Some features of the manufacture of R-100F-1 carbonyl iron powder

Raising the temperature in the reactor increases the concentrations of carbon and nitrogen impurities in a carbonyl iron powder, the increase in the nitrogen content being greater than that in the carbon content. A rise in reactor temperature increases both the goodness factor Qreland the temperature coefficient of magnetic permeability TCμ. Increasing the rate of feed of ammonia to the decomposition reactor brings about a growth in the concentration of nitrogen in a carbonyl iron powder, which lowers the TCμ of the powder and at the same time slightly decreases its goodness factor Qrel. The optimum conditions for the manufacture of a starting R-100 powder of lower TCμ. (not more than 80·10−6 1/deg C) are: upper, middle, and lower zone temperatures of 311, 306, and 337°C, respectively, an ammonia concentration in the decomposition products of 9 vol. %, and an iron pentacarbonyl feed rate of 32 liters/h. For the manufacture of R-100F-1 powder, the fine powder fractions from cyclones 2, 3, and 4 are used. The quantitative yield of carbonyl iron powder is 1.5–1.7%.