Density sorting with the STEINERT XSS® T – via x-ray transmission under the dual-energy principle

For a wide range of application options and a high level of stability

The STEINERT XSS® T x-ray sorting system is used for dry density sorting. A transmitting procedure detects material-dependent differences in the absorption of x-rays then classifies and uses them for sorting into density classes.
The extent of absorption of x-rays depends both on the material density and on the thickness or the radiated path of an object. The larger the atomic mass and the thicker a material part, the more radiation will be absorbed. The absorption in the material to be sorted is measured at two different energy levels to compensate for the influence of the object thickness. The so-called dual-energy procedure uses software to determine the material-specific absorption and thus conclude the density of the material. The radiation passing through the objects enables both the conclusion of an average density for an object and the identification of inclusions in rocks or clumps of material.

The main advantage of our x-ray transmission is that its transmissive detection makes the system insensitive to surface soiling and enables the detection of inclusions. This is the case for example with pyrite accumulations in chunks of ore in mining or with heavy metal inclusions in pieces of aluminium in recycling. There is also the option of masking materials with low density and thus significantly increasing the throughput in certain applications and removing impurities from a closed supply flow (e.g. metals from waste wood).

Separation, detection, sorting

A vibration conveyor is used to carry the sortable material on an acceleration belt, which breaks the supply flow down in the supply direction thus achieving material separation. The feed material is transported through the scanner area in a resting position on the conveyor belt, whereby the x-ray source is positioned below the conveyor belt and radiates a narrow area of it. The proportion of radiation not absorbed by the material is measured by detectors in the beam above the conveyor belt. The variation between initial and measured radiation can be used to reveal differences in density between or within individual objects. Each individual object is subsequently classified according to application-related criteria. Should the decision to sort be positive, the relevant object is deflected from the discharge parabola using a short, targeted blast of compressed air, thereby ejecting it out of the material stream and thus separated from the remainder of the material flow.

Resilience and high availability characterise the well-balanced scanner unit, which as a closed system has an internal cooling circuit. The high service life of the x-ray source means you benefit from the comparatively low maintenance costs for this sorting system.

A semi-mobile variant is a special version of the STEINERT XSS® T. In this case our x-ray sorting system with 1 m working width is installed in a 40' container. A further 40” container contains the operating room with controller. We can optionally include a diesel generator set, compressors, conveyor belts and feed hoppers in the scope of supply. This enables a comprehensive overall concept to be provided to meet the requirements and ambient conditions and allows processing even in remote areas without essential infrastructure. The necessary operating power for the overall system can be generated using a diesel generator set if self-sufficient operation is to be enabled. The focus of the semi-mobile STEINERT XSS® T is on mineral processing, although it can also be used in other sectors. Please contact us and we will be happy to advise you.

  • XSS T = x-ray sorting system with transmission
  • Uses the dual-energy principle for detection, discerns material-specific differences in density
  • Grain sizes: 10 – 200 mm
  • Working widths: 1,000 mm, 1,200 mm, 2,000 mm
  • Semi-mobile STEINERT XSS with 1,000 mm working width in a 40” container