PREPARATION AND CHARACTERIZATION OF MICRON AND SUBMICRON-SIZED VERMICULITE

Abstract

The effect of ultrasounds on natural macroscopic vermiculite flakes has been studied. Conditions for the preparation of submicron vermiculite particles of narrow particle-size distribution by sonochemistry are described. The resulting material is crystalline, as assayed by X-ray diffraction. Effects of ultrasound treatment on the mean particle size, crystal structure, crystallite dimensions in different directions, and specific surface area of the resulting particles are investigated. Under the conditions used in this work, there is a practical limit at 40 h in the sonication time for the preparation of submicron particles; longer treatment times promoted aggregation.