How do blast furnaces produce ferromanganese?

Ferromanganese is produced by the smelting of manganese-bearing ores in a blast furnace or an electric furnace.12

In a blast furnace, the process involves the reduction of manganese oxides by carbon, which is supplied as coke. The furnace is charged with a mixture of manganese ore, coke, and a flux such as limestone. As the charge descends through the furnace, it reacts with ascending reducing gases, primarily carbon monoxide, at high temperatures. While higher manganese oxides can be reduced to manganous oxide (MnO) by carbon monoxide, the final reduction to metallic manganese requires higher temperatures and the presence of carbon.13

The resulting product is a carbon-saturated ferroalloy that typically contains 76 to 80 percent manganese, along with iron, carbon, and silicon. During this process, the chemical conditions also cause some silica and manganous oxide to be reduced, allowing the manganese to dissolve into the hot metal.45