How Does Ferro Silicon Work?

Author: GE

Apr. 21, 2025

Minerals

Ferrosilicon: Particle Size & Shape Analysis - Microtrac

Ferrosilicon (FeSi) is an alloy of iron and silicon with a very variable silicon content between 10% and 90%. It is used as a so-called master alloy in steel production, which is added in small amounts in order to adjust the properties of the melt, the cooling process and the finished product.

The main advantage of FeSi is its deoxidizing effect (i. e. it reduces metals from their oxides), but it also helps to prevent the loss of carbon. Furthermore, ferrosilicon is used in electrode coatings and in the production of silicon, hydrogen and magnesium.

Ferrosilicon is produced either in a blast furnace or electric arc furnace by the reduction of quartz sand (SiO2) with coke in the presence of iron. The melt is poured out of the furnace and solidifies in the form of a flat sheet.

After cooling, this sheet is crushed by appropriate machinery and then further processed in a crusher. The resulting particle size distribution ranges from fine dust-like particles to cm-sized chunks. The FeSi is sifted into different size grades for further use.

Microtrac's CAMSIZER series is ideally suited for the particle size distribution analysis of ferrosilicon and other granular metals. Microtrac analyzers are used both for quality control industrial applications as well as research purposes. 

You will get efficient and thoughtful service from CHIDA.

The CAMSIZER P4 dynamic image analyzer determines particle size and shape in a range from 20 μm to 30 mm and is therefore ideally suited for the routine analysis of ferrosilicon. The particles under investigation are conveyed by a vibratory chute into the measurement zone where they are passing a planar light source in free fall. The resulting shadow projections are captured by a camera system and evaluated in real time. The CAMSIZER P4 features the unique Dual-Camera Technology. One camera (ZOOM) detects fine particles with great accuracy and a second camera (BASIC) with lower magnification, but larger field of view detects large particle simultaneously. This is an invaluable advantage because the CAMSIZER P4 can analyze all particles within one sample without any hardware adjustments and without losing accuracy for either very large or very fine particles. Thanks to the two cameras, ideal measurement conditions can be established for the entire size range, the analysis is therefore extremely convenient and accurate.

The huge advantage of this arrangement is the vast amount of sample that can be processed in a very short analysis time of only a few minutes. The CAMSIZER P4 is maintenance-free and therefore offers a faster and more reliable alternative to traditional sieve analysis. Thanks to its robust design, the CAMSIZER P4 unsusceptible to vibration and dust. The instrument can therefore operate in an industrial plant as well as in a laboratory environment.

In this example we present the results of the particle size analysis of different grades of ferrosilicon (Fig. 4). All measurements have been made with a CAMSIZER P4 image analyzer. The finest sample is in a size range from 0,2 mm to 0,7 mm. The largest sample contains particles up to 30 mm, which is the upper size limit of the CAMSIZER P4. Repeatability of the results is a key factor to evaluate the reliability of a measurement device. The CAMSIZER P4 can detect and analyze hundreds of thousands or even millions of particles within a few minutes. The size distribution is therefore based on a huge dataset, giving the result a high confidence level and leading to great repeatability (Fig. 5).

Particle characterization with Dynamic Image Analysis offers a wide range of different parameters that can be determined for every particle: different size definitions for length, width and equal area diameter are available, as well as various shape parameters such as aspect ratio, roundness, convexity and many more. If comparability to traditional sieve analyse is required, the size definition “particle width” is used to calculate the distribution. Sieving allows width measurement as well since the particles pass the apertures with the smallest projection surface (Fig. 6). Comparability of CAMSIZER P4 results and sieve analysis can easily be established (Fig. 7).

Ferrosilicon - Wikipedia

Alloy of silicon and iron

Ferrosilicon is an alloy of iron and silicon with a typical silicon content by weight of 15–90%. It contains a high proportion of iron silicides.[1]

Production and reactions

[edit]

Ferrosilicon is produced by reduction of silica or sand with coke in the presence of iron. Typical sources of iron are scrap iron or millscale. Ferrosilicons with silicon content up to about 15% are made in blast furnaces lined with acid fire bricks.[2]

Ferrosilicons with higher silicon content are made in electric arc furnaces.[2] The usual formulations on the market are ferrosilicons with 15%, 45%, 75%, and 90% silicon. The remainder is iron, with about 2% consisting of other elements like aluminium and calcium. An overabundance of silica is used to prevent formation of silicon carbide. Microsilica is a useful byproduct.

A mineral perryite is similar to ferrosilicon, with its composition Fe5Si2. In contact with water, ferrosilicon may slowly produce hydrogen. The reaction, which is accelerated in the presence of base, is used for hydrogen production. The melting point and density of ferrosilicon depends on its silicon content, with two nearly-eutectic areas, one near Fe2Si and second spanning FeSi2-FeSi3 composition range.

Physical properties of ferrosilicon[3][4] Si mass fraction (%) 0 20 35 50 60 80 100 Solidus point (°C) Liquidus point (°C) Density (g/cm3) 7.87 6.76 5.65 5.1 4.27 3.44 2.33

Uses

[edit]

Ferrosilicon is used as a source of silicon to reduce metals from their oxides and to deoxidize steel and other ferrous alloys. This prevents the loss of carbon from the molten steel (so called blocking the heat); ferromanganese, spiegeleisen, calcium silicides, and many other materials are used for the same purpose.[5] It can be used to make other ferroalloys. Ferrosilicon is also used for manufacture of silicon, corrosion-resistant and high-temperature-resistant ferrous silicon alloys, and silicon steel for electromotors and transformer cores. In the manufacture of cast iron, ferrosilicon is used for inoculation of the iron to accelerate graphitization. In arc welding, ferrosilicon can be found in some electrode coatings.

Are you interested in learning more about Ferro Silicon? Contact us today to secure an expert consultation!

Ferrosilicon is a basis for manufacture of prealloys like magnesium ferrosilicon (MgFeSi), used for production of ductile iron. MgFeSi contains 3–42% magnesium and small amounts of rare-earth elements. Ferrosilicon is also important as an additive to cast irons for controlling the initial content of silicon.

Magnesium ferrosilicon is instrumental in the formation of nodules, which give ductile iron its flexible property. Unlike gray cast iron, which forms graphite flakes, ductile iron contains graphite nodules, or pores, which make cracking more difficult.

Ferrosilicon is also used in the Pidgeon process to make magnesium from dolomite.

Silanes

[edit]

Treatment of high-silicon ferrosilicon with hydrogen chloride is the basis of the industrial synthesis of trichlorosilane.

Ferrosilicon is also used in a ratio of 3–3.5% in the manufacture of sheets for the magnetic circuit of electrical transformers.

Hydrogen production

[edit] See also: Hydrogen production § Ferrosilicon method

The method has been in use since World War I. Prior to this, the process and purity of hydrogen generation relying on steam passing over hot iron was difficult to control.[6] The chemical reaction uses sodium hydroxide (NaOH), ferrosilicon, and water (H2O). While in the "silicol" process, a heavy steel pressure vessel is filled with sodium hydroxide and ferrosilicon, and upon closing, a controlled amount of water is added; the dissolving of the hydroxide heats the mixture to about 200 °F (93 °C) and starts the reaction; sodium silicate, hydrogen and steam are produced.[7] The overall reaction of the process is believed to be:[2][note 1]

2NaOH + Si + H2O → Na2SiO3 + 2H2

Ferrosilicon is used by the military to quickly produce hydrogen for balloons by the ferrosilicon method. The generator may be small enough to fit in a truck and requires only a small amount of electric power, the materials are stable and not combustible, and they do not generate hydrogen until mixed.[8]

One report notes that this method of hydrogen production wasn't thoroughly investigated for about century despite being reported by the US military in the beginning of 20th century.[2]

The company is the world’s best Mica Powder Wholesale supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

References

[edit]

Further reading

[edit]

2

0

Comments

Please Join Us to post.

0/2000

All Comments ( 0 )

Guest Posts

If you are interested in sending in a Guest Blogger Submission,welcome to write for us!

Your Name: (required)

Your Email: (required)

Subject:

Your Message: (required)