| 摘要 |
PURPOSE:To obtain ferromagnetic iron oxide power performing simple and low-cost measure by a method wherein mill scale powder whose specific surface area is more than 0.1m<2>/g is heated in antireduction atmosphere at less than 500 deg.C. CONSTITUTION:For the purpose of obtaining ferromagnetic iron oxide powder, which contains magnetite phase of more than 50wt% making almost eustite phase FeO of mill scale powder to magnetite phase Fe3O4, at first the formation of the said iron oxide powder is promoted with the use of mill scale powder whose specific surface is more than 0.1m2/g, then it is contrived to get enough reaction speed. The powder is put in semiclosed container whose aperture is sealed by coke powder and the like and the magnetite phase is created by eutectoid reaction of 4FeO Fe+Fe3O4 in antireduction atmosphere at less than 560 deg.C avoiding the creation of excessive hematite Fe2O3. At this time, the fact, which content rate of magnetite phase is about 50wt%, is accomplished and ferromagnetic iron oxide powder is obtained. |
