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The steel industry is an important foundation of the national economy and the livelihood of the people, producing a large amount of carbon dioxide gas, accounting for about 70% of the carbon dioxide gas generated in the steel industry, which occurs during the ironmaking process. Therefore, the key technology to reduce the pollution and improve competitiveness is to increase the stability of blast furnace production and the quality of hot metal. Since the operation requirements for temperature control in the vanadium-titanium blast furnace are dramatically different compared to the traditional ones due to the low fluidity of vanadium-titanium slag, maintaining the required hot metal temperature within a narrow range with smaller fluctuations is essential. In addition, the adjustment parameters of the lower part have a significant influence on the tuyere combustion flame temperature during the daily operation of blast furnaces. At present, there is no relevant research on the online detection and analysis of vanadium-titanium blast furnace tuyere combustion flame temperature. In this study, the temperature of four tuyeres in a 500 m3 vanadium and titanium blast furnace at Jianlong Steel was detected by an online detection system. The tuyere combustion flame temperature was then calculated using colorimetric temperature measuring methodology at various times and at four distinct locations. After that, the calibration analyses, imaging parameter and the temperature tendencies in different directions of the blast furnace were investigated. This study not only offers new methods for understanding the regularity of operation and increasing the degree of visualization in vanadium and titanium smelting blast furnaces but also provides technical support for intelligent and low-carbon operation in blast furnaces.

In view of the high loss of iron during hot metal desulfurization treatment at Pangang Steel, the factors influencing slag skimming iron loss were analyzed thoroughly by thermodynamic calculation with the aid of FactSage. A desulfurization modifier containing Na2O and Al2O3 was designed. An industrial verification test was conducted for the newly designed calcium-based agent. The test results indicate that adding 8% of the modifier to the passivating lime achieves the optimal modification effect on the desulfurization slag. After modifying the desulfurization slag, the consumption of magnesium powder for every 0.001% sulfur removed decreased from 0.0149 kg to 0.0136 kg, the iron loss during slag skimming reduced from 3.52% to 2.28%, and the average slag skimming time shortened by 1.5 min. These improvements significantly lowered production costs, enhanced desulfurization efficiency, and laid the foundation for the widespread application of the semi-steel silicon addition process.

High-chromium vanadium and titanium magnetite (HCVTM) sinter has poor properties. The coke ratio has an important effect on the behavior of HCVTM sintering as it affects the mineral phases in the high-chromium vanadium and titanium sinter (HCVTS) via changing the sintering temperature and atmosphere. In this work, the sintering behavior of HCVTM mixed with varying coke ratios was investigated through sintering pot tests, X-ray diffraction (XRD), gas chromatographic analysis, and mineral phase analysis. The results show that, with the increase of the coke ratio from 4.0% to 6.0%, leading to the increase of the combustion ratio of the flue gas, the vertical sintering rate and sinter productivity decrease. Meanwhile, with the change of the coke ratio, the content of magnetite, silicate, and perovskite increase, while the hematite and calcium ferrite decrease. In addition, the tumble strength and reduction ability of HCVTS decrease, and its degradation strength increase. It was found that the appropriate coke ratio for the sintering process was 5.0 wt %.

A new process of extracting titanium from vanadium–titanium magnetite (VTM) in the Panxi area in Sichuan, China is introduced in this work. Various experiments, including reduction–magnetic separation, leaching and hydrolyzing experiments, are carried out. The results show that the optimum conditions for leaching experiments are an acid/slag ratio of 4:1, a leaching temperature of 60 °C, a leaching time of 80 min, and a liquid/solid ratio of 3.2:1. The leaching rate of titanium in Ti-bearing slag is 92.41%. The optimum conditions for hydrolyzing experiments are an H+ concentration of 0.75 g·L−1, hydrolyzing temperature of 100 °C, and hydrolyzing time of 180 min, and the hydrolyzing rate of titanium in acid leaching liquor is 96.80%. After the leaching and hydrolyzing experiments, the recovery rate of titanium from the Ti-bearing slag is 89.45%.

Raman spectroscopy and Electron Paramagnetic Resonance (EPR) studies were performed on a series of V2O5/TiO2 catalysts prepared by a modified sol-gel method in order to identify the vanadium species. Two species of surface vanadium were identified by Raman measurements, monomeric vanadyls and polymeric vanadates. Monomeric vanadyls are characterized by a narrow Raman band at 1030 cm−1 and polymeric vanadates by two broad bands in the region from 900 to 960 cm−1 and 770 to 850 cm−1. The Raman spectra do not exhibit characteristic peaks of crystalline V2O5. These results are in agreement with those of X-ray Diffractometry (XRD) and Fourier Transform Infrared (FT-IR) previously reported (C.B. Rodella et al., J. Sol-Gel Sci. Techn., submitted). At least three families of V4+ ions were identified by EPR investigations. The analysis of the EPR spectra suggests that isolated V4+ ions are located in sites with octahedral symmetry substituting for Ti4+ ions in the rutile structure. Magnetically interacting V4+ ions are also present as pairs or clusters giving rise to a broad and structureless EPR line. At higher concentration of V2O5, a partial oxidation of V4+ to V5+ is apparent from the EPR results.

A critical analysis of the available thermodynamic data for the Fe-V-Ti-C-N system has been performed, and a self-consistent thermodynamic description of this system has been proposed based on the CALPHAD (calculation of phase diagrams) method. Using the constructed thermodynamic description, we calculated the phase equilibrium states of the system under study and considered some laws of the effect of the alloy composition on the phase composition of steels alloyed with vanadium and titanium.

This work describes a modified sol-gel method for the preparation of V2O5/TiO2 catalysts. The samples have been characterized by N2 adsorption at 77 K, X-ray Diffractometry (XRD), Scanning Electronic Microscopy (SEM/EDX) and Fourier Transform Infrared Spectroscopy (FT-IR). The surface area increases with the vanadia loading from 24 m2 g−1 for pure TiO2 to 87 m2 g−1 for 9 wt% of V2O5. The rutile form is predominant for pure TiO2 but becomes enriched with anatase phase when vanadia loading is increased. No crystalline V2O5 phase was observed in the diffractograms of the catalysts. Analysis by SEM showed heterogeneous granulation of particles with high vanadium dispersion. Two species of surface vanadium were observed by FT-IR spectroscopy: a monomeric vanadyl and polymeric vanadates. The vanadyl/vanadate ratio remains practically constant. Ethanol oxidation was used as a catalytic test in a temperature range from 350 to 560 K. The catalytic activity starts around 380 K. For the sample with 9 wt% of vanadia, the conversion of ethanol into acetaldehyde as the main product was approximately 90% at 473 K.

The effect of diboron trioxide (B2O3) on the crushing strength and smelting mechanism of high-chromium vanadium-titanium magnetite pellets was investigated in this work. The main characterization methods were X-ray fluorescence, inductively coupled plasma-atomic emission spectroscopy, mercury injection porosimetry, X-ray diffraction, metallographic microscopy, and scanning electron microscopy-energy-dispersive X-ray spectroscopy. The results showed that the crushing strength increased greatly with increasing B2O3 content and that the increase in crushing strength was strongly correlated with a decrease in porosity, the formation of liquid phases, and the growth and recrystallization consolidation of hematite crystalline grains. The smelting properties were measured under simulated blast furnace conditions; the results showed that the smelting properties within a certain B2O3 content range were improved and optimized except in the softening stage. The valuable element B was easily transformed to the slag, and this phenomenon became increasingly evident with increasing B2O3 content. The formation of Ti(C,N) was mostly avoided, and the slag and melted iron were separated well during smelting with the addition of B2O3. The size increase of the melted iron was consistent with the gradual optimization of the dripping characteristics with increasing B2O3 content.

High-chromium vanadium–titanium magnetite (HVTM) is a crucial polymetallic-associated resource to be developed. The all-pellet operation is a blast furnace trend that aims to reduce carbon dioxide emissions in the future. By referencing the production data of vanadium-titanium magnetite blast furnaces, this study explored the softening-melting behavior of high-chromium vanadium–titanium magnetite and obtained the optimal integrated burden based on flux pellets. The results show that the burden with a composition of 70wt% flux pellets and 30wt% acid pellets exhibits the best softening-melting properties. In comparison to that of the single burden, the softening-melting characteristic temperature of this burden composition was higher. The melting interval first increased from 307 to 362°C and then decreased to 282°C. The maximum pressure drop (Δ P max ) decreased from 26.76 to 19.01 kPa. The permeability index ( S ) dropped from 4643.5 to 2446.8 kPa·°C. The softening–melting properties of the integrated burden were apparently improved. The acid pellets played a role in withstanding load during the softening process. The flux pellets in the integrated burden exhibited a higher slag melting point, which increased the melting temperature during the melting process. The slag homogeneity and the TiC produced by over-reduction led to the gas permeability deterioration of the single burden. The segregation of the flux and acid pellets in the HVTM proportion and basicity mainly led to the better softening-melting properties of the integrated burden.

In order to clarify the slag system of high Cr2O3 vanadium-titanium magnetite smelting in BF （blast furnace）, the melting properties of slag samples prepared by analytically pure reagents were measured. By means of orthogonal test synthetic weighted score method, the optimal slag for high Cr2O3 vanadium-titanium magnetite was obtained, which contained 10% MgO, 8% TiO2 and 15% Al2O3, with the binary basicity being 1.15. In addition, the effects of basicity, MgO, TiO2 and A12 03 on slag melting properties were investigated by single factor test, and the results showed that, with increasing the basicity or TiO2 content, melting temperature （Tin） increased, whereas initial vis- cosity （r/0） and high temperature viscosity （r/h） decreased. With increasing the MgO content, Tm decreased firstly and then increased. With increasing the Al2 O3 content, Tm increased, and η0 and r/h decreased firstly and then increased.