Stirring patterns in foaming oxygen steel making slags.

A slice reactor has been constructed to study stirring patterns in jetted liquid/liquid reaction systems of the type found in top blown oxygen steel making processes. The two liquids used in the study have been mercury and highly viscous glycerol water mixture. The reaction has involved the oxidation of metallic sodium dissolved in the mercury by hydrochloric acid produced in the glycerol water mixture by jetting the liquids with a nitrogen hydrogen chloride gas mixture. The reaction takes place between droplets of the mercury amalgam and the acidified glycerol water solution, this reaction modelling the reaction that takes place in top blown steel making processes between droplets of iron carbon alloy and the oxidising slag. Gaseous hydrogen is produced by the reaction that has been studied, and it is bubbles of hydrogen that produce and maintain the foam within the slice reactor. The slice reactor has been constructed to represent a vertical section cut across the diameter of a centrally jetted axi-symmetric reactor of the BOS type, so that the jet is provided by a slit nozzle set at right angles to the sides of the reactor. The symmetry of gas and liquid flow patterns in the slice reactor is thus essentially two dimensional as opposed to the axi-symmetric flow patterns that exist in actual BOS reactors. The interactions between the two-dimensional jet and the liquids have been studied in the absence of any reaction in order to establish the extent to which the two dimensional system behaves in the same way as the axi-symmetrical system. Particular attention was paid in this study to the depth of the depression produced in the liquid surface by the impact of the jet and the conditions under which liquid was splashed out from the impact region. These studies showed that the characteristics of the two-dimensional jetting system are very similar to those of the axi-symmetric systems that have been extensively studied previously. The behaviour of the slice reactor in the presence of the reaction that produces and sustains the foaming slag has been studied by injecting a colour tracer into the foam and studying its movement. Two distinct flow zones have been observed in the foam, and the effect of changes in operating variables, such as lance height and gas flow rate, on these two flow zones has been studied. The presence of the tracer has allowed the metal droplets sprayed out from the jet impact region to be visible during their path through the foam. The size, velocity and spatial distribution of these droplets have been studied and their response to changes in the operating variables ascertained. As well as studying the behaviour of the reactor with a vertical jet produced from a single slit nozzle, a series of experiments have been carried out with two slit nozzles in which two jets of gas are produced at different angles of divergence. The behaviour of the system with these two slit nozzles has been compared with its behaviour with the single slit nozzle. The results of the investigation have been discussed in relation to the operation of industrial oxygen steel making processes.