Magnetic separation in a magnetic fluid.

摘要

Paramagnetic particles of different saturation magnetisation are separated by subjecting a suspension of the particles in a paramagnetic fluid to a magnetic field of sufficient strength to saturate them magnetically. By selecting the magnetisation of the fluid, the particles are separated on the basis of how their individual saturation magnetisation compares to the magnetisation of the fluid; thus they may behave paramagnetically or diamagnetically. The magnetisation of the fluid may be controlled by altering the size of the applied field or the susceptibilty of the fluid. Preferably Vortex Magnetisation Separation is employed. The method is particularly suitable to sort synthetic diamonds using an aqueous solution of MnCl 2 , the impurities in the diamonds causing paramagnetic behaviour which aids separation. Diamonds with ferromagnetic impurities are removed by a sequential or simultaneous application of a magnetic field.