Magnetic separation

In a Frantz magnetic separator, the individual mineral phases are separated according to their different magnetic susceptibilities. These material constants are given as Xm = M / H = effective magnetization / magnetic field strength. According to this criterion, one can roughly distinguish four groups of minerals: ferro-/ferri-, para-, dia- and non-magnetic minerals. Ferro- and ferrimagnetic minerals contain Weiss domains, so that even without an external magnetic field they have a high, but altogether undirected magnetization. Even a small magnetic field causes a rearrangement and alignment of the Weiss domains. In ferrimagnetic minerals, with otherwise identical properties, only the saturation magnetization is significantly lower than in ferromagnetic minerals. Ferro- and ferrimagnetic minerals must be removed from the sample with a hand magnet before using the magnetic separator.

The Frantz magnetic separator is used to separate "magnetic" and "non-magnetic" minerals.