Abstract
Characteristics of CaO-CaCl2 fluxes were studied in order to develop a new refining process of hot metal which would enable the production of steelmaking slag to decrease from the standpoint of environmental issues and improvement of controllability of LD process. Conditions of simultaneous dephosphorization and desulphurization of hot metal were investigated based on electrochemistry of the slag-metal system.
The results are summerized as follows:
1) Larger distribution ratios of sulphur and phosphorus of the flux to the metal are necessary for simultaneous dephosphorization and desulphurization of hot metal from equilibrium and kinetic considerations.
2) Anodic reaction of phosphorus removal from the iron saturated with carbon is coupled with the cathodic reaction of sulphur removal, in the case of using a flux with large sulphide and phosphate capacities such as CaO-CaCl2. But additional oxidizers are necessary to attain effective dephosphorization.
3) CaO-CaCl2 was found to have many excellent characteristics such as larger phosphate as well as sulphide capacities than those of conventional slags, extremely low viscosity like water, low melting point and the small rate of vaporization.
4) High alumina brick is hardly attacked by CaO-CaCl2 but high zirconia brick is eroded remarkably.
