siliconmetal

Silicon metal, also known as metallurgical-grade silicon, is the metallic form of silicon produced for industrial use. It is an elemental form of silicon with a high silicon content, typically around 98% to 99.9%, and contains minor amounts of impurities such as iron, aluminum, calcium, titanium, boron, and phosphorus. It is usually sold as ingots, blocks, granules, or powder and is distinct from higher-purity silicon used in electronics.

Production of silicon metal is primarily by carbothermic reduction of silica (silicon dioxide) in electric arc furnaces. In this process, silica is reacted with carbon (from coke or coal) at high temperatures to yield molten silicon and gaseous byproducts. The molten material is refined and solidified into various shapes for commercial sale. Further processing can produce higher-purity forms, including grades intended for aluminum alloys, chemical use, or, with extensive refining, solar-grade or semiconductor-grade silicon.

Common uses of silicon metal include as a feedstock for silicon-containing alloys, particularly aluminum-silicon (Al-Si) casting alloys, where silicon improves castability and strength. It also serves as a raw material for producing organosilicon compounds and silicones through subsequent chemical processes. In the solar and electronics industries, higher-purity silicon derived from silicon metal is refined to very high purities for photovoltaic cells and, with additional steps, semiconductor applications.

Environmental and safety considerations reflect the energy-intensive production process and standard industrial hygiene practices for handling dust and fine powders.