Effect of rotation rates on dissolution behavior of lime in CaO-FeTo-SiO2-MgO system

For the converter steelmaking process, incompletely dissolved lime will exist in steel slag in the form of f-CaO, which reduces the utilization rate of metallurgical slag and causes the waste of resources. It is extremely important to reduce the production of f-CaO in steel slag and promote the rapid and sufficient dissolution of lime. This paper is based on the early and middle stages of the converter slag-forming route based on the CaO component. The dissolution rate of lime in four different slags was measured by rotating rod method. The evolution behavior of the lime-slag interface and the change behavior of the lime dissolution rate were studied by X-ray diffractometer and an electron probe micro-analyzer. The experimental results show that CaO-FeO solid solutions and (Ca, Mg, Fe) olivine are formed when lime reacts with molten slag at 1400?. When the FeO content decreases, CaO reacts with the calcium-magnesia-silica to form a high melting point and dense 2CaO?SiO2 layer. In addition, at different rotation rates, a 3CaO?SiO2 phase layer is formed between the CaOFeO solid solution layer and the C2S layer. As the rotation rate increases, the dissolution rate of lime also increases and the mass transfer coefficient reaches the maximum at a rotation rate of 180 rpm. The maximum values are 20.54?10-6 m/s, 7.86?10-6 m/s, 9.38?10-6 m/s, 5.53?10-6 m/s, respectively.