Viscosities of Some Fayalitic Slags Containing CaF_2

摘要

In the effort to systematize the knowledge of the viscosities fo slags containing CaF_2 and to enable the prediction of the change of viscosities of mould flux slags, viscosity measurements of synthetic slags in the system "FeO"-SiO_2-CaF_2 were carried out in the temperature range 1450-1763 K. Five different fayalite slag compositions with "FeO" contents was varying between 55-65mass/100 in the homogeneous liquid range were chosen for the studies. The CaF_2 content was varied between 5 and 15 mass. Due to the reactions between the slag components and CaF_2, some CaO was formed during the premelting of the slags. Through analyais, it was found that, compositional changes due to fluoride evaporation occurred during the long premelting period. The libration of the volatile components SiF_4 AND FeF_2 during sample preparation was the main source for compositional changes. DTA experiments were carried out in order to determine the liquidus points of the slags studied. CaF_2 was found to decrease the liquidus temperatures.