Inclusion engineering models currently use thermodynamic models to describe slag-metal equilibria at various processing stages. Often, however, the predicted slag-derived inclusions do not compare well with measured compositions and reoxidation or solute reactions must be included for calculated results to agree with those observed. Clearly, the non-metallic inclusion population in the final product will be the result of a whole series of interactive events involving local equilibria and process kinetics. To understand the individual mechanisms that take place during inclusion generation, their interaction with steel, refractories, slag, and atmosphere, and their removal from or retention in the steel, it is necessary to account for the time dependent interactions that occur during steel processing. This holistic approach requires a step by step account of the changing element concentration and temperature gradients in the steel, taking into account the effect of fluid flow and stability of the resulting inclusions. As a first step, two- and three-dimensional mathematical modelling of the fluid flow and the temperature and concentration gradients within a steel ladle during tapping, alloy addition, and stirring operations has been carried out and the local inclusion compositions within the steel predicted.