Sungmo Jung

Slag foaming measurements were carried out for BOF type slags that exist during the first half of the blowing period in order to better understand slopping of slag. The foam index (Σ) decreases with increasing FeO up to about 20% FeO content and is almost constant for FeO from 20 to 32 % FeO. This is believed tobe because above about 25% FeO, the viscosity is nearly constant. The foam index shows a minimum value at basicity[5(CaO1MgO)/(SiO2+Al2O3 )] of 1.4 at 1 713 K; it increases at higher basi

The gasification of metallurgical cokes with CO 2 and H 2 O on their porosity and macrostrength were investigated in the current study. Cokes were reacted with CO 2 or H 2 O in the temperature range of 1100 to 1500 °C. During the reaction, the compositional change of product gases were measured by quadruple mass spectrometry (QMS) for evaluating the gasification rate. Image analysis was carried out to measure the porosity according to the distance from the coke surface. The porosity at the surfa

It is necessary to have information on the thermodynamic behavior of titanium oxide in ladle type slags in order to control the titanium content in several grades of steel. In the present study, the thermodynamics was determined from the equilibrium between Fe–Csat–Ti and CaO–SiO2-–30%Al2O3–MgO–TiOx slags in equilibrium with CO and from the equilibrium between Fe–Csat–(1618)%Cr–Si–Ti and CaO–SiO2–20%Al2O3–MgO–TiOx slags in equilibrium with CO. From the experiment with Fe–Csat–Ti alloy, the activ

It is necessary to understand the thermodynamic properties of MnO in steelmaking slags for the smelting reduction of Mn ore in BOF process. Studies of the manganese distribution between CaO–SiO2–FetO–MnO slags and liquid silver in equilibrium with solid Fe in the temperature range of 1623 to 1723 K were carried out under a CO/CO2 atmosphere.The FetO content in (32.436.3)%CaO–(31.644.0)%SiO2–(9.924.1)%FeO–(0.42.6)%Fe2O3–(8.910.8)%MnO slags was found to have a linear relationship with oxygen parti

Experiments were carried out on a system with artificially prepared slags in a graphite crucible, in order to examine the possibility of recycling BOF slags produced in the steelmaking process. More than 80% of FeO and P 2 O 5 was reduced within 20 minutes and the FeO reduction rate was greater than that of P 2 O 5 . P 2 O 5 reduction began after more than 60% of FeO was reduced. Increasing slag basicity enhanced the reduction of FeO and P 2 O 5 . Temperature also improved slag reduction. The ov

In order to understand the behavior of manganese oxide in smelting reduction process, the manganese equilibrium between ironmaking slag containing FeOand silver melt was investigated over the temperature range of 1 400-1 500'C. The oxygen partial pressure was controlled by COICO, ratio. Test results on Mn content in silver have been thermodynamically converted into those in supercooled or carbon-saturated iron melts and the activity coefficient of MnO in slag was determined experimentally. The a

Experiments were carried out in a system with BOF slags from industrial operations in order to optimize the conditions of recycling BOF slags produced in the steelmaking process. Reduction reactions of FeO and P 2 O 5 proceeded steadily and the FeO reduction rate was almost identical to that of P 2 O 5 . The reduction reaction of FeO and P 2 O 5 in BOF slag at the slag/gas interface is the rate‐controlling step. The reaction rates of FeO and P 2 O 5 by dissolved carbon in molten iron are of firs

The carbothermic reduction of MnO2 with graphite has been investigated for the reduction mechanism in the temperature range of 1000–1300°C. Although several researchers studied the reduction step from MnO2 to MnO, it was attempted to employ the in situ testing of reduction behaviour with the analysis of product gas composition simultaneously from the different points of view. The overall reduction rate increased with temperature, which was controlled by the carbon gasification. It is because the

The equilibria of manganese and sulfur between liquid iron and CaO-SiO 2 -Fe t O-MgO slags saturated with dicalcium silicate and MgO were studied in the temperature range of 1 823 to 1 923 K. The solubility of MgO decreases with increasing Fe t O content. The values of (%MnO)/[%Mn] increase with increasing Fe t O content and its relation was formulated by an empirical equation. The activity of Fe t O for the present slag system almost stays unchanged with increasing Fe t O content investigated.

Abstract The reduction of hematite–graphite pellet was investigated from a kinetic viewpoint in the temperature range of 1173–1473 K (900–1200°C). The experimental procedure included thermogravimetric analysis (TGA) for measuring the weight change of the pellet and quadruple mass spectrometry (QMS) for monitoring the compositional change of the product gases. By applying a uniform internal reduction model to the current system, the activation energies for the reduction of Fe 3 O 4 to wustite and

The worldwide steel companies are expected to use low grade iron ores such as pisolitic iron ores, high Al 2 O 3 iron ores and ultrafine iron ores etc. in their sinter blends due to the depletion of high grade iron ores or for the economic reason. This study investigated the methods for improving sintering characteristics without deteriorating sintering productivity and sinter quality by blending mini-pellets comprising high Al 2 O 3 pisolitic iron ores and ultrafine iron ores containing low alu