What is FeSi?
Nov 04, 2025
I. Basic Concepts of Ferro silicon
Ferro silicon is an iron-silicon alloy composed of iron and silicon. It is produced by smelting coke, steel scrap, and quartz (or silica) in an electric furnace. Because silicon and oxygen readily combine to form silicon dioxide, ferro silicon is commonly used as a deoxidizer in steelmaking. Furthermore, the large amount of heat released during SiO2 formation contributes to both deoxidation and increasing the temperature of molten steel. Ferro silicon is also widely used as an alloying element in low-alloy structural steel, spring steel, bearing steel, heat-resistant steel, and electrical silicon steel. In ferroalloy production and the chemical industry, it is commonly used as a reducing agent.
II. Main Uses of Ferro silicon
1. Iron and Steel Smelting: Ferro silicon is an important deoxidizer and alloying additive in the steelmaking process. Adding it to molten steel effectively removes oxygen and increases the strength of the steel. Statistics show that approximately 3-5 kg of ferro silicon is consumed per ton of crude steel.
2. Foundry Industry: Adding ferro silicon to cast iron improves fluidity and reduces porosity defects. Gray cast iron typically requires the addition of 1%-3% ferro silicon.
3. Other Applications: Ferro silicon can also be used to produce magnesium metal (via the Pidgeon process), prepare silicone materials, and even serve as a raw material for welding electrode coatings.
III. Ferro silicon Market and Production Status
Global annual ferrosilicon production is approximately 12 million tons (2022 data), with China being the largest producer, accounting for over 60%. Major production areas are concentrated in regions rich in electricity resources, such as Inner Mongolia and Ningxia, as production requires a large amount of electricity (approximately 8000-9000 kWh per ton of ferrosilicon). Market prices are significantly influenced by silicon content, energy costs, and steel demand.
IV. Frequently Asked Questions
- Is ferro silicon flammable?: Solid ferro silicon is not flammable, but powdered ferro silicon may release hydrogen gas when exposed to moisture, requiring moisture-proof storage.
- Difference from calcium silicon alloy: Calcium silicon alloy contains calcium (10%-30%), resulting in stronger deoxidation, but at a higher cost.
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