1. Definition
Metallurgical silicon (also known as industrial silicon or crystalline silicon) is a high-purity form of silicon produced by carbonthermal reduction of silica (SiO₂) in an electric arc furnace. It typically contains 98%-99.5% silicon with impurities such as iron (Fe), aluminum (Al), and calcium (Ca).
2. Main Features
Chemical symbol: Si
Appearance: Bluish-gray, brittle crystalline solid
Purity Grades:
Metallurgical class of silicon (MG-Si): 97%-99% Si (used in alloys, chemicals).
Chemical Grade Silicon: >99% Si (for the production of silicone).
Electronic Grade Silicon (EG-Si): 99.9999%+ (for semiconductor manufacturing).
Density: 2.33 g/cm³
Melting point: 1414°C (2577°F)
Boiling point: 3265°C (5909°F)
3. Production Method
Main process: Carbothermic reduction in submerged arc furnaces.
Raw materials: Quartz (SiO₂) + carbon (petroleum coke/coal/coal).
Reaction:
SiO2+2C1800–2000°CSi+2CO↑
Energy-intensive: Requires 12,000-14,000 kWh per ton of silicon.
4. Main Applications
Metallurgy:
Aluminum alloys (increase strength and heat resistance).
Silicon steel (for transformer cores).
Chemical industry:
Silicones (sealants, lubricants, resins).
Polysilicon (for solar cells and semiconductors).
Electronics:
Ultra-high purity silicon for semiconductors, chips and photovoltaic cells.
5. Market And Industry
Leading producers: China (~70% of world production), Norway, Brazil, USA.
Price factors: Cost of electricity, environmental policy, demand for solar energy.
6. Storage And Security
Sensitive to moisture: Must be stored in dry conditions to prevent oxidation.
Flammable: Fine silicon powder may explode when struck by a spark.