On the relation between optical basicity and phosphorus capacity of complex slags

In this work, the coexistence of monomer and dimer phosphate ions is considered and their relative proportions, as related to the slag phosphorus content, is used to accurately calculate the slag capacity of phosphorus as monomer and dimer phosphate ions respectively. The slag capacity of phosphorus as monomer phosphate ions is discussed to clarify the applicability of different scales of optical basicity. It is found that the theoretical optical basicity is an excellent measure of slag phosphorus capacity for a wide range of slags and seems not to be restricted to certain components or compositional limits. As a result, excellent relationship is displayed between phosphorus capacity, temperature and theoretical optical basicity. The influence of slag composition on equilibrium oxygen distribution is also considered and it is found that the oxygen concentration in liquid iron can be closely related to temperature and theoretical optical basicity.