The process of AOD refining furnace

Source: | Author:ChangXing Refractory | Published time: 1610 days ago | 940 Views | Share:

At the beginning of AOD furnace oxygen blown to oxidize and decarbonize. During the oxidation period, the oxidizability of slag is enhanced and the temperature rises to above 1700 ℃. Then, ferrosilicon or aluminum is added to reduce chromium in slag to improve alloy yield. At this time, the basicity of slag is still very low. Finally, lime is added to remove sulfur, and high basicity slag is required for desulfurization. In the whole smelting process, the slag changes from acid to alkaline atmosphere, from oxidation atmosphere to reduction atmosphere, and then intermittent operation, the lining temperature is high and fluctuates greatly. Therefore, the service life of AOD lining is very low.

In the past, the service life of AOD furnace was only about 30 heats. By improving smelting conditions and adopting gunning maintenance measures, the service life of AOD refining furnace generally reached more than 70 heats, many of which exceeded 100 heats. For AOD furnace, magnesia chrome brick is generally used. Due to the complex production process of magnesia chrome brick, ultra-high temperature firing, high energy consumption, high cost, especially environmental pollution problems, magnesium chromium brick is gradually replaced by magnesium calcium brick.

At present, there are more and more magnesia calcium bricks, and some parts are made of low-carbon magnesium calcium materials. For magnesium calcium materials, there are also asphalt impregnation. It is worth pointing out that when the smelting temperature is very high, the carbon containing refractories are not suitable due to the internal oxidation-reduction reaction. Only use magnesia chrome brick or magnesia calcium brick.