At the top blowing AOD furnace decarbonization process, molten steel is refined with argon oxygen decarburization (AOD) process in a vacuum state. This process is highly efficient and can remove high amounts of carbon, silicon, and phosphorus all within a low-cost operation and a high degree of safety.
By using argon and oxygen, the initial furnace temperature can be lowered at the start of the AOD process. This increases the decarbonization rate and reduces the risk of excessive oxidation. As steel is heated and also cooled, it is continuously stirred to create an even, consistent temperature throughout the furnace. The stirring process allows for the most efficient removal of impurities and carbon from molten steel, resulting in a desirable product.
The decarbonization process is done in a completely sealed environment. As oxygen and argon are added to the bottom of the furnace, a vacuum is created and pressure is then slowly lowered until the optimum decarbonization temperature is reached. Afterward, the pressure is kept constant until decarburization is complete. During this process, the oxygen reacts with the steel to form oxides which are then removed during the thermal vacuum process. The slag resulting from this process is then regularly removed from the furnace.
With the AOD process, decarbonization can occur quickly and safely, while providing an optimum product. A low concentration of carbon dioxide is created that is shortly exhausted through the roof of the furnace while nitrogen is also injected in order to ensure that the process occurs quickly and efficiently.
In the top blowing AOD furnace, the oxygen and argon mixture is introduced near the furnaces upper limit. This arrangement increases the yields of decarburization and is also beneficial for reducing operating costs. In addition, it also prevents the oxygen and argon from reacting with the slag and forming hard masses which might block or disturb the flow of molten steel.
The top blowing AOD furnace technology is reliable and cost-effective. It is used in highly demanding steel plants and has proven advantageous in controlling dregs and inclusions while also producing superior quality steel. This process has had an immense impact on the ecology and on the future of industrial metallurgy.