| 摘要 |
PURPOSE:To obtain metallic magnetic powder having high bulk density and excellent packing property by adding an anionic high molecular flocculant and a cationic inorganic flocculant into a liquid in which iron oxyhydroxide powder or iron oxide powder is suspended into water, coagulating these substances and baking and reducing the powder. CONSTITUTION:Iron oxyhydroxide powder or iron oxide powder is suspended into water. The anionic high molecular flocculant and the cationic inorganic flocculant are added into a suspension, and iron oxyhydroxide powder or iron oxide powder is coagulated. The powder is baked and reduced. Substances up to a high polymerization rate of several million molecular weight from a low one of not less than one thousand molecular weight are used as the anionic high molecular flocculant, and starch, etc are cited, and aluminum sulfate, etc. are used as the cationic inorganic flocculant, and the rate of it used is kept within a range of 1:10-10:1 at the weight ratio. Both flocculants jointly used at such rates are used within a range of 0.1-4wt% in total to iron oxyhydroxide powder or iron oxide powder in the water suspension. alpha-FeOOH powder, alpha-Fe2O3 powder, gamma-Fe2O3 powder, Fe3O4 powder and powder corresponding to these intermediate type and the like are cited as iron oxyhydroxide powder and iron oxide powder, and powder having excellent needle property is used. |
