DISSOLUTION OF MGO IN STAGNANT CAO-FEO-SIO2 SLAGS

The rate of dissolution of pure dense MgO compacts in synthetic, stagn ant CaO-FeO-SiO2 acid slags has been studied in the temperature range 1473-1673 K. The results indicate the topochemical formation of a dens e magnesiowustite layer at the interface between MgO and the slag phas e. The growth of the product layer during the reaction as well as the decrease of the radius of the MgO core in partially reacted samples we re measured at various time intervals by microscopic analysis. The con centration profiles of iron and magnesium in the magnesiowustite layer for various slag compositions and temperatures were measured by elect ron dispersive spectroscopy. The mechanism of MgO dissolution in the s lag and the growth of the oxide layer are discussed in relation to the diffusivities of the cations in the solid solution.