The magnetic separator is designed to separate magnetic coarse and fine particles from the emulsion in the water-miscible cooling lubricants used in metalworking (rolling, drilling, turning, milling and grinding) with minimum oil discharge. High-performance magnets separate the emulsion from the metallic magnetizable particles in full flow or in bypass. The unit operates without pressure and without chemicals. It also enables a reduction in energy and disposal costs and a reduction in metal sludge by a factor of 50.