Patent ID: 7041925

Claim:
Apparatus for the electrostatic separation of a mixture of particles that exhibit difference in electrical conductivity, comprising: a conductive surface to which conducting particles lose their charge; feeding means for feeding the mixture of particles onto the conductive surface; an ionizing electrode for ionizing individual particles in the mixture of particles; and a first static electrode having the same polarity as the ionizing electrode and which serves to generate a static electric field, the first static electrode being located sufficiently close to the ionizing electrode that the static electric field acts continuously on the particles as they are ionized, and being of sufficient length to continue to act on the particles once ionized; wherein conducting particles are separated from non-conducting particles on the basis of their different retained charge after a period of contact with the conductive surface, said apparatus further comprising a second static electrode which serves to extend the distance over which the static electric field is applied to the conductive surface.