DETERMINATION OF THE KINETIC PARAMETERS OF THE DISSOLUTION PROCESS OF ALUMINUM PARTICLES IN THE REFINING SLAG OF THE INTERMEDIATE BUCKET

Abstract

The work shows that the introduction of intermediate ladle metallurgy was one of the most significant developments in steelmaking over the past decades. It is noted that the purpose of secondary steel smelting is the production of a high-quality and economically justified product. It is highlighted that one of the main functions of the intermediate ladle is the minimization of the number and size of non-metallic inclusions in steel products by their transition from the metal phase to slag. The purpose of the study was to establish the kinetic parameters of the process of dissolution of non-metallic inclusions in the slag of the intermediate ladle, namely, the limiting stage of the process and the value of the activation energy. The process of dissolution of Al2O3 solid particles, the weight of which was 0.25 g, the purity of 99.9% and the diameter of 500±0.05 μm, in the slag of variable composition CaO-SiO2-Al2O3-FexO was studied. The dissolution behavior of Al2O3 solid particles was investigated using an apparatus that was equipped with a video camera and an optical microscope at temperatures of 1550, 1575, and 1600 °C, and the experimental time was 120, 240, and 360 seconds for each condition. Analytical studies have shown that the process of dissolving Al2O3 solid particles can be described both by the kinetics of heterogeneous processes and by the kinetics of homogeneous chemical reactions. The study shows that the control of the rate of dissolution of Al2O3 solid particles can be described by the laws of mass transfer at the boundary of the separation of two liquid phases, steel melt – slag. The mathematical dependence of the process of dissolution of Al2O3 solid particles was established, with the help of which the rate of dissolution was calculated. The activation energy was determined analytically using the Arrhenius equation. As a result of the research, the rate of dissolution of Al2O3 solid particles was determined and it was established that it increases with the increase in the content of FexO in the slag of the intermediate ladle and the temperature. It was established that the dissolution of Al2O3 solid particles occurs at the boundary of phase separation, which is confirmed by scanning electron microscopy data. The activation energy of the process was determined and it was shown that the process of dissolution of Al2O3 solid particles in slags of different composition occurs in the kinetic region. It is shown that an increase in the content of FexO in the slag of the intermediate ladle leads to an increase in the activation energy and a greater dependence of the process of dissolution of Al2O3 solid particles on temperature.