Ferrosilicon 75 Physical Properties: Density, Melting Range & Handling

Quick Answer

Ferrosilicon 75 (FeSi75) is a high-silicon ferroalloy containing a nominal minimum of 75% silicon. Its key physical properties include a reference material density of approximately 3.20 g/cm³, a reference melting range of approximately 1200–1350°C, and a hard, brittle mechanical structure. These properties influence how we process, store, transport and add FeSi75 during steelmaking and foundry operations.

When evaluating FeSi75, it is important to distinguish material density from bulk density and melting range from actual dissolution behavior. Material density describes the solid alloy, while bulk density depends on particle size, particle shape and packing conditions. The actual melting and dissolution behavior also depends on alloy composition, addition size and molten metal conditions.

The physical values below are technical reference data, not guaranteed acceptance limits for every production batch. For procurement, confirm the agreed chemical composition, particle size distribution and applicable batch documentation before ordering.

Key Takeaways

• Silicon content: FeSi75 is specified at a nominal minimum of 75% Si, subject to the agreed product standard.
• Material density: Approximately 3.20 g/cm³ as a technical reference value.
• Melting range: Approximately 1200–1350°C as a reference range; exact solidus and liquidus values require composition-specific data.
• Mechanical behavior: Hard and brittle, making crushing and screening practical but also creating fines during repeated handling.
• Bulk density: Not a fixed grade value; it changes with particle size distribution and packing conditions.
• Industrial handling: Particle size, moisture condition and fines content affect storage, feeding and material recovery.
• Procurement: Check the technical data sheet, batch COA, particle size report and applicable SDS.

FeSi75 Physical Properties at a Glance

The values in this table are intended for preliminary technical evaluation. Material density and melting range should be checked against the current FeSi75 technical data sheet. Bulk density, hardness and thermal conductivity should not be assumed from the nominal silicon grade alone.

You can also review our Ferrosilicon 75 specification for chemical composition, available product forms, particle sizes and packing information.

What Is the Density of Ferrosilicon 75?

The reference material density of Ferrosilicon 75 is approximately 3.20 g/cm³. This value describes the density of the solid alloy itself. It is useful for understanding the physical characteristics of the material, but it should not be used directly to estimate the volume occupied by loose FeSi75 lumps or granules.

Silicon has a lower density than iron. As the silicon proportion increases, the density of a ferrosilicon alloy generally tends to decrease. However, the actual density also depends on the alloy's complete chemical composition and phase structure. A nominal grade designation alone is not sufficient to establish an exact density for every batch.

Material Density vs. Bulk Density

Material density and bulk density describe two different physical conditions:

• Material density: The mass per unit volume of the solid FeSi75 alloy itself.
• Bulk density: The mass of loose FeSi75 divided by the total occupied volume, including the spaces between particles.

This distinction matters when calculating storage capacity, designing hoppers and selecting automatic feeding equipment. One metric ton of large FeSi75 lumps may occupy a different volume from one metric ton of small granules, even when both products have the same chemical composition.

Bulk density is influenced by several factors:

• Particle size and size distribution.
• Particle shape and surface irregularities.
• The proportion of fines between larger particles.
• Filling method and packing conditions.
• The presence of moisture or foreign material.

How to Calculate FeSi75 Bulk Density

For storage and equipment planning, bulk density should be measured using a representative sample of the actual particle size being purchased.

Bulk Density = Net Sample Mass ÷ Occupied Container Volume

For example, if a measured volume of 0.01 m³ contains 15 kg of FeSi75, the calculated bulk density is:

15 kg ÷ 0.01 m³ = 1,500 kg/m³

This is an illustrative calculation, not a measured FeSi75 product value. For meaningful comparison, use the same container volume, filling procedure and sample condition when testing different batches or particle sizes.

If you need to size a hopper, storage bin or automatic feeder, request bulk density data for the actual FeSi75 size range rather than substituting the solid alloy density.

For more information on size selection, see our Ferrosilicon Particle Size for Steelmaking guide.

How Does Silicon Content Affect Ferrosilicon Density?

Iron and silicon have different densities, so changing their proportions changes the physical density of the resulting alloy. In general, higher silicon content tends to produce a lower-density ferrosilicon alloy than a lower-silicon grade, although the exact relationship is also influenced by other alloying and impurity elements.

When comparing FeSi75, FeSi72, FeSi65 and FeSi45, do not assume that their densities can be calculated accurately from the grade names alone. Use composition-specific technical data if density is important for process engineering or equipment design.

What Is the Melting Range of FeSi75?

The reference melting range used for FeSi75 is approximately 1200–1350°C. However, ferrosilicon is an alloy rather than a pure element, so it does not necessarily have one single melting temperature.

Two temperatures are important when describing alloy melting behavior:

• Solidus temperature: The temperature at which the first liquid phase begins to form during heating.
• Liquidus temperature: The temperature above which the alloy is completely liquid.

The reference melting range should not automatically be interpreted as independently verified solidus and liquidus values. If your process requires precise thermal data, request a composition-specific technical report with the applicable measurement method.

Melting Temperature vs. Dissolution Behavior

Melting and dissolution are related but different processes. The melting range describes the thermal transition of the alloy. Dissolution describes how the added ferrosilicon heats, melts and distributes its silicon into the surrounding molten metal.

In steelmaking, FeSi75 is added to molten steel for deoxidation and silicon adjustment. The actual dissolution behavior depends on:

• Particle size and specific surface area.
• Molten steel temperature at the addition point.
• Addition position and timing.
• Bath circulation and stirring conditions.
• Actual alloy composition and surface condition.

Smaller particles generally heat faster because they provide more surface area relative to their mass. However, excessive fines can increase dust generation, oxidation and material losses during handling. The correct size therefore depends on the addition system and the operating conditions, not simply on melting temperature.

If you use FeSi75 for steel deoxidation or silicon adjustment, our Ferrosilicon 75 for Steelmaking guide explains the metallurgical application in more detail.

Hardness, Brittleness and Crushing Behavior

FeSi75 has a hard and brittle structure. Unlike ductile metals that can bend or stretch under mechanical force, ferrosilicon tends to fracture when subjected to impact or compression.

This mechanical behavior makes crushing and screening practical methods for preparing commercial FeSi75 lump and granular products. During production, the alloy can be broken into different particle-size ranges and separated through screening.

Why Does FeSi75 Generate Fines?

The same brittleness that makes FeSi75 suitable for crushing also creates a handling challenge. Repeated mechanical impact can break larger pieces into smaller particles. Fines may be generated during:

• Crushing and screening.
• Transfer between conveyors and storage bins.
• Loading and unloading operations.
• Long-distance transport involving repeated movement.
• Repeated handling of material in bulk bags.

For buyers, the important point is not simply whether FeSi75 is brittle. It is whether the delivered product maintains the agreed particle-size distribution after transportation and unloading.

Before ordering, confirm both the nominal size range and the acceptable undersize and oversize percentages. If the material will be fed through an automatic system, also specify the maximum allowable fines content.

FeSi75 Physical Properties vs. Other Ferrosilicon Grades

Different ferrosilicon grades contain different proportions of silicon and iron. Their physical properties can therefore differ, but the exact values must be based on the actual alloy composition rather than the grade designation alone.

For technical comparisons, request the corresponding data sheet for each grade. A nominal silicon percentage is not a substitute for a measured physical-property report.

How Physical Properties Affect Industrial Handling

Physical properties become commercially important when they influence the way FeSi75 is stored, weighed, transferred and added to a furnace or ladle.

For most steelmaking orders, chemical composition and particle size should be confirmed together. A batch that meets the required Si content but has an unsuitable size distribution may still create problems during storage, weighing and furnace feeding.

How to Verify FeSi75 Physical Properties Before Ordering

When evaluating a FeSi75 supplier, do not rely on a general product description alone. Request technical documentation that separates typical physical properties from actual batch inspection results.

Important: A standard COA generally focuses on chemical composition. It should not automatically be assumed to include density, hardness or melting-temperature test results. If these properties are important to your process, specify the required tests before placing the order.

For chemical composition and batch verification, see our Ferrosilicon 75 COA and Certificate of Analysis guide.

For available product specifications, grades and commercial forms, visit our Ferrosilicon 75 product specification.

FeSi75 Storage and Safety

FeSi75 should be stored in dry conditions and protected from unnecessary moisture exposure. The handling requirements depend on the product form, particularly when the material contains a high proportion of fine particles.

Fine ferrosilicon dust requires specific safety controls. Under certain conditions, contact with moisture, acids or incompatible chemicals may lead to hazardous gas generation, including hydrogen and potentially toxic phosphine or arsine. Airborne combustible dust may also present an ignition or explosion hazard under suitable conditions.

For routine storage and handling:

• Keep bags and storage areas dry.
• Avoid unnecessary dust generation during transfer and charging.
• Provide suitable ventilation where fine material is handled.
• Keep FeSi75 away from acids and incompatible chemicals.
• Follow the product-specific SDS and the site's approved safety procedures.
• Inspect packaging for damage and moisture exposure before use.

Do not use a general physical-property table as a replacement for the applicable SDS or workplace risk assessment. For more information, read our Ferrosilicon 75 Storage and Handling Safety guide.

What Should You Confirm Before Purchasing FeSi75?

Physical properties are only one part of a complete purchasing specification. Before confirming an order, we recommend checking the following details with your supplier:

For a complete comparison of available grades and product forms, you can also visit our Ferrosilicon grades and products page.

FeSi75 Physical Properties FAQ

Q: What is the density of Ferrosilicon 75?
A: The reference material density used for FeSi75 is approximately 3.20 g/cm³. This describes the solid alloy itself. Actual values should be confirmed against the applicable technical data for the specified composition.

Q: Is FeSi75 bulk density the same as material density?
A: No. Material density describes the solid alloy, while bulk density includes the spaces between individual particles. Bulk density changes with particle size, particle shape, fines content and packing conditions.

Q: What is the melting point of FeSi75?
A: The reference melting range is approximately 1200–1350°C. Because FeSi75 is an alloy, its thermal behavior depends on composition. This range should not be treated as a separately measured solidus and liquidus specification.

Q: What is the difference between solidus and liquidus temperatures?
A: Solidus is the temperature at which the first liquid phase begins to form during heating. Liquidus is the temperature above which the alloy is completely liquid. These values require composition-specific thermal data.

Q: Why is FeSi75 hard and brittle?
A: FeSi75 has a brittle alloy structure and tends to fracture under mechanical impact rather than bend. This allows it to be crushed and screened into different commercial sizes, but repeated handling can also generate fines.

Q: Does FeSi75 particle size affect bulk density?
A: Yes. Different particle sizes and size distributions produce different packing arrangements. Smaller particles may fill the gaps between larger lumps, changing the total occupied volume. Bulk density should therefore be measured using the actual product size.

Q: Does particle size affect FeSi75 dissolution in molten steel?
A: Yes. Smaller particles generally heat faster because they have a greater surface area relative to their mass. However, excessive fines may increase dust and handling losses. The appropriate size depends on the steelmaking addition system and operating conditions.

Q: Does FeSi75 need to be stored in dry conditions?
A: Yes. Keep FeSi75 dry and follow the applicable SDS. Fine ferrosilicon requires particular attention because moisture exposure and contact with incompatible chemicals may create additional safety hazards.

Q: Which documents should I request when purchasing FeSi75?
A: Request the technical data sheet for reference physical properties, a batch COA for chemical composition, a particle size inspection report where required, and the applicable SDS for safe handling.

Q: Can the supplier provide a FeSi75 density test report?
A: Physical-property testing should be agreed before ordering. If density or bulk density is a contractual requirement, specify the sample condition, test method and acceptance criteria so the results can be evaluated consistently.

Request FeSi75 Technical Data & Quote

ZHEN AN METALLURGICAL MATERIALS

 

Established in 1993, ZHEN AN integrates production, processing and international trade in metallurgical and refractory materials. With 30,000 m² of facilities, 8 furnaces and annual production and sales exceeding 150,000 metric tons, we supply metallurgical materials to customers in more than 100 countries and regions.

 

01

 

Production Facilities

Our production facilities cover 30,000 m² and include 8 furnaces, supporting the production and processing of metallurgical alloy materials.

 

02

 

Product Specification Support

We coordinate chemical composition, particle size, packaging and batch documentation according to the agreed product requirements.

 

03

 

Processing and Quality Control

Our processing and screening arrangements support different ferrosilicon product forms and particle-size requirements. Batch specifications can be checked against the agreed order requirements.

 

04

 

International Export Support

We serve customers in more than 100 countries and regions, coordinating product specifications, export packaging and shipping documentation according to order requirements.