Thermodynamic analysis and experimental study of manganese ore alloy and dephosphorization in converter steelmaking
G Chen, S He
In this study, the effects of slag compositions, slag amount, temperature,
and carbon content of steel on the manganese and phosphorus distribution
ratios during converter steelmaking were analysed using the classical
regular solution theory, and industrial tests were performed using two 80 t
top-and-bottom combined blown converters (duplex melting process). The
results indicate that the slag amount, temperature, and carbon content in
steel are the main factors affecting the manganese yield when converter
slag compositions remain constant. The FeO content of the slag has a
strong impact on the manganese distribution ratio, while the slag basicity
and MgO content have no obvious effect. The calculations and experimental
results show that the phosphorus distribution ratio increases
sharply with increasing slag basicity R, but then decreases with the
increase of MgO and MnO contents in the slag. The final slag in converter
steelmaking should have the following characteristics: 3.5 < R < 4.5, 15% <
(FeO) < 20%, and 6% < (MgO) < 8%. The slag amount should be controlled
appropriately at the same time. The results of this investigation would be
useful in deciding on the application of manganese ore in alloying and
identifying the slagging regime in converter steelmaking.
Keywords: slag compositions, distribution ratios, classical regular solution theory,
slagging regime.