Metal silicon, also known as industrial silicon, is a product smelted from silica and carbonaceous reducing agents in submerged arc furnaces. The main component silicon content is usually above 98.5% and below 99.99%. The remaining impurities are iron, aluminum, calcium, etc. . In China, metal silicon is usually divided into different grades such as 553, 441, 421, 3303, 2202, and 1101 based on the content of iron, aluminum, and calcium in metal silicon.