Apparatus and process for producing powders and other granular materials

Apparatus for manufacturing powders or granular materials from liquids capable of quickly forming a coalescent resistant surface in a particular environment, comprising:

• an electrostatic spray head having a spraying site, an electrically conducting or semiconducting liquid contacting surface and means for delivering the said liquid to the spraying site a reference surface external to the sprayhead;
• high voltage supply means for charging the liquid contacting surface to said high voltage of one polarity relative to a reference surface, said voltage being sufficiently high and in combination the spraying site being sufficiently sharp, as to intensify the electric field strength at the spraying site sufficiently when covered, in use, by the liquid to be sprayed, that the liquid at the spraying site is drawn out preponderantly by electrostatic forces into a spray of at least one cone from which a corresponding ligament issues and breaks up into electrostatically charged droplets;
• means for providing said environment in a space sufficient that droplets from the spray head form, in flight, particles having a substantially coalescent resistant surface;
• and means for collecting the particles so formed.