Application of pulsed HV discharges to material fragmentation and recycling

The physical basis of electric impulse fragmentation and its applications t o the recycling of composite materials are reviewed. The method is based on the initiation of a pulsed electric discharge inside the solid dielectric material. With pulse amplitudes of similar to 300 kV, material layers of si milar to 2 cm can be punctured. Specific energy deposition, of less than or similar to 100 J/cm at a GW power level, leads to pressure buildup of less than or similar to 10(10) Pa in the discharge channel. Pressure waves and radially propagating cracks are launched into the solid body, which can lea d to the separation of inclusions from the matrix or to detachment at mater ial boundaries. To induce the discharge in the solid dielectric it must be immersed in a dielectric liquid with higher breakdown strength. Most applic ations use water, which has excellent breakdown strength at fast ramp rates and, due to its high permittivity, leads to field concentration in the sol id dielectric. Electric impulse fragmentation is a clean physical method wi thout any environmental burden and therefore well suited for recycling appl ications. In this paper we consider applications in the fields of demolitio n debris, incineration ashes, contaminated surface layers, electric applian ces, glass, and elastoplastic materials. Finally, the economy and the scali ng of the technique to large material throughput are discussed.