H C Ferro Manganese

Brief introduction:

Ferro manganese alloy is the deoxidizing agent which is usually used in steel making. It also has the performance that it can desulfurize and decrease the harmfulness of sulfur. So when we make steel and cast iron, we always need certain account of manganese. It is also used as an important kind of alloying constituent to be widely applied to alloy steel, such as structural steel, tool steel, stainless and heat-resistant steel and abrasion-resistant steel.

Application:

1. It can be applied to low carbon alloy structural steel, especially to high quality steel, and does not need to change the original steelmaking process, can optimize the alloy, reduce the cost of steelmaking alloy, with very obvious economic benefits;

2. In steelmaking, it can be used as deoxidizer and alloy additive

3. The use of smelting can use coke as a reducing agent, some factories are also matched with lean coal or anthracite, the auxiliary raw material is mainly lime, smelting manganese silicon alloy with silica

4. Ferro Manganese is used in coil coatings, high performance industrial paints, and heat-resistant engineering plastics. It is an excellent solar absorber and can be used in coatings for solar collectors.

The methods of producing high carbon ferromanganese usually include two ways： blast furnace and electric furnace . The characteristics of these two methods are respectively introduced as below.

（1）Blast furnace process

High carbon ferromanganese was first produced by blast furnace. Its high output and low cost are still widely used.The blast furnace method is to add manganese ore, coke and lime to the blast furnace respectively for smelting, and obtain blast furnace manganese containing 52%~76%/ Phosphorus containing 0.4%~0.6.The only difference between blast furnace and electric furnace smelting high carbon ferromanganese is that the heat source is different, so their furnace structure, geometry and operation method are different, but the two furnaces smelting high carbon ferromanganese principle is the same.The phosphorus content of the two furnaces is different due to the smelting of the same kind of manganese ore. The higher the product of blast furnace is, the higher the content is.This is because the amount of coke in the charge composition of blast furnace smelting is 5~6 times that of electric furnace smelting, so there is more phosphorus in the coke into the alloy, and the blast furnace smelting temperature is lower, so the amount of phosphorus volatilization in the smelting process is about 10% lower than electric furnace

（2）The electric furnace process

There are three methods for smelting high carbon ferromanganese by electric furnace.

1) Flux-free method.For rich manganese ore containing manganese oxide is higher, can be used without the burden of flux method smelting ferromanganese smelting and time are not worthy to add lime, equipment and operating similar ferrosilicon, and is under the condition of insufficient reductant by acidic slag operation, the furnace temperature of about 1320 ~ 1400 ℃, lower than the flux method production in this way both to obtain qualified high carbon ferromanganese, and to be greater than 35%, for smelting manganese manganese content in the alloy with low phosphorus, low iron rich manganese slag.The distribution of manganese is as follows: alloy rate is 58%~60%, slag rate is 30%~32%, volatilization rate is 10%.Obviously, the smelting of high carbon ferromanganese by flux-free method must use manganese ore with high manganese content and require relatively low phosphorus content in the ore.Although the recovery rate of manganese is low, most of the manganese can be recovered by smelting manganese alloy with manganese rich slag, and the total recovery rate of manganese is higher than flux.The process of solvent-free smelting of high carbon ferromanganese is continuous. The charge is continuously added into the furnace along with the melting process. The material batch can be composed of 300kg manganese ore, 60-70kg coke and 15-20kg steel chips.In solentless smelting, the unit power consumption of the product is very low, and it is easy to produce high-carbon ferromanganese with low silicon, because most of the silicon is concentrated in the slag.

2) Solvent method.Solvent method is a widely used method for smelting high carbon ferromanganese.In addition to manganese ore and coke, high alkalinity slag is used to operate alkalinity, B=1.3~1.4, and enough reducing agent is used to reduce the content of manganese in waste residue as far as possible and improve the recovery rate of manganese.This method is used for the smelting of high carbon ferromanganese with lean and rich manganese ore and will be discussed in detail later.

3) Less solvent method.This method is operated by the so-called "weak acid slag method", which is between the solvent method and the solvent-free method.The law is to burden with addition of appropriate amount of lime or limestone, slag basicity m (CaO)/m (SiO2)/m (CaO + MgO style)/m (SiO20) is the ratio of control between 0.6 ~ 0.8, which can improve the recovery rate of manganese, and can obtain 25% ~ 30% and a moderate amount of manganese content in slag containing CaO, try to match the slag in smelting manganese silicon alloy furnace charge, can save the lime, and can reduce dust increase by lime deliquescence burden, thus improving the burden permeability.Foreign high carbon ferromanganese smelting by electric furnace mostly adopts the acid method of solventless method and less flux method.In the 1950s, China also used flux-free smelting, producing manganese 76%80% carbon ferromanganese with manganese 46%~47%, and obtaining manganese 35%~40% rich slag.However, due to the large amount of lean manganese ore in China, the solvent method or a small amount of solvent method is usually used at present.