Preparation of Micropowder by a Combination of Jet-Milling and Electrostatic Dispersion

We develop a new method to prepare micropowders with a combination of jet-milling and electrostatic dispersion techniques. The dispersiveness of the powder can be obviously improved by charging the particles during the process of jet-milling. Calcium carbonate (CaCO₃) powders with high dispersion are prepared by using this method from two different initial particle sizes (10.93 and 25.43 μm). The experimental studies and theoretical analysis about the effects of preparation parameter on dispersiveness of the powder are investigated, showing that the jet-milling/electrostatic dispersion (J/E) is a considerably effective way to prepare micropowder in ambient atmosphere. It is found that the strength of electrostatic field and particle radius of the raw powder strongly affect the dispersion. The average particle size of both powders decreases with the increase in charging voltage while the reduction of particle size is more obvious in the powder with larger initial particle size.