Ferro manganese can be classified into three grades: high carbon ferro manganese, medium carbon ferro manganese, and low carbon ferro manganese. Each grade has different content specifications. High carbon ferromanganese has a carbon content of 7-8%, while low carbon ferromanganese has a carbon content of less than 1%. Observing the medium carbon ferro manganese specification, we can see that the manganese content ranges from 75-85% and the carbon content ranges from 1-2%.
Medium Carbon Ferro Manganese Specification
| Brand | Mn | C | Si | P | S | ||
| Ⅰ | Ⅱ | Ⅰ | Ⅱ | ||||
| FeMn82C1.0 | 78.0-85.0 |
1 |
1 | 2.5 | 0.2 | 0.35 | 0.03 |
| FeMn82C1.5 | 78.0-85.0 | 1.5 | 1.5 | 2.5 | 0.2 | 0.35 | 0.03 |
| FeMn78C2.0 | 75.0-82.0 | 2 | 1.5 | 2.5 | 0.2 | 0.4 | 0.03 |
The production of ferro manganese from manganese ore can be carried out using electric furnaces, blast furnaces, and other smelting methods. Taking blast furnace smelting as an example, improving the manganese recovery rate is a key concern. Ferromanganese plants achieve this by optimizing slag formation, adjusting the charge structure, and increasing the hearth temperature to reduce the loss of manganese as MnO in the slag.
As an alloying element, the addition of ferromanganese and silicomanganese enhances the strength, hardness, ductility, and formability of carbon steel and alloy steel. The formulation depends on the production method and the final application. Generally, carbon steel contains 0.25%-1.0% Mn, alloy steel contains 0.3%-1.9% Mn, high-strength low-alloy steel contains 0.2%-1.5% Mn, stainless steel contains 0.3%-10.0% Mn, and manganese steel and abrasion-resistant steel can contain up to 14% Mn.
Ferromanganese is added during steelmaking to remove excess sulfur and oxygen from the steel. High sulfur content in steel billets can cause cracking, as it reduces the uniformity of the billets. Manganese combines with sulfur to form manganese sulfide slag, which separates easily from the molten steel, thereby removing the sulfur. Although large quantities of manganese are used in steelmaking, the majority is used in steel with low manganese content. High-manganese steel, containing more than 5% Mn, accounts for less than 2% of total manganese consumption. In other words, over 70% of global manganese demand comes from crude steel with less than 1% manganese content, which constitutes more than 80% of total steel production.
