| 摘要 |
A method is disclosed for separating a preselected metal fraction from a stream of discrete particles containing a plurality of metals that are not strongly ferromagnetic. According to this method, a detection zone is established within the stream of particles, and a static magnetic field is established within the detection zone. The static magnetic field so established is of insufficient strength or flux density to induce in the particles of metal in the stream an opposing magnetic field of such strength as to cause the particles in the stream to move. The presence of a particle within the detection zone is detected, and changes in the magnetic flux density of the field are measured as the particle passes through the detection zone. The changes so measured are then compared with a predetermined change pattern for the preselected metal fraction to be removed, and the particles whose passage through the detection zone change the magnetic flux density of the field according to the predetermined change pattern are separated from the stream.
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