Fundamental difference
Essentially an alloy of silicon and iron. It is an artificially designed smelting product, primarily composed of silicon (Si) and iron (Fe), with trace amounts of elements such as aluminum and calcium. Common grades like FeSi75 indicate a silicon content of approximately 75%, with the remainder being mainly iron.
Essentially, it is high-purity elemental silicon. This elemental product is obtained through high-temperature reduction and purification of silicon-containing raw materials such as quartz stone, featuring an extremely high silicon content (typically ≥98.5%). The remainder consists of impurities that require strict control, such as iron, aluminum, and calcium.
Specific differences
| Comparison Dimensions | Ferrosilicon | Silicon Metal |
| Chemical Composition | Si + Fe (silicon as the main component, iron as an essential element), common grades: FeSi75, FeSi65, FeSi45 (numbers represent silicon content in %) | Si ≥ 98.5% (iron, aluminum, calcium are harmful impurities), common grades: 553, 441, 3303 (numbers represent upper limits for Fe, Al, Ca content) |
| Production Process | Quartz stone, steel scrap/iron ore, and coke are mixed and smelted together in an electric arc furnace to directly produce ferrosilicon alloy. | High-purity quartz stone, petroleum coke, and charcoal undergo high-temperature reduction in an electric arc furnace, demanding extremely high purity of raw materials and precise process control. |
| External Appearance | Appearing as silver-gray lumps, granules, or powder, with a hard and brittle texture. | A deep gray, lumpy or granular substance with a blue metallic sheen; its fracture exhibits a crystalline luster. |
| Core Functionality | As an "element carrier," it simultaneously introduces silicon and iron elements into the molten metal. | As a "source of silicon," it provides only high-purity silicon itself for deep processing. |
| Primary Use | 1. Steel Industry: - Deoxidizer: Consumes oxygen in molten steel. - Alloying Agent: Enhances steel strength, hardness, and elasticity. 2. Foundry Industry: Improves cast iron properties and promotes spheroidization. 3. Other Applications: Serves as a reducing agent in magnesium smelting. |
1. Chemical Industry: Core raw material for producing organosilicon compounds (silicone oil, silicone rubber, sealants, etc.). 2. Photovoltaics and Semiconductors: Purified into polysilicon/monocrystalline silicon for solar panels and electronic chips. 3. Aluminum Alloy Industry: Enhances alloy fluidity and strength. |
| Price Logic | Metallurgical raw materials, priced per ton, are significantly influenced by steel market conditions and electricity rates. | High-value-added raw materials are priced based on purity grades, commanding high unit values. Their prices are more significantly influenced by demand from the chemical and photovoltaic industries. |
How to choose correctly based on application?
If you are involved in steel smelting or casting:
Select: Ferrosilicon.
Key considerations: Silicon content (e.g., FeSi75), impurity control (e.g., Al, Ca, P, S content), physical particle size.
If you are involved in organosilicon, polysilicon production, or aluminum alloy formulation:
Select: Metallic silicon.
Key considerations: Impurity content (paramount-select based on grades like 553, 421), trace elements (e.g., titanium content), slag-free appearance, and batch consistency.
