RESUMEN

The article presents the results of research carried out using a water model of a refining ladle for the Fe-Si ferroalloys treatment. These studies were aimed at improving the efficiency of refining and homogenization of liquid Fe-Si ferroalloy in the refining ladle by using a new method of blowing gas through a system of nozzles installed at the bottom of the ladle. The obtained results allowed to determine the proper location of the plug at the bottom of the refining ladle and the possibility of using combined blowing. The tests were carried out for a refining ladle with a capacity of 3 m3 using a physical model on a linear scale of 1:3. The gas flow rate used in the model corresponded proportionally to the value previously used in industrial practice and amounted to 26.8 l/min. Experiments were performed for both combined blowing applications and through a purging plug at the bottom of the ladle. In the case of combined blowing, the volume of the gas stream was divided into two blowing sources (lance and purging plug). As a result of laboratory tests, one of the variants was selected and tested in industrial conditions. These studies confirmed the improvement in the efficiency of refining treatment of the FeSi alloy in terms of reducing the carbon and aluminum content in the alloy.x.

RESUMEN

Biocoke has the potential to reduce the fossil-based materials in metallurgical processes, along with mitigating anthropogenic CO2- and greenhouse gas (GHG) emissions. Reducing those emissions is possible by using bio-based carbon, which is CO2-neutral, as a partial replacement of fossil carbon. In this paper, the effect of adding 5, 10, 15, 30, and 45 wt.% biomass pellets on the reactivity, the physicomechanical, and electrical properties of biocoke was established to assess the possibility of using it as a fuel and reducing agent for a blast furnace (BF) or as a carbon source in a submerged arc furnace (SAF). Biocoke was obtained under laboratory conditions at final coking temperatures of 950 or 1100 °C. Research results indicate that for BF purposes, 5 wt.% biomass additives are the maximum as the reactivity increases and the strength after reaction with CO2 decreases. On the other hand, biocoke's physicomechanical and electrical properties, obtained at a carbonization temperature of 950 °C, can be considered a promising option for the SAF.

RESUMEN

Several industrial wastes including biomass, fly ashes, red mud, mill scales, water treatment residues, have significant concentrations of metal oxides: Fe2O3, Al2O3, TiO2, SiO2 etc. Several efforts have been made towards recovering metals within these wastes. Rather than recovering one metal at a time, we report a novel approach for simultaneously extracting multiple metals from mixed oxides in a single process step. Using three distinct furnaces/heating regimes, the carbothermic reduction of Fe2O3/Al2O3/SiO2 system was investigated at 1450-1700 °C for up to 2 h over a wide composition range. Complete reduction was achieved for both Fe2O3 and SiO2 in all cases leading to the formation of Fe and Fe-Si alloys. The reduction of alumina at moderate temperatures was the key challenge. No alumina reduction was observed during reductions at 1450 °C. A partial reduction of alumina and the formation of Fe-Al alloys was detected in the Al2O3/Fe2O3/C system at 1550 °C. The formation of Fe-Si-Al alloys was also observed in the Fe2O3/SiO2/Al2O3/C system at 1550 °C. Complete reduction of alumina was observed at 1600-1700 °C, even for up to 50 wt% alumina in the system. Optimal operating conditions and reference standards were established for the simultaneous recovery of multiple metals from waste oxides. While conserving natural resources, this novel route will lower the burden on waste storage facilities with significant contributions to the economic and environmental sustainability of industrial waste management.

Asunto(s)

Residuos Industriales , Hierro , Óxido de Aluminio , Ceniza del Carbón , Residuos Industriales/análisis , Dióxido de Silicio

RESUMEN

The main objective of this paper is to present results of the research in the development of a specialized self-propagating high-temperature synthesis (SHS) technology for ferroalloy composites, as applied to steelmaking. The problem of creating such a production cycle has been solved by developing a new approach to the practical implementation of self-propagating high-temperature synthesis, as applied to metallurgy. The metallurgical variation of SHS is based on the use of different metallurgic alloys (including waste in the form of dust from ferroalloy production) as basic raw materials in the new process. Here, the process of synthesis by combustion is realized through exothermic exchange reactions. The process produces a composite, based on inorganic compositions with a bond of iron and/or alloy based on iron. It has been shown that in terms of the aggregate state of initial reagents, metallurgical SHS processes are either gasless or gas-absorbing. Combustion regimes significantly differ when realized in practice. To organize the metallurgical SHS process in weakly exothermic systems, different variations of the thermal trimming principle are used. In the present study, self-propagating high-temperature synthesis of ferrovanadium nitride, which is widely used in steel alloying, was investigated. It has been shown that the phase composition of the initial alloy has a profound impact on the regular patterns in ferrovanadium combustion in nitrogen and on the mechanism itself. During the nitriding of σ-(Fe-V), process activation is taking place. The activation is due to the transformation of the intermetallide into an α-solid solution, when the temperature of phase transition is reached (~1200 °C). The composite structure of the products of ferrovanadium is nitriding by the fusion of particles-droplets composed of molten Fe and solid VN.

RESUMEN

This paper is related to the evaluation of the possibility of using ferroalloys for the production of conventional (CMGs) and bulk metallic glasses (BMGs) as well as determining their magnetic properties. The structure and magnetic properties of Fe-Co-based CMGs and BMGs prepared from ferroalloys and pure elements, were studied. The CMGs and BMGs were in the form of ribbons and rods, respectively. The thickness of the ribbons were 0.07, 0.12, and 0.27 mm and the diameters of the rods were 1.5 and 2.5 mm. The investigations of the structure of the test specimens were carried out using the X-ray diffraction (XRD) method and electron microscopy methods (HRTEM-high-resolution transmission electron microscope, SEM-scanning electron microscope). The relationship between the structure and magnetic properties of the Fe36.00Co36.00B19.00Si5Nb4 and Fe35.75Co35.75B18.90Si5Nb4Cu0.6 CMGs and BMGs was determined. The possibility of using new materials, i.e., CMGs and BMGs, prepared on the basis of ferroalloys, lies in the scope of the presently conducted research and allows us to obtain the utility properties, while avoiding high costs associated with the purchase of raw materials.