Iron Powder
The size of iron powder is less than 1 mm. It's color is black. It is the main raw material of powder metallurgy. According to the particle size, it is usually divided into five grades: coarse powder, medium powder, fine powder, fine powder and ultra-fine powder. Iron powder with particle size of 150-500 μ m is coarse powder, medium powder with particle size of 44-150 μ m, fine powder with particle size of 10-44 μ m, extremely fine powder with particle size of 0.5-10 μ m, and ultrafine powder with particle size less than 0.5 μ M.
Reduced iron powder, gray or black powder, also known as "double absorbent", can absorb water and oxygen in the air, and is often used in food preservation.
The reduced iron powder is generally produced by the reduction of Fe3O4 in hydrogen or carbon monoxide gas stream under high heat conditions, and the main component is the loose elemental iron. Because the reduced iron powder itself is powder, and its microstructure is very loose, so its surface is active. It is often used as reducing agent in chemical production and laboratory operation.