Steelmaking Metal Silicon

The main component of metallic silicon is silicon, so it has similar properties to silicon. Silicon has two allotropes: amorphous silicon and crystalline silicon. Amorphous silicon is a gray-black powder, which is actually a microcrystal. Crystalline silicon has the crystal structure and semiconductor properties of diamond, with a melting point of 1410°C, a boiling point of 2355°C, Mohs hardness of 7, and brittleness. Amorphous silicon is chemically active and can burn violently in oxygen. It reacts with non-metals such as halogen, nitrogen, and carbon at high temperatures, and can also react with metals such as magnesium, calcium, and iron to form silicides. Amorphous silicon is almost insoluble in all inorganic and organic acids, including hydrofluoric acid, but is soluble in a mixed acid of nitric acid and hydrofluoric acid. Concentrated sodium hydroxide solution can dissolve amorphous silicon and release hydrogen gas. Crystalline silicon is relatively inactive and does not combine with oxygen even at high temperatures. It is not soluble in any inorganic acid or organic acid, but is soluble in mixed acids of nitric acid and hydrofluoric acid and concentrated sodium hydroxide solution.