The dissolution rate of Al 2 O 3 into the CaO-SiO 2 -Al 2 O 3 slag system was investigated at 1 873 K by employing a novel experimental method which involved continual measurement of the torque variation on a rotating alumina rod dipped into a molten slag. Measured torque variation was successfully related to the dissolution rate of the rod. The dissolution rate of alumina was found affected by a number of factors: the rate increased with increasing temperature, the rotating speed of the rod, the CaO content in the slag, and the Al 2 O 3 content in the slag for a fixed CaO content. It was found that the dissolution rate was highly dependent on the viscosity and the diffusivity of slags. The activation energy obtained from an Arrhenius type analysis was in the range of 84 kJ mol Ϫ1. It was concluded that the dissolution of Al 2 O 3 into the CaO-SiO 2 -Al 2 O 3 slag system was controlled by the mass transfer in the slag phase. An iso-dissolution rate diagram was constructed for the dissolution of Al 2 O 3 into the CaO-SiO 2 -Al 2 O 3 slag system at 1 873 K.

The rate of desulfurization was investigated by allowing liquid iron droplets to fall through a CaO-Al 2 O 3 -MgO slag layer at 1 600°C. Droplet falling velocity decreased by increasing the sulfur content in the metal. The sulfur transfer was well represented by a first order reaction rate with respect to the sulfur concentration of the metal. The rate of desulfurization during dynamic contact while falling through the slag layer was about two orders of magnitude larger than that of the static contact between the metal and slag. The enhanced rate of desulfurization during the dynamic contact was attributed to the combined effect of (1) the continual contact of fresh slag while falling, (2) enhanced internal circulation in the metal phase, and (3) most importantly, emulsification of the metal/slag interface, which greatly increases the reaction area. The rate of desulfurization was affected to a large extent by slag composition. It was tentatively concluded that slag composition influences the rate of desulfurization by affecting both emulsification of the metal/slag interface and the interfacial reaction of sulfur transfer.

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The steam power plant is becoming more important to supply a stable power lately. Desuperheater of the steam power plant facility plays a role in maintaining the proper superheat to avoid damage turbine power due to the superheated steam produced in the boiler. In this study, when the steam flows 530℃, 36.7 kg/s, 1.36 MPa in the 460mm pipe, variable orifice nozzle developed in Korea was carried out the performance analysis in coolant injection conditions of 150℃, 4.28 MPa. Findings, steam pipe coolant temperature was maintained at 446 ℃ and sprayed droplet size was verified by 50μm or less.

An equilibrium study was carried out at 1873K to ascertain the effect of carbon in CaO‐SiO2‐Al2O3‐MgO‐MnO‐FetO slag systems on their FetO and MnO activity coefficients, representing the slags’ thermodynamic potential for steel reoxidation. Both γfeto and γmno showed not only a sharp increment but also a simultaneous slow decrement by increasing carbon content in slag, suggesting opposite roles of the carbon according to its stable forms. XPS (X‐ray photoelectron spectroscopy) was introduced to clarify the stable forms of carbon in slag. XPS results prove that carbon dissolves in slag as carbonate, and carbide ions under oxidizing and reducing atmospheres, respectively. It was concluded that carbonate ions increase γfeto and γmno, but that carbide decreases them. This paper suggests an application method of the present results to actual ladle refining processes, in order to enhance steel cleanliness with maintaining (FetO + MnO) in slag to some allowable amount.