Vaporization of iron and phosphorus from iron-phosphorus melts in oxygen-bearing gas streams

Experiments have been made to demonstrate that when an oxygen-bearing gas is blown on the surface of iron-phosphorus melts, iron and phosphorus vaporize at rates enhanced by vapor-gas phase reactions. These findings are in accord with the theoretical predictions. The reaction mechanism considered is based on the concept of vaporization of phosphorus at the surface of iron as volatile PO and PO₂, which then react with iron vapor and oxygen in the gas close to the surface of the melt. If powdered lime were present, as in the Q-BOP, a relatively stable calcium phosphate would form, thus bringing about dephosphrization. From the available thermodynamic data and reaction-equilibrium data, equilibrium constants have been derived for the reaction of PO and PO₂ with liquid iron.