Kinetic model of dephosphorization in the new double slag converter steelmaking process

ABSTRACT

The kinetic investigation of the dephosphorization in the new double slag converter steelmaking process was carried out based on the coupled reactions model combining with a heat balance temperature model for the 220-ton industrial experiment. The calculated results of [%C], [%Si], [%P] in the hot metal, and the slag compositions are in good agreement with the experimental results. When the heat balance temperature model is applied, the P prediction results are better rather than those predicted by using the fixed temperatures. The calculated phosphorus distribution ratio increases with the refining time, while the phosphate capacity shows a downward trend due to the decrease in slag basicity and the increase in temperature. The rate-controlling step of the dephosphorization is determined to be the mixed control of the mass transfer of P in the hot metal and P₂O₅ in the slag. As the initial Si concentration is increased, the interfacial oxygen activity required for starting the dephosphorization is increased, leading to the delay of the dephosphorization start time.

KEYWORDS:

• Dephosphorization
• kinetic model
• heat balance temperature model
• double slag
• converter steelmaking

Acknowledgements

The authors gratefully acknowledge the financial support from the Natural Science Foundation of China (No. U1960202), and the Science and Technology Commission of Shanghai Municipality (No. 19DZ2270200).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Science and Technology Commission of Shanghai Municipality [grant number 19DZ2270200]; Natural Science Foundation of China [grant number U1960202].