PHYSICO-CHEMICAL MODEL OF REFINING MELT IN LIQUID PHASE REDUCTION CONVERTERS

From the point of view of resource conservation, it is important to improve existing and develop new modifications of converter processes, including technologies with combined purging and liquid-phase recovery elements, which ensure the processing of various wastes and save materials while improving technical and economic performance and environmental conditions. The main provisions of processes with liquid-phase recovery of industrial waste involving two-stage oxygen-gas refining of the melt with spatial distribution of technological operations in the volume of the unit are presented. To implement the technology, the converter must have systems for supplying various process gases to the melt, including bottom mixing with inert gas, using two-flow purge and side tuyeres. A high degree of reduction of iron oxides from man-made waste is achieved at the first (reducing) stage. At this stage, iron-containing waste and carbon-containing materials (reducing agents) are added to the cast iron poured into the unit. A theoretical analysis of the process made it possible to identify the main interacting phases and the zones (surfaces) of their contact. Thermodynamic and kinetic patterns of liquid-phase reduction reactions are described. The rate of the oxidation‒reduction process is proposed to be considered as the total rate of oxidation of iron in liquid cast iron with gaseous oxygen and reduction of iron oxides with silicon, phosphorus and carbon. The main parameters influencing the speed and completeness of the iron oxide reduction process of the processed waste by impurity elements of liquid cast iron, as well as an additional carbon-containing reducing agent, are determined. A mathematical model describing the interaction of phases is proposed, the use of which makes it possible to purposefully influence kinetic factors depending on the current thermodynamic conditions and the tasks being solved.

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