Abstract: A method and apparatus are disclosed for magnetically separating particles from a liquid, which particles include diamagnetic, non-magnetic and/or very weakly paramagnetic particles. To achieve separation, the magnetic susceptibility of the liquid is modified, such as through dissolving a paramagnetic substance (such as manganese chloride) or a diamagnetic substance (such as bismuth diiodide) in a liquid (such as water, alcohol or glycerine), after which the modified paramagnetic liquid is passed through a filter formed of magnetic material in a magnetic field with the filter being preferably formed of ferromagnetic material establishing a high gradient magnetic filter.

Abstract: A method of magnetically separating particles having different magnetic susceptibilities. A magnetic field is established in a colloidal suspension of magnetic particles which distribute to form a magnetic susceptibility gradient. The particles to be separated are introduced into the colloidal suspension. The introduced particles migrate along the magnetic susceptibility gradient to different regions having approximately the same magnetic susceptibilities as the introduced particles.