Ferrosilicon is an iron alloy composed of iron and silicon. Ferrosilicon is an iron-silicon alloy made of coke, steel shavings, quartz (or silica) as raw materials and smelted in an electric furnace. Since silicon and oxygen are easy to synthesize silicon dioxide, ferrosilicon is often used as a deoxidizer during steelmaking. At the same time, a large amount of heat is released when SiO2 is generated. While deoxidizing, it is also beneficial to increase the temperature of the molten steel. 

        As a kind of iron alloy, ferrosilicon is widely used in low alloy structural steel, spring steel, bearing steel, etc. Ferrosilicon is often used as a reducing agent in the production of iron alloys and the chemical industry. During steelmaking, harmful substances such as carbon, phosphorus, and sulfur in molten iron will be removed through processing. In this process, the oxygen content of the molten iron will increase, too high oxygen content will damage the mechanical properties of the steel, ferrosilicon is easier to oxidize with the oxygen in the molten iron, thereby removing the oxygen in the molten iron.

       The finely ground or atomized ferrosilicon powder can be used as a suspended phase or as a coating for welding rods. The main uses of ferrosilicon are still in the casting, steelmaking and ferroalloy industries. The basic principle of ferrosilicon smelting reaction formula is: sio2 + c = si + co, the melting point of ferrosilicon is about 1300 degrees Celsius, the density of ferrosilicon depends on the silicon content of ferrosilicon, its density increases with the silicon content in the alloy Increase and decrease.

       At the same time, ferrosilicon can also be used as an alloying agent. It is widely used in low alloy structural steel, spring steel, bearing steel, heat-resistant steel and electrical silicon steel. Ferrosilicon is often used as a reducing agent in the production of ferroalloys and the chemical industry. An iron alloy composed of iron and silicon (silicon, steel, coke as raw materials, silicon reduced at a high temperature of 1500-1800 degrees is melted in the molten iron to form a ferrosilicon alloy). It is an important alloy variety in the smelting industry.

Application:

(1) Used as a deoxidizer and alloying agent in the steelmaking industry. In order to obtain the steel with qualified chemical composition and ensure the quality of the steel, deoxidation must be carried out in the final stage of steelmaking. The chemical affinity between silicon and oxygen is very large. Deoxygenation. Adding a certain amount of silicon to steel can significantly improve the strength, hardness and elasticity of steel. Therefore, in smelting structural steel (containing silicon 0.40-1.75%), tool steel (containing SiO.30-1.8%), spring steel ( When containing SiO.40-2.8%) and silicon steel for transformers (containing 2.81-4.8% of silicon), ferrosilicon is also used as an alloying agent. At the same time, improving the shape of inclusions and reducing the content of gas elements in the molten steel is an effective new technology to improve the quality of steel, reduce costs, and save iron. It is especially suitable for the deoxidation requirements of continuous casting steel. Practice has proved that ferrosilicon not only meets the deoxidation requirements of steelmaking, but also has the advantages of desulfurization performance, large specific gravity and strong penetration.

In addition, in the steel-making industry, the use of ferrosilicon powder at high temperature can release a lot of heat, which is often used as a heating agent for steel ingot caps to improve the quality and recovery rate of steel ingots.

(2) Used as inoculant and spheroidizing agent in the cast iron industry. Cast iron is an important metal material in modern industry. It is cheaper than steel and easy to melt and smelt. It has excellent casting performance and much better seismic resistance than steel. Especially for ductile iron, its mechanical properties are at or close to those of steel. Adding a certain amount of ferrosilicon to cast iron can prevent the formation of carbides in iron and promote the precipitation and spheroidization of graphite. Therefore, in the production of ductile iron, ferrosilicon is an important inoculant (helps precipitate graphite) and nodularizer .

(3) Used as a reducing agent in the production of ferroalloys. Not only is the chemical affinity between silicon and oxygen great, but the carbon content of high silicon ferrosilicon is very low. Therefore, high silicon ferrosilicon (or silicon alloy) is a reducing agent commonly used in the production of low carbon iron alloys in the ferroalloy industry.

(4) 75 # ferrosilicon is commonly used in the high-temperature smelting process of magnesium metal in the Pijiang method magnesium smelting process. It replaces the magnesium in CaO.MgO and consumes about 1.2 tons of ferrosilicon for every ton of magnesium produced It plays a big role in the production of magnesium metal.

(5) Use in other aspects. The ground or atomized ferrosilicon powder can be used as the suspended phase in the beneficiation industry. It can be used as electrode coating in electrode manufacturing. High silicon ferrosilicon can be used to manufacture silicone and other products in the chemical industry.

Among these uses, the steelmaking industry, foundry industry and ferroalloy industry are the largest users of ferrosilicon. They consume about 90% of ferrosilicon in total. Among various grades of ferrosilicon, At present, the most widely used is 75% ferrosilicon. In the steel-making industry, about 3-5 kg of 75% ferrosilicon is consumed for every 1 t of steel produced.

Smelting：

Ferrosilicon is made of coke, steel shavings, quartz (or silica) as raw materials and is smelted in an electric furnace. In the traditional refining of ferrosilicon, silicon is reduced from silica containing SIO2. Most smelting ferrosilicon uses metallurgical coke as a reducing agent, and steel shavings are regulators of ferrosilicon.

Production of one ton of ferrosilicon raw materials and power consumption are:

Silica: 1780-1850kg

Coke: 890-930kg

Steel shavings: 220-230kg

Electrode paste: 45-55kg

Power consumption: 8400-9000kwh / t

Specification

Grade 

SI 

AI 

MG

S 

C 

CR 

FeSi75A 

74.0-80.0 

- 

- 

0.02 

0.1 

0.3 

FeSi75B 

72.0-80.0 

- 

- 

0.02 

0.2 

0.5 

FeSi65 

65.0-72.0 

- 

- 

0.02 

-