Dissolution Rate of Burnt Dolomite in Molten Fe_tO-CaO-SiO₂ Slags

Abstract

Cylinders of burnt dolomite with the apparent porosities of 20 to 35% were immersed into molten Fe_tO-CaO-SiO₂ slags at temperatures of 1350 to 1425°C and rotated at 100 to 400rpm. The dissolution rates were determined by measuring the decrease in radius of cylinder.
The dissolution rate increased with increases in temperature and revolutional speed of cylinder, but was not affected by the difference in apparent porosity of burnt dolomite. From the analysis of experimental results, it was concluded that the dissolution rate was controlled by the mass transport of CaO in burnt dolomite for low Fe_tO slag (slag A) and that of MgO for other slags in the boundary layer of molten slag. Mass transport coefficients calculated were in the range of 4.7×10^-4 to 1.7×10^-3cm/s at 1400°C.
It was found that the burnt dolomite after the experiment was widely covered with (Fe, Mg) O solid solution in the case of high Fe_tO slag.