STUDY OF HOMOGENIZATION AND TRANSFER PROCESSES IN THE CASTING LADLE USING PHYSICAL MODELLING

The paper deals with modelling of homogenization and transfer processes in the 180 t ladle under different conditions of inert gas blowing. The model study was carried out on an acrylic glass model in the geometrical scale 1:9. Homogenization processes were observed on the base of the concentration response (monitored by temperature and concentration probes) when the concentration of potassium chloride (KCI) in water solution changed. Homogenization time (tau(H)) was determined at the time of the consistent concentration response on all probes. The experiments devoted to modelling of transfer processes were supposed to simulate the effect of inert gas blowing into the ladle on the kinetics of elements extraction into the steel slag. The steel is replaced with water and the slag phase is simulated by a carefully selected type of paraffin oil. The extracted element, such as sulphur under the operating conditions, is simulated in the modelling by iodine. Its concentration in extracted samples is determined by titration using sodium thiosulphate. Such obtained data are used to produce kinetics curves graphically showing the time-dependant decrease of iodine in a water solution. The discussion below is focused on the results in terms of homogenization as well as transmission processes between steel and slag phases during the argon blowing. The impact of various blowing modes on these processes is compared here too. Positions of the stir element at the bottom of the tundish are changed based on different argon flow rates in individual experiments of both methods. The results are organized into graphs of homogenization times (tau(H)) dependence on the gas volumetric flow, and into the kinetic curves showing the changes in iodine concentration in the water solution.