InsightsMetal recycling
How does XRT separate aluminium from heavy metals?
Direct answer
Dual-energy X-ray transmission measures how much X-ray energy passes through each piece, which exposes density and effective atomic-number differences. That separates aluminium from copper, brass, zinc, lead and stainless steel — and because it reads through the piece rather than off its surface, oxidised, dusty or coated scrap is not judged on appearance.
Reading through the piece, not across its surface
For metal, colour is not enough. A scrap piece arrives oxidised, dusty, painted or coated, and its surface says very little about what it is. Two pieces that look the same can be worth completely different amounts.
Dual-energy X-ray transmission takes a different reading entirely. It measures internal attenuation — how much energy passes through — and the difference between the two energies exposes density and effective atomic number. Those are properties of the material itself, so surface condition stops being the deciding factor.
What it is asked to separate
| Stream | What leaves | Platform |
|---|---|---|
| Coarse aluminium-rich scrap, Zorba-type feed | Copper, brass, zinc, lead and stainless steel | FR-XRT |
| Remelter feed being cleaned before charging | Dense heavy-metal contaminants that reduce feed value | FR-XRT |
| Complex mixed streams — ASR, IBA, heavy non-ferrous, e-waste | Non-metals and misclassified fractions, using density and appearance together | FR-XRT Pro |
The commercial point is upstream of the furnace: cleaner aluminium feed and better remelter control before charging, by removing the contaminants that reduce the value of the aluminium fraction.
When appearance is added back
FR-XRT Pro adds RGB imaging alongside the X-ray reading. That is not a contradiction of the point above — it is for decisions where internal density response and external appearance have to be reviewed together, which is what complex mixed streams often need.
One signal is enough for a clean aluminium-versus-heavy-metal question. Two are worth having when the stream is not clean and the classes overlap.
What it will not promise
The published position is unusually direct: fixed purity, universal separation and guaranteed alloy separation are not promised without sample testing. Particle size, thickness, presentation and contaminant rate all shift the decision boundary.
Cast versus wrought aluminium is the clearest case. It depends on alloy composition, shape, thickness, X-ray response and the customer's real samples, so it should not be promised universally — a limitation worth stating up front rather than discovering during commissioning.
Where this stops applying
- Fixed purity, universal separation and guaranteed alloy separation are not promised without sample testing.
- Cast versus wrought aluminium separation should not be promised universally; it depends on alloy composition, shape, thickness, X-ray response and real samples.
- FR-XRT is a coarse scrap sorter, not a fine-particle color sorter. The recommended particle size comes from the supplied technical data.
- Whether a rejected heavy-metal stream is worth a second pass depends on its value, contamination level and the recovery target.
- The configuration is built from accepted aluminium, target rejects, borderline pieces and the real size distribution.
Common follow-ups
Is FR-XRT a color sorter?
No. It is positioned around dual-energy X-ray transmission for density and effective atomic-number response, and is used when surface colour alone is not enough to define aluminium quality.
Which metals can it remove from aluminium?
It can be configured for heavy metal removal from aluminium-rich streams, targeting copper, brass, zinc, lead and stainless steel. Final performance depends on representative sample testing, particle size, thickness, presentation and reject rate.
Can it separate cast aluminium from wrought aluminium?
This should not be promised universally. It depends on alloy composition, shape, thickness, X-ray response and the customer's real samples.
Why does surface condition not matter as much here?
Because the reading is internal. X-ray attenuation passes through the piece, so oxidised, dusty or coated scrap is not judged only by visible appearance.
When is FR-XRT Pro the right choice?
When internal density response and external appearance need to be reviewed together — complex mixed streams such as ASR, IBA, heavy non-ferrous and e-waste, where one signal is not enough.