slag

The vitreous mass left as a residue by the smelting of metallic ore.

To change into or form slag.

To form a slag, or to cohere when heated so as to become a slag-like mass.

The earthy matter separated, in a more or less completely fused and vitrified condition, during the reduction of a metal from its ore.

The scoria of a volcano.

A hollow or depression of land.

In the puddling process for making wrought-iron, the slag which forms when, as a preliminary step not always taken, air is blown down upon the surface of a charge of melted cask iron in a specially constructed hearth. Silicon is the principal substance removed from the iron, and the slag consists mainly of ferrous silicate.

In metal: To convert into slag: as, an excess of limestone used as a flux may to a greater or less extent slag the lining of a furnace.

To cake together as the result of chemical action at a heat lower than that of fusion.