Patent ID: 6659283
Filing Date: 2003-12-09
Classification: B03C,B22F,C01B,C22B

Abstract:
A method for purifying capacitor grade powders, comprising the steps of:a) placing a capacitor grade powder into a purifying machine that disperses at least one contaminate into the capacitor grade powder; b) moving the contaminated capacitor grade powder through a magnetic separation device comprising spaced apart pole pieces having their respective longitudinal axes aligned perpendicular to an intended travel direction of the capacitor grade powder, wherein the magnetic separation device establishes a nonuniform magnetic field between the pole pieces and along the travel direction, the nonuniform magnetic field providing a magnetic energy gradient having, in contiguous sequence, a katadynamic field region, an isodynamic field region, and an anadynamic field region, whereby the magnetic energy gradient along the travel direction is at a maximum at a locus of the isodynamic field region and decreases therefrom on either side thereof towards the katadynamic field region and towards the anadynamic field region, wherein the contaminated capacitor grade powder enters the magnetic energy gradient at either the katadynamic field region or the anadynamic field region and moves along the travel direction to exit the magnetic energy gradient at the other of the katadynamic field region or the anadynamic field region as a product capacitor grade powder having less contamination than the contaminated powder entering the magnetic separation device; and c) processing the product capacitor grade powder into an electrical energy storage device.