Simulation study on the influence of thickness and relative foaming height of refining slag on electrothermal characteristics in ladle furnace

Abstract

Electrothermal characteristics play a crucial role in ladle furnaces that utilize electric energy for heating purposes. In this paper, a three-dimensional electrothermal power calculation model of ladle furnace is established based on electromagnetism, the influence of thickness and relative foaming height of refining slag on electrothermal characteristics was studied, and the electrical conductivity of refining slag was measured using AC impedance method. The study revealed that the electrical conductivity of the primary slag and final slag is 101 S/m and 92 S/m respectively at 1575 °C. During energization and heating, the current is mainly conducted through electrodes, arcs, and molten steel, the three-phase current is finally connected in the molten steel near the interface between slag and molten steel, and a small amount of current is connected through refining slag. The electrothermal power of the arc accounts for the largest proportion of the total electrothermal power, reaching 96.8%, while the electrothermal power of the molten steel is the smallest. When the thickness of the refining slag increases from 0 mm to 150 mm, the electrothermal power of the refining slag increases from 0 kW to 759.7 kW, while the electrothermal power of the molten steel and arc decrease from 60.9 kW, 18783.5 kW to 44.3 kW and 17440.2 kW, respectively. When the relative foaming height increases from 0 to 150%, the electrothermal power of refining slag increases from 412.4 kW to 449.6 kW, and the electrothermal power of molten steel and arc decreases from 54.1 kW, 18172.1 kW to 51.1 kW and 17194.3 kW, respectively.