How is silicon metal produced?

Silicon metal is produced from quartz and coke in an electric heating furnace. Quartz will undergo oxidation and reduction and become molten silicon liquid. Once cooled, it will turn into a solid as we can see. The chunks of raw silicon metal are very large. It is then made into smaller pieces, which we call standard sizes. The size of silicon metal lumps is 10-100mm， silicon metal powder (particle size 100, 200, 325 mesh).

Silicon metal is produced primarily through the carbothermic reduction of quartz (SiO₂) in electric arc furnaces. The production process is highly energy-intensive and involves several critical steps:

1. Raw Material Preparation:

• Quartz: The primary raw material is high-purity quartz, typically with a silicon dioxide (SiO₂) content of at least 98.5%.

• Carbon: Reducing agents such as charcoal, coal, petroleum coke, or wood chips are used to provide the carbon necessary for the reduction process.

2. Smelting Process:

• Electric Arc Furnace: The quartz and carbonaceous materials are mixed and then fed into an electric arc furnace. The furnace operates at temperatures between 1,900°C and 2,300°C.

• Reduction Reaction: At these high temperatures, the carbon reacts with the silicon dioxide in quartz to form silicon metal and carbon monoxide (CO) gas according to the following reaction:  SiO2+2C→Si+2CO 

• Refining: The molten silicon settles at the bottom of the furnace, while impurities and by-products like slag float on top. The silicon metal is periodically tapped from the furnace and further refined if necessary.

3. Casting and Cooling:

• The molten silicon is then cast into molds to form silicon metal ingots. These ingots are cooled and solidified.

• After solidification, the silicon metal is crushed into smaller pieces according to the required specifications.

4. Post-Processing:

• Crushing and Sizing: The solidified silicon metal is crushed and sized to meet the specific needs of various applications.

• Purification (if needed): Depending on the required purity levels, additional purification steps such as acid leaching or zone refining might be employed to remove trace impurities.

5. Quality Control:

• The final product undergoes rigorous testing to ensure it meets industry standards for purity, composition, and size.

Environmental Considerations:

• The production of silicon metal generates significant amounts of CO₂ and CO gases. The industry has implemented measures to capture and utilize these by-products to reduce environmental impact.

• The energy consumption in silicon metal production is substantial, leading producers to explore energy-efficient technologies and processes.

Applications:

• Silicon metal is a critical material used in various industries, including aluminum alloy production, the chemical industry (for silicones), electronics (as the base material for semiconductors), and solar energy (in the production of photovoltaic cells).

HS can produce different grades of industrial silicon. At the same time, there are also different categories and different particle sizes of silicon metal powder. And support the customization of silicon metal blocks, silicon metal particles and silicon metal powder products according to customer needs.