X-ray transmission sorting (XRT)
XRT (X-ray transmission) is an automated sorting method in which every object on the conveyor is scanned by X-rays while the software determines the material type in real time and issues a command to the actuator (typically air-jet pneumatic valves). Unlike security screening, the operator does not see the image: the decision is made by the algorithm.
RöntgenTek develops software and algorithms for XRT sorting — from acquiring detector data to building the command map for ejection. At its core lies the same multi-energy (dual energy) material discrimination as in our security-screening software, but tuned for automatic classification at high speed.
Why X-ray (XRT), not optics
Optical sorters see only the surface — color and shape. X-rays penetrate the object all the way through and measure the density and effective atomic number (Zeff) of the material across its entire volume. This makes it possible to:
- distinguish materials regardless of contamination, moisture and surface color;
- "see" internal inclusions and foreign objects;
- separate materials with a similar appearance but different density/composition;
- work with a stream of heterogeneous material.
Dual energy strengthens the method: measurement across several energy bands makes it possible to separate light elements (organic) from heavy ones (metals, heavy minerals) even at different object thicknesses.
Areas of application
♻️ Sorting of waste and recyclables
- Separation of the target fraction by material type, identification of foreign inclusions.
- Increasing the purity and value of recyclables (plastic, wood, metal, inert).
- Removal of unwanted impurities from the stream before further processing.
- RDF/SRF fuel control: removal of heavy and chlorine-bearing fractions.
⛏️ Sorting of ore and minerals
- Pre-concentration — separation of ore from waste rock by density before crushing and beneficiation.
- Lowering grinding and processing costs by removing waste rock.
- Lump-ore sorting on the conveyor or in the stream.
- Applicable to various ore types where there is a density/composition contrast.
🔩 Sorting of scrap and metals
- Separation by substance type: metal / non-metal, light / heavy fractions.
- Cleaning scrap of contaminants, extracting valuable components.
🏭 Industrial inspection and rejection
- Detection of foreign objects in product and raw-material streams.
- Rejection of non-conforming items on production lines.
What we develop
XRT sorting software is a real-time pipeline that runs "without an operator":
- Line-scan detector
- data acquisition
- calibrationoffset · gain
- segmentationobjects on the belt
- material classificationdual energy
- sorting rules
- command map
- pneumatic valvesvia the controller
Processing and classification
- Real-time acquisition of line-scan detector data at high belt speed.
- Detector calibration (offset/gain), on-board and off-board modes.
- Segmentation — isolating individual objects within a continuous stream.
- Material classification by density and Zeff (dual energy), robust to different object thicknesses.
- Configurable sorting rules for a specific material and task (thresholds, classes, fraction priorities).
Ejection control
- Building the "shot" map for the pneumatic-valve array.
- Accounting for conveyor speed, geometry and valve actuation delays.
- Precise binding of the command to the object's position (tracking along the belt).
- Integration with the controller for managing actuators and safety.
Performance and operation
- Real-time operation (deterministic processing latency).
- Sorting statistics, fraction counters, logs.
- Calibration and tuning for a new material without rewriting the software.
- Cross-platform: Windows / Linux.
How it comes together as a system
The XRT separator combines all of our competencies:
- Detector integration — stable data acquisition and synchronization (including experience with Detection Technology).
- Image processing (dual energy) — separation and classification of materials.
- Controller — X-ray generator, conveyor, ejection valves, interlocks and safety.
We can develop the sorting algorithm and software for your separator or take part in building the entire installation.
Engagement formats
- Classification algorithm — material-discrimination software adapted to your material and detector.
- Complete sorting software — from data acquisition to valve control.
- Integration into an existing separator — replacing/improving the classification software.
- Pilot and feasibility assessment — verifying material contrast on test samples before full-scale development.
Let's discuss your sorting task
Tell us which material you need to separate and on what equipment — we will assess the applicability of X-rays (XRT) and propose a processing pipeline and a work plan. Where possible, prepare a description of the fractions and test samples.