Thermophysical Properties of CaO–SiO2–Al2O3–MgO–TiO2–FeOx–V2O3 Slag with CaO/SiO2 = 1.13 with Different TiO2 and V2O3 Additions

In this study, it is aimed to assess the feasibility of converting vanadium pentoxide into vanadium metal via hydrogen reduction. To achieve this, V2O5 powder is pressed into a cylindrical shape and subjected to a reduction in a high‐temperature microscope under a constant hydrogen flow rate of 0.5 L min−1, within a temperature range of 600–1400 °C. The experimental results are complemented by thermodynamic calculations using FactSage 7.2. The microstructure and composition of the samples are analyzed using scanning electron microscopy with energy‐dispersive X‐ray spectroscopy and X‐ray diffraction analyses. Subsequent to the experiment, only V2O3 and VO are identified in the samples, and no metallic vanadium is observed.

Direct Reduction of Solid V₂O₅ with Hydrogen at 600–1400 °C

Levchenko,

Kovtun,

Guhl

et al. 2024

Corrosion of MgO–C Refractory with Ladle Slags

Wei,

Yehorov,

Volkova

2024

Herein, MgO–C refractory brick is immersed into the molten ladle slags with various CaO/Al2O3 ratios (located in the range of 0.56–0.78 and 1.99–1.36) and SiO2 addition from 1 to 20 wt%, at two temperatures of 1550 and 1650 °C. After the interaction with the slag with a CaO/Al2O3 ratio range of 0.56–0.78, the MgAl2O4 phase with various sizes is found to form in the solidified slag layer adhering to the MgO–C sample surface, and a layer consisting of MgAl2O4 on the interface of MgO–C brick is observed. For the slag with the CaO/Al2O3 ratio range of 1.99–1.36, a small amount of minor size of MgAl2O4 particle is detected only with 20 wt% of SiO2 addition. Instead of a formation of the MgAl2O4 layer, the Fe phase containing Mn, metallic Ti, and Si is scattered on the side of the solidified slag layer. The corrosion is more pronounced in the slag with a high CaO/Al2O3 ratio and is enhanced via the addition of SiO2 along with the increased solubility of MgO. The increased solubility of MgO in the slag with increasing SiO2 has also been predicted via FactSage.

Effect of SiO₂ and Al₂O₃ on the Thermophysical Properties and the Foaming Index of Electric Arc Furnace Slag from the Production of Construction Steel

Levchenko,

Kovtun,

Angelini

et al. 2024

Viscosity, density, and surface tension of an industrial electric arc furnace (EAF) slag from production of construction steel with varying SiO2 and Al2O3 contents are investigated using a rotating viscometer and the maximum bubble pressure method. In addition, influence of thermophysical properties on foaming index is discussed. To predict the behavior of the solid phase in the slag at different temperatures, thermodynamic calculations are performed using FactSage 8.1 software. The experiments demonstratethat SiO2 and Al2O3 act as network formers in the studied slag systems, resulting in increased viscosity values in the liquid‐dominant region and decreased density of the slag. The presence of alumina and silica altered the behavior of the slag in the liquid‐dominant region, shifting the breaking point of the slags. Furthermore, the addition of silica decreases the surface tension of the slag, confirming its role as a surfactant. However, the addition of Al2O3 increases the surface tension due to the high surface tension of pure alumina. Consequently, the foaming index of the slag can increase by ≈40%, primarily due to the polymerization of the slag.