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The process of steelmaking in the route from primary steelmaking in the oxygen steelmaking converter or the electric arc furnace via the secondary metallurgy ladle treatment up to the continuous casting plant is connected with a high throughput of energy. A significant part of the energy input is needed to adjust the melt temperature according to the requirements of the continuous casting process. In general already at the primary steelmaking plant or within a following ladle furnace treatment an energy buffer is built up to compensate the energy losses during the following ladle treatment. The aim is to deliver the steel melt with an optimal temperature with respect to the continuous casting process at a predefined time.
For optimisation of melt temperature control for the complete steelmaking process route a through process approach is required. Based on analytical energy and mass balance models for the single process steps a through process, dynamic on-line observation and prediction of the temperature evolution during the steelmaking process is built. It comprises the treatment in the aggregate for primary steelmaking (oxygen steelmaking converter or electric arc furnace), starting with the last process step where the tapping temperature is adjusted, and the complete ladle treatment up to casting of the melt at the continuous casting plant. Special focus is laid on the thermal status of the ladle, which strongly influences the evolution of the melt temperature. Based on the dynamic prediction of the melt temperature evolution, the energy input and the temperature control in the different process stages is optimised. The target casting temperature is thus adjusted with less correction steps with high accuracy under minimized energy consumption.
This method is displayed below for a typical oxygen steelmaking route. An optimised through process temperature control is of great importance for those steel plants, where the complete energy buffer for secondary metallurgy ladle treatment has already to be adjusted before tapping of the primary steelmaking aggregate.
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