Display devices | Elektro ade zum Inhalt springen zur Hauptnavigation springen

Display devices

General

Recycling of a cathode-ray tube (© EAK, 2018)

Within the collection and processing category of display devices, two basic types of devices are distinguished:

Tube-based devices (cathode-ray tube)

  • Televisions,
  • computer monitors,
  • surveillance and
  • security monitors

Flat-screen devices (which are thinner and do not rely on CRT technology)

  • Televisions,
  • computer monitors,
  • laptops,
  • educational and gaming computers,
  • surveillance and security monitors

e.g. LCD screens (liquid crystal display), LED screens (Light Emitting Diodes) and plasma screens

Currently, tube-based display devices still make up about 85% by mass of all electrical and electronic devices in the “display device” collection category. In terms of the number of devices, the lighter flat-screen displays already make up about 30% of this category. The proportion of flat-screen displays will rise sharply in coming years, since tube-based devices are no longer being manufactured.

Recovering raw materials – tube-based devices

The following table and graph present the approximate quantity of raw materials recovered each year in the processing of tube-based display devices, and the proportion of different specific materials that are recovered.

 

Portions Mass [t] Proportion [%]
Metals 1.309 11,20
Screen glass (barium glass) 3.741 32,00
Cone glass 3.273 28,00
Plastic materials 1.683 14,40
Circuit boards 935 8,00
Electrolytic capacitor 140 1,20
Luminescent coating 4 0,03
Remainder 604 5,17
Total 11.691 100,00

Materials recovered from tube-based display devices (2017)

 

Breakdown of display devices by percentage of total mass (2017)

 

Recovering raw materials – flat-screen displays

Currently, flat-screen displays make up about 15 % by mass of all electrical and electronic devices in the “display device” collection category. The following table and graph present the approximate quantity of raw materials recovered each year in the processing of flat-screen displays, and the proportion of different specific materials that are recovered.

 
Portions Mass [t] Proportion [%]
Ferrous metals 722 35,00
Non-ferrous metals 144 7,00
Plastic materials 784 38,00
Remainder 413 20,00
Total 2.063 100,00

Materials recovered from flat-screen display devices (2017)

 

Breakdown of flat-screen display devices by percentage of total mass (2017)

 

Hazardous substance removal and disassembly – tube-based display devices

Professional disassembly of tube-based display devices proceeds in the following steps (e.g., in Austria, by the Saubermacher company in Wien and Premstätten, see www.saubermacher.at):

  1. Disassemble rear panel and housing.
  2. Remove printed circuit boards.
  3. Allow air to enter the picture tube (the vacuum in the picture tube poses a risk of
    implosion).
  4. Remove the electron beam unit, made of high-grade nickel-alloy steel.
  5. Extract the toxic getter plate, which contains barium.
  6. Separate the picture tube into screen glass and cone glass.

For tube-based devices, the screen coating (which contains toxic cadmium and yttrium compounds) must be removed.

To do this, the metal clamping ring is first removed from the picture tube, and hot wire is then used to separate the tube into two halves: the screen glass (barium glass) and the cone glass (lead glass). The metal shadow mask is removed as well. Finally, the screen coating is vacuumed off and captured in collection containers. The screen coating is stored in an underground disposal site.

The barium and lead glass from picture tubes can be used in the recycling of industrial glass, in the lead industry, or as recycled building materials.

Hazardous substance removal and processing – flat-screen displays

Flat-screen displays can be disassembled by hand or processed mechanically in special processing facilities (e.g. www.mgg-recycling.com in Amstetten).

The flat-screen displays are gently broken apart in a special separation unit (smasher). After this initial step, manual and mechanical separation processes (sifting, aspiration) are used to separate dangerous components and substances like mercury, printed circuit boards, accumulators and batteries.

As manual and mechanical sorting proceeds, later separation steps extract plastic, ferrous and non-ferrous metal portions (using ferrous and non-ferrous separators).