COMPOSITE FINE PARTICLE AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To easily produce composite particles having new functions and physical properties in which at least two kinds of different particles are hetero- bonded, by forming prism hematite particles and radially growing planer goethite particles from the c-axis of the hematite crystal as the symmetric center in the direction along the c-axis of the goethite crystal. SOLUTION: The composite fine particles are produced by preparing a prism hematite and growing planer goethite particles in such a manner that the goethite particles are radially hetero-bonded to the c-axis of the hematite crystal as the symmetric center and are grown in the c-axis direction of the goethite crystal. The planer goethite particles are grown along opposite directions to each other from the symmetric axis or bonded at the positions spirally rotating each of them by the angle 60 deg. in the clockwise direction. The composite fine particles are obtd. by adding an alkali phosphate soln. containing phosphate ion to the suspension described below and then ageing. The suspension contains a gel amorphous material of either iron (III) hydroxide produced by mixing iron (III) salt soln. and strong alkali soln., or FeOOH containing a minute amt. of water inside.