High carbon ferromanganese is an alloy composed of manganese and iron.Produced by blast furnace method and electric furnace.
Modern large-scale ferromanganese reduction electric furnace has a capacity of 40000~75000 KVA, which is generally fixed and enclosed.The smelting power consumption of flux method is generally 2500~3500 kW · h/ton, and the power consumption of flux-free method is 2000~3000 kW · h/ton.Manganese silicon alloy is smelted by closed or semi-closed reduction furnace.Generally, manganese ore with high silica content and low phosphorus content or silica as raw material.Mn-rich slag is a good raw material for smelting Mn-Si alloy with low phosphorus content and high silica content.Smelting power consumption is generally about 3500~5000 kW · h/ton.The feedstock is pretreated, including whole grain, preheating, pre-reduction and sintering of powder, etc., which can significantly improve the operation and technical and economic indexes of electric furnace.
In electric furnace refining, low carbon fermanganese is generally carried out desilication refining with electric furnace of 1500~6000 kV, taking manganese silicon, manganese rich ore and lime as raw materials, and the reaction is as follows :MnSi+2MnO+2CaO─→3Mn+2CaO·SiO2
Using high basicity slag can reduce the manganese content of slag and reduce the manganese loss caused by slag abandonment.The slag with high manganese content (20~30%) is used for smelting Mn-Si alloy when the slag basicity is lower (CaO/SiO2 less than 1.3).It is helpful to shorten the smelting time and reduce the power consumption by preheating the charge or loading the liquid manganese silicon alloy.Refining power consumption is generally about 1000 kW · h.Medium and low carbon ferromanganese are also produced by mutual heat mixing of liquid manganese silicon alloy, manganese ore and lime melt.
Medium and low carbon ferromanganese can be produced by blowing liquid ferromanganese or manganese-silicon alloy with pure oxygen.After many years of experimental research, this method entered into industrial scale production in 1976.