Silicon Metal, Metallic Silicon, Elemental Silicon, Crystal Silicon, 7440-21-3

SILICON METAL (METALLIC SILICON)

PRODUCT IDENTIFICATION INFORMATION

CHEMICAL STRUCTURE

    Silicon Metal (Si)
    
    Diamond Cubic Crystal Structure
    
         Si  Si  Si  Si
           \  |  /  |
            Si Si Si Si
           /  |  \  |
         Si  Si  Si  Si
    
    Diamond Cubic Crystal Structure
    Semiconductor Properties

Molecular Formula: Si (Elemental)
Crystal Structure: Diamond Cubic
Electron Configuration: [Ne] 3s² 3p²
Oxidation States: +4, -4 (primary)
Band Gap: 1.12 eV (indirect semiconductor)
Synonyms: Silicon Metal, Metallic Silicon, Elemental Silicon, Crystal Silicon

SECTION 1: CHEMICAL IDENTITY AND DEFINITION

SECTION 2: PHYSICAL AND CHEMICAL PROPERTIES

SECTION 3: GRADE CLASSIFICATION AND QUALITY CODES

Standard Silicon Metal Grades

High-Purity Silicon Grades

SECTION 4: PHYSICAL AND CHEMICAL PROPERTIES BY GRADE

SECTION 5: PRODUCTION METHODS

Method 1: Carbothermal Reduction (Most Common Industrial Method)

• Reaction: SiO₂ + 2C → Si + 2CO (at 1,700-2,000°C)

• Description: Quartz (SiO₂) is reacted with carbon (coal, coke, wood chips) in electric arc furnaces; Produces metallurgical grade silicon (98-99% purity); Most common industrial production method

Method 2: Metallurgical Grade Refining

• Process: Crude silicon → Acid leaching → Refining → Metallurgical grade silicon

• Description: Removes impurities through acid treatment and refining; Produces 99-99.5% purity silicon

Method 3: Siemens Process (High-Purity)

• Process: Silicon → Trichlorosilane (SiHCl₃) → Purification → CVD deposition → High-purity silicon

• Description: Silicon is converted to trichlorosilane, purified by distillation, and deposited as high-purity polycrystalline silicon through chemical vapor deposition; Produces 99.9999%+ purity (semiconductor grade)

Method 4: Fluidized Bed Reactor (FBR) Process

• Process: Silicon → Silane (SiH₄) → Fluidized bed deposition → Granular silicon

• Description: Silicon is converted to silane gas, which is decomposed in a fluidized bed reactor; Produces granular high-purity silicon

SECTION 6: FUNCTIONAL PROPERTIES AND MECHANISM OF ACTION

SECTION 7: MAIN APPLICATION AREAS

SECTION 8: QUALITY SPECIFICATIONS (METALLURGICAL GRADE 553)

SECTION 9: COMPARISON OF SILICON METAL ALTERNATIVES

SECTION 10: TOXICOLOGICAL PROFILE

SECTION 11: GHS CLASSIFICATION AND LABELING

GHS Classification (Compliant with CLP and UN GHS):

Note: Silicon metal is generally considered non-hazardous. However, fine dust may cause mechanical irritation.

Signal Word: No signal word required (non-hazardous) or WARNING (optional)

Hazard Pictograms: GHS07 (optional)

Hazard Statements (H-Codes) - if classified:

NFPA 704 Hazard Classification:

SECTION 12: PRECAUTIONARY STATEMENTS (P-CODES)

SECTION 13: FIRST AID MEASURES

SECTION 14: FIREFIGHTING MEASURES

SECTION 15: STORAGE AND SHELF LIFE

SECTION 16: PACKAGING OPTIONS

SECTION 17: TRANSPORT INFORMATION

SECTION 18: OTHER NAMES AND SYNONYMS

SECTION 19: SUMMARY TABLE

SECTION 20: CRITICAL WARNINGS AND BEST PRACTICES

CRITICAL WARNINGS:

• Non-hazardous material but fine dust may cause respiratory tract irritation.

• Non-combustible. Does not burn. Stable at high temperatures.

• Powder form may be combustible. Avoid dust generation.

• High melting point (1,414°C). Suitable for high-temperature applications.

• Semiconductor properties. High-purity grades are essential for electronics.

• Incompatibilities: Keep away from strong oxidizing agents and halogens.

• Moisture: Forms protective oxide layer; Keep dry.

• Silicosis risk: Prolonged inhalation of crystalline silica dust may cause silicosis.

• Hygiene Requirement: Wash hands thoroughly after handling.

BEST PRACTICE RECOMMENDATIONS:

• Aluminum Alloys: Use grade 553 for general casting applications; Higher purity grades for specialized alloys; Typical Si content 10-20%; Provides improved castability, hardness, and wear resistance.

• Semiconductor Industry: Use high-purity silicon (6N-11N); Handle in clean room environments; Requires extreme purity control; Used for wafers, chips, and integrated circuits.

• Solar Energy: Use solar-grade silicon (4N-6N); Polysilicon production; Monocrystalline and polycrystalline solar cells; High efficiency and reliability.

• Chemical Industry: Use metallurgical grade silicon (553-441); Silane and silicone production; Silicon-based chemicals; Sealants and adhesives.

• Handling: Use in well-ventilated areas; Avoid dust generation; Wear protective gloves and safety goggles (if dust).

• Personal Protective Equipment: Safety goggles, protective clothing, protective gloves (nitrile, neoprene), NIOSH-approved dust mask (if dust).

• Hygiene: Wash hands thoroughly after handling; Do not eat, drink, or smoke when using.

• Storage: Store in cool, dry, well-ventilated area; Protect from moisture; Keep away from oxidizing agents and halogens.

• Spill Response: Avoid dust generation; Vacuum or sweep; Place in closed containers; Do not allow to enter drains or waterways.

• Disposal: Dispose of in accordance with local, regional, and national regulations; Silicon is recyclable; Recycle where possible.

SPECIAL NOTE ON SILICON GRADES:

Silicon metal is classified based on impurity content:

• 553 Grade: Fe ≤0.5%, Al ≤0.5%, Ca ≤0.3% → Primary use: Aluminum alloys

• 441 Grade: Fe ≤0.4%, Al ≤0.4%, Ca ≤0.1% → Chemical, metallurgical

• 3303 Grade: Fe ≤0.3%, Al ≤0.3%, Ca ≤0.03% → High-purity applications

• 2202 Grade: Fe ≤0.2%, Al ≤0.2%, Ca ≤0.02% → Electronics, photovoltaic

• 1101 Grade: Fe ≤0.1%, Al ≤0.1%, Ca ≤0.01% → High-purity electronics

SPECIAL NOTE ON HIGH-PURITY SILICON PRODUCTION:

High-purity silicon is produced through specialized processes:

• Siemens Process: Conversion to trichlorosilane (SiHCl₃); Purification by distillation; CVD deposition; Produces polycrystalline silicon (6N-9N)

• Fluidized Bed Reactor (FBR): Conversion to silane (SiH₄); Fluidized bed deposition; Produces granular silicon (4N-6N)

• Applications: Semiconductor wafers (6N-9N); Solar cells (4N-6N); Advanced electronics (9N-11N)

LEGAL DISCLAIMER:

The information provided in this document is based on our current knowledge and experience and is presented in good faith. However, as all conditions of use are beyond our control, this document does not constitute a binding specification or warranty. This Technical Data Sheet is for informational purposes only. Users are responsible for testing suitability for their own applications. For complete safety, storage, handling, transportation, waste, and regulatory compliance information, please refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier.