Speaker
Description
Ladle furnace (LF) refining is one of the most popular secondary refining processes to produce clean steel and largely takes the responsibility in the whole steelmaking process. The performance of slag dramatically determines the refining efficiency. In order to realize the precise control of the composition content for refining slag to ensure the optimal performance of CaO-SiO2-MgO-Al2O3 slag system, the optimization model of thermodynamic performance for refining slag was established and verified based on thermodynamic simulation and laboratory test. Firstly, the experimental scheme was designed according to the Box-Behnken principle. The melting point, sulphide capacity, and slag viscosity were selected as the response variables, and the temperature, basicity, w(MgO) and w(Al2O3) were selected as the process parameters. The value of response variables was obtained using the Factage© and KTH model based on the experimental scheme. Meanwhile, the effect of different process parameters on each response variable was analyzed. In addition, a continuous variable surface model of each response variable and different process parameters was established with the response surface methodology (RSM). Furthermore, the multi-response problem was transformed into a single response problem with the maximization of the weighted geometric mean of the composite desirability function by introducing the desirability function, and then the optimal experimental scheme was obtained. Finally, the laboratory test was conducted under the optimal scheme to verify the reliability and accuracy of the optimization model. This method can be used to calculate the precise composition content of slag system to ensure that refining slag meets the requirements of low melting point, high sulphide capacity and reasonable viscosity ranges.