Silicon metal is primarily produced through the carbothermic reduction process, where high-purity silica (SiO₂, typically from quartz sand or quartzite) is smelted with carbon-based reducing agents—such as coal, charcoal, or petroleum coke—in a submerged electric arc furnace at temperatures of 1,800–2,000°C. The key chemical reaction is:

{SiO2 + 2C -> Si + 2CO}

This process reduces silica to molten silicon, which is then tapped from the furnace, cast into ingots, and crushed into blocks or powder.

The initial silicon metal produced is ~98–99% pure, with impurities like iron, aluminum, and calcium. For higher purity (e.g., 99.99% Si), further refining techniques like fractional crystallization, zone refining, or chemical purification (e.g., using acid leaching) are employed to remove trace contaminants. The final product is categorized into grades (e.g., 553, 441, 1101) based on impurity levels, tailored for applications in aluminum alloys, solar cells, semiconductors, and silicones.