 cm3 /g. This unique combination of CoFe2O4 nanoparticles with MCM-41 and PA supports, decorated with Ni creates some outstanding reaction that leads to exceptional performance in synthesizing 5-substituted 1H tetrazoles. This catalyst was recovered and reused several times without significantly decreasing efficiency and stability. [ABSTRACT FROM AUTHOR]

To prepare a magnetic nano-adsorbent for efficient and fast removal of a dye, especially if present in trace concentration, along with a facile green synthetic methodology is a great challenge. The present work realises this task by combining the well-known advantages of both solvent-free microwave approach, nanoscale particle size and the fast magnetic separation. Thus, silica-coated magnetite nanoparticles (Fe3O4 NPs@SiO2) as an important precursor were produced directly via an optimised solid-solid interaction between silica and Fe3O4 NPs at 200 watt of microwave irradiation for only 10 min. The as-developed adsorbent was characterised using Fourier Transform Infrared (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) analysis. Its performance with no further modification for removal of Methylene blue (MB) dye from aqueous solution was achieved in a batch mode as a function of pH, contact time, adsorbent dose and initial dye concentration. The results demonstrate excellent removal efficiency (98.9%) within 5 min, as compared with recent adsorbents synthesised through a multi-steps reaction. Modelling of the experimental data denoting well-fitting with both Langmuir sorption isotherm (monolayer capacity 47.98 mg/g) and pseudo-second-order kinetic model. A possible MB binding mechanism has been proposed taking in account values of dissociation constants of the different forms of silica surface silanol groups. The adsorbent after first was successfully regenerated in situe for five consecutive cycles. Moreover, it was proved to be valid for collecting efficiently trace concentrations of MB spiked environmental water samples to be in the range 92.4–98.8%. [ABSTRACT FROM AUTHOR]

The increasing reliance on electronic technologies has elevated the urgency of effective electromagnetic interference (EMI) shielding materials. This review explores the development and potential of magnetite-incorporated one-dimensional (1D) carbon nanostructure hybrids, focusing on their unique properties and synthesis methods. By combining magnetite's magnetic properties with the electrical conductivity and mechanical strength of carbon nanostructures such as carbon nanotubes (CNTs) and carbon fibers (CFs), these hybrids offer superior EMI shielding performance. Various synthesis techniques, including solvothermal synthesis, in situ growth, and electrostatic self-assembly, are discussed in detail, highlighting their impact on the structure and properties of the resulting composites. This review also addresses the challenges in achieving homogeneous dispersion of nanofillers and the environmental and economic considerations of large-scale production. The hybrid materials' multifunctionality, including enhanced mechanical strength, thermal stability, and environmental resistance, underscores their suitability for advanced applications in aerospace, electronics, and environmental protection. Future research directions focus on optimizing synthesis processes and exploring new hybrid configurations to further improve electromagnetic properties and practical applicability. [ABSTRACT FROM AUTHOR]

The Washan iron deposits in Ningwu district contain different magma-related genetic natures, including magmatic, magmatic–hydrothermal and hydrothermal types, and their ore-forming processes remain a subject of debate. To elucidate the ore-forming processes of iron ores from Washan, we present textural, major element analytical, and thermal data of magnetites from various ore bodies in Washan, probing the crystallization conditions and subsequent formation sequence of magnetites. SEM analysis with back-scattered electron (BSE) imaging reveals diverse magnetite textures, including mineral inclusions, exsolution lamellae, and recrystallization features, reflecting the transitional environment from magmatic to hydrothermal. Based on Ti, V, and Cr compositions of magnetite from different ore bodies, two distinct evolution trends of genetic processes are identified, including evolution paths from porphyry-type to IOA- and IOCG-type magnetite. High-resolution WDS mapping highlights the intensifying alterations during this process. Calculated magnetite crystallization temperatures among different types of magnetite range from 597 °C to 378 °C, suggesting a cooling trend from porphyry-type magnetite (~558 °C) to IOA-type magnetite (~515–439 °C) and IOCG-type magnetite (~378 °C). These results underscore the significant role of magma-derived hydrosaline liquids and vapors in the formation of iron ores from Washan, where variations in the salinity of ore-forming fluids lead to different evolutionary paths for subsequent generations of magnetite. The metallogenic model of the Washan iron deposit suggests that highly saline, iron-rich fluids connect the varying geneses of magnetite, transitioning from deeply formed porphyry-type magnetite to IOA- or IOCG-type magnetite generated in the subaerial zone. [ABSTRACT FROM AUTHOR]

This article presents the results of thermodynamic and experimental studies on the joint processing of a mixture of Shalkiya deposit zinc–lead sulfide ore and its concentration tailings in the presence of coke and magnetite. Using the HSC-6.0 software package, it was established by thermodynamic modeling that the silicon-containing products of the SiO2 reduction in the system under consideration are FeSi, Si, Fe3Si, Fe5Si3, FeSi2, FeSi2.33, and SiOg, which, based on the starting reduction temperature, form an increasing series: Fe3Si (1200 °C); Fe5Si3, Si (1400 °C); and SiOg, FeSi2, FeSi2.33 (1500 °C). The smelting of the zinc–lead sulfide ore and concentration tailings mixture in the case of replacing 55% of the iron contained in the magnetite concentrate with steel shavings iron allowed us to produce FeSi45 ferrosilicon (41.9%–42.1% Si), with the extraction of 85% of the silicon in it, and sublimates containing 26.03% zinc and 13.47% lead, with the extraction of 97% of the zinc and 99% of the lead in them. In comparison with the initial ore-tailings mixture, the resulting sublimates are 11.83 times richer in zinc. [ABSTRACT FROM AUTHOR]

The beneficiation of low-grade iron ores is a key research and development topic in the mineral processing industry. The gradual exhaustion of high-grade iron ore reserves, and rising consumer iron and steel demand globally necessitate efficient low-quality iron ore beneficiation to meet steelmaking quality requirements. This comprehensive review explores various beneficiation techniques for low-quality iron ore, focusing on conventional methods including comminution, froth flotation and gravity separation. This article discusses the principles, processes, and equipment used in these techniques and highlights recent advancements and research efforts in the field. This review also emphasizes the importance of effective beneficiation processes in enhancing economic viability, sustainable resource management, and environmental conservation. Furthermore, it presents a case study of iron ore deposits in Botswana, highlighting the potential economic growth and sustainable development that can be achieved by maximizing resource utilization through reductive roasting, followed by magnetic separation of iron ore using semi-bituminous coal as a reductant. Overall, this review provides valuable insights into low-grade iron ore beneficiation techniques and their significance in meeting the growing demand for high-quality iron and steel products. [ABSTRACT FROM AUTHOR]

With the rapid development of wireless communication technologies and the miniaturization trend in the electronics industry, the reduction of electromagnetic interference has become an important issue. To solve this problem, a lot of attention has been focused on polymer composites with combined functional fillers. In this paper, we report a method for creating an acrylonitrile butadiene styrene (ABS) plastic composite with a low amount of conductive carbon and magnetic fillers preparation. Also, we investigate the mechanical, thermophysical, and electrodynamic characteristics of the resulting composites. Increasing the combined filler amount in the ABS composite from 1 to 5 wt % leads to a composite conductivity growth of almost 50 times. It is necessary to underline the temperature decrease of 5 wt % mass loss and, accordingly, the composite heat resistance reduction with an increase in the combined filler from 1 to 5 wt %, while the thermal conductivity remains almost constant. It was established that electrodynamic and physical–mechanical characteristics depend on the agglomeration of fillers. This work is expected to reveal the potential of combining commercially available fillers to construct effective materials with good electromagnetic interference (EMI) protection using mass production methods (extrusion and injection molding). [ABSTRACT FROM AUTHOR]

Producing an eco-friendly fuel with the least amount of sulfur compounds has been an ongoing issue for petroleum refineries. In this study, bentonite (which is a cheap material and is locally available in abundance) is employed to prepare a nano-silica catalyst with a high surface area to be used for the oxidative desulfurization of kerosene. Two composite catalysts of Fe/silica were supported on CAT-1 (0% HY-zeolite and 100% nano-silica) and CAT-2 (20% HY-zeolite and 80% nano-silica). The activity of the catalysts was evaluated in a batch ODS (oxidative desulfurization) process at temperatures of 30, 60, 90, and 120 °C, a pressure of 1 atm, and a reaction time of 30, 60, 90, and 120 min using 120 L/h of air as the oxidant. The results revealed that the highest total sulfur removal efficiency was 50% and 87.88% for 100% nano-silica (CAT-1) and 80% nano-silica (CAT-2), respectively. The experimental data were then used to construct and validate an accurate mathematical model of the process. The operational parameters for eliminating more than 99% of sulfur and producing eco-friendly fuel were then achieved by using the model. The testing methods for these characterizing materials included X-ray diffraction (XRD), thermal gravimetric examination (TGA), X-ray fluorescence (XRF), and surface area (BET). The outcomes indicated that the addition of HY-zeolite increased the activity of the catalyst (CAT-2 > CAT-1). [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles (nano‐Fe3O4) and nano‐Fe3O4 immobilized with bacterial extracellular polymeric substances (EPSs) extracted from Lysinibacillus sp. WH (Fe3O4/bact) were comparatively studied for the removal of Cr (VI) ions from aqueous solution in batch study. The objectives were to explore the removal of Cr (VI) efficiency by nano‐Fe3O4 and Fe3O4/bact under varying bacterial concentrations at a range of acidic pH. Results indicated that 150 ppm Cr (VI) could be effectively removed by 5 g/L of nano‐Fe3O4 at pH 4, with the efficiency of 89.2 ± 12%. The equilibrium time, determined by a pseudo‐second‐order model (R2 = 0.9983), was after 5 h, indicating chemical adsorption. The Cr (VI) removal by the nano‐Fe3O4 immobilized with bacterial EPS was effective and steady under a wide range of acidic conditions although bacterial EPS has an alkaline nature. Here, we are the first to demonstrate that Cr (VI) removal efficiency by different concentrations of EPS was not significantly different, suggesting EPS concentration is possibly not the most crucial factor to be optimized for Cr (VI) removal in the future. This study shows the potential application of nano‐Fe3O4 immobilized with bacterial EPS for wastewater treatment. Practitioner points: The equilibrium time for magnetite nanoparticles to remove Cr (VI) is 5 h, suggesting chemical adsorption.The Cr (VI) removal efficiency of either magnetite nanoparticles or bacterial EPS is stable under a wide range of acidic conditions.Magnetite nanoparticles immobilized with bacterial EPS extracted from Lysinibacillus sp. WH has a potential application for Cr (VI) removal in wastewater. [ABSTRACT FROM AUTHOR]

In order to gain insights on the conditions of aqueous alteration on asteroid Ryugu and the origin of water in the outer solar system, we developed the measurement of water content in magnetite at the micrometer scale by secondary ion mass spectrometry (NanoSIMS) and determined the H and Si content of coarse‐grained euhedral magnetite grains (polyhedral magnetite) and coarse‐grained fibrous (spherulitic) magnetite from the Ryugu polished section A0058‐C1001. The hydrogen content in magnetite ranges between ~900 and ~3300 wt ppm equivalent water and is correlated with the Si content. Polyhedral magnetite has low and homogenous silicon and water content, whereas fibrous magnetite shows correlated Si and water excesses. These excesses can be explained by the presence of hydrous Si‐rich amorphous nanoinclusions trapped during the precipitation of fibrous magnetite away from equilibrium and testify that fibrous magnetite formed from a hydrous gel with possibly more than 20 wt% water. An attempt to determine the water content in sub‐μm framboids indicates that additional calibration and contamination issues must be addressed before a safe conclusion can be drawn, but hints at elevated water content as well. The high water content in fibrous magnetite, expected to be among the first minerals to crystallize at low water–rock ratio, points to the control of water content by local conditions of magnetite precipitation rather than large‐scale alteration conditions. Systematic lithological variations associated with water‐rich and water‐poor magnetite suggest that the global context of alteration may be better understood if local water concentrations are compared with millimeter‐scale distribution of the various morphologies of magnetite. Finally, the high water content in the magnetite precursor gel indicates that the initial O isotopic composition in alteration water must not have been very different from that of the earliest magnetite crystals. [ABSTRACT FROM AUTHOR]

In total, 24 brick samples for archaeomagnetic studies were taken from ten historical buildings constructed between c.1280 AD and 1630 AD in northern Poland. Eight of them are from the gothic period. The Thellier–Thellier archaeointensity protocol was used in order to determine the ancient intensity and inclination registered by the bricks. In total, 28 representative specimens from 16 bricks gave successful archaeointensity determination with category B of results quality. For 25 of them the corrections for anisotropy of thermoremanent magnetization and cooling rate were introduced. A large number of specimens classified as category C (48%) is due to a high value of relative additivity check error d(AC) caused most probably by the presence of multi-domain magnetite. The curvature parameter k exceeds the limit value in 11 specimens. However, in the same sample specimens with k higher than 0.270 have provided very similar values of archaeointensity than those with k below this limit. Corrected data are convergent with the Central European master curve of archaeointensity. The corrections of raw data reduce their dispersion at specimen/sample level in most of sites. [ABSTRACT FROM AUTHOR]

Seafloor massive sulfides form in various marine hydrothermal settings, particularly within volcanic arcs, where magmatic fluids may contribute to the metal budget of the hydrothermal system. In this study, we focus on the Kolumbo volcano, a submarine volcanic edifice in the central Hellenic Volcanic Arc hosting an active hydrothermal system. Diffuse sulfate-sulfide chimneys form a Zn-Pb massive sulfide mineralization with elevated As, Ag, Au, Hg, Sb, and Tl contents. These elements have similar behavior during magmatic degassing and are common in arc-related hydrothermal systems. Trace-element data of igneous magnetite, combined with whole rock geochemistry and numerical modelling, highlights the behavior of chalcophile and siderophile elements during magmatic differentiation. We report that, despite early magmatic sulfide saturation, chalcophile element contents in the magma do not decrease until water saturation and degassing has occurred. The conservation of chalcophile elements in the magma during magmatic differentiation suggests that most of the magmatic sulfides do not fractionate. By contrast, upon degassing, As, Ag, Au, Cu, Hg, Sb, Sn, Pb, and Zn become depleted in the magma, likely partitioning into the volatile phase, either from the melt or during sulfide oxidation by volatiles. After degassing, the residual chalcophile elements in the melt are incorporated into magnetite. Trace-element data of magnetite enables identifying sulfide saturation during magmatic differentiation and discrimination between pre- and post-degassing magnetite. Our study highlights how magmatic degassing contributes to the metal budget in magmatic-hydrothermal systems that form seafloor massive sulfides and shows that igneous magnetite geochemistry is a powerful tool for tracking metal-mobilizing processes during magmatic differentiation. [ABSTRACT FROM AUTHOR]

Superparamagnetic iron oxide micro- and nanoparticles have significant applications in biomedical and chemical engineering. This study presents the development and evaluation of a novel low-cost microfluidic device for the purification and hyperconcentration of these magnetic particles. The device, fabricated using laser ablation of polymethyl methacrylate (PMMA), leverages precise control over fluid dynamics to efficiently separate magnetic particles from non-magnetic ones. We assessed the device's performance through Multiphysics simulations and empirical tests, focusing on the separation of magnetite nanoparticles from blue carbon dots and magnetite microparticles from polystyrene microparticles at various total flow rates (TFRs). For nanoparticle separation, the device achieved a recall of up to 93.3 ± 4% and a precision of 95.9 ± 1.2% at an optimal TFR of 2 mL/h, significantly outperforming previous models, which only achieved a 50% recall. Microparticle separation demonstrated an accuracy of 98.1 ± 1% at a TFR of 2 mL/h in both simulations and experimental conditions. The Lagrangian model effectively captured the dynamics of magnetite microparticle separation from polystyrene microparticles, with close agreement between simulated and experimental results. Our findings underscore the device's robust capability in distinguishing between magnetic and non-magnetic particles at both micro- and nanoscales. This study highlights the potential of low-cost, non-cleanroom manufacturing techniques to produce high-performance microfluidic devices, thereby expanding their accessibility and applicability in various industrial and research settings. The integration of a continuous magnet, as opposed to segmented magnets in previous designs, was identified as a key factor in enhancing magnetic separation efficiency. [ABSTRACT FROM AUTHOR]

In order to realize the comprehensive and efficient recovery of vanadium–titanium magnetite, a mass action concentration calculation model for direct melting reduction was established, and the mechanisms and limiting factors for the separation and enrichment between Fe, V, and Ti were also studied through molten vortex direct reduction experiments. The mass effect concentration modeling results show that increasing the temperature and carbon–iron ratio promotes Fe, Ti, and V reduction, while adding CaO and MgO inhibits Ti reduction. CaO and MgO in the slag preferentially combine with TiO2 rather than SiO2, and increasing MgO in the slag contributes to the decomposition of the Al2O3.TiO2. Vortex stirring efficiently prevents slag crusting, alleviates foam slag problems, and promotes full reaction in the melt. Appropriate increases in reaction temperature, carbon–iron ratio, and holding time are beneficial for reduction in the molten vortex direct reduction process, while excessive increases in these parameters will result in titanium reduction. Under optimal experimental conditions, the recovery of Fe and V in the metal is 99.61 to 99.74 pct and 92.63 to 94.3 pct, respectively, with TiO2 content in the slag being 50.9 to 51.2 pct, and TiO2 in the slag mainly concentrated in Mg0.6Ti2.4O5. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease is a prevalent chronic metabolic condition, for which no approved medications are available. As a condiment and traditional Chinese medicine, ginger can be useful in reducing the symptoms of non-alcoholic fatty liver disease. Although its active ingredients and mechanisms of action are unknown, there is a lack of research on them. The purpose of this study is to prepare magnetite (Fe3O4)@Stearoyl-CoA desaturase 1 (SCD1) materials and analyze them using ultra-high performance liquid-chromatography-mass spectrometry (UPLC-MS) for rapid screening of potential inhibitors of SCD1 in ginger. Based on this analysis, it has been shown that the primary components in ginger that bind SCD1 directly are gingerols, with 10-gingerol having a greater affinity for binding to SCD1 than 8-gingerol and 6-gingerol. Moreover, further studies indicated that free fatty acids (FFA)-induced lipid accumulation is improved by this class of compounds in normal human hepatocytes (THLE-3), with 10-gingerol being the most effective compound. This study provides a new insight into the mechanism, by which ginger contributes to the improvement of non-alcoholic fatty liver disease (NAFLD) and provide support for the effective use of 10-gingerol for the treatment of NAFLD. [ABSTRACT FROM AUTHOR]

Taking a complex and difficult-to-process iron ore from western Yunnan as the research object, X-ray fluorescence spectroscopy (XRF), chemical multi-element analysis, X-ray diffraction (XRD) and other methods were used to analyze the ore. The results show that the most valuable metal element in the ore is iron, which is mainly present in the form of magnetite. The sulfide minerals primarily include magnetite, pyrite and sphalerite, and the gangue minerals mainly include serpentine and talc. Based on the ore properties of the mine, a combined beneficiation process involving stage grinding and separation, magnetic separation, and flotation desulfurization was adopted to process the iron ore. By studying the effect of process parameters such as magnetic field strength, grinding fineness, types of activators, collectors and foaming agents on the quality improvement of iron ore by magnetic separation and flotation desulfurization, the optimal process parameters were obtained and closed-circuit tests were carried out according to the obtained best process conditions. Finally, a sulfur concentrate with an S grade of 21.90% and an S recovery rate of 68.52%, as well as an iron concentrate with a TFe grade of 61.56%, a TFe recovery rate of 67. 41%, and an S content of 0.67%, were obtained. The results could provide support for the efficient utilization of the iron ore resources. [ABSTRACT FROM AUTHOR]

Magnetic ion-imprinted polymers (MIIPs) are an innovative material that combines the selectivity of ion imprinting with the ease of separation provided by magnetic properties. Recent advancements in MIIPs have shown that they have higher selectivity coefficients compared to non-imprinted materials. The synthesis of MIIPs involves creating specific recognition sites for target ions in magnetic nanomaterials. Various nanomaterials, such as graphene oxide, carbon nanotubes, and silica, have been incorporated into the IIPs to improve their analytical performance for different environmental applications, including metal extraction, monitoring, detection, and quantification. This review stresses the need to develop new monomers with a high affinity for the target analyte and to find supporting materials with groups that facilitate the effective removal of the target analyte. It also explores the influence of experimental parameters on metal determination. [ABSTRACT FROM AUTHOR]

Magnetic hysteresis measurements are routinely made in the Earth and planetary sciences to identify geologically meaningful magnetic recorders, and to study variations in present and past environments. Interpreting magnetic hysteresis data in terms of domain state and paleomagnetic stability are major motivations behind undertaking these measurements, but the interpretations remain fraught with challenges and ambiguities. To shed new light on these ambiguities, we have undertaken a systematic micromagnetic study to quantify the magnetic hysteresis behavior of room‐temperature magnetite as a function of particle size (45–195 nm; equivalent spherical volume diameter) and shape (oblate, prolate and equant); our models span uniformly magnetized single domain (SD) to non‐uniformly magnetized single vortex (SV) states. Within our models the reduced magnetization associated with SV particles marks a clear boundary between SD (≥0.5) and SV (<0.5) magnetite. We further identify particle sizes and shapes with unexpectedly low coercivity and coercivity of remanence. These low coercivity regions correspond to magnetite particles that typically have multiple possible magnetic domain state configurations, which have been previously linked to a zone of unstable magnetic recorders. Of all the hysteresis parameters investigated, transient hysteresis is most sensitive to particles that exhibit such domain state multiplicity. When experimental transient hysteresis is compared to paleointensity behavior, we show that increasing transience corresponds to more curved Arai plots and less accurate paleointensity results. We therefore strongly suggest that transient behavior should be more routinely measured during rock magnetic investigations. Plain Language Summary: Characterizing the magnetic properties and behavior of natural materials in the Earth and planetary sciences is key to identifying reliable magnetic recorders and variations in the environment. One standard method for achieving this is through room‐temperature measurements of magnetic hysteresis. However, the interpretation of magnetic hysteresis data remains one of the most challenging aspects of rock magnetism. To improve our understanding of magnetic hysteresis data, we have systematically investigated how the hysteresis properties of distributions of randomly oriented magnetite change as a function of particle size and shape and how this can help us quantify the contents of natural materials and identify rocks that may give unreliable magnetic signals. We model prolate, oblate and equant magnetite particles in the size range 45–195 nm. We show that magnetic hysteresis defines a clear boundary between simple uniform magnetic structures and more complex non‐uniform magnetic structures. We also identify the sizes and morphologies of magnetic particles that are likely to have unstable remanent magnetizations. These unstable particles are associated with distinctive hysteresis behavior, suggesting that hysteresis data can be used to identify rock samples dominated by such behavior. Key Points: Magnetic hysteresis is micromagnetically modeled for oblate, prolate and equant magnetite particles (45–195 nm)Hysteresis loop shape is highly dependent on particle size/shape due to complex switching behavior of single vortex statesTransient magnetic hysteresis is a powerful tool for identifying stable remanent magnetizations but is currently infrequently reported [ABSTRACT FROM AUTHOR]

This study presents LHRH conjugated drug delivery via a magnetite nanoparticle-modified microporous Poly-Di-Methyl-Siloxane (PDMS) system for the targeted suppression of triple-negative breast cancer cells. First, the MNP-modified PDMS devices are fabricated before loading with targeted and untargeted cancer drugs. The release kinetics from the devices are then studied before fitting the results to the Korsmeyer–Peppas model. Cell viability and cytotoxicity assessments are then presented using results from the Alamar blue assay. Apoptosis induction is then elucidated using flow cytometry. The in vitro drug release studies demonstrated a sustained and controlled release of unconjugated drugs (Prodigiosin and paclitaxel) and conjugated drugs [LHRH conjugated paclitaxel (PTX+LHRH) and LHRH-conjugated prodigiosin (PG+LHRH)] from the magnetite nanoparticle modified microporous PDMS devices for 30 days at 37 °C, 41 °C, and 44 °C. At 24, 48, 72, and 96 h, the groups loaded with conjugated drugs (PG+LHRH and PTX+LHRH) had a significantly higher (p < 0.05) percentage cell growth inhibition than the groups loaded with unconjugated drugs (PG and PTX). Additionally, throughout the study, the MNP+PDMS (without drug) group exhibited a steady rise in the percentage of cell growth inhibition. The flow cytometry results revealed a high incidence of early and late-stage apoptosis. The implications of the results are discussed for the development of biomedical devices for the localized and targeted release of cancer drugs that can prevent cancer recurrence following tumor resection. [ABSTRACT FROM AUTHOR]

Magnetic colloidal nanocrystalline clusters (MCNCs) exhibit a color‐changing response to a magnetic field due to their tunable assembly into photonic crystals demonstrating visible light diffraction. The use of this response to obtain a magnetically sensitive color micropattern on the surface of a solid substrate requires appropriate scalable technologies for deposition of MCNCs. Here, inkjet printing of MCNCs onto the surface of a solid substrate coated with uncured polydimethylsiloxane is addressed and demonstrate their capability to form desired patterns with structural colors from blue to red controlled by external magnetic field. The results, thereby, pave the way to semi‐commercial manufacture an anticounterfeiting imaging at a large scale. [ABSTRACT FROM AUTHOR]

Inkjet printing of magnetic materials has increased in recent years, as it has the potential to improve research in smart, functional materials. Magnetostriction is an inherent property of magnetic materials which allows strain or magnetic fields to be detected. This makes it very attractive for sensors in the area of structural health monitoring by detecting internal strains in carbon fibre-reinforced polymer (CFRP) composite. Inkjet printing offers design flexibility for these sensors to influence the magnetic response to the strain. This allows the sensor to be tailored to suit the location of defects in the CFRP. This research has looked into the viability of printable soft magnetic materials for structural health monitoring (SHM) of CFRP. Magnetite and nickel ink dispersions were selected to print using the JetLab 4 drop-on-demand technique. The printability of both inks was tested by selecting substrate, viscosity and solvent evaporation. Clogging was found to be an issue for both ink dispersions. Sonicating and adjusting the jetting parameters helped in distributing the nanoparticles. We found that magnetite nanoparticles were ideal as a sensor as there is more than double increase in saturation magnetisation by 49 Am2/kg and more than quadruple reduction of coercive field of 5.34 kA/m than nickel. The coil design was found to be the most sensitive to the field as a function of strain, where the gradient was around 80% higher than other sensor designs. Additive layering of 10, 20 and 30 layers of a magnetite square patch was investigated, and it was found that the 20-layered magnetite print had an improved field response to strain while maintaining excellent print resolution. SHM of CFRP was performed by inducing a strain via bending and it was found that the magnetite coil detected a change in field as the strain was applied. [ABSTRACT FROM AUTHOR]

Iron oxide nanoparticles were synthesized by co-precipitation using three different iron salt stoichiometric mole ratios. Powder X-ray diffraction patterns revealed the inverse cubic spinel structure of magnetite iron oxide. Transmission electron microscopic images showed Fe3O4 nanoparticles with different shapes and average particle sizes of 5.48 nm for Fe3O4-1:2, 6.02 nm for Fe3O4-1.5:2, and 6.98 nm for Fe3O4-2:3 with an energy bandgap of 3.27 to 3.53 eV. The as-prepared Fe3O4 nanoparticles were used as photocatalysts to degrade brilliant green (BG), rhodamine B (RhB), indigo carmine (IC), and methyl red (MR) under visible light irradiation. The photocatalytic degradation efficiency of 80.4% was obtained from Fe3O4-1:2 for brilliant green, 61.5% from Fe3O4-1.5:2 for rhodamine B, and 77.9% and 73.9% from Fe3O4-2:3 for both indigo carmine and methyl red. This indicates that Fe3O4-2:3 is more efficient in the degradation of more than one dye. This study shows that brilliant green degrades most effectively at pH 9, rhodamine B degrades best at pH 6.5, and indigo carmine and methyl red degrade most efficiently at pH 3. Recyclability experiments showed that the Fe3O4 photocatalysts can be recycled four times and are photostable. [ABSTRACT FROM AUTHOR]

The increasing application of nuclear technology in medical fields has amplified the demand for radiation shielding materials. Traditional large-volume concrete cannot simultaneously exhibit excellent neutron and gamma-ray shielding capabilities while ensuring superior mechanical properties. This study tailored a novel lead fiber-reinforced high-performance concrete (LFRHPC) with lead fibers and magnetite aggregates, focusing on radiation attenuation. The effect of lead fibers on the mechanical performance, microstructure and radiation attenuation characteristics for LFRHPC was comprehensively evaluated. The results indicate a significant improvement in the mechanical performance of LFRHPC compared to traditional radiation shielding concrete (RSC), due to the scientific skeleton design. Additionally, the pore structure in LFRHPC is refined by incorporating lead fibers. Moreover, the interfacial transition zone (ITZ) between the cementitious matrix and magnetite is improved because of the very low water-to-binder ratio. To assess the radiation attenuation ability of LFRHPC, both direct measurements and simulation models were utilized. The data reveals that the porosity of LFRHPC plays a crucial role in its shielding effectiveness against neutron and gamma radiation. Furthermore, the addition of lead fibers considerably boosts its neutron and gamma-ray shielding attenuation capabilities. In summation, LFRHPC combines excellent mechanical properties and radiation shielding capabilities, making it suitable for construction applications in medical settings. [ABSTRACT FROM AUTHOR]

2D magnetic materials hold substantial promise in information storage and neuromorphic device applications. However, achieving a 2D material with high Curie temperature (TC), environmental stability, and multi‐level magnetic states remains a challenge. This is particularly relevant for spintronic devices, which require multi‐level resistance states to enhance memory density and fulfil low power consumption and multi‐functionality. Here, the synthesis of 2D non‐layered triangular and hexagonal magnetite (Fe3O4) nanosheets are proposed with high TC and environmental stability, and demonstrate that the ultrathin triangular nanosheets show broad antiphase boundaries (bAPBs) and sharp antiphase boundaries (sAPBs), which induce multiple spin precession modes and multi‐level resistance. Conversely, the hexagonal nanosheets display slip bands with sAPBs associated with pinning effects, resulting in magnetic‐field‐driven spin texture reversal reminiscent of "0" and "1" switching signals. In support of the micromagnetic simulation, direct explanation is offer to the variation in multi‐level resistance under a microwave field, which is ascribed to the multi‐spin texture magnetization structure and the randomly distributed APBs within the material. These novel 2D magnetite nanosheets with unique spin textures and spin dynamics provide an exciting platform for constructing real multi‐level storage devices catering to emerging information storage and neuromorphic computing requirements. [ABSTRACT FROM AUTHOR]

The study analyzes the black color factors of black-burnished pottery excavated from the Pungnap Fortress and the Seokchon Tomb during the Hanseong period of the Baekje Kingdom. The current hypothesis surrounding the pottery's black color factors suggests the use of magnetite, manganese oxide, and carbon. To compare the results of the black pottery, red pottery was used as the control group. To identify these black color factors, each hypothesis was investigated using several spectroscopic techniques. However, it was difficult to detect sufficient magnetite and manganese oxide on the surface of the black pottery to account for its black color. In contrast, a larger amount of carbon was located on the surface and core of the black pottery compared to the red pottery. These results indicate that the black factors can be credibly attributed to carbon rather than to magnetite or manganese oxide. The firing temperature of the black-burnished pottery was estimated from the mineral composition based on X-ray diffraction, and the firing atmosphere was deduced from the redox conditions based on the reduction index from Mössbauer spectroscopy. In addition, seven pieces of pottery excavated from Gunsu-ri Temple Site and Buyeo Ancient Tomb from the Sabi period of Baekje were investigated and compared the five pieces of pottery from the Hanseong period. Although the results were based on a limited number of potteries, various firing temperatures and redox atmosphere for pottery from the Hanseong and Sabi periods were carefully proposed. [ABSTRACT FROM AUTHOR]

Emerging as a revolutionary strategy to fabricate dynamic three dimesional (3D) structures, 4D printing (4DP) mainly refers to printed materials capable of changing form over time when exposed to a predetermined stimulus. Nevertheless, the 4D concept can be extended beyond shape‐morphing, by including also changes in the properties and/or functionalities of printed materials over time. To this end, this work explores the 4DP of multifunctional nanocomposites that can adapt to different application scenarios exploiting the stimuli‐activable properties of two functional nanofillers embedded into the polymeric matrix. In particular, a photocurable system loaded with both Fe3O4 nanoparticles (NPs) and AgNO3, as precursors for the in situ photo‐induced generation of Ag NPs, is used for the digital light processing of magnetic nanocomposites with integrated electrical and antibacterial functions. The composition of formulations is designed to both optimize their printability and maximize the magneto‐responsiveness and the electrical conductivity and/or antibacterial activity of the printed objects, given by Fe3O4 and Ag NPs, respectively. Finally, it is shown that the functional responses of the nanocomposites can be activated individually or in combination, which may be of particular interest for the fabrication of smart multifunctional devices with potential applications ranging from soft electronics to biomedicine. [ABSTRACT FROM AUTHOR]

AbstractThe synthesis of composites comprising chitosan (CS) and magnetite using the co-precipitation method yielded a compound denoted as CS/Fe3O4, which demonstrated magnetic properties. FTIR analysis confirmed the presence of magnetite nanoparticles within the composite. This CS/Fe3O4 composite proved to be highly efficient in adsorbing tetracycline (TC) from solutions of tetracycline hydrochloride (HTCCl), achieving an adsorption efficiency exceeding 65%. Moreover, the composite maintained its adsorption capacity over five cycles of sorption-desorption, indicating its robustness and reusability. The Langmuir isotherm provided a suitable description of the liquid-solid equilibrium of TC at 25 °C and 35 °C. Thermodynamic analysis revealed interesting insights into the nature of TC adsorption on CS. At low concentrations, the adsorption process was found to be exothermic, while at very high concentrations, it became endothermic. This observation suggests that the adsorption of TC at low concentrations is governed by protonation of chitosan and, at high concentrations, by entropic factors, highlighting the importance of considering thermodynamic parameters in understanding the adsorption mechanism. Overall, these findings contribute to the development of efficient and cost-effective adsorbents for the removal of TC from aqueous solutions. [ABSTRACT FROM AUTHOR]

The utilization of hydrogen-based direct reduction methods for magnetite ore smelting is an important way to achieve the goal of reducing carbon emissions. At present, the coupling mechanism of the multi-step reaction during the reduction process is unclear, which restricts the understanding of the rate-limiting steps and the accurate description of kinetic parameters. In this paper, the reaction characteristics and multi-step kinetics of isothermal reduction of magnetite by hydrogen with varying concentrations are investigated at 600–900 °C. Results indicate that the coupling relationship between Fe 3 O 4 →FeO and FeO→Fe two steps is temperature-dependent. In the low-temperature range (600–700 °C), the coupling relationship between the two steps can be described by the parallel model. In the high-temperature range (750–900 °C), the coupling relationship can be described by the series model. Meanwhile, the first-step reaction Fe 3 O 4 →FeO is controlled by the nucleation or chemical reaction model, and the apparent activation energies are determined to range from 27.25 to 48.59 kJ/mol. The second-step reaction FeO→Fe is controlled by the combination of nucleation and diffusion models, and the apparent activation energies are determined to range from 30.70 to 45.14 kJ/mol. • Multistep kinetics of isothermal reduction of magnetite by hydrogen are studied by TGA. • The coupling relationship of two-step reduction is found to be temperature-dependent. • The parallel model and series model are used to decouple the two-step reactions in two temperature ranges respectively. • The relationship between activation energy and hydrogen concentration is obtained. [ABSTRACT FROM AUTHOR]

Magnetite (Fe3O4) particles deposited with zeolite, which was made from sodium hydroxide (NaOH), sodium aluminate (NaAlO2) and sodium trisilicate (Na2O7Si3) using the hydrothermal process, were used in the adsorption of methylene blue (MB). A continuous stirred tank reactor (CSTR) system was used for the adsorption of MB using zeolite/Fe3O4. This study encircled the continuous reactor with a magnet to prevent the adsorbent from flowing to the output, thus producing clean water devoid of Fe3O4 particles. The performance of the adsorbent was assessed based on the effects of adsorbent mass, flow rate, pH and concentration. The adsorbent was able to remove approximately 90% of the 20 mg L−1 methylene blue from a 500 mL solution in 2 h, with a maximum adsorption capacity of 30.8528 mg g−1. This adsorption process also exhibited high removal efficiency even after 5 regeneration cycles and 55 h of operation, confirming the successful production of zeolite/Fe3O4 as an effective MB adsorbent. [ABSTRACT FROM AUTHOR]

Carbonate rocks, widely used for quantifying paleolatitude of the Gondwana‐derived terranes on the Tibetan Plateau and the geodynamic evolution of the Tethyan Oceans, are prone to remagnetization. However, diagnosing such secondary remanent magnetization is difficult and the mistakes have induced confusion in paleogeographic reconstructions. To evaluate if the Upper Triassic limestones of the Duoburi Formation from the Lhasa terrane carry a primary remanence, we report comprehensive rock magnetic, diffuse reflectance spectroscopic, and petrographic results of these rocks. We discover that magnetic carriers vary systematically from magnetite to magnetite plus minor hematite/goethite to hematite/goethite plus minor magnetite with change of rock color and demagnetization behavior of the specimens. Most magnetite and all hematite/goethite grains have clear authigenic origin and were possibly formed during oxidation of early diagenetic pyrite. Such a process was likely assisted by oxic fluid circulation as shown by omnipresent calcite veins within the rocks. These authigenic iron oxides have widely distributed grain sizes with most of them being superparamagnetic at room temperature. Detrital (titano)magnetite is also recognized in some specimens, but its concentration is much lower than that of the authigenic magnetic grains. Based on these results, we conclude that limestone from the Duoburi Formation was remagnetized due to fluid circulation during late diagenesis. We discuss criteria used for diagnosing remagnetization in carbonate rocks, and suggest that a robust evaluation of the remanence origin should integrate field tests, statistics of the remanence direction, rock magnetic properties, and petrographic observations with the limits of each criterion being carefully considered. Plain Language Summary: The Lhasa terrane from the central Tibetan Plateau was one of the continental blocks that rifted from the Gondwana supercontinent, drifted northward, and accreted to Eurasia in the Mesozoic. Paleolatitude determined by paleomagnetism can provide quantitative information which is critical to restore these geodynamic processes. However, paleomagnetic investigations on the ancient carbonate rocks on the Tibetan Plateau are often troubled by remagnetization, a process during which the primary remanent magnetization acquired during or soon after formation of the rocks was replaced by secondary remanent magnetization with an unknown younger age. In this study, we provide an example of Upper Triassic limestones from the Lhasa terrane. Within these rocks, detrital (titano)magnetite, which can carry a primary magnetic signal, was mostly altered, and nonmagnetic pyrite largely transformed to authigenic magnetite/hematite/goethite, which acquired remanent magnetization at an unknown later time. The magnetic record from these rocks thus cannot be used to determine the Late Triassic paleolatitude of the Lhasa terrane. Our analysis reveals the most common mechanisms of remagnetization in carbonate rocks. More importantly, we provide universal tools and criteria that can be used in future paleomagnetic studies of carbonate rocks to evaluate their remanence origin. Key Points: Magnetic carriers of the Duoburi Formation limestone are authigenic magnetite, hematite and goethite and little detrital titanomagnetiteLimestones of the Duoburi Formation were remagnetized due to circulation of oxic fluid through the rock at a late stageDiagnosis of remagnetization in carbonate rocks should integrate different criteria but consider the limits of each criterion carefully [ABSTRACT FROM AUTHOR]

The Rogaland Igneous Complex (RIC) in southern Norway intruded into Sveconorwegian granulite crust beginning ∼930 Ma. Three massif anorthosite bodies, Egersund–Ogna, Helleren and Åna-Sira, were intruded some 10 Myr later by the Bjerkreim–Sokndal layered intrusion. The Garsaknatt leuconorite and the ilmenite-rich Tellnes norite, one of the youngest rock in the complex at ∼920 Ma, intrude the anorthosite or nearby country rock. Magnetic mineralogy and palaeomagnetic studies carried out on the Tellnes norite, the Garsaknatt leuconorite and the surrounding Åna-Sira anorthosite, indicate the magnetization of all three bodies are dominated by hemo-ilmenite carrying the remanence as a thermochemical remanent magnetization, although magnetite is present in some samples. The three bodies yield steep negative inclinations with northwesterly declinations (Tellnes, I = −71.9°, D  = 305.0°, α95 = 10.6°; Garsaknatt, I = −73.1°, D  = 312.7°, α95 = 4.7°; and Åna-Sira, I = −81.2°, D  = 326.3°, α95 = 6.7°). When combined with data from other bodies in the RIC, the older anorthosites have steeper inclinations, and higher palaeolatitudes, while the younger units have less steep inclinations and shallower palaeolatitudes by nearly 10°, indicating northward plate motion during cooling of the intrusions. Age of the remanence is difficult to determine precisely, however, best estimates are ∼910 Ma for the older anorthosites and ∼900 Ma for the younger intrusions. Although these differences are significant, a unified pole position (35.6° N, 215.1° E), combining all the 111 sites from the RIC, strongly supports the assumed position of southern Baltica in Rodinia at ∼900 MA. [ABSTRACT FROM AUTHOR]

Heavy oil spills from stranded oil tankers are a global problem. The recovery of spilled oil must have a low environmental impact and must be capable of processing large quantities at high speeds. In this study, we investigated the application of magnetic separation for the recovery of spilled oil. Pickering emulsions were formed by heavy oil and magnetite, and recovery was carried out using a drum‐type permanent magnet. Pickering emulsions were successfully formed by stirring heavy oil A and magnetite, and magnetic separation experiments showed that up to 90% of the heavy oil A could be recovered. To recycle magnetite, a small amount of heavy oil was added to the recovered Pickering emulsions, and then a strong magnetic field of a superconducting bulk magnet was applied, which resulted in easy solid–liquid separation. The possibility of recycling magnetite after separation was also demonstrated. Finally, a small‐scale system using drum‐type permanent magnets was developed, and magnetic separation experiments were performed. The results showed that approximately 77% of the heavy oil A could be recovered. Particle trajectory simulations also demonstrated the recoverability of heavy oil at the sea surface. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In the dense-medium coal preparation process magnetite powder is used, however, due to poor recovery of the magnetite, the consumption of magnetite increases which ultimately reflects in the economics. In order to continuously and efficiently recover the magnetite, a novel three-phase conical magnetic separator based on the principle of an alternating magnetic field generated by a three-phase linear motor, was developed. The distribution law of the magnetic field in the separation chamber was studied, and the magnetic separator's basic structure and parameters were determined. By varying the feed rate, coil current, coil turns, and particle size, magnetic separation experiments were conducted and compared with traditional magnetic separators. The results confirmed the excellent sorting performance of the conical AC magnetic separator. [ABSTRACT FROM AUTHOR]