Study On Dephosphorization And Its Influencing Factors In Combined Blowing Converter

Phosphor is one of the elements destroying the properties of steel product. It needs low phosphor for high quality steel. Ironmaking process due to reducing atmosphere, almost no dephosphorization capacity, thus dephosphorization during the steelmaking becomes the main mission.Based on consulting the extensive literatures and summarizing the study on the top–bottom combined blowing converter process at home and abroad, through the methods of industrial tests and sampling from production field, analyzing the composition of molten steel and slag what come from each time point of smelting, testing the each slag's melting point in the lab and so on, the desulfurization effect have been studied in 100t top-bottom combined blowing converter.The results indicate that the phosphorus partition ratio of the slag-steel increases with the increase of oxidativity of slag; It increases with the increase of alkalinity of slag or superheat of slag within limits; But when the alkalinity of slag or superheat of slag increases to a fixed level, it decreases when their increase over the limits. The format reasons of above-mentioned influences and the changes and the reasons of changes about the major influencing factors at the process of blowing have been explained.According to the results of this study, in order to improve the top end of the dephosphorization effect in combined blown converter, I make the following recommendations: In the early-mid stage of converter smelting , when slag superheat is low, the proper operation of the high-gun position with a view to improve the slag superheat as soon as possible, so as to enhance the effect of slag dephosphorization in purposes; In the mid-later stage of converter smelting, control the slag temperature and alkalinity appropriatly, so that the use of dephosphorization slag to achieve better results; Increase the volume of slag appropriatly; At the same time to avoid return to phosphorus.