The ZIG ZAG separator has been ideated for effecting a dry pre-separation of materials with different specific weight, above all those derived from rigid copper cables or stiff metalloid pieces. This pre-separator can select the input material before it reaches the turbine pulverizer and, by removing the heaviest pieces of metal, it can facilitate the turbine work and avoid any mechanical stress or wear of the pulverizer blades. The ZIG ZAG separator structure is equipped with operational cyclones and dosing valves. The airflow can be adjusted in accordance with the type of material to separate.