Study of the interrelations of blowing parameters, options of electric influence and nature of liquid spraying by physical modeling

The main and decisive factor of blowing in oxygen converters is interaction of high-speed oxygen jet with a molten bath. The features of this interaction determine hydrodynamics and level of metal losses with slopping and spitting. Their study is most accessible with cold modeling. The paper presents results of laboratory studies on the physical model of a 160 ton converter manufactured at a scale of 1:30 to study the influence of blowing modes on character of liquid spraying. It is blown through a lance with five nozzle tips at 10 horizons in model height on three zones of working volume of converter model: area near lance, area near the wall and out-of-model area. That in practice corresponds to intensity of formation of skull on the lance, on converter mouth and on elements of the fume gas collecting system. It was found that the total amount of liquid sprays carried out of the model is extreme and depends on level of lance position, with a noticeable decrease in the amount of sprays at zero height above the liquid, and above certain values. The possibility of reducing of the intensity of splashing formation and the level of liquid loss within the investigated zones was determined by applying a low-voltage electric potential: with negative polarity in the area near the lance and near the walls, and with positive polarity – out of the model. It was revealed that beginning of practical influence of the potential and the maximum value of “useful” power allocated in the sublance zone is determined by specific combination of pressure before the nozzle and the level of tip of the lance: the higher the pressure in front of the nozzle is, the higher lance position is needed to reach maximum values of “useful” power. The experiments, conducted on physical model during blowing of saline solutions with gases at using of electric potentials, have shown possibility of extending the scope of developed method to processes not related to metallurgy.

High-temperature study of the features of metal blowing in the converter through the top oxygen lance with an annular slit nozzle

The aim of the work is to study on the physical model of an oxygen converter the interaction of an oxygen jet flowing from a coaxial slotted nozzle with an iron-carbon melt. During cold modeling of the blowdown, it was found that the gas jet flowing out of the nozzle along the propagation axis has a large dynamic pressure compared to the cylindrical nozzle, as a result of which it penetrates deeper into the liquid. Comparative analysis of video materials obtained during high-temperature melting revealed gas-dynamic differences in the nature of the interaction of the jet from the coaxial slit nozzle with the surface of the melt, especially at the beginning of the melt blowing, when the slag emulsion was not yet formed. Comparison of the results of high-temperature modeling of the interaction of the oxygen jet flowing from the coaxial slit nozzle with the metal melt when compared with the work of the four-nozzle tip showed that earlier ignition of the heat was observed, active absorption of lime and visually more rigid character of the blowdown with the formation of a smaller amount of slag than in the comparative melts. The conclusions obtained at the «cold» modeling stage were confirmed on a higher dynamic head and deep penetration into the jet melt using an experienced tip. It is revealed that the use of an experienced tip contributes to a greater heating of the bath and a reduction in the level of dust.