The main objective of this review is to demonstrate the significant role of physicochemical principles in the development and improvement of technologies of iron and steelmaking. We discuss how the principles have been useful in the reduction of coke rate and improvement of productivity of the blast furnace. These principles have also contributed greatly in the continuous evolution of steelmaking processes from the Bessemer to the Top Blown LD to the Combined Blown Converters, the refining by synthetic slag, and stainless steelmaking processes such as argon oxygen decarburization (AOD) and vacuum oxygen decarburization (VOD).