Development status and prospects of bottom-blown O₂-CaO technology in converter steelmaking process

In order to achieve green and clean production in BOF steelmaking and to meet the requirements of high scrap ratio smelting,the bottom-blown O₂-CaO technology with metallurgical advantages such as high efficiency,cleanliness and low carbon has become a research hotspot. The development history and application status of bottom-blown O₂-CaO technology in BOF steelmaking are summarized. The advantages of application in converter for high integration of control system,excellent metallurgical targets and low cost are presented in industrial applications. However,some problems are still existing which including short life for the bottom of furnace,the limited production cost advantages,small scale applications. Typical technologies including top and bottom blown converter steelmaking(K-BOP method),bottom blown CaO powder technology in top and bottom mixed blowing converter(K-OBM method),bottom-blown O₂-CO₂-CaO technology. The movable furnace bottom is used in K-BOP converter and K-OBM converter. The O₂-CaO are sprayed into the furnace with multiple annulus bottom blowing elements,propane is blown into the annulus as cooling gas. The K-OBM method also achieves fully automatic smelting from charging to slag splashing,100% steel can be discharged without reversing the furnace. Consistency,high quality,high efficiency and low cost. The bottom-blown O₂-CO₂-CaO technology developed independently by USTB adopts fully automated smelting. The CO₂ is mixed into O₂ to take advantage of its heat absorption effect,weak oxidation,bubble multiplication and non-increasing nitrogen and hydrogen characteristics,to reduce the temperature of the bottom-blown fire-spot zone and extend the life of the bottom-blown components. It has the characteristics of high efficiency and clean,green and low carbon and low cost. In the end,we think about the development trend of the bottom-blown O₂-CaO technology based on the low-carbon development strategy. And proposed that we should overcome erosion problems to match the safety and longevity smelting,expand the powder spraying function to meet the needs of low-carbon steelmaking,upgrade the automatic control system to adapt to the smelting of "Smart converter",analysis of the reaction mechanism of the bottom-blown O₂-CO₂-CaO converter to develop adapted process system. China′s bottom powder spraying technology will enter a period of vigorous development.