High Quality 5–10 cm FeSi75% Iron-Silicon Lumps

 

High Quality 5–10 cm FeSi75 Iron-Silicon Lumps are supplied in three chemical composition options: FeSi75A, FeSi75B and FeSi75C. Although these grades belong to the same commercial product range, their silicon ranges and impurity limits are not identical. Buyers should therefore evaluate the actual chemical specification rather than selecting a grade based only on its name.

The featured product has a nominal lump size of 5–10 cm (50–100 mm). For quality acceptance, two independent requirements need to be considered: chemical composition and physical particle size. A batch may meet its chemical limits while still requiring a separate particle-size inspection.

This page focuses on the chemical differences between the listed FeSi75 grades, impurity verification, batch analysis and product acceptance. For other ferrosilicon grades and product forms, visit our Ferrosilicon Product Range.

 

 

The following table presents the three chemical composition options in our existing FeSi75 product specification. The differences are particularly important when buyers need to control minimum silicon content, manganese, carbon and phosphorus.

Grade	Si (%)	Mn (%)	Al (%)	C (%)	P (%)	S (%)
FeSi75A	75.0–80.0	≤0.4	≤2.0	≤0.2	≤0.035	≤0.02
FeSi75B	73.0–80.0	≤0.4	≤2.0	≤0.2	≤0.04	≤0.02
FeSi75C	72.0–75.0	≤0.5	≤2.0	≤0.1	≤0.04	≤0.02

Important: FeSi75A, FeSi75B and FeSi75C are the commercial grade options listed in this product specification. Their designations should not be assumed to represent universally interchangeable standard grades. Always confirm the applicable standard and contractual chemical limits before purchasing.

 

 

FeSi75A: Minimum Silicon Content of 75%

FeSi75A has a silicon range of 75.0–80.0%, making it the appropriate option among these three listed grades when the purchase specification requires a minimum silicon content of 75%.

Its phosphorus limit is ≤0.035%, compared with ≤0.04% for FeSi75B and FeSi75C. This distinction may matter when the buyer has a specific phosphorus control requirement.

FeSi75B: A Wider Silicon Range

FeSi75B has a silicon range of 73.0–80.0%. Its listed manganese, aluminum, carbon and sulfur limits are the same as FeSi75A, while its phosphorus maximum is slightly higher at 0.04%.

Buyers should note that the minimum silicon value is 73.0%, not 75.0%. If the purchase contract specifically requires Si ≥75%, this grade must not be accepted solely on the basis of its FeSi75B designation.

FeSi75C: A Lower Carbon Limit

FeSi75C has a silicon range of 72.0–75.0% and a maximum carbon content of 0.1%, lower than the 0.2% limit listed for FeSi75A and FeSi75B.

Its maximum manganese content is 0.5%, compared with 0.4% for the other two options. Buyers who require tighter carbon control should evaluate this specification while checking whether its silicon range meets their minimum requirement.

Key Differences at a Glance

Comparison Item	FeSi75A	FeSi75B	FeSi75C
Minimum Si (%)	75.0	73.0	72.0
Maximum Mn (%)	0.4	0.4	0.5
Maximum Al (%)	2.0	2.0	2.0
Maximum C (%)	0.2	0.2	0.1
Maximum P (%)	0.035	0.04	0.04
Maximum S (%)	0.02	0.02	0.02

There is no universal rule that one grade is superior in every application. The correct selection depends on the minimum silicon content and impurity limits specified by the buyer.

For a broader comparison of silicon grades, see our Ferro Silicon Grade Selection Guide.

 

 

Silicon content alone does not provide a complete assessment of ferrosilicon quality. Buyers should also check the impurity limits relevant to their production requirements.

Aluminum (Al)

Aluminum is an important controlled element in many steelmaking specifications. Its permitted level should be stated numerically in the purchase agreement. The three FeSi75 options listed above have an aluminum maximum of 2.0%. If a buyer requires Al ≤1.0%, ≤0.5% or another tighter limit, that requirement must be confirmed separately rather than assumed from the FeSi75 grade name.

Carbon (C)

Carbon content is particularly relevant when purchasing ferrosilicon for steel grades with specific carbon restrictions. In the listed specifications, FeSi75C has a maximum carbon content of 0.1%, compared with 0.2% for FeSi75A and FeSi75B.

Phosphorus (P) and Sulfur (S)

Phosphorus and sulfur are residual elements that buyers may need to control according to the requirements of the finished steel or casting. The listed phosphorus limits are 0.035% for FeSi75A and 0.04% for FeSi75B and FeSi75C. All three options have a maximum sulfur content of 0.02%.

Manganese (Mn)

Manganese content should also be checked when it is included in the agreed chemical specification. FeSi75A and FeSi75B have a maximum of 0.4%, while FeSi75C has a maximum of 0.5%.

For a complete reference to the chemical requirements, inspection items and specification-writing process, see What to Check in a Ferrosilicon 75 Specification.

 

 

Quality acceptance should be based on the purchase specification and the actual condition of the delivered batch. A product label or general technical sheet is not sufficient evidence that a shipment meets every contractual requirement.

1. Verify the Product Grade

Check whether the product identification, purchase order and inspection documents refer to the same grade. Pay particular attention to the difference between a specification requiring Si ≥75% and one that allows a lower silicon range.

2. Compare Actual Chemical Results

Check the measured silicon and impurity values against the limits agreed before purchase. A Certificate of Analysis should provide actual test results for the identified batch rather than simply repeat the nominal product specification.

3. Confirm Batch Traceability

Check the batch or lot identification and confirm that it corresponds with the relevant material and shipment documents. A test report that cannot be connected to the delivered batch is insufficient for reliable quality verification.

4. Inspect Physical Particle Size

The nominal 5–10 cm size corresponds to 50–100 mm. Physical inspection should establish whether the supplied lumps fall within the agreed size range. Where size consistency matters, the purchase specification should also define acceptable undersize, oversize and fines percentages.

5. Confirm the Inspection Method

Sampling, sample preparation and chemical analysis methods should be agreed before shipment. If independent inspection is required, the inspection scope, sampling point and acceptance criteria should be confirmed with the supplier and inspection agency in advance.

For a detailed explanation of batch analysis and document verification, read our Ferrosilicon 75 COA: What to Check in a Certificate of Analysis.

 

 

For this product, 5–10 cm refers to a nominal particle size of 50–100 mm. The nominal range should be distinguished from the actual particle-size distribution of a shipment.

During inspection, buyers should pay attention to the following points:

Inspection Item	What to Verify
Nominal Size	Confirm the specified 50–100 mm range.
Undersize Material	Check the proportion of pieces below the agreed minimum size.
Oversize Material	Check the proportion of pieces exceeding the agreed maximum size.
Fine Particles	Confirm whether fines content has a separate contractual limit.
Foreign Material	Check for visible contamination or unwanted foreign materials.
Inspection Record	Record the sampling method and measured size distribution where required.

A nominal size label does not automatically guarantee that every lump falls within the stated range. Buyers should specify measurable size tolerances before ordering.

For further information about particle-size selection and inspection, read What Ferrosilicon Particle Size Is Used in Steelmaking.

 

 

Technical discussions with customers help clarify product grade requirements, chemical composition limits and quality acceptance expectations. Before confirming a purchase, buyers can communicate their required FeSi75 grade and inspection criteria with our team.

 

 

A product specification and a Certificate of Analysis serve different purposes in quality control. Buyers should use both documents when verifying FeSi75.

Document	Main Function	What Buyers Should Check
Product Specification	Defines the required chemical and physical limits.	Grade, Si range, impurity limits and particle size.
Batch COA	Reports actual chemical analysis for a specific batch.	Measured values, batch number and test date.
Inspection Report	Records the agreed inspection or testing results.	Sampling scope, inspection method and acceptance criteria.
MSDS	Provides product safety and handling information.	Storage, handling and safety precautions.

One important point is that a chemical COA does not automatically prove particle-size compliance. If both chemical composition and physical size are contractual requirements, they should be verified separately.

Buyers can also review our separate guide to Ferrosilicon 75 for Steelmaking for technical information about the role of FeSi75 in steel production.

 

 

Before accepting a FeSi75 shipment, buyers can use the following checklist to compare the delivered material with the agreed purchasing specification.

Check Item	Acceptance Reference
Product Grade	Matches the agreed FeSi75A, FeSi75B or FeSi75C specification.
Silicon Content	Actual result meets the contracted minimum or range.
Aluminum Content	Actual result does not exceed the agreed maximum.
Carbon Content	Actual result meets the specified carbon limit.
Phosphorus and Sulfur	Both results comply with the agreed limits.
Manganese Content	Actual result meets the specified manganese limit.
Batch Identification	COA and related records correspond to the supplied batch.
Particle Size	50–100 mm nominal size and agreed tolerances are verified.
Inspection Documents	Required COA and inspection records are available.

The final acceptance decision should follow the applicable standard and the contractual specification. If a particular element or physical property is not included in the agreed requirements, it should not be assigned an assumed acceptance limit after shipment.

 

 

For additional product information and technical guidance, the following resources cover different aspects of FeSi75 selection and purchasing:

• Ferrosilicon 75 Specification – Chemical composition and specification requirements.
• Ferrosilicon 75 COA Guide – How to verify batch chemical analysis.
• Ferrosilicon Particle Size Guide – Particle-size selection and inspection considerations.
• Ferro Silicon Grade Selection Guide – Differences between commercial silicon grades.
• Ferrosilicon 75 for Steelmaking – Technical applications in steel production.
• 75% Ferro Silicon 50–100mm Product – Separate product information for the 50–100mm size range.

 

 

Q1: What is the difference between FeSi75A, FeSi75B and FeSi75C?
A: They have different silicon ranges and impurity limits. FeSi75A has a silicon range of 75.0–80.0%, FeSi75B has 73.0–80.0%, and FeSi75C has 72.0–75.0%. Their carbon, manganese and phosphorus limits also differ.

Q2: Which FeSi75 grade guarantees at least 75% silicon according to the listed specifications?
A: FeSi75A has a minimum silicon content of 75.0%. FeSi75B and FeSi75C have lower minimum values, so they should not be selected when the contract strictly requires Si ≥75%.

Q3: Why should aluminum content be checked separately?
A: The FeSi75 grade name does not automatically guarantee a particular aluminum level. Buyers requiring tighter aluminum control should state the exact maximum Al percentage in the purchase specification.

Q4: Does a FeSi75 COA confirm particle size?
A: Not necessarily. A COA primarily reports chemical analysis. Particle size should be verified through the agreed physical inspection or screening procedure.

Q5: What should buyers check before accepting FeSi75 lumps?
A: Confirm the grade, actual chemical results, batch identification, particle-size distribution and required inspection documents against the purchase agreement.

 

 

ZHEN AN INTERNATIONAL CO., LIMITED supplies ferrosilicon and other metallurgical materials to industrial customers. We can discuss FeSi75 grade options, chemical composition requirements and quality inspection arrangements according to your purchasing specifications.

If you require FeSi75A, FeSi75B or FeSi75C, please provide your target silicon content, impurity limits and required particle size. Our team can review the technical requirements and confirm the applicable product specification.

Contact Us for FeSi75

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