Mathematical model of hot metal desulphurization by powder injection

A macro kinetic analysis of the hot metal desulphurization with powder inje ction has led to that there are three basic parameters which determine the desulphurization rate, as well as the powder utilization efficiency. They a re the penetration ratio (PR) of injected powder into the melt, the residen ce time distribution (RTD) of injected powder in the bath. as well as the h omogeneous mixing time (HMT) of the bath. Both PR and HMT have been experim entally determined with water modeling, while the RTD has been determined f rom either flow field information or experimental measurements of water mod el with stimulus-response method. arriving at the correlation formulas betw een the parameter and the injection operation variables as well as powder c haracteristics. This has enabled the development of a mathematical model to predict the desulphurization process. Based on further analysis of the mechanism and macro kinetics of the proces s. a mathematical model has been developed, with the three basic parameters being taken into account. to simulate the variation of [S] in hot metal wi th time. Water-model experiment results, flow field information and industr ial data are used to determine the model parameters and verify the model, l eading to the result that the prediction from the model agrees well with pr actical results. In addition to CaO and CaC2 powders, the use of granular M g has been particularly included and emphasized in the model for its more a nd more popular application. The coupling effect of hot metal desulphurizat ion by injection of magnesium-CaC2 mixture was discussed.