Study On Smelting Process And Desulphurization's Influencing Factors In Combined Blowing Converter

Based on the top and bottom blowing converter, top–bottom combined blowing converter process integrates the advantages of both top and bottom blowing converter process and overcomes the disadvantages of them. At present, it has become the main steelmaking process in the world. In the past 30 years, the practice shows that top–bottom combined blowing converter process can make the reaction between molten steel and slag at the process of smelting is more closed to the balance. It can decrease the oxidizability of molten steel and slag at the process of smelting. It also can increase the capability of desulfurization and produce good economic efficiency, etc.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 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 metallurgical process and desulfurization effect have been studied in 100t top-bottom combined blowing converter.The main conclusions are drawn as follows. The effects of desulfurization are the best when the final slag's basicity is about 5. Under certain melting-temperature of slag, the higher furnace temperature, the higher degree of superheat, the nicer liquidity, so that the reaction of desulfurization will be accelerated. In the infancy of high carbon content, the capability of desulfurization has been reduced because of the low furnace temperature and the low alkalinity. But it will be ascended in the middle or later stage of lower carbon content because of higher furnace temperature, alkalinity and liquidity and lower oxidbillity.According to the researches, in order to improve the desulfurization effect in 100t top-bottom combined blowing converter under the current conditions, the slagging flux and the metal materials with lower sulfur content should be selected. Under this pre-condition which the temperature of normal molten steel is guaranteed, the process temperature should be ascended as soon as possible. For getting the condition of higher sulfur partition ratio, the slag should be confected what has nicer liquidity and suitable composition. The quantity slag should be used from making for desulfurization and so on.