The Carbonyl Iron INN powder is used to react with iron in high temperature and high pressure, producing 5 carbonyl iron oil, and then being separated by low pressure to get the product. It can be shipped by annealing and oxidation treatment. When the temperature is 200 ℃, 200 bar under the condition of carbonyl synthesis reaction is as follows
Fe + 5CO = Fe (CO) 5
Carbonyl iron at 300 ℃, 1 bar under the condition of decomposition for Fe and CO
In the decomposition process, since Fe has a function of catalyzing the mutual conversion of CO and CO2, NH3 is generally used as a shielding gas to suppress the reaction. As a result, the presence of N element is inevitable in the carbonyl iron powder. The products collected from the cyclone collector generally have an iron content of about 97%, and the contents of C and N are less than 1%. Due to the presence of impurities such as Fe2O3 and Fe3N and the iron powder also has a certain adsorption on CO and NH3 gases. These factors cause the iron powder to have a relatively high hardness, which is usually called hard powder.
When the iron powder is reduced with H2 gas for 1 hour, the iron content will increase to about 99.0%, and the content of other elements will also be significantly reduced. This reduced Carbonyl Iron INN powder has a slightly lower hardness and is also called a soft powder.
The carbonyl iron powder is very active, and after a period of time, self-agglomeration occurs due to an increase in entropy. The iron powder particle size of the agglomeration increases, and the particles are sticky, which has a relatively large impact on injection molding applications. The best quality carbonyl iron powder on the market is produced by BASF, Germany.
The Carbonyl Iron INN powder has very high requirements on the production processes. When the iron pentacarbonyl is decomposed, its temperature changes by 3 degrees, and the gas flow rate increases by 5%, which can significantly change the particle size and carbon content of the carbonyl iron powder.