What is Ferrosilicon used for? DMS Powders
DMS Powders
What Is Ferrosilicon Used For?
Find out more about Ferrosilicon Applications across Mining, Recycling, and Industry. DMS Powders is a leading supplier of Ferrosilicon for Dense Media Separation of Diamonds & Minerals.
Understanding Ferrosilicon: Composition and Properties
To understand what ferrosilicon is used for, it’s important to first look at what it is. Ferrosilicon (FeSi) is a ferrous alloy made from iron and silicon, typically containing between 15% and 90% silicon by weight. It is created by reducing quartz (silicon dioxide) with coke in the presence of scrap iron or mill scale in an electric arc furnace.
Ferrosilicon is known for several properties that make it valuable across different industries:
- High density
- Strong magnetic behaviour
- Resistance to oxidation and corrosion
- Ability to remain stable in harsh chemical environments
These characteristics make ferrosilicon essential in mineral separation processes, steel manufacturing, and even metal recycling operations.
DMS Powders:
Primary Use: Dense Media Separation (DMS) in Mining
The most widespread use of ferrosilicon is in Dense Media Separation (DMS), a method used to separate valuable ore from waste rock by suspending crushed material in a heavy liquid made from ferrosilicon and water.
How It Works
Ferrosilicon is mixed with water to create a slurry of a specific density. When ore is introduced into this medium, lighter waste materials float while denser, valuable particles sink. This “sink-float” method is widely used in mineral processing to achieve highly accurate separation results.
The medium’s density can be fine-tuned by adjusting the concentration of ferrosilicon, allowing for versatile use across different minerals and ores.
What Is Ferrosilicon Used For in Mining?
1. Diamond Mining
One of the most notable applications is in the recovery of diamonds. Diamonds have a specific gravity of around 3.5 g/cm³, which allows them to be separated from lighter kimberlite rock in a DMS plant.
Ferrosilicon creates the ideal medium density for diamonds to sink while waste material floats. This ensures higher recovery rates with minimal loss of valuable stones. Countries like South Africa, Botswana, and Canada all utilise this process in their diamond mines.
2. Iron Ore Beneficiation
In iron ore processing, ferrosilicon is used to separate magnetite or hematite from silica-based gangue. The dense medium allows the heavier iron-rich particles to sink while the waste material is removed. This is particularly important in improving the quality of the ore before further refinement or smelting.
3. Chromite and Mineral Sands
Minerals like chromite, zircon, and ilmenite have much higher specific gravities, often over 4.0 g/cm³. Ferrosilicon enables the separation of these heavy minerals from lighter components in mineral sands deposits.
Due to the need for extremely dense media, atomised ferrosilicon is preferred in these applications for its spherical shape and higher medium stability.
4. Coal Washing
Ferrosilicon is also widely used in coal preparation plants to remove impurities like shale and rock. By separating low-density coal from higher-density contaminants, ferrosilicon helps improve the calorific value of coal and makes it more suitable for energy production.
In these cases, milled ferrosilicon is typically used for its angular shape and better retention in drum separators.
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Automised FeSi
Coarse, Fine, Cyclone 60, Cyclone 40, DMS 70
Milled FeSi
65D, 100D, 150D, 270D, 270F
DMS Powders
Packaging
Our packaging has been specifically designed for:
Ease of handling
Safety
Product integrity
Durability
Water resistance
Applications in Recycling and Metal Recovery
1. Aluminium Separation
Ferrosilicon plays a crucial role in scrap metal recycling, particularly in separating aluminium from heavier materials like copper, steel, or zinc. Since aluminium has a much lower density (~2.7 g/cm³), it floats in a ferrosilicon slurry while the other metals sink.
This process is used in both post-consumer and industrial recycling to ensure clean and efficient sorting of valuable metals.
2. Automotive and E-Waste Processing
DMS systems using ferrosilicon are becoming increasingly common in the recovery of non-ferrous metals from shredded vehicles, appliances, and electronic waste. Using ferrosilicon media, recyclers can achieve high-purity separation of components for reuse or resale.
Steel Manufacturing and Foundry Use
Apart from mineral and metal separation, ferrosilicon is widely used in the steel industry as a deoxidiser and alloying agent.
1. Deoxidising Agent
During steelmaking, ferrosilicon is added to molten steel to remove excess oxygen. This improves the final product’s strength and reduces the risk of structural weakness due to oxidation.
2. Alloying in Special Steels
Ferrosilicon enhances the quality of electrical steels, stainless steels, and silicon steels, which are used in transformers, electrical motors, and specialty tools. The addition of silicon improves the magnetic and corrosion-resistant properties of the metal.
Grades of Ferrosilicon and Their Uses
The choice of ferrosilicon grade depends heavily on the intended application. Suppliers like DMS Powders offer both milled and atomised ferrosilicon with tailored particle size distribution (PSD) and silicon content.
Atomised Ferrosilicon
- Shape: Spherical particles
- Used in: Cyclones, high-density separation systems
- Applications: Diamond recovery, chromite, high-value mineral processing
- Benefits: Quick settling, high medium stability, easy recovery
Milled Ferrosilicon
- Shape: Angular, irregular particles
- Used in: Drum separators and coal DMS systems
- Applications: Coal washing, iron ore separation
- Benefits: Better suspension retention, cost-effective, slower settling
Both forms are magnetic, allowing for effective recovery using magnetic separators, and reusable, which makes them economically and environmentally efficient.
Range of Milled and Atomised Ferrosilicon from DMS Powders
As a trusted global supplier, DMS Powders offers a comprehensive range of milled and atomised ferrosilicon (FeSi) grades to suit the varied density and process requirements of Dense Media Separation systems across mining, recycling, and mineral processing industries.
Each grade is engineered for medium stability, magnetic recovery, and density control, helping clients achieve precise separation results, reduce losses, and increase overall plant efficiency.
Milled Ferrosilicon Products
Milled ferrosilicon is produced by grinding high-purity ferrosilicon into angular particles with a controlled particle size distribution (PSD). These are best suited for drum separators and applications where slower settling and increased medium stability are required - such as in coal washing or iron ore beneficiation.
Available Grades Include:
- 65D – A versatile medium grade ideal for general separation processes with moderate density requirements.
- 150D – Finer than 65D, suited for more precise separations where sharper cut points are needed.
- 270D & 270F – Very fine milled products often used in high-precision separation or where maximum recovery and minimal ferrosilicon loss are crucial.
Typical Applications:
- Coal preparation
- Iron ore separation
- Medium-grade mineral processing
Key Benefits:
- Excellent suspension stability
- Low medium viscosity
- Improved retention in drum separators
- Cost-effective due to slower settling rates
Atomised Ferrosilicon Products
Atomised ferrosilicon is created by melting the alloy and then spraying it into a mist, resulting in spherical particles. This form of FeSi is particularly effective in cyclone separators and high-density media circuits, such as those used for diamond recovery or chromite processing.
Available Grades Include:
- Coarse Atomised – Designed for systems requiring rapid medium cleaning and high throughput.
- 150 Atomised – A high-performance grade commonly used in diamond DMS circuits and where media density must be maintained precisely under high shear forces.
Typical Applications:
- Diamond mining
- Chromite and mineral sands
- High-density DMS systems
- Recyclable metal separation (e.g. aluminium, copper)
Key Benefits:
- Superior medium stability
- Fast settling and easy magnetic recovery
- Ideal for sharp sink-float separation
- Maintains density under turbulent conditions
Why Custom Ferrosilicon Grades Matter
DMS Powders understands that no two DMS plants are exactly the same. Factors like:
- Ore density
- Cyclone or drum design
- Medium operating density
- Process temperature and pH
... all influence how ferrosilicon behaves in suspension.
That’s why DMS Powders works closely with clients to recommend grade selection, provide technical advice, and support plant trials where necessary.
Their commitment to consistent product quality, precise PSD control, and low impurity levels ensures that each batch of milled or atomised FeSi meets the operational demands of global mining and industrial facilities.
Supplying Ferrosilicon Globally
DMS Powders, based in South Africa, is one of the world’s leading manufacturers and suppliers of ferrosilicon for Dense Media Separation. With decades of experience, we provide both technical expertise and high-quality products to:
- Mining operations
- Coal washing plants
- Recycling centres
- Steel manufacturers
Our ferrosilicon is exported globally, including to markets in:
- Australia
- South America
- Europe
- Russia
- Southern Africa
- Asia
For more information, visit: www.dmspowders.com
Conclusion: A Versatile Material With Multi-Industry Importance
So, what is ferrosilicon used for? In short, it is a multifunctional material that is essential to modern industry. From separating minerals and improving the quality of iron ore, to recycling metals and enhancing steel production, ferrosilicon plays a foundational role in numerous applications.
Its high density, magnetic recoverability, and resistance to breakdown make it irreplaceable in Dense Media Separation systems. Whether it’s used in a diamond mine or a scrap metal yard, ferrosilicon enables efficient, accurate, and sustainable material handling.
When choosing a supplier, companies like DMS Powders offer reliability, technical support, and proven product performance to meet the growing demands of the mineral and metal industries.
Contact DMS Powders today for expert guidance, high-quality product options, and dependable service tailored to your operation.
Let DMS Powders help you make the most of every tonne you process.
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