REACTIONS OF SLAG WITH REFRACTORIES: I, SURFACE REACTIONS *

A bstract Several new methods of studying the surface reactions of slags, glass, and Portland cement clinker with refractories were compared. The penetration of the slag into refractories and the slump of slag spheres disclosed considerable information regarding surface reactions which other tests failed to show. For the more refractory slags, such as Portland cement clinker, acid open‐hearth, copper reverberatory, and basic open‐hearth slags, these reactions were governed largely by the relative acidity or basicity of the slags and the refractories, i.e. , basic slags showed the greatest reaction with acid refractories and vice versa. For the more fusible materials, such as glass, lead blastfurnace slag, and coal ash, the relative acidity or basicity of the slag and refractory is less important. With these slags, the low porosity of the refractory, which prevents the penetration of the very fluid slags, probably is more important.