SIMULATION-MODELS TO DESCRIBE SECONDARY M ETALLURGY REACTIONS AND THEMELTING OF SOLIDS

Objective. In secondary metallurgy, it is extremely important to descr ibe the occurring reactions as a function of time and to have knowledg e of the melting behaviour of alloying and cooling agents in order to control production optimally and reproducibly and to keep with very ti ght analysis ranges. The exact description of these reactions is possi ble only by a computer simulation. Presented are two of the simulation models applied at Dillinger Huttenwerke AG. Summary. Two simulation m odels have been developed which constitute important tools for the opt imisation of secondary metallurgy. One model permits the description o f steel/slag reactions, such as desulphurisation using a lime-saturate d slag, while giving additional consideration to slag reduction. It is shown that this simulation model makes it possible to calculate the a chievable final concentrations as well as the requisite treatment time s. A further simulation model makes it possible to calculate the melti ng behaviour of ladle additions such as ferroalloys and cooling scrap in the steel heat. Taking the example of iron pellets, it is illustrat ed what influence the pellet radius, the superheating of the steel bat h, and the stirring action in the ladle has on the melting rate. With both simulation models presented, it is possible to optimize the metal lurgical treatment and utilise the plant and equipment capacity to opt imum effect. The simulation models also represent important tools with in the context of process control and quality systems.