Ferrosilicon (FeSi) 72 & 75 | Specifications & Applications

Grades & Specs

Available Ferrosilicon Grades

Ferro silicon is an iron-silicon alloy produced through the reduction of quartz with carbonaceous reductants in a submerged arc furnace.

It is one of the widely used ferroalloys in steelmaking and foundry industries, where silicon provides key deoxidising, inoculating and alloying functions.

In steel production, ferro silicon is primarily used to help remove dissolved oxygen from molten steel and to introduce controlled silicon content into the final alloy.

FeSi 72 & FeSi 75

Silicon Alloy Industria LDA offers three standard ferro silicon grades.

Grade	Silicon (Si)	Aluminium (Al)	Phosphorus (P)	Sulphur (S)	Carbon (C)
FeSi 72	72% min	1.5% max	0.05% max	0.05% max	0.1% max
FeSi 75	75% min	1.5% max	0.05% max	0.05% max	0.1% max

Physical Specifications

Ferro Silicon Physical Specifications

Our ferro silicon products are strictly manufactured to maintain consistent physical characteristics and superior metallurgical performance.

Appearance

Metallic silver-grey lumps

Available Sizes

Fine Powder (0-1mm), Granules (1-3mm), Granules (3-10mm), Lumps (10-100mm)

Custom Sizing

Available on request

Packaging

1 MT woven sling bags

Bulk Density

Approximately 2.0–2.5 MT/m³

Key Properties

Key Properties of Ferro Silicon

The silicon content in ferro silicon gives the alloy important functions in metallurgical processing.

Deoxidising

Ferro silicon is used as a deoxidising material in steel production. Silicon reacts with dissolved oxygen in molten steel, helping reduce oxygen-related defects and support steel cleanliness.

Inoculation

In cast iron production, ferro silicon is used as an inoculant to promote graphite nucleation and support desired casting characteristics.

Alloying

Ferro silicon provides controlled silicon addition for the production of silicon steels and other alloy steels.

Low Aluminium Specification

The standard maximum aluminium specification of 1.5% is particularly relevant to applications where aluminium control is important, including electrical steel production.

Ferro Silicon Applications

WHERE IS FERRO SILICON USED?

Ferro silicon is used across steelmaking, foundry, chemical and other industrial applications.
One material. Multiple industries. Countless possibilities.

STEEL
MANUFACTURING

DEOXIDISATION & ALLOYING

Ferro silicon is primarily used as a deoxidiser and alloying material in steel production.

When added to molten steel, silicon reacts with dissolved oxygen, forming stable silicon dioxide and helping reduce porosity and improve steel cleanliness. It is also used as an alloying addition in silicon steels, spring steels, tool steels and high-strength structural steels.

ELECTRICAL STEEL
PRODUCTION

LOW ALUMINIUM SPECIFICATION

Silicon steel used in transformer and motor laminations typically contains controlled silicon levels.

Ferro silicon with low aluminium content is used as an addition material where aluminium control is important for maintaining the desired magnetic properties. The FeSi 72 and FeSi 75 grades specified with a maximum 1.5% aluminium are relevant to this application.

CAST IRON &
FOUNDRY

GRAPHITE NUCLEATION

In grey iron and ductile iron foundries, ferro silicon is used as an inoculant to promote graphite nucleation.

It is also used in the production of nodular or ductile iron through magnesium-ferro silicon treatment, yielding specific desired casting characteristics for heavy industrial components.

SILICON METAL
PRODUCTION

HIGH PURITY FEEDSTOCK

Higher-purity ferro silicon can be used as a feedstock for silicon metal production.

Silicon metal is subsequently used in industries including advanced aluminium alloy production, semi-conductors, and solar photovoltaic panels ensuring high conductivity and performance.

CHEMICAL
INDUSTRY

PRECURSOR MATERIAL

Ferro silicon is used as a precursor in the production of materials including silicones, fumed silica and silicon tetrachloride.

These materials have widespread applications in consumer and industrial products such as robust sealants, specialized coatings, optical fibres and other specialty chemicals.

MAGNESIUM
PRODUCTION

PIDGEON PROCESS REDUCTANT

Ferro silicon containing approximately 70–75% silicon is used directly as a reductant in the Pidgeon process for magnesium metal production.

This thermal reduction process relies heavily on the quality and composition of the ferrosilicon to safely and effectively extract pure magnesium.

WELDING ELECTRODE
MANUFACTURING

FLUX FORMULATIONS

Ferro silicon powder is widely utilized in welding electrode manufacturing.

It is commonly mixed into submerged arc welding flux formulations to serve as an essential deoxidising and alloying component, ensuring strong, clean welds in structural applications.

Steel
Manufacturing

Deoxidiser and alloying agent in steel production to improve quality and cleanliness.

Electrical Steel
Production

Used in silicon steel with controlled aluminium for optimal magnetic properties.

Cast Iron &
Foundry

Acts as inoculant and nodulariser in grey iron and ductile iron production.

Silicon Metal
Production

Used as feedstock for silicon metal in aluminium alloys and solar applications.

Chemical
Industry

Precursor for silicones, fumed silica, silicon tetrachloride and specialty chemicals.

Magnesium
Production

Used as reductant in the Pidgeon process for magnesium metal production.

Welding Electrode
Manufacturing

Used in welding electrodes and fluxes as deoxidising and alloying component.

DISCUSS YOUR REQUIREMENT

From Raw Material to Finished Product

How Our Ferro Silicon Is Produced

Our production process is designed around controlled raw material preparation, submerged arc furnace smelting, chemical testing and finished product preparation.

Raw Material Qualification

Incoming quartz, charcoal, coal and iron scrap are inspected and tested before entering production. Quartz is assessed for chemical composition and particle sizing, while other raw materials are checked against defined production requirements.

Controlled Furnace Charging

Raw materials are proportioned and weighed according to the required charge composition before being fed into the Submerged Arc Furnace.

Submerged Arc Furnace Smelting

The furnace operates with PLC-based automation and real-time monitoring of key production parameters.

Tapping & Solidification

Molten ferro silicon is tapped, slag is removed and the hot alloy is cast for cooling and solidification.

Chemical Analysis

Production batches are chemically analysed for key elements including silicon, aluminium, phosphorus, sulphur and carbon. Only batches meeting the specified grade requirements are released for dispatch.

Sizing & Packaging

Solidified ferro silicon is sized according to customer requirements, weighed and packaged in 1 MT sling bags.

Quality Control

Quality Control From Raw Material to Shipment

Quality control is integrated throughout the production process rather than being limited to final inspection.

Raw Material Testing

Incoming materials are inspected and tested before production.

Real-Time Process Monitoring

PLC and SCADA systems monitor key furnace and operating parameters.

Batch Chemical Analysis

Each production batch is analysed against the specified grade.

Finished Product Certification

A Certificate of Chemical Analysis is prepared for confirmed production lots.

Shipment Documentation

Chemical analysis, weight and country-of-origin documentation accompany shipments.

Independent Inspection

Third-party inspection through SGS, Bureau Veritas or Intertek is available upon buyer request.

Packaging & Documentation

Prepared for Industrial Shipment

Ferro silicon is packaged in 1 MT woven sling bags, with standard sizing available in 10–50 mm and 50–100 mm fractions.

Each confirmed production lot is assigned a batch number, and the finished product is weighed before dispatch.

Shipment Documentation Includes

We ensure every shipment comes with all necessary and certified documentation for seamless import clearance and quality assurance.

Certificate of Chemical Analysis

Confirms the chemical composition of the supplied grade.

Weight Certificate

Documents the dispatched lot weight using calibrated weighing systems.

Certificate of Origin

Issued from the Republic of Angola per shipment.

Product FAQ

Frequently Asked Questions About Ferro Silicon

What ferro silicon grades do you offer?

Silicon Alloy Industria LDA offers FeSi 72 and FeSi 75 grades with defined silicon, aluminium, phosphorus, sulphur and carbon specifications.

What sizes of ferro silicon are available?

Standard sizes are Fine Powder (0-1mm), Granules (1-3mm), Granules (3-10mm), Lumps (10-100mm). Custom sizing is available on request.

How is ferro silicon packaged?

The standard packaging format is 1 MT woven sling bags.

What industries use ferro silicon?

Ferro silicon is used in steelmaking, foundries, electrical steel production, silicon metal production, chemical manufacturing, magnesium production and welding electrode manufacturing.

Do shipments include chemical analysis certificates?

Yes. Chemical composition certificates are provided with each shipment.

Is third-party inspection available?

Yes. SGS, Bureau Veritas or Intertek third-party inspection can be arranged upon buyer request.

Can you provide custom ferro silicon specifications?

Custom grades and sizing are available on request, subject to production and customer requirements.

Where is Silicon Alloy Industria LDA's ferro silicon produced?

The ferro silicon production facility is located at Zona Industrial dos Cabrais, Biopio, Benguela Province, Angola.

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Ferro Silicon (FeSi) for Steelmaking & Industrial Applications