THERMODYNAMIC ANALYSIS OF THE TECHNOLOGICAL OPERATION OF CAST IRON REFINING WITH A MIXTURE OF OXIDE COMPONENTS OF THE CaO-FeO-Na2CO3 SYSTEM

Abstract

At present, at the metallurgical plants of Ukraine, a charge with an unstable chemical composition is used, which leads to significant fluctuations in temperature, the content of sulfur, silicon in cast iron and to a significant decrease in the technical and economic indicators of the further process of the production of iron-carbon semi-products. The application of standard technology of step-by-step multi-stage refining of cast iron from sulfur, silicon and phosphorus leads to an increasemelting cycle, a significant decrease in temperature, which reduces the technical and economic indicators of converter melting. Therefore, studies of the processes of one-stage removal of sulfur and silicon from liquid cast iron are relevant for the development of recommendations for reagents and technology of complex treatment of cast iron before steelmaking processing. The purpose of the work is to clarify the features of the physicochemical transformations occurring in the volume of liquid cast iron when the refining mixture of the CaO-FeO-Na2CO3 system is injected when the carrier gas is supplied in the jet. Information on the interaction of melt components with oxidation products formed in the zone of action of the gas jet was summarized, and the dependence of lgKp on temperature was constructed for possible reactions of chemical transformationsA thermodynamic analysis of the refining process was carried out due to the injection of the refining mixture of the CaO-FeO-Na2CO3 system using different carrier gases. It has been established that silicon removal processes mainly take place in the zone of direct impact of the gas-powder jet on the melt, and the silicon dioxin formed at the same time is effectively bound into dicalcium silicate. Removal of sulfur from the melt proceeds directly due to the interaction of elements of the melt with products formed in the zone of influence of the gas-powder jet on liquid cast iron and is based on desulfurization with soda in the presence of high concentrations of soda in the melt.