The development of useful models for predicting and controlling Oxygen Steelmaking is very difficult because of the complex multi-phase physics and chemistry of the process. In particular, the relationship between the physics of droplet generation and behaviour in the emulsion with the physico-chemical behaviour of the droplets has been difficult to quantify. Recently, researchers at Swinburne University of Technology have been developing models that link the dynamic physics associated with the lance with the chemical processes. This has resulted in a more comprehensive understanding of the process dynamics of the oxygen steelmaking and a fully predictive model for the de-carburisation kinetics is under development. Result and discussion on how this work impacts on the practical operation of steelmaking furnaces will be discussed in the paper.