The processing
Fluorescent tubes contain various metals, rare earths and other materials that can be separated and reused through recycling. However, in order to achieve the separation into a magnetisable fraction, a non-ferrous metal fraction, a glass fraction and a plastic fraction, a suitable separation process is required. High recovery rates combined with a high degree of purity are of central importance.
Process step 1: screening technology
As with most separation processes, efficient screening forms the basis for all 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.
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.
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.
Process step 3: eddy current separation
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.
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.