NIRE Annual Report 1999

NIRE Annual Report

1999

Preparation of Composite Particulate Materials by a Mechanical Processing and Its Characterization

Objectives: Attention has been paid to a mechanical coating for producing advanced composite particles and modification of the surface. It is essential for the application to develop design of the composite by the mechanical processing. Thus we analyzed and described the composing process, quantitatively.

Results: Hematite fine particles of mean diameter 0.48 mm deposited onto the surface of glass beads of diameter 107 mm with a high-speed elliptical-rotor-type mixer. The deposition rate of hematite, f defined as the rate of the hematite deposited onto the glass particles to the initially charged hematite was correlated with the coverage factor h acquired from the measurement of brightness of composite particles, as shown in Fig. 1. The coverage factor means the quality of the coating layer. Every curve at any rotor rotational speed, Nr can be displayed on a single curve for f<0.2. The mechanical process is composed of the following stages; the first collision-deposition stage and the second compression-growth stage. The correlation between f and the factor related to accumulated shear energy E' is shown in Fig. 2. It is concluded that chronological changes in the amount of deposited particles depended upon the accumulated shear energy, that mainly affected the powder layer in the mixer.


Fig.1. Correlation between deposition rate and coverage factor	Fig.2. Varying of deposition with accumulated shear energy

1)	Characterization of Composite Particle Layer Formed with a High-speed Elliptical-rotor-type Mixer, Kagaku Kogaku Ronbunshu, 25, 92-96 (1999).

National Institute for Resources and Environment