Basic Process

Ferro-alloys are produced by reducing metals from their oxides contained in ores by using a suitable reduction under conditions created to ensure a high recovery of the valuable elements from the starting materials. Such reduction reactions are characterized by stability of an oxide at high temperatures. The stability of all oxides will become more stable with increasing temperature. An element which forms a stronger oxide can under appropriate conditions be used as reductant for a less strong oxide. The reaction will proceed successfully if the difference of oxygen involved with a small difference, favorable conditions should be formed to make the reaction proceed.

The presence of iron or iron oxides can facilitate some reduction processes. Iron dissolves the reduced element, forms a compound with it, and thus lowers the melting point of an iron element alloy is lower than that of the pure element, e.g. in Ferro-manganese production, and therefore the reaction of reduction of the element can proceed at a lower temperature.

Silico-manganese an alloy of manganese with silicon and iron is a semi-product used for smelting of medium and low carbon Ferro-manganese. As mentioned earlier, Silico- manganese is also employed as a complex deoxidant in steel making and (upon melting together with aluminium) to produce a complex manganese-silicon-aluminium (M-Si-A) deoxidant.

The process for smelting Silico-manganese essentially consists in manganese and silicon being simultaneously reduced from manganese silicates, slag, ore and quartzite. The process relies on a higher temperature than that needed for smelting Ferro-manganese. The process is carried out continuously under slag having a ratio of 1:1.

Charging and furnace top maintenance are done essentially in the same way as in Ferro- manganese. The metal and slag are tapped from the furnace every two hours. The thick slag at tapping entrains much of metal beads, which has a negative effect on manganese recovery. The slag can be made more fluid by adding raw dolomite.

The metal and slag are tapped through same tap hole in a similar way to Ferro-manganese.