Study And Application Of Slagging And Desulphurization Model For Ladle Furnace Refining Process

LF refining as an important part of steelmaking has the function of desulphurization with white slag refining. Therefore, stuying reasonable slagging system and the factors of desulfurization, establishing the slagging and desulfurization model of LF refining and predicting the sulfur content of molten steel and refining slag content accurately have an important meaning.This article is based on the thermodynamics and kinetics of deoxidation and desulphurization, study deoxidation and desulphurization of a steel plant during converter tapping process, and the stuy focuses on 135t ladle furnace of the steel plant, real-time forecasting model of molten steel sulfur content and refining slag content are established, and the automatic control and online verification of the model is achieved. The main contents and conclusions were drawn as follows:(1) The sulfur content of molten steel is controlled below 0.005% through establishing predeoxidation and predesulfurization model during the process of converter tapping, so the desulfurization task will advance and then relieve the burden of LF refining.(2) It obtains the yield of aluminum under different oxygen content through analyzing experimental data and thermodynamic calculation, and establishes feed line deoxidation model according to the change of aluminum's yield in deoxidation process.(3) The article established slagging desulfurization model of LF refining, and the KTH sulfur capacity model is used to calculate sulfur distribution ratio in desulfurization mechanism in the model, and according to the actual production implement the real-time calculation of sulfur distribution ratio, so that the model can calculate the real-time sulfur content in molten steel and refining slag content.(4) The online validation of slagging and desulfurization model for LF refining shows that:the hit rate whose forecast error of feed rate of aluminium wire within ±10 m is 84.2%, the hit ratio whose forecast error of sulphur content within ±8×10-6 is 86.8%, and the hit ratio whose forecast error of refining slag within ±10 kg is 81.6%.(5) The online automatic control and application of the model is achieved, and prediction hit ratio will be improved through the further study on slagging desulfurization mechanism and field debugging.