Effect of magnesium injection process on hot metal desulfurization

To solve the technical problems of hot metal desulfurization by injecting magnesium particulate, a new method of hot metal desulfurization by bottom-blowing magnesium vapor combined with mechanical agitation was put forward. The effects of three different desulfurization processes on the desulfurization efficiency were studied in view of thermodynamics and kinetics. It was found that the utilization efficiency of magnesium can reach 82.6% and desulfurization efficiency can reach 86.2% during the first 4 min using the method of magnesium vapor injection combined with mechanical agitation. The gasification of magnesium powder leads to significant splashing and magnesium losses in the process of magnesium powder injection, resulting in a low utilization efficiency of magnesium of 51.8% and a low desulfurization efficiency of 55.76%. Activation energy for a first-order kinetic relationship between magnesium powder and sulfur was measured from the experiments, which was 142.82 kJ/mol in the temperature range of 1573-1723 K. The activation energy of the reaction between magnesium vapor and sulfur was around 54.8-65.0 kJ/mol in the temperature range of 1573-1723 K, which indicates that the desulfurization with magnesium vapor proceeds relatively easier than the desulfurization with magnesium powder.

Kinetics of hot metal desulfurization by bottom blowing magnesium vapor

To solve the technical problems of hot metal desulfurization by injecting magnesium particulate,a new idea of hot metal desulfurization by bottom-blowing magnesium vapor was put forward.The reaction mechanism of hot metal desulfurization with magnesium vapor injection was analyzed,and the kinetic model of the desulfurization rate during the process of hot metal desulfurization with magnesium vapor injection was established.The dimensionless equation of the gas–liquid mass transfer coefficient under the injection conditions was obtained by the dimensional analysis method.And the theoretical calculation results were in good agreement with the experimental measurements.The results show that the diameter of the bubbles and the viscosity of the melt significantly affect the desulfurization rate of hot metal injected with magnesium vapor.When the temperature is 1573 K and the gas flow rate is 3 L/min,the desulfurization rate can reach 79%and the utilization rate of magnesium can reach 83%.

The Recent Progress of Hot Metal Desulfurization in CSC and DSC

There are two kinds of existing processes for hot metal desulfurization in CSC. One is the injection process in torpedo car, the other is the impelling process in transfer ladle. Lime-based fluxes have been used for both processes. The former was introduced to CSC in 1982. The latter was adopted by CSC and DSC respectively in 2004 and 2010. This paper comprises a theoretical analysis on lime-based flux as desulfurizing agent and an experimental evaluation on impelling process of Kambara (or Kikai) Reactor with a water model and a hot model established in 2001. The comparison of recent mass-production performance for both processes in steelmaking shop has also been included.