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Reducing the amount of inclusions during the steelmaking process as much as possible and much earlier plays a vital role in improving the quality of steel products. To reveal the dissolution mechanism of inclusions in slag during the converter tapping process, some comparison experiments were conducted by adding isolated spherical alumina balls as inclusions in CaO–SiO2–Al2O3–FetO–MgO slag, and FetO content up to 10% was contained in slag. The results showed that the dissolution rate of alumina balls in the slag was mainly affected by the diffusion of Al2O3, and the diffusion coefficients of Al2O3 were 4.2 × 10–11, 7.5 × 10–11, and 1.5 × 10–10 m2/s at 1500℃, 1550℃, and 1600℃, respectively. In addition, the upgraded diffusion‐distance‐controlled dissolution model (DDD‐Model), in which FetO content was introduced and applied in the study. The results illustrated that the Al2O3 inclusion apparent dissolution rate was improved by a high FetO content, increasing CaO/SiO2 and raising the temperature as soon as possible at the early stage of the converter tapping process. It is not necessary to increase the FetO content in the slag to enhance the dissolution rate of the Al2O3 inclusion at the last tapping stage. The predicted complete dissolution time of spherical Al2O3 inclusions with 1000 µm in diameter based on the upgraded DDD‐Model was approximately 1796 s during the actual converter tapping process. [ABSTRACT FROM AUTHOR]

During converter steelmaking process, large amounts of slags are generated which take away heat and iron resources from molten bath. The slag-remaining operation is a kind of hot slag recycling. It is that all or most of the slags are left in the converter for next heat during continuous production of several successive heats. The basicity of the remaining slag is about 3, and the content of (FeO) is about 20%.When slag-remaining operation is adopted, it increases the slagging speed in the early stage. Influence of slag-remaining process on the dephosphorization during converter steelmaking was studied through industrial practice and theoretical calculation. The results show that the slag-remaining operation can realize low cost and high efficiency for converter steelmaking. It can reduce the consumption of lime and achieve better dephosphorization effect. But phosphorus content in slag increases gradually with the increase of slag remaining times and the dephosphorization capacity of slag is reduced, which result in the poor dephosphorization of steel. Therefore, the times of slag-remaining should be less than 5 to ensure the dephosphorization of steel. [ABSTRACT FROM AUTHOR]