<p> Iron-vanadium alloys were levitation melted and equilibrated at controlled temperatures with water vapour/hydrogen atmospheres of controlled composition, quenched and analysed for oxygen. The effect of vanadium on the behaviour of oxygen has been expressed in terms of first order free energy, enthalpy and entropy interaction parameters. </p> <p> The reduction of phosphorus from synthetic blast furnace slags by carbon saturated iron was studied under laboratory conditions. The rate of phosphorus transfer was determined and the results have been interpreted in terms of chemical reaction control at the slag/metal interface. </p> <p> The dephosphorisation of induction melted mild steel by synthetic basic slags was investigated. The rate of dephosphorisation was determined and the results have been interpreted in terms of mass transfer control in the slag phase. </p> / Thesis / Doctor of Philosophy (PhD)