Browsing by Author "Eric, RH"
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Item Activity of MnO in MnO-CaO-M9O-SiO2-Al2O3 Slags at 1500°CCengizler, H; Eric, RHA thermodynamic study was made on the MnO-CaO-MgO-SiO2-Al2O3 slags that are typical of the production of ferromanganese in submerged arc furnaces. The Al2O3 content of the slags was kept constant at 5 per cent by mass. The activity-composition relationship in Pt-Mn binary alloys were re-determined for calibration purposes at 1300, 1400 and 1500 degrees C and po(2) values between 5.40 x 10(-6) and 4.54 x 10(-13) atm. A linear regression equation was derived to predict the activity coefficients of manganese, in Pt-Mn alloys at 1500 degrees C. The effect of concentration, basicity ratio and CaO-to-MgO ratio on MnO activities in above mentioned complex slags was investigated at 1500 degrees C and at two different po2 values of 4.76 x 10(-7) and 5.80 x 10(-8) atm. It was found that a(MnO) values increase with increasing MnO, and tend to increase with an increasing CaO-to-MgO ratio. The amnovalues also increase with increasing basicity ratio. The activity coefficient of MnO increases with an increase in its mole fraction in the slag. Quadratic multivariable regression model equations which represent the activity data successfully and which can be used to predict the MnO activities in the compositional range of this study were developed. The MnO activity data was interpreted in terms of a slag model which describes the thermodynamic properties of the slag successfully.Item SILICON AND MANGANESE PARTITION BETWEEN SLAG AND METAL PHASES AND THEIR ACTIVITIES PERTINENT TO FERROMANGANESE AND SILICOMANGANESE PRODUCTIONCengizler, H; Eric, RHEquilibrium between MnO-CaO-MgO-SiO2-Al2O3 slags and carbon saturated Mn-Si-Fe-C alloys was investigated under CO at 1500oC. Manganese and silicon activities were obtained by using the present data and the previously determined MnO and SiO2 activities of the slag. Quadratic multi-coefficient regression equations were developed for activity coefficients of manganese and silicon. The conclusions of this work are:(i)increase in the basicity and the CaO/Al2O3 ratios decreases the Mn distribution ratio,(ii)increase in the silica concentration and the MgO/CaO ratio increases the Mn distribution ratio, iii)carbon and manganese as well as carbon and silicon of the metal phase are inversely proportional,(iv)as Mn/Fe and Mn/Si ratio increases in the metal the carbon solubility increases,(v)decrease in the basicity increases the silicon content of the metal and (vi)increase in the silica content of the slag increases the silicon content of the metal and this effect is more pronounced at the higher Mn/Fe and Mn/Si ratios.