1. Basis of classification
Ferrosilicon is classified mainly based on the following factors:
Silicon content: it is divided into high-silicon (70%~90%), medium-siliceous (60%~70%) and low-siliceous (45%~60%).
Control of impurities: such as the content of aluminum, carbon, phosphorus and sulfur, which determine the level of purity.
Application: deoxidation of steelmaking, casting grafting, reduction of magnesium content in metal and other various application scenarios.
2. International Standards
(1) ISO 5445
Brand name: Expressed as "FeSi + silicon content range" (e.g., FeSi75 corresponds to a silicon content of 72%~80%).
Key parameters:
Grade Silicon (Si) /% Aluminum (Al) /% Carbon (C) /%
FeSi90 87~95 ≤1.5 ≤0.1
FeSi75 72~80 ≤1.5 ≤0.2
FeSi65 65~72 ≤2.0 ≤0.2
Application: General metallurgical use, suitable for global trade.
(2) American ASTM A100
Features: Stricter impurity restrictions (Al, C).
Grade of Silicon (Si)/% Aluminum (Al)/% Carbon (C)/%
FeSi75 74~80 ≤1.0 ≤0.15
FeSi65 63~68 ≤2.0 ≤0.2
Application: Production of high-quality steel and alloy steel.
(3) European Standard EN 13835
Environmental requirements: Focus on low emissions and sustainable production.
Grade Silicon (Si)/% Environmental Protection Level
FeSi75 72~80 General Purpose (Low Emission)
FeSi65 65~72 Industrial Grade
3. Chinese Standard (GB/T 2272)
Brand name: Expressed as "FeSi + average silicon content" (e.g., FeSi75 contains 72%~80% silicon).
Key parameters:
Silicon (Si) /% Aluminum (Al) /% Carbon (C) /% Phosphorus (P) /% Sulfur (S) /%
FeSi90 87~95 ≤1.5 ≤0.2 ≤0.04 ≤0.02
FeSi75 72~80 ≤1.5 ≤0.2 ≤0.04 ≤0.02
FeSi45 40~47 ≤2.0 ≤0.3 ≤0.04 ≤0.02
Application: Mainly used in domestic steel and foundry industry and for export.
4. Classification by special purpose
(1) Low aluminum ferrosilicon
Options: Al ≤0,5%, Si ≥75%.
Application: Reduction of magnesium metal (Pidgeon process) to avoid aluminum contamination of magnesium purity.
(2) High-Purity FeSi
Options: Si ≥90%, total impurities <1%.
Application: High-quality materials such as electrical steel and nuclear-grade zirconium alloys.
(3) Ferrosilicon for foundry
Options: Al 1%~3%, Si 65%~75%.
Application: Contributes to the graphitization of cast iron (e.g., ductile iron).
5. Environmental Protection and Safety Standards
China's "dual carbon" policy: Limits the use of small, high-energy furnaces (<25,000 kVA) and promotes clean energy production.
EU REACH Regulations: Limits emissions of heavy metals (Pb, Cd) and dust.
Safe storage: Moisture-proof packaging that complies with the International Maritime Dangerous Goods Code (IMDG Code) is required.
6. Comparison of standards in the main producing countries
Country/Standard Typical Brand Silicon Content (%) Impurity Control Application Scope
China (GB) FeSi75 72~80 Al, C, P, S Steelmaking, Casting
USA (ASTM) FeSi75 74~80 Al≤1.0%, C≤0.15% High Quality Steel
Grades Norway FeSi75-LA 75~80 Al≤0.3%, Low Ca Magnesium Metal Reduction
7. Selection recommendations
Deoxidation in steelmaking: FeSi75 (low aluminum, low carbon) is preferred and must meet GB/T or ASTM standards.
Injection seed: FeSi65/FeSi75 (1%-2% aluminum) is used to stimulate graphitization.
Magnesium Metal Production: Low-aluminum FeSi75 (Al≤0.5%) must be used to ensure recovery efficiency.
