The effect of hot metal temperature and rotation speed on the desulfurization rate in mechanical stirring process was investigated with laboratory scale (30 kg), pilot plant scale (4 ton) and commercial plant (270 ton) tests. The results obtained were summarized as follows.
1) Desulfurization rate of the experiments started at 1250°C was 0.7 times lower, than that started at 1350°C.
2) Activation energy of the desulfurization rate was 43.9-143.9 kJ/mol. The observed rate of desulfurization was interpreted in terms of the rate controlled by sulfer transfer in hot metal and the entrainment of desulfurization flux into the hot metal.
3) Difference of the desulfurization rate between the experiments at 1250°C and at 1350°C was decreased by increasing the stirring energy in pilot plant scale tests.
4) In the commercial plant test, sulfer content could be reduced less than 0.001 wt% by high speed rotation (>120 rpm) in spite of low hot metal temperature below 1250°C.
