This alloy, containing 65 to 68 percent manganese, 16 to 21 percent silicon, and 1.5 to 2 percent carbon, is produced by the smelting of slag from high-carbon ferromanganese or of manganese ore with coke and a quartz flux. Smelting temperatures are higher than in ferromanganese production, and greater energy is needed to reduce the quartz to silicon.

Lumpy, 65-75% Mn basis, 14-25% Si, min. 65% Mn, max 17% Si