BLACK COMPOUND IRON OXIDE PARTICLE

摘要

PROBLEM TO BE SOLVED: To provide titanium-containing compound iron oxide particles containing a large amount of titanium, being lowly magnetizable, and having a high FeO content and a high degree of blackness. SOLUTION: The black compound iron oxide particles have a crystal structure of Fe3O4and (FexTiy)zO4(wherein x is a number of 0.5 to 3; y is a number of 0.25 to 1.25; and z is a number of 0.5 to 1.5) and have a titanium content of 4.5 to 10 wt.%. The particles can be desirably produced by blowing air into an aqueous solution containing ferrous ions and titanium ions in the presence of an organic acid or an organic acid salt to subject it to wet oxidation under conditions that the rate of ferrous ions consumed during the wet oxidation is 4 to 8 g/L per hour. COPYRIGHT: (C)2005,JPO&NCIPI