The TCOX database not only contains solid oxide phases (refractory materials, non-metallic inclusions, and so on) and the oxide and sulfide liquid phase (often termed slag and matte phase respectively), but -very importantly- it also contains the full description of the metallic liquid phase, and also the most important solid metal phases, such as FCC_A1, BCC_A2 (austenite and ferrite, respectively) and a comprehensive collection of carbides. This means that full process metallurgical calculations involving metallic, non-metallic, and the gas phase can be performed using one single database.
In this example, the composition of 100t of liquid steel that is in equilibrium with about 3t of a CaO-rich slag phase at 1600 °C is plotted as a function of oxygen partial pressure. The important result is that the Phosphorous partitions to the slag phase at high oxygen partial pressures, whereas the Sulfur partitions to the slag at low oxygen partial pressures. This result has far reaching consequences in steelmaking and -refining and explains why it is extremely difficult to simultaneously desulfurize and dephosphorize steel and why the two are performed in separate processing steps.