This is a master alloy of manganese and ironused for deoxidizing steels, and for adding manganeseto iron and steel alloys and bronzes.Manganese is the common deoxidizer andcleanser of steel, forming oxides and sulfides that are carried off in the slag. Ferromanganeseis made from the ores in either the blast furnaceor the electric furnace. Spiegeleisen is a formof low-manganese ferromanganese and the Germanname, meaning mirror iron, is derived fromthe fact that the crystals of the fractured faceshine like mirrors. Spiegeleisen has the advantagethat it can be made from low-grade manganeseores, but the quantity needed to obtainthe required proportion of manganese in thesteel is so great that it must be premelted beforeadding to the steel. It was used for making ironsand steels by the Bessemer process.
