Insights into the processing of fluorescent tubes

Fluorescent tubes contain various metals, rare earths and other substances that can be separated and reused through proper recycling. However, in order to achieve the separation into a magnetizable fraction, a non-ferrous metal fraction, a glass and a plastic fraction, a suitable separation process is required. High recovery rates combined with a high degree of purity are of central importance.

1st process step: screening technology

As with most separation processes, efficient screening forms the basis for any further processing steps!

IFE therefore recommends the implementation of a protective screen after the material has been shredded. The control screening machine helps to remove disturbing long parts (at a screen cut of 50 mm; see Ill.1) and to keep the longs safely away from the undersize fraction.

Illustration 1: Input fraction for the control screen

An IFE waste screen in a flat design without steps and equipped with specially designed louver-type panels ideally meets this requirement. In addition, the design of the waste screen allows the material to be distributed evenly over the required width, which facilitates the treatment on the downstream equipment.

2nd process step: metal separation technology

The shredded and screened material (grain size < 50 mm; see Ill. 2) was placed on a barium ferrite drum and a high-intensity drum (neodymium) as part of a material test in the IFE test center.

Illustration 2: Input fraction metal separation (picture enlarged)

The tests carried out previously clearly showed that a strong neodymium magnetic drum type KHP is the right choice in order to also split off the small ferrous wires that were still present within the material. A large content of magnetizable material (23 %) was regained by choosing this method.

Illustration 3: Magnetizable product

3rd process step: non-ferrous metal separation technology

The remaining mixture of fractions (non-ferrous metals, glass and plastics) was then fed onto an IFE STRATOS eddy current separator. In this process, the non-ferrous metals contained (11 %) have been separated.

The residuals (glass and plastics; see Ill. 5) can be separated again with additional sensor sorting technology.

Illustration 4: Non-ferrous fraction
Illustration 5: Residual fraction

An alternative option is to split the remaining fines from the glass with the help of the IFE flip-flop screen TRISOMAT.

After the multi-stage separation process has been completed, the fluorescent tube mixture is optimally fractionated and prepared for further processing.

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