Capacities of some CaO–SiO₂–FeO–MnO–MgO slags and slag–solid mixtures in capturing phosphorous

Abstract

Slag is of great importance for dephosphorisation in converter steelmaking. In the present study, slag samples were equilibrated with copper at 1923 K to study their capacities in capturing phosphorous. The phosphate capacities of the slags were calculated. Some of the samples were liquid–solid mixtures. The solid phases in these samples were identified by SEM analysis, and the identified phases were found to agree well with Thermocalc calculations. On the other hand, the fractions of the solid phase did not agree with the Thermocalc calculation. Phosphorous distributions in the different phases were examined, and the phosphate capacities of the samples were evaluated. The MgO content did not show any appreciable impact on the phosphate capacity. The activities of FeO in the pure liquid slag samples were calculated and found to deviate positively from ideality.

Keywords:

• Phosphate capacity
• Converter
• Slag
• Activity of FeO
• Solid particles

The EU Commission and the Research Fund for Coal and Steel are gratefully acknowledged for the financial support through the project BATHFOAM (project no. RFSR-CT-2008-00004).