| 摘要 |
A flowable mixture of particles is separated in accordance with the magnetic susceptibilities of the particles by feeding the mixture into a magnetic field in such a manner that the mixture is urged by a non-magnetic force, e.g., gravity, towards the locus at which the magnetic energy gradient H DIFFERENTIAL H/ DIFFERENTIAL X of the field is at a maximum. The magnetic energy gradient defines a magnetic barrier along the locus of its maximum magnitude which exerts a magnetic force on the particles in opposition to the non-magnetic feeding force. Particles having a magnetic susceptibility lower than that value at which the force exerted by the magnetic barrier balances the non-magnetic feeding force pass through the barrier, whereas particles of greater magnetic susceptibility are prevented from crossing from one side of the barrier to the other side and may thereafter be recovered separately from the less susceptible particles. Continuous separations may be carried out by giving the mixture a velocity component lengthwise of the barrier such that particles deflected by the barrier will move therealong to a collection point. The magnitude of the maximum magnetic energy gradient may be varied along the length of the barrier or plural barriers of different strengths may be provided in succession to provide for progressive separation of the mixture into fractions of different magnetic susceptibilities.
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