Reducing the Cost of Steel Desulfurization during Secondary Refining in a Ladle-Furnace Unit

摘要

Based on the conducted studies, the authors have determined the changes in the structural and chemical conditions of calcium silicates that are present in slag during steel smelting in a 120-ton electric arc furnace of the Danark system and its secondary refining in a steel-pouring ladle of the ladle-furnace unit. The following chain of calcium silicate transformations has been established:CaO·SiO2→2CaO·SiO2→3CaO·SiO2→4CaO·SiO2.documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$ mathrm{CaO}cdotp Si{O}_2to 2kern0.1em CaOcdotp Si{O}_2to 3kern0.1em CaOcdotp Si{O}_2to 4kern0.1em CaOcdotp Si{O}_2. $$end{document}A method based on the theory of MHS-phases (model of harmonic structures) was used to determine the structural conditions of calcium silicates and present them in the form of structural-ionic-molecular (SIM) complexes. It was found that 4?CaO???SiO2 (eutectic) and 3?CaO???SiO2 compounds have the highest and the second highest desulfurizing abilities, respectively. The obtained results enable control of the slag activation process to significantly increase its refining capacity, as well as predict and optimize the technological parameters of steel desulfurization without the use of expensive and scarce materials.