The technology applied is based on an X-ray sorting system that makes it possible to automatically sort material mixtures. The system determines the material density according to the dual-energy method and thus works regardless of material thickness and shape. It “sees” through the components, recognizing different material densities, different metals, halogens and organic substances.

This X-ray diagnosis makes it possible to separate the existing coal from other materials, especially soil. The absorption rate of the X-rays depends on the material density as well as on the thickness of the components. The larger the atomic mass and the thicker the part, the greater the absorption. To compensate for this, the thickness of the material to be sorted is measured at two different energy levels – the so-called “dual-energy method”.

The software is able to determine the material-specific absorption and thus the material. The long, fast-running conveyor belt ensures that the components are separated and evenly distributed. As they pass through the zone between the x-ray source and the camera, they are detected in fractions of a second and classified according to specific criteria defined for each application. The system’s flexible software enables these criteria to be preset.

If the classification result matches one of the preset criteria, the particle in question is ejected by means of a powerful air blast from compressed air valves that react very quickly and reliably.