Metallurgical Reaction Characteristic for the Combined Blowing Process of Top-Bottom Blown Oxygen and Bottom Blown Natural Gas

The experiment was carried out in a combined blowing converter.The natural gas was supplied as the cooling medium for the bottom lance.The blow- ing practice of medium P hot metal (0.30-0.85% [P]) indicated that with better stirring at the bottom of the converter and lower P_(CO),this steelmgking process was favorable to reduce the amount of [C] and [O] and increase the (P_2O_5)/[P]. The maximum rate of dephospborization might be high up to 0.0a5%/min and the P content in steel could be reduced to lower than 0.03% by single slag-forming operation.

Physical simulation of bubble refinement in bottom blowing process with mechanical agitation

In order to increase the contact area and promote the mass transfer process of gas and liquid,the process of the bubble refine-ment in a metallurgical reactor with mechanical agitation was studied by physical simulation.Based on the capillary number,a prediction equation for the bubble refinement was established.The effects of the gas flow rate,the stirring speed and thestirring depth on the bubble refinement in the reactor were discussed in detail.The distribution of the bubble diameter in thereactor was obtained under different conditions.The results show that when the stirring speed reaches 300 r/min,the bubblediamcter mainly distributes in the range of 1-2 mm.A higher gas flow rate may increase the number of bubbles in the meltand promote the bubble refinement process.The mechanism of bubble refinement under mechanical agitation was analyzed.and the results indicated that the stirring speed.,the blade area and the blade inclination are the main influencing factors.

Physical Modeling of the Vacuum Circulation Refining Process of Molten Steel

The available studies in the literature on physical modeling of the vacuum circulation (RH, i.e. Ruhrstahl Heraeus) refining process of molten steel have briefly been reviewed. The latest advances made by the author with his research group have been summarized. Water modeling was employed to investigate the flow and mixing characteristics of molten steel under the RH and RH KTB (Kawasaki top blowing) conditions and the mass transfer features between molten steel and powder particles in the RH PTB (powder top blowing) refining. The geometric similarity ratio between the model and its prototype (a multifunction RH degasser of 90 t capacity) was 1:5. The effects of the related technological and structural factors were considered. These latest studies have revealed the flow and mixing characteristics of molten steel and the mass transfer features between molten steel and powder particles in these processes, and have provided a better understanding of the refining processes of molten steel.

Mathematical Modeling of the Vacuum Circulation Refining Process of Molten Steel

The available studies in the literature on mathematical modeling of the vacuum circulation (RH) refining process of molten steel have briefly been reviewed. The latest advances obtained by the author with his research group have been summarized. On the basis of the mass and momentum balances in the system, a new mathematical model for decarburization and degassing during the RH and RH KTB refining processes of molten steel was proposed and developed. The refining roles of the three reaction sites, i.e. the up snorkel zone, the droplet group and steel bath in the vacuum vessel, were considered in the model. It was assumed that the mass transfer of reactive components in the molten steel is the rate control step of the refining reactions. And the friction losses and drags of flows in the snorkels and vacuum vessel were all counted. The model was applied to the refining of molten steel in a multifunction RH degasser of 90 t capacity. The decarburization and degassing processes in the degasser under the RH and RH KTB operating conditions were modeled and analyzed using this model. Besides, proceeded from the two resistance mass transfer theory and the mass balance of sulphur in the system, a kinetic model for the desulphurization by powder injection and blowing in the RH refining of molten steel was developed. Modeling and predictions of the process of injecting and blowing the lime based powder flux under assumed operating modes with the different initial contents of sulphur and amounts of powder injected and blown in a RH degasser of 300 t capacity were carried out using the model. It was demonstrated that for the RH and RH KTB refining processes, and the desulphurization by powder injection and blowing in the RH refining, the results predicted by the models were all in good agreement respectively with data from industrial experiments and practice. These models may be expected to offer some useful information and a reliable basis for determining and optimizing the technologies of the RH and RH KTB refining and desulphurization by powder injection and blowing in the RH refining and for controlling the processes.

Multi-model coupling-based dynamic control system of ladle slag in argon blowing refining process

Since the current slagging of argon blowing refining process is relatively fixed,which cannot adapt to the fluctuation of converter smelting process,it poses the problems of poor metallurgical property of refining slag and a large amount of molten heel.An optimization system coupled with multiple models was proposed to dynamic control the ladle slagging in the argon blowing refining process.It can compile the optimal dynamic slagging scheme in real time under the guarantee of deoxidation performance and reasonable fluidity.The argon blowing refining slag composition range of CaO/Al_(2)O_(3)=1.3-1.7,CaO/SiO_(2)=6-12,w(MgO)=2%-6% was determined based on FeO activity and liquidus temperature by equilibrium thermodynamic calculation.In addition,it demonstrated better performance in the viscosity prediction task of the presented Visual Geometry Group 16-like one-dimensional convolutional neural network deep learning algorithm versus the Random Forest ensemble learning algorithm,as the adjusted coefficients of determination were 0.9712 and 0.9637,respectively.After the system was applied in operation,the argon blowing refining process was stable,and the steel yield was enhanced,which promoted the intelligent steelmaking level while achieving the cost reduction and efficiency improvement.