1. A method for optimizing the operation of a metallurgical plant using a model, comprising the steps of: modeling a number of units of the metallurgical plant to which to be supplied and discharged media streams are assigned; predetermining structure parameters to an optimization computer by a user and transmitting the parameters from the optimization computer to the model, the structure parameters defining at least the number and type of the units as variables for the model; predetermining a linking of the media streams on the basis of the structure parameters, in such a manner that each media stream which is to be fed to one of the units is fed to the respective unit either from outside the plant or from another of the units, and each media stream discharged by one of the units is discharged either to outside the plant or to another of the units; predetermining starting parameters which describe initial states of the units as variables for the model; predetermining input operating parameters, which describe a first part of the media stream profiles, as variables for the model; determining and outputting output operating parameters, which describe the remainder of the media stream profiles, by the model; determining and outputting end parameters, which describe end states of the units, by the model; predetermining an assessment criterion that provides a relative priority of at least one measurable characteristic related to the operation of the metallurgical plant; predetermining at least one unit of the metallurgical plant to be flexibly linked to at least one other unit via one or more media streams, and predetermining conditions for such flexible linking to be used as input by the model; and determining optimized operating parameters by the optimization computer on the basis of the starting parameters and the assessment criterion in accordance with an optimization algorithm using the model.