Difference about Silicon Carbide (SiC) and Ferro Silicon (FeSi)

Definitional Analysis

Silicon Carbide (SiC)

Silicon carbide is a compound formed by reacting high-purity quartz sand with high-quality washed anthracite coal in an electric resistance furnace. The formation process relies on specific raw materials and a high-temperature reaction environment, which provides the basis for its unique properties.

Silicon carbide consists of silicon and carbon, and is notable for its naturally low content of impurities such as aluminum, nitrogen and hydrogen. This pure compositional structure is an important reason for its excellent performance in many fields.

Ferrosilicon (FeSi)

Ferrosilicon is an alloy of iron and silicon with an average silicon content of between 15% and 90%. Commonly marketed models contain 15%, 45%, 75% and 90% silicon, the rest being mainly iron, with about 2% of other elements such as aluminum and calcium. The different silicon contents give them different emphasis in applications.

Ferrosilicon has iron and silicon as its main components, and its silicon content fluctuates widely. It also contains a certain amount of aluminum, calcium and other impurities, the presence of which has an impact on its performance and application scenarios.

Physical and Chemical Properties

Silicon Carbide (SiC)

Chemical properties: Silicon carbide is chemically stable and extremely hard, with a Mohs hardness close to that of diamond. In addition, it has excellent heat and wear resistance, and can remain stable in a variety of complex chemical environments.

Physical Properties: Possessing high thermal conductivity and a low coefficient of expansion, this allows it to maintain structural and performance stability in extreme environments, such as high temperatures and drastic temperature changes.

Ferro Silicon (FeSi)

Silicon has a strong chemical affinity for oxygen, which makes ferrosilicon highly reducible. Based on this property, it can be used in processes such as reduction of metal oxides, deoxidation of steel and ferroalloys.

Advantages 

Advantages of silicon carbide (SiC) in steel mills

Low impurity content

Excessive amounts of aluminum, nitrogen, hydrogen and other elements can lead to steel defects such as porosity and inclusions. Silicon carbide, on the other hand, has a naturally lower content of these impurities compared to other silicon and carbon sources, which produces purer steel and improves steel quality.

Reducing converter (BOF) costs

Adding silicon carbide to a converter allows the furnace to reach higher temperatures. This property allows mills to increase scrap usage and reduce lime consumption, improving steelmaking efficiency and reducing production costs in several ways.

Reducing ladle furnace costs

Silicon carbide provides both silicon and carbon to the steel, replacing two raw materials and directly reducing the cost of adding alloying elements. Moreover, during the transfer process from the electric furnace to the ladle furnace, deoxidizing the steel with silicon carbide will not generate operational risks, thus guaranteeing the smooth running of production.

Ferrosilicon (FeSi)

Steelmaking

Acts as an efficient deoxidizer via precipitation and diffusion, removing oxygen to boost steel purity and mechanical properties.

Functions as a superior alloying agent, enhancing steel's strength, hardness, and elasticity, vital for structural steel, tool steel, and transformer silicon steel.

Cast Iron Production

Serves as a critical inoculant and spheroidizing agent, promoting graphite precipitation and spheroidization to improve cast iron's strength and toughness, especially for ductile iron.

Ferroalloy Manufacturing

High-silicon ferrosilicon, with strong oxygen affinity and low carbon content, is an ideal reducing agent for low-carbon ferroalloys, ensuring quality and avoiding excess carbon.

Fields of application

Silicon Carbide (SiC)

Non-ferrous metal smelting industry

Utilizing its high temperature resistance, high strength, good thermal conductivity and impact resistance, silicon carbide is used as a high temperature indirect heating material. It plays an important role in such equipment as pot stills, stills trays, aluminum electrolysis tanks, and copper melting furnace linings.

Steel industry

With its corrosion and thermal shock resistance, abrasion resistance and good thermal conductivity, silicon carbide can be used for lining large blast furnaces. This application effectively extends the service life of the blast furnace and reduces equipment maintenance costs.

Metallurgy and Mineral Processing Industry

Because of its high hardness and wear resistance (5-20 times that of cast iron and rubber), silicon carbide has become an ideal material for manufacturing wear-resistant pipes, impellers, pump bodies, etc. It is also used in the lining of aviation runways. At the same time, it is also one of the ideal materials for aviation runways.

Building materials, ceramics and grinding wheel industry

Using its thermal conductivity, heat radiation and high thermal strength, silicon carbide can be used to manufacture thin plate kiln furniture. This not only reduces kiln capacity, but also improves kiln filling and product quality, shortens production cycles and enhances productivity.

Ferro Silicon (FeSi)

Steelmaking Industry

As a deoxidizer and alloying agent, ferrosilicon is widely used in smelting structural steel, tool steel, and silicon steel for transformers. Adding a certain amount of silicon can significantly improve the strength, hardness and elasticity of steel, and meet the performance requirements of different steels.

Iron casting industry

In cast iron manufacturing, ferrosilicon is used in the gestation treatment of iron to accelerate graphitization. In the production of ductile iron, it is an important inoculant and spheroidizing agent, helping ductile iron to obtain excellent mechanical properties.

Ferroalloy production

High silica ferrosilicon, due to its high affinity for silicon and oxygen and low carbon content, has become a commonly used reducing agent in the production of low carbon ferroalloys, safeguarding the quality and efficiency of low carbon ferroalloy production.

Other aspects

Ground or atomized ferrosilicon powder can be used as a suspension phase in the mineral processing industry. In arc welding, some electrode coatings also contain ferrosilicon. In addition, it can be used in the manufacture of silicon metal, corrosion- and temperature-resistant iron-silicon alloys, etc. It has a wide range of applications.

Conclusion

Silicon carbide plays a role in many high-end fields with its high purity, high hardness, excellent heat and wear resistance, etc. Ferrosilicon, on the other hand, occupies an important position in metallurgy and other industries by virtue of its alloying properties and reducibility. Understanding these differences will help you make the right choice in actual production and application.