Vanadium Titanium Research Articles

Natural Vanadium–Titanium Magnetite Activated Peroxydisulfate and Peroxymonosulfate for Acid Orange II Degradation: Different Activation Mechanisms and Influencing Factors

Persulfate-based advanced oxidation processes have emerged as a promising approach for the degradation of organic pollutants in aqueous environments due to their ability to generate sulfate radicals (SO4−·) within catalytic systems. In this study, peroxydisulfate (PDS) and peroxymonosulfate (PMS) were investigated with the natural vanadium–titanium magnetite (VTM) as the activator for the degradation of acid orange II. The degradation efficiency increased with higher dosages of VTM or persulfate (both PDS and PMS) at lower concentrations (below 10 mM). However, excessive PMS (higher than 10 mM) in the PMS/VTM system led to the self-consumption of free radicals, significantly inhibiting the degradation of acid orange II. The VTM-activated PDS or PMS maintained an effective degradation of acid orange II in a wide pH range (3~11), suggesting remarkable pH stability. The SO4−· was the main active species in the PDS/VTM system, while hydroxyl radical (·OH) also contributed significantly to the PMS/VTM system. In addition, PMS exhibited better thermal stability during VTM activation. Coexisting ions in an aqueous environment such as bicarbonate (HCO3–), carbonate (CO32–), and hydrogen phosphate (HPO42–) had obvious effects on persulfate activation. Our study systematically investigated the different activation processes and influencing factors associated with PDS and PMS when the natural VTM was used as a catalyst, thereby providing new insights into the persulfate-mediated degradation of organic pollutants in aqueous environments.

Clinopyroxenite-Wehrlite Porya Guba Complex with Fe-Ti-V and PGE-Cu-Ni Mineralization in the Northeastern Part of the Fennoscandian Shield: Evidence of Post-Orogenic Formation from Sm-Nd Isotope System

The Porya Guba clinopyroxenite–wehrlite complex is located in the core of the Lapland–Kola collisional orogen (~2.0–1.9 billion years old) in the northeastern part of the Fennoscandian Shield and contains iron–titanium–vanadium and nickel–copper mineralization with platinum group elements (PGEs). The controversial geological position of the complex within the mafic granulites of the Kolvitsa mélange (pre-, syn- or post-orogenic) is clarified by Sm-Nd isotopic dating of the rocks and mineralization. The Sm-Nd age of the barren clinopyroxenites that dominate the complex is 1858 ± 34 Ma (εNd(T) = −1.5) and is interpreted as the time of its emplacement as evidenced by a sample from the largest intrusion, named Zhelezny. This age is younger than that of the peak of granulite metamorphism in the host rocks (1925–1915 Ma) and coincides within error with the age of rutile from granulites (1880–1870 Ma), indicating the time at which cooling to 450 °C occurs. Emplacement in the cooled rocks is confirmed by the detection of quenching zones in clinopyroxenites around granulite xenoliths. Magnetite ores, as well as mineralized pyroxenites with sulfide disseminations, are formed during a late stage of the complex development, as suggested by active assimilation of granulite xenoliths by these rocks. The isotopic age of mineralized pyroxenites enriched in PGEs is 1832 ± 35 Ma (εNd(T) = –2.0), while the age of magnetite ores is 1823 ± 19 Ma (εNd(T) = –2.5). Thus, the obtained isotopic data indicate that the emplacement of the Porya Guba complex and probably other small mafic–ultramafic intrusions in the Kolvitsa mélange granulites took place after the end of the Lapland–Kola collision.

Numerical Simulation of Vanadium–Titanium Blast Furnace under Different Smelting Intensities

The blast furnace smelting of vanadium–titanium ore plays a crucial role in the efficient utilization of vanadium-titanium resources. In this research, a detailed numerical simulation study of the temperature, velocity, and concentration fields during the smelting process in a vanadium–titanium blast furnace was conducted. The actual production data from a 1750 m3 vanadium–titanium blast furnace was utilized, combined with softening and dripping parameters and material balance calculations, to develop a two-dimensional blast furnace model. This model was employed to analyze the effects of varying smelting intensities on the internal operating conditions of the furnace. The study found that as smelting intensity increased, significant changes occurred in the temperature fields and CO concentration fields within the furnace, thereby affecting the reduction efficiency of the burdens. Additionally, this research also shows that increasing the proportion of Baima pellets in the furnace will lead to the expansion of the soft melting zone and the upward movement of the soft melting zone. This investigation not only revealed the variations in the internal physical fields of the blast furnace under different operating conditions but also provided theoretical foundations and references for optimizing the design and operation of vanadium–titanium blast furnaces. By comparing the velocity field under different smelting intensities, it was found that the difference was small, which was mainly related to the expansion behavior of the pellets. These findings provide an important scientific basis for further improving the efficiency of blast furnace smelting and reducing costs.

Preparation of Oxidized Pellets of Vanadium Titanium Magnetite and Direct Reduction Behavior in Hydrogen‐Based Shaft Furnace

Herein, the optimized process parameters for the preparation of vanadium‐titanium magnetite (VTM) pellets are determined, and an efficient and green utilization technology for VTM based on the integration of oxidation roasting‐hydrogen‐based shaft furnace direct reduction is established. The results indicate that the preferable VTM oxidized and pre‐reduced pellets can be prepared by preheating at 925 °C for 18 min and roasting at 1200 °C for 25 min, followed by the reduction temperature of 1050 °C at the reduction atmosphere of 4% CO2 and H2/CO = 8. The corresponding compressive strength of the preheated and roasted pellets is 516 N per pellet and 2028 N per pellet, respectively. In addition, the LTD+6.3 and LTDUP of roasted pellets are 80.86% and 93.90%, and the corresponding reducibility index, reduction swelling index, and the reduction sticking index are 0.0428, 2.32%, and 2.50%, respectively. All of which meet the production requirements of hydrogen‐based shaft furnace.

Synthesis of titanium-vanadium oxide thin films through thermal oxidation process for their use in CO gas sensing application

The thermal oxidation of evaporated titanium-vanadium thin films was carried out at different post-annealing temperatures. The structural, morphological, compositional, optical, electrical, and gas sensing properties of titanium-vanadium oxide thin films were primarily investigated. The results of the XRD study and Raman spectroscopy verified the presence of the orthorhombic V2O5, tetragonal TiO2, and monoclinic V2Ti3O9 phases. The crystallinity of TVO thin films was improved at higher annealing temperatures. The grain size (seen from SEM images) and oxygen compositions (obtained from EDS measurement) of TVO samples are also enhanced when the post-annealing temperature is increased from 500 to 575 °C. From the transmittance curves, the bandgap values for TVO samples were estimated and found in the range of 2.14–2.36 eV. The n-type conductivity of TVO films was confirmed by the negative Hall coefficient values. At last, the CO gas sensing response of TVO thin films was analyzed by monitoring the change in the surface electrical resistances at different operating temperatures and CO gas concentrations. The dynamic and static resistances were assessed at different operating temperatures varying from 100 to 300 °C. The TVO sample prepared at 550 °C showed the best conditions by examining the materials and CO sensing properties.

Neural network interatomic potential-driven analysis of phase stability in Ti–V alloys at the atomistic scale

The evolution of the ω phase in titanium–vanadium (Ti–V) alloys is critical for their mechanical properties, particularly in aerospace and biomedical applications. This study employs a Rapid Artificial Neural Network (RANN) potential to model the ω phase evolution at the atomistic level, demonstrating a high degree of consistency with experimental observations, unlike the Modified Embedded Atom Method (MEAM), which fails to capture this phase transformation accurately. RANN simulations replicate key phenomena such as the nucleation of α precipitates at ω/β interfaces and accurate lattice orientations, enhancing our understanding of phase stability and transformation kinetics. The findings affirm that RANN potentials can significantly improve the prediction accuracy of complex material behaviors, offering a powerful tool for designing advanced materials with tailored properties such as solute effect in various stacking fault energies. This approach not only bridges the gap between theoretical predictions and empirical data but also sets a new direction for future research in materials science, emphasizing the integration of machine learning techniques in the development and optimization of new alloys.

Process mechanism research on direct vortex melting reduction of vanadium–titanium magnetite

Process mechanism research on direct vortex melting reduction of vanadium–titanium magnetite

Fabrication of silver-doped titanium vanadium nitride (TiVN) coatings for biomedical applications

The term "silver-doped vanadium titanium nitride" refers to a class of composite biomaterial that combines the characteristics of vanadium titanium nitride with silver's antibacterial and bioactive capabilities. Using the physical vapor deposition (PVD) technique, the coating was applied by first depositing a single layer of Titanium on a titanium substrate, followed by a layer of TiVN(Ag), with fixed power for the Titanium (450W) and vanadium (350W), and variable power for the silver (25–100W). Atomic force microscopy (AFM) was used to evaluate surface morphology, transmission electron microscopy (TEM) was used to evaluate cross-sectional microstructural analysis of coatings, X-ray diffraction (XRD) was used to evaluate the phase formation of the coating, X-ray photoemission spectroscopy (XPS) was used to evaluate composition and atomic bonding, and finally, the biocompatibility test was conducted individually to evaluate the viability of MG-63 cells. Our results showed that the fluctuation of the silver concentration in the system impacts the microstructural and biological characteristics of the coating. The best balance between cell viability and microstructure was obtained using a sample of TiVN(Ag) and 50W of electricity.

Influence of Top Slag Containing TiO2 and VOx on Hot Metal Pre-Desulfurization

The desulfurization capacity of top slag in the process of pre-desulfurization of hot metal containing vanadium and titanium was researched. The top slag system of CaO-SiO2-MgO-Al2O3-TiO2-VOx that was formed by blast furnace slag and a CaO desulfurization agent reduced the sulfur in hot metal from 0.08 wt.% to 0.02 wt.%. It was found that the resulfurization of the slag happened in the later periods of the desulfurization process. The vanadium–titanium oxides were both acidic in the desulfurization slag. TiO2 and VOx reacted with the basic oxides to form CaTiO3 and MgV2O4 at 1623 K, which reduced free CaO and was not conducive to top slag desulfurization. The results of calculation showed that the top slag desulfurization accounted for 15% of the total desulfurization. Using the ionic and molecule coexistence theory of slag structure, it is shown that the desulfurization efficiency could be enhanced by adjusting both the amount of desulfurization agent and the composition of the blast furnace slag before pre-desulfurization.

Investigation of Basicity on Compressive Strength and Oxidation Induration Mechanism of Vanadium–Titanium Magnetite Pellets

Currently, the typical charge structure for blast furnace smelting of vanadium–titanium magnetite (VTM) is the addition of acidic pellets, high‐basicity sinters, and lumps. To increase the percentage of pellets entering the blast furnace, it is necessary to transfer the basicity burden to the pellets. In this study, the effect of basicity on the phase transition and oxidation hardening mechanism of VTM pellets is investigated. In the results, it is indicated that when the preheating temperature is 950 °C, the preheating time is 15 min, the roasting temperature is 1260 °C, and the roasting time is 15 min, with the basicity (CaO/SiO2) increasing from 0.08 to 1.3, the compressive strength of pellets shows a trend of “increasing first and then decreasing,” with the highest value reaching 3159 N pellet−1 at basicity of 0.5. As the basicity increases, calcium ferrate can be generated by CaO in the liquid phase with Fe2O3 in addition to silicate with SiO2, which will increase the amount of the liquid phase. With the increase of basicity, the oxide‐bonded induration is gradually weakened, and the slag‐bonded induration is gradually enhanced. A moderate amount of liquid phase can play the role of bonding and filling, thereby improving compressive strength.

Parameter Optimization and Reaction Kinetics of the Reduction of Vanadium–Titanium Sinter by CO–CO2–H2–N2 Mixed Gases

Parameter Optimization and Reaction Kinetics of the Reduction of Vanadium–Titanium Sinter by CO–CO2–H2–N2 Mixed Gases

Wettability and corrosion behavior between alkaline slag from sodium smelting of vanadium–titanium magnetite and refractory substrates

Wettability and corrosion behavior between alkaline slag from sodium smelting of vanadium–titanium magnetite and refractory substrates

Effect of nitrogen content on the static recrystallization and precipitation behaviors of vanadium–titanium microalloyed steels

Abstract Double compression tests were performed on vanadium–titanium microalloyed steels with different nitrogen contents by using a Gleeble-3800 thermo-mechanical simulator to study the softening behaviors of the deformed austenite during different time intervals between the two passes. The static recrystallization fractions were calculated by the stress offset method and static recrystallization diagrams for the tested steels were obtained. The effects of deformation temperature and interval time on the softening behaviors were analyzed. Especially, the effect of nitrogen on the softening behaviors of the tested steels is discussed in detail. The results showed that the softening behaviors of the tested steels with various nitrogen contents are different. As far as the steel with low nitrogen content is concerned, the softening fraction increases monotonically with increasing time interval, and higher temperature can promote the static recrystallization. However, with more nitrogen added into vanadium–titanium microalloyed steel, precipitated particles of vanadium titanium carbonitride can be observed in the tested steel at the temperature of 850 °C or 800 °C, which leads to the formation of plateaus on the softening curves. An increase in nitrogen content in the steel is favorable for vanadium titanium carbonitride precipitation, which leads to a stronger prohibition of static recrystallization and a longer plateau on the softening curves. Moreover, the precipitated particles in the tested steel will not play an inhibition role in static recrystallization until the nitrogen content in the steel reaches a critical value.

Forecasting of blast furnace gas utilisation rate via convolutional autoencoders and K-nearest neighbour methods

Gas utilisation rate (GUR) is an essential parameter to characterise the level of energy utilisation efficiency and operation status of blast furnaces (BFs). In the present study, data collected from a BF plant with vanadium–titanium magnetite were subjected to correlation and distribution analyses. Based on the operation cycle of the BF, production parameters from the preceding eight consecutive hours were selected as input parameters for the model. Convolutional autoencoders (CAEs) were employed to extract coded features from the selected data, serving as indirect inputs to the prediction model. Subsequently, K-nearest neighbour (KNN) was utilised to establish a mapping relationship between the coded features and GUR, facilitating forecasting for the subsequent 3 hours. Additionally, a hybrid approach incorporating both supervised and unsupervised training methods was utilised to facilitate GUR prediction, and the performance of the CAE–KNN model was re-validated using data from the remaining sections of the plant. The hit rate of predictions is no less than 96% as the permissible error was within 1.5%.

Effect of Basicity and MgO/Al2O3 Ratio on Viscosity and Crystallization Behavior of HIsmelt Titanium‐Containing Slag

Numerous challenges persist in the smelting of vanadium–titanium magnetite using the blast furnace process. These challenges can be overcome by adopting the HIsmelt process, without the need for additional ore or enhanced slag operations. In this study, the effects of basicity and the MgO/Al2O3 ratio on slag viscosity and crystallization behavior are investigated through thermodynamic calculations and experiments. In the results, a decrease in slag viscosity with an increase in basicity and MgO/Al2O3 ratio is demonstrated. Notably, MgO/Al2O3 ratios have a minor impact on the viscosity and break temperature of the slag. With a TiO2 content of 40 wt% in the slag, perovskite phases are identified as the main equilibrium solid precipitates during the crystallization process under various basicity and MgO/Al2O3 ratios. As the slag temperature decreases further, the liquid phase content in the slag progressively decreases, reaching complete crystallization at 1159.0 °C. For industrial production, it is advisable to maintain the binary basicity of the slag within the range of 1.0–1.1, with the MgO/Al2O3 ratio around 0.6. Herein, the research findings contribute to a deeper understanding of the viscosity and crystallization behavior of HIsmelt titanium‐containing slag.

Electropolymerization of an EDOT-Quinoxaline Monomer for Green Electrochromic Thin Films and Devices.

In this study, we present a 5,8-bis(3,4-ethylenedioxythiophene)quinoxaline monomer with two 4-(octyloxy)phenyl side chains (EDOTPQ) that can be electropolymerized on ITO glass in standard electrolytes containing lithium salts and propylene carbonate as solvent. The electrochemically deposited PEDOTPQ layers show very good adhesion and homogeneity on ITO. The green-colored polymer thin films exhibit promising electrochromic (EC) properties and are interesting for applications such as adaptive camouflage, as well as smart displays, labels, and sensors. Novel organic-inorganic (hybrid) EC cell configurations were realized with Prussian blue (PB) or titanium-vanadium oxide (TiVOx) as ion storage electrodes, showing a highly reversible and fast color change from green to light yellow.

Influence of Vanadium–Titanium Sinter Basicity on Cohesive Dripping Properties of Blast Furnace Comprehensive Burden

Vanadium–titanium ore possesses significant mining and utilization value. The basicity of vanadium–titanium sinter has a direct impact on the formation, location, thickness, permeability, and heat exchange of the cohesive zone in the blast furnace. This paper investigated the influence of increasing the basicity of the sinter on the comprehensive burden’s cohesive dripping properties in the blast furnace, while keeping the final slag basicity constant. This study was conducted through cohesive dripping property experiments. The findings indicated that as the sinter basicity in the comprehensive burden structure increased and the corresponding increase in the proportion of pellets occurred, the softening performance of the comprehensive burden improved, the cohesive zone became thinner, the lower edge of the cohesive zone shifted upward, and the softening melting properties became better in general. With an increase in the sinter basicity, the dripping difference pressure of the comprehensive burden decreased, and the dripping rate firstly increased and then decreased. An increase in the sinter basicity of the comprehensive burden structure promoted V reduction, and the V element yield and Cr element yield of the sinter were both increased; the optimal sinter basicity was 2.5, and the corresponding pellet proportion was 42%.

Optimizing pre-reduction of vanadium–titanium magnetite through recycling and integrating of top gas from melting furnace and tail gas from rotary kiln

In this study, the pre-reduction impact of CO and H2 on vanadium–titanium magnetite (VTM) was examined considering the composition of the top gas of the melting furnace. Additionally, the recycled and upgraded tail gas from the rotary kiln was mixed with the top gas of the melting furnace to enhance the pre-reduction effect and meet the temperature requirements of the rotary kiln. By analyzing the variations in the tail gas composition, the possible reactions occurring during the VTM pre-reduction process were determined. The results demonstrate the crucial role of H2 in the reduction process. A 20% H2 concentration yields a reduction effect similar to that achieved with 55% CO, resulting in a complete reduction of magnetite. However, the presence of CO2 in the gas hinders the reduction reaction by decreasing the reduction capacity of CO or inducing a secondary oxidation of the reduction products. Furthermore, the introduction of half of the tail gas of the rotary kiln into the top gas of the melting furnace increases the metallization rate of VTM pellets from 37.84% to 57.2%. These findings provide valuable references for utilizing the high-temperature top gas of the melting furnace for VTM pre-reduction in rotary kilns.

High-chromium vanadium–titanium magnetite all-pellet integrated burden optimization and softening–melting behavior based on flux pellets

High-chromium vanadium–titanium magnetite all-pellet integrated burden optimization and softening–melting behavior based on flux pellets

The mechanism and reaction kinetics of visible light active bismuth oxide deposited on titanium vanadium oxide for aqueous diclofenac photocatalysis.

Non-uniform, non-spherical bismuth oxide deposited on titanium vanadium oxide (3%-BVT1) was successfully synthesized via co-precipitation method and assessed forvisible light degradation of aqueous diclofenac. The synthesized photocatalysts were characterized using X-ray diffraction, diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. Up to 80.7% diclofenac degradation was observed with a significant increment in reaction rate compared to commercially available Degussa P25 (kapp = 0.0013 → 0.0083min-1) achieved within 3h treatment time under optimized parameters of diclofenac concentration (10mg L-1), catalyst loading (0.1g L-1), and pH (5). The enhanced photocatalysis could be due to electron-hole separation and contribution of powerful oxidative species •OH > O2•- > h+ > > e-. The recyclability experiments indicate that 3%-BVT1 retained its efficiency up to 74.1% over five reaction cycles. Gas chromatography-mass spectrometry analysis indicated the formation of several transformation products during the degradation pathway. The studies of interfering ions depicted mild interference by sulfates, while interference by phosphates and nitrates was negligible during photocatalytic process, i.e., 70, 78.01, and 78.43% for the selected concentrations of 50, 25, and 40mg L-1 as per their maximum concentrations detected in the natural wastewaters. Thus, 3%-BVT1 is a potential versatile candidate to treat various organic pollutants including pharmaceuticals.