MANGANESE ALLOYS

Fe-Alloys such as Ferro-Manganese (FeMn) and Silico-Manganese (SiMn) are an integral part of steel production for the functions of deoxidization and desulphurization. They also impart special properties to steel such as increased resistance to corrosion, improved hardness, wear and abrasion resistance and improved tensile strength at high temperatures. For production of 1 tonne of crude steel, about 3 – 4 kg of FeMn and 4 – 6 kg of SiMn is required. Mn has no suitable substitutes in its major applications and also there is no way to recover the same from steel scrap as it combines with other elements present and goes out as slag during the steel scrap melting process. FeMn is produced in both Blast Furnace (BF) and Submerged Electric Arc Furnace (SEAF) and requires high-grade Mn ore while SiMn on the other hand is produced in SEAF and utilizes low- grade Mn ore. Also, SiMn consumes high amount of electricity as compared to FeMn yet it accounts for about 56% of the total production of Mn-Alloys.

Ferro Manganese: This is a type of Ferro alloy with a high content of Manganese. Made by heating mixture of MnO2 and Fe2O3 oxides with carbon in a furnace. These undergo thorough thermal decomposition reaction and are used as steel deoxidizer.

Silico Manganese: It’s a Ferro alloy with high Manganese and Silicon content. Made by heating a mixture of oxides, namely, Manganese oxide, Silicon dioxide, and Iron oxide with Carbon in a furnace. Silico-manganese undergoes a thermal decomposition reaction. Like others, it is also used as a deoxidizer and an alloying element in steel.

Demand of ferro-alloys (Fe-Alloys) which is obtained from Manganese ore is driven by the steel industry with about 90% of all the Fe-Alloys used in steel production while the balance 10% used in foundries and welding as represented in below chart. Further, out of the total Fe Alloys used in steel making, 70% is used as an alloying element and the remaining 30% is used as a deoxidizing and desulphurizing agent. Fe-Alloys are power intensive products requiring 3000 – 4000 KWH of power per metric tonne (t) of production hence most Fe-Alloy production plants have a captive power plant to support their operations.