Flux Composition Research Articles

We present new results of the coccolith fluxes in the Perdido and Coatzacoalcos areas of the Gulf of Mexico (GoM) and explore the environmental variables that may control them. The deep-water region of the GoM is known for its oligotrophic, nutrient-limited surface waters, which are relatively isolated from eutrophic waters near the coast; however, it is seasonally affected by nutrient-rich plumes of coastal waters that increase export production. Two sediment trap moorings located at a water depth of 1100 m collected settling particles from June 2016 to July 2017. The Perdido trap collected 47 species of coccoliths, and the Coatzacoalcos trap 56 species throughout the study period. Total coccolith fluxes showed a seasonal response in both trap locations, with lower fluxes during spring and summer, associated with highly stratified water column conditions that were evident in the Coatzacoalcos trap, and higher fluxes during late autumn and winter, associated with deepening mixed layer in response to cooling and to the strong “Nortes” winds. The Perdido trap showed higher total coccolith fluxes with an annual average of 3.1 x 109 ± 0.9 x 109 coccoliths per m-2d-1, than the Coatzacoalcos trap of 1.9 x 109 ± 1.1 x 109 coccoliths m-2d-1. The upper photic zone (mainly, Emiliania huxleyi and Gephyrocapsa oceanica) showed high fluxes throughout the study period in both traps, reflecting the coastal shelf influence. Overall, three species dominated the composition of the coccolith fluxes in both areas: E. huxleyi, G. oceanica, and Florisphaera profunda, reaching 88% in the Perdido and 84% in the Coatzacoalcos trap. These results suggest that the coccolith export production in the Perdido and Coatzacoalcos traps is strongly influenced by the cooling and deepening of the mixed layer depth during autumn and winter, as well as advection processes between the continental shelf and the offshore region, and multifactorial processes such as loop current mesoscale eddies that affect the GoM.

High-temperature sintering for ceramsite preparation is a safe and effective approach to recycle solid waste. Flux components are critical in ceramsite sintering, as they can reduce sintering temperature, modulate the viscosity and content of the liquid phase, and ultimately optimize ceramsite performance. However, existing studies on lead–zinc tailings (LZTs) and coal gangue (CG)-based ceramsite lack systematic exploration of key fluxes (Na2O, MgO, CaO, Fe2O3), limiting the high-value utilization of these wastes. Under fixed sintering conditions (preheating at 400 °C for 30 min, sintering at 1250 °C for 30 min, heating rate of 10 °C/min), this work systematically investigated the effects of these fluxes (in the forms of carbonates, except for Fe2O3) on LZTs-CG ceramsite. The mechanical properties, mineral composition, microstructure and heavy metal leaching of samples were analyzed using various methods, including uniaxial compression, X-ray diffraction (XRD), scanning electron microscopy (SEM), and inductively coupled plasma optical emission spectrometry (ICP-OES). Results showed that, while Fe2O3 exerted a non-monotonic influence, Na2O, MgO, and CaO improved apparent density and compressive strength, concurrently reducing water absorption, with these effects enhancing in a dose-dependent manner. Na2O, MgO and Fe2O3 facilitated the formation of labradorite, cordierite and hematite, respectively. All fluxes weakened the diffraction peaks of quartz and mullite. ICP-OES results indicated that the fluxes slightly increased Pb and Zn leaching, yet the highest values (0.1975 mg/L for Pb, 0.0485 mg/L for Zn) were well below the limits specified in the Chinese national standard GB 5086.2-1997 (Leaching Toxicity of Solid Waste—Horizontal Vibration Extraction Procedure). This work shows optimized flux composition enables high-performance, eco-safe LZTs-CG ceramsite, supporting LZTs and CG high-value utilization and sustainable development.

The influence of the granulometric composition of ferroalloy components in the core of metal-cored wire (MCW) on the stability of the arc surfacing process, MCW melting characteristics, deposition quality, microstructural features, and properties of the multi­layer deposited metal was investigated. The MCW core contained an identical mixture of ferroalloy components designed to produce deposited metal of the 50Kh2N2MFS type. The difference between the studied CWs consisted in the granulometric composition of their core: 50…300 μm for the reference MCW and 50…100 μm for the experimental MCW. The feasibility of using ferroalloy compositions with a minimal particle size distribution (50…100 μm) in the MCW core for arc surfacing was demonstrated, as it improved MCW melting characteristics, process stability, and deposition quality, which in turn positively affected the structure and properties of the deposited metal.

Single-crystal LiNiO2 (LNO) is a promising cathode material for lithium-ion batteries due to its high capacity and enhanced structural stability, attributed to the absence of grain boundaries. However, its high-temperature synthesis often induces undesired cation mixing. In this study, a minimal-flux solid-state synthesis approach was employed to control the structure and electrochemical behavior of single-crystal LNO using small amounts (0.05 mol) of various flux additives (KOH, NaOH, LiCl, LiNO3, KI). Among them, LiNO3 yielded the best overall performance, with reduced cation mixing, stable lattice structure, and superior cycling stability—without requiring post-synthesis washing.</br>The effect of deionized water washing was also examined. Although washing typically removes residual flux, its impact varied depending on the flux type. KOH-washed samples showed improved layer ordering and higher initial capacity, whereas NaOH and LiCl led to degraded surface structure or lower performance. Notably, all washed samples exhibited extra side reactions during the initial charge, indicating that washing could introduce surface chemical heterogeneity.</br>These findings highlight the coupled effects of flux composition and washing process on the structural and electrochemical properties of LNO. Careful optimization of both factors is essential for developing high-performance single-crystal cathodes.

Abstract The composition and flux of mineral dust are largely driven by the entrainment and transport of sediment from both natural and human sources, resulting in varying ecological impacts at the deposition site. To investigate the influence of natural and human sources of dust in montane environments, we measured dust composition and deposition rate on San Jacinto Peak in Southern California from 2019 to 2022 at six sites spanning 2,462 m in elevation and 20 km in distance. We find unique interannual variations in fine dust (0.2–30 μm) flux and chemical composition between sites. The greatest average dust flux occurs during July–November (0.14–3.50 g m−2 y−1), followed by March–July (0.24–4.07 g m−2 y−1) and is lowest during November–March (0.29–2.76 g m−2 y−1). Wildfires led to significant increases in dust flux, with the highest dust flux occurring at the lowest elevation site following the 2020 Snow Creek fire. Greater enrichment of metals and depletion of rare earth elements at higher relative to lower elevations indicate spatial and temporal variability in dust sources, consistent with variations in natural and anthropogenic inputs. Positive matrix factorization (PMF) indicates that high elevation sites on average receive a higher proportion of anthropogenic dust input (64%–75%), whereas low‐elevation sites receive a higher proportion of alluvium and local rock inputs (35%–63%), particularly on the north side of the mountain. This study highlights the complexity of interannual dust deposition in mountain environments and the modulation of dust flux and composition by anthropogenic activity and wildfire.

ABSTRACT It is anticipated that mass accretion rates exceeding approximately $10^{19}\, {\rm g\, s^{-1}}$ in X-ray pulsars lead to radiation-driven outflows from supercritical accretion discs. The outflows launched from the disc influence the angular distribution of X-ray radiation, resulting in geometrical beaming. The beaming, in turn, impacts the apparent luminosity of the X-ray pulsar, detectability of pulsations, and the spectral composition of the X-ray flux. We employ a straightforward geometrical model of the outflows, perform Monte Carlo simulations, and model the spectra of radiation, reprocessed by the walls of the accretion cavity formed by the outflows. We consider the reprocessed emission only; direct pulsar emission is not included in our modelling. Our results demonstrate that the spectra of reprocessed radiation depend on the actual luminosity of the central engine, the geometry of the outflows, and the viewing angle – most notably on the latter, through changing visibility of the hotter wall regions near the disc plane. The high-energy part of the reprocessed spectrum depends strongly on viewing angle (harder at lower inclinations), while the soft flux varies comparatively little with inclination. In our model, this contrast is a prediction: variable ultraluminous X-ray sources are expected to exhibit strong high-energy angle sensitivity together with comparatively modest soft-band variation, naturally arising if precession modulates the effective inclination.

To meet the demanding requirements of continuous casting for low-alloy peritectic steel, this study aimed to design high-performance mold fluxes with optimized properties. The melting properties, crystallization behavior, mineralogical characteristics, and heat transfer mechanism of the industrial mold fluxes and flux films were investigated by melting tester, viscometer, in situ thermal analyzer, thermal conductivity meter, polarizing microscope, X-ray diffraction, and thermodynamic software. The results demonstrate that mold fluxes suitable for low-alloy peritectic steel possess a narrow melting temperature range, low melting point (<1200 °C), and low viscosity (<0.1 Pa·s) to ensure adequate fluidity and lubrication. A key characteristic of the mold fluxes is strong crystallization ability, reflected by a high critical crystallization cooling rate (>50 °C/s) and high initial crystallization temperature (>1350 °C), facilitating the rapid formation of a stable crystalline layer and uniform heat transfer. The flux films with outstanding characteristics have a multilayered structure and high crystallization ratio (60–80 vol%), predominantly comprising a high fraction of coarsened cuspidine crystals. Further analysis of the heat transfer mechanism reveals that the highly crystalline and coarse-grained microstructure promotes the formation of micropores and crystal boundaries in flux films, which substantially increase thermal resistance, leading to low thermal conductivity (0.47–0.67 W/m·K) and effective control of heat transfer rate. It is concluded that enhancing crystallization performance through optimizing flux composition (boosting Na2O content and basicity) to promote cuspidine formation and tailor crystallinity, is the crucial route for acquiring the desired mineralogical structure of flux films and enabling efficient continuous casting of low-alloy peritectic steel.

Abstract Volatile organic compounds (VOCs) are key atmospheric species influencing oxidative capacity and secondary organic aerosol formation. Oceans emit a variety of VOCs via complex biological, chemical, and physical processes. Although dimethyl sulfide (DMS) is a known precursor in marine aerosol formation, marine emissions of organic gases are more diverse. Here, we quantify semi‐controlled sea‐to‐air net fluxes of isoprene (0.50 ± 0.30 ng m−2 s−1), monoterpenes (0.93 ± 0.73 ng m−2 s−1), and oxygenated organics (methanol: 2.50 ± 1.13 ng m−2 s−1) using in situ mesocosm studies of natural seawaters in the south‐west Pacific Ocean. Under wind speeds &lt;3 m s−1, flux compositions varied between Frontal, Subtropical, and Subantarctic seawaters, with several VOCs exhibiting fluxes comparable to or exceeding DMS (0.75 ± 0.86 ng m−2 s−1). Significant associations were observed among biogenic VOC fluxes and phytoplankton groups, notably with nanophytoplankton. The impact of atmospheric ozone changes was tested by introducing additional ozone into one mesocosm, which increased methanol emissions while decreasing monoterpene and acetaldehyde fluxes, making the ocean a sink for the latter. Such studies provide quantitative links between natural phytoplankton assemblages and emissions of climatically relevant marine VOCs, offering the potential to use satellite oceanographic data to improve the representation of these emissions in chemistry‐climate models.

Compared to traditional TIG welding, which is utilized to increase the weld’s quality and penetration depth, flux-bonded tungsten inert gas welding offers many benefits. These tests investigate how various fluxes, such as zinc oxide (ZnO), manganese oxide (MnO2), and titanium dioxide (TiO2), affect the welding properties of SS 304 stainless steel. Arc voltage, current, travel speed, and shielding gas flow rate were all kept constant during the controlled tests, which involved varying the flux composition, the distance between the flux layer, and the flux thickness. With a balanced aspect ratio (∼0.70), the results demonstrate that TiO2 had the maximum penetration (6.0 mm), surpassing MnO2 by 1.69% and surpassing ZnO by 75%. The best weld shape is indicated by MnO2, which has the largest aspect ratio (∼0.72) and moderate penetration (5.9 mm). ZnO produced the widest bead and greatly reduced penetration (up to 57.2% less than TiO2), which decreased the aspect ratio (∼0.35–0.40). Microhardness results indicate that flux composition has a significant influence on mechanical properties. TiO2 and MnO2 fluxes improved microhardness, enhancing their suitability for FB-TIG welding applications. In contrast, ZnO demonstrates comparatively lower effectiveness in hardness enhancement.

Abstract A new method of non-electric welding based on self-propagating high-temperature synthesis (SHS) technology for reliable and efficient connection of cable breakage has been proposed. The principle of wire SHS welding has been elucidated, the composition of the welding flux has been optimized, and the welding mould and special fixture have been designed. Welding tests have been carried out, and the performance has been studied. It was shown that the broken wire could be welded reliably and efficiently by SHS welding. The appearance of the joint was perfect, and there were no inclusions, pores, cracks, pits, or other obvious defects in it. Micromorphology analysis suggested that the matrix of the joint metal was an α-copper solid solution with granular iron-rich second phase dispersedly on it. Performance tests found that the tensile strength of SHS welded wire was above 280 N/mm2, the average Vickers hardness of the weld joint was 206, the average impact toughness was 33.3 J/cm2, and the average resistivity was about 1.58×10−7 Ω·m, which meets the emergency maintenance needs. Research showed that SHS welding does not require external energy and complex equipment, it is simple to operate and easy to carry, and the joint has favourable performance; the broken wire could be welded reliably and efficiently. It is an ideal method for cable maintenance in an emergency.

High cost of aqua-feed production translates to low profitability and high cost of production of fish. There is need to utilize low cost agro-wastes feed ingredients in aqua-feed production. Palm kernel cake (PKC) and brewers' spent grain (BSG), are plausible proteinous fishmeal alternatives and agro-industrial feed ingredients. However PKC and BSG contain high fiber and anti-nutritional factors (ANFs) that limit their usage and fed ingredient value. Solid state fermentation can remove this ANFs, degrade high fibers and elevate the protein and amino acid contents of PKC and BSG. The species, Saccharomyces cerevisiae was used in the fermentation of PKC and BSG. Thereafter, the fermented feed stuff were incorporated at varying levels: Feed 1 (40:0), Feed 2 (30:10), Feed 3 (20:20), Feed 4 (10:30) and Feed 5 (0:40) for PKC : BSG respectively to formulated the different experimental diets. The formulated diets were then analyzed for proximate and amino acid compositions following standard procedure. Results showed that fermentation processes reduced fiber content of PKC and BSG from 21.78±0.01% to 12.54±0.01% and from 26.75±0.07% to 18.74±0.01% respectively while increasing protein content of PKC and BSG from 19.24±0.01% to 22.89±0.01% and from 23.84±0.71% to 26.32±0.03% respectively. This may indicate that solid state fermentation can significantly improve the nutritional profile of PKC and BSG. Solid state fermentation enhanced the essential amino acid profile, with notable increases in amino acid contents.

Neutrino propagation in the Galactic and extragalactic magnetic fields is considered. We extend an approach developed in [A. Popov and A. Studenikin, Neutrino eigenstates and flavour, spin and spin-flavour oscillations in a constant magnetic field, .] to describe neutrino flavor and spin oscillations using wave packets. The evolution equations for the neutrino wave packets in a uniform and nonuniform magnetic fields are derived. The analytical expressions for neutrino flavor and spin oscillations probabilities accounting for damping due to the wave packet separation are obtained for the case of a uniform magnetic field. It is shown that terms in the flavor oscillations probabilities that depend on the magnetic field strength are characterized by two coherence lengths. One of the coherence lengths coincides with the coherence length for neutrino oscillations in vacuum, while the second one is proportional to the cube of the average neutrino momentum p03. The probabilities of flavor and spin oscillations are calculated numerically for neutrino interacting with the nonuniform Galactic magnetic field. It is shown that oscillations on certain frequencies are suppressed on the Galactic scale due to the neutrino wave packets separation. The flavor compositions of high-energy neutrino flux coming from the Galactic center and ultra-high energy neutrinos from an extragalactic source are calculated accounting for neutrino interaction with the magnetic field and decoherence due to the wave packet separation. It is shown that for neutrino magnetic moments ∼10−13μB and larger these flavor compositions significantly differ from ones predicted by the vacuum neutrino oscillations scenario. Published by the American Physical Society 2025

Tailoring flux composition to control welding fume and hexavalent chromium emissions in flux cored arc welding

Predicting the flavor composition of neutrinos from supernovae is a challenging task, primarily due to the high neutrino densities at their core. In such an environment, neutrino self-interactions give rise to collective effects that have dramatic yet poorly understood consequences for their flavor evolution. In this paper, however, we show that standard matter effects in the outer layers of supernovae can significantly constrain the flavor composition of the neutrino flux. We assume that, since a large number of neutrinos undergo different evolutions within the core, their state upon entering the Mikheyev–Smirnov–Wolfenstein-dominated region is affected by decoherence. This assumption simplifies the problem and suggests that the fraction of neutrinos with electron flavor reaching Earth, denoted as fνe, is constrained to be less than 0.5 for all energies throughout the emission phase in the case of normal mass ordering. In contrast, for inverted mass ordering, we anticipate neutrinos arriving in near flavor equipartition (fνe≈1/3). These predictions, and consequently their underlying assumptions, could be tested by future observations and may provide valuable insights into the properties of neutrino fluxes emerging from supernovae. Published by the American Physical Society 2025

One of the key problems in the billet and shaped casting of aluminum alloys is the presence of various undesirable inclusions and impurities in the melt, which can serve as stress concentrators in the finished product, as well as dissolved hydrogen, which contributes to the formation of porosity. The interaction of aluminum with other gases produced by the combustion of fuel particles, oil, and paint materials brought into the furnace together with charge and scrap increases the amount of nitrides, oxides, carbides, and sulfides in the melt. Flux treatment is widely used as protection of aluminum alloys from oxidation and removal of impurities. The present paper reports the data of a comparative analysis of five widely used flux compositions based on sodium, potassium, and magnesium chlorides. The study covers the following aspects: chemical composition, moisture content, melting temperature and melting range, particle size distribution, and refining ability as measured by the change in Na, Ca, and H2 content after melt treatment.

BaTaO2N (BTON) is a visible-light-responsive photocatalyst used for water splitting. The flux method, which involves the use of a molten salt, is an effective synthetic strategy for achieving a high photocatalytic activity. Fluxes with alkali metal cations strongly affect the photocatalytic activity of the BTON crystals. In particular, RbCl flux-grown BTON exhibits hydrogen evolution activity over several times higher than that grown in other chloride fluxes, such as NaCl, under visible-light irradiation. One factor of this difference is presumably owing to the change in the Ta(O,N)6 octahedral arrangement in the BTON triggered by the doping of alkali metal ions into the crystal lattice. However, the precise Ta(O,N)6 octahedral arrangement remains unclear. Herein, X-ray absorption spectroscopy, structural analysis by neutron diffraction, and computational structural modeling based on comprehensive structural energy predictions were performed for two types of BTONs. The results suggested that the configuration manners of Ta(O,N)6 octahedral units strongly depend on the flux composition. Specifically, in NaCl-flux-grown BTON crystals, the number of N20 cis planes parallel to the (100), (010), and (001) crystal planes in a TaO4N2 unit is anisotropic, resulting in differences in their electron-hole conduction characteristics. The findings indicate that in addition to lattice defects, the interconnections of mixed-anion units such as Ta(O,N)6 should be taken into account to improve the photocatalytic activity of BTONs and develop other mixed-anion compounds.

This research explores the effects of different plate thicknesses on the three-dimensional temperature distribution modeling in Butt-Joint welding using the finite difference approximation. Through computational simulations, the study investigates how varying plate thickness influences temperature profiles within welded structures. The findings offer insights into the thermal behavior of welds with varying thicknesses, aiding in the optimization of welding processes for enhanced efficiency and quality. Key aspects addressed include the formulation of governing heat transfer equations, treatment of boundary conditions, and integration of welding parameters and material properties. Validation of the model against experimental data ensures its reliability and applicability across various welding scenarios. By providing insights into the intricate temperature dynamics during welding processes, this research facilitates improved weld quality, reduced defects, and enhanced process efficiency. Introduction: Welding is a key process used in industries like automotive, aerospace, construction, and manufacturing. The quality of welded joints is essential for the reliability and performance of structures and components. Proper temperature control in the weld is vital for achieving high-quality welds. Temperature distribution is affected by factors like welding parameters, material properties, joint configuration, and heat source characteristics. Understanding these factors is critical for optimizing welding processes and ensuring defect-free welds. Numerical modeling, particularly the finite difference method (FDM), helps simulate heat transfer and predict temperature distribution accurately. Objectives: The objective of this research is to investigate the effects of plate thickness on the three-dimensional temperature distribution during Butt-Joint welding using the finite difference method. Specifically, the study aims to: Model the temperature profiles within welded structures for varying plate thicknesses. Analyze the influence of welding parameters, material properties, and joint configurations on temperature distribution. Optimize welding processes to enhance weld quality and minimize defects. Validate the developed model through comparison with experimental data to ensure its reliability and applicability across different welding scenarios. Provide insights into the thermal behavior of welds, contributing to improved process efficiency and quality control in welding operations. Methods: This study uses the heat conduction equation to model heat transfer in submerged arc welding. A fine mesh (1 mm resolution) is applied for x- and z-axes, while a coarser mesh is used along the welding axis. Only half of the plate is considered for computation. The arc efficiency (η) is 0.9, with heat distribution modeled as ηVI. Boundary Conditions: Heat source along the y-axis. Convective heat dissipation along edges and surfaces. Convection Coefficient Newtonian convection cooling is applied: h = 4.5 × 10⁻⁴ W/mm²K (within 50 mm of the weld line). h = 1.8 × 10⁻⁵ W/mm²K (remaining plate area). Material Properties: Carbon-manganese steel is used, with temperature-dependent thermal properties. Finite Difference Approximation (FDA) FDA replaces differential equations with finite difference equations (FDE): Discretize the domain into a grid. Convert the heat equation to FDE. Formulate and solve equations using Leibmann’s iteration method. A central difference implicit scheme ensures stability. The iteration scheme incorporates temperature-dependent properties. The computational code is implemented in C. Results: The model used grid systems for different plate thicknesses: 127×29×8 (6 mm), 132×36×10 (8 mm), 127×27×12 (10 mm), and 122×32×14 (12 mm). Temperature history was computed over 1500-time steps (0.2 s each) using heat flow equations and material properties. Heat input followed welding parameters. Figure shows the temperature distribution for a 6 mm plate, and presents contour plots for a 10 mm plate. Peak temperature decreases away from the weld line, with a fusion zone and heat-affected zone (HAZ). Thicker plates dissipate more heat, reducing fusion depth and increasing cooling rates. Experimental Verification: Bead-on-plate welding experiments validated the numerical model using C-Mn steel samples of varying thicknesses. Welding parameters were applied in submerged arc welding. Flux and filler metal compositions were analysed via scanning electron microscopy. Temperature was measured with K-type thermocouples on upper and lower surfaces and recorded at one-second intervals using an Agilent 34970A Data Acquisition system. Welding was performed with direct current electrode positive polarity and a 25 mm contact tube-to-workpiece distance. A total of 76 mild steel samples (6 mm, 8 mm, 10 mm, 12 mm) were tested, with peak temperature deviations under 3% at 15 mm from the weld line. Figures 8 and 9 confirm a close match between numerical and experimental results, validating the heat flow model. Conclusions: This study develops and validates a theoretical heat flow model for welding using experiments on C-Mn steel (6–12 mm thick). Key findings include: An implicit central difference approximation effectively simulates 3D thermal cycles, closely matching real conditions. The model accurately captures temperature flow, including convection effects and material property variations. Numerical results align with experiments (deviation &lt;3%), ensuring reliable predictions for weld microstructures, distortion, and residual stress. Cooling rates increase with thickness, raising hydrogen embrittlement risks but stabilizing faster in thicker plates. The model proves effective for welding process optimization and material control.

BackgroundThe high reactivity of mafic minerals, such as olivine and pyroxene, plays a crucial role in controlling the global magnesium (Mg) flux and its isotopic composition. This study investigates the mechanisms and extent of Mg isotope fractionation during the dissolution of these minerals under far–from–equilibrium conditions. These findings provide valuable insights into the behavior of Mg isotopes in natural environments and their potential as a geochemical proxy for understanding Earth's carbon cycle.MethodsMafic minerals (olivine, enstatite, and diopside) with particle sizes ranging from 63 to 245 µm were subjected to dissolution experiments in a plug–flow reactor under far–from–equilibrium conditions. Effluent solutions were collected over a period of 1872 h. Elemental concentrations were determined using a Inductively Coupled Plasma Optical Emission Spectroscopy (ICP–OES), while Mg isotopic compositions were analyzed using Multi–Collector Inductively Coupled Plasma Mass Spectrometry (MC–ICP–MS).ResultsElemental concentrations displayed distinct temporal trends for olivine and pyroxene. Olivine dissolution demonstrated a gradual increase in elemental concentrations during the initial 20 h, followed by a subsequent decline towards baseline levels. In contrast, pyroxene dissolution exhibited a rapid initial release of elements within the first 4 h, followed by an abrupt decrease towards near-zero concentrations. Olivine dissolution exhibited pronounced oscillations in δ2⁶Mg values, ranging from − 0.53‰ to − 0.21‰. Conversely, pyroxene dissolution (enstatite and diopside) displayed more gradual trends, with δ2⁶Mg values ranging from − 0.41‰ to − 0.26‰ for enstatite and from − 0.43‰ to − 0.21‰ for diopside.ConclusionsThe output solutions exhibited an initial period of rapid, incongruent mineral dissolution, followed by a sharp decline towards near–zero rates. The observed δ2⁶Mg variations between solution and mineral, ranging from − 0.43‰ to + 0.18‰, suggest that these shifts are likely influenced by either differences in their crystal structures or the formation of secondary phases. This finding highlights the significant influence of mafic minerals, with their high reactivity compared to other silicate minerals, on the Mg flux and isotopic compositions in terrestrial waters draining basalts and the ocean.

The conventional CaO–SiO2-based mold fluxes are not suitable for high-Al steel casting because of the strong reaction between silica in the flux and aluminum in the steel strand. In the process of casting of high-Al steel, flux composition changes, with the decrease of the silica concentration and increase of alumina. Knowledge and understanding of the effect of the Al2O3/SiO2 ratio on flux structure and properties are useful for flux design for the high-Al steel continuous casting. This paper investigated the effect of the Al2O3/SiO2 ratio in the range from 0.7 to 10.8 on structure, viscosity, and heat transfer of CaO–Al2O3–SiO2–B2O3–Na2O–Li2O–MgO–F fluxes. It was found that flux melting temperature increased with the increase in Al2O3/SiO2 ratio. Viscosity of the flux melts increased significantly with the increase of the Al2O3/SiO2 ratio from 0.7 to 1.2, reaching the maximum value, and then decreased with further increase of the Al2O3/SiO2 ratio. Raman spectroscopy analysis revealed that the change of the Al2O3/SiO2 ratio led to the change of aluminate and silicate structural units. The turning point for viscosity was attributed to the change in the degree of flux polymerization which was governed by the amphoteric nature of Al2O3. X-ray diffraction (XRD) analysis showed that increasing Al2O3/SiO2 ratio increased crystallization tendency of the fluxes. Heat transfer measurement by infrared emitter technique (IET) revealed that increasing Al2O3/SiO2 ratio led to the decrease in heat flux which is correlated well with the increased crystallinity of the flux. The results suggested that the fluxes with Al2O3/SiO2 ratio 2.1–4.3 are the best candidates among the studied CaO–Al2O3-based mold fluxes for casting of high-Al steel.Graphical

In response to the growing demand for critical raw materials, the European Commission is actively pursuing strategies to recycle these materials from various sources, including disused batteries. One of the significant challenges in this endeavor is the heterogeneous nature of the materials arriving at recycling plants, necessitating effective process evaluation. In this study, crushed scooter batteries were utilized, and a range of analytical techniques were employed to initially characterize the composition of the raw material and subsequently evaluate previous physical separation processes efficiently, effectively, and economically. The analytical methods utilized included scanning electron microscopy with energy-dispersive X-rays spectroscopy (SEM–EDS), X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), loss of ignition (LOI), and differential scan calorimetry (DSC). In addition, two separation techniques were conducted: froth flotation and sink-and-float tests. The cathode's oxide type was identified through XRD analysis, and statistical methods were applied to all XRF analyses. Furthermore, the other analytical methods facilitated the determination of flux compositions, enabling the assessment of process performance. Regarding the robustness of the presented method, as is well known, performing a complete characterization of a material, including XRD, AAS, XRF, DSC, and SEM, could comprise a relatively high time if it is to identify the efficiency of a process (we estimate in several days, and even weeks). However, by reducing the analytical methods to LOI, XRF, and stream sampling, it is possible to conduct process efficiency evaluation in a few hours. This methodology would give the opportunity to achieve effective verifications in a short time and reduce possible efficiency problems in a treatment plant of this type of material.