The Influence of Oxygen on the Rate of Nitrogen Absorption into Molten Iron and Marangoni Convection
Under the condition of non-induction stirring, the Marangoni convection that occurred in the process of nitrogen absorption into the liquid iron with various oxygen contents was investigated. Using the periscopic high temperature lens and X-ray radiography system, the surface velocity induced by the Marangoni effect due to the nitrogen absorption into liquid iron was observed and the surface velocity was measured. The surface velocity decreased with the increase of oxygen contents. In the present study, the rate of nitrogen absorption into liquid iron containing 20-500 ppm oxygen could be described with a first order rate equation, and the process of nitrogen absorption is dominated by the mass transfer in the liquid iron. The apparent mass transfer coefficient was reduced with increasing oxygen concentration. This is mainly due to the dwindling of the Marangoni convection on the surface of liquid iron.
- ISIJ international
ISIJ international 38(3), 220-228, 1998-03-15
The Iron and Steel Institute of Japan