Recycling critical raw materials from waste electronic equipment

Recycling critical raw materials
from waste electronic equipment
4.8 Status of recycling technology for smartphones
The recycling of smartphones – although as a relatively new product group they have not yet
reached the end-of-life stage in any great quantity – can be compared to the recycling of
mobile phones and is just as easy. It is important to remove the cobalt-containing lithium-ion
batteries in order to send these separately to suitable battery recycling plants (see Section
6). Mobile phones are normally fed into pyro-metallurgical plants such as e.g. Umicore's
facility in Belgium, without any further disassembly. This processing primarily recovers high
yields of metals such as copper, lead, nickel and tin and precious metals such as gold, silver
and palladium.
4.9 Potential for optimization in the recycling chain
The most important measure for increasing the optimization potentials in the recycling chain
for smartphones is clearly to raise the currently very low collection rate. Furthermore, the
importance of removing the cobalt-containing batteries must be stressed. Recycling using the
proven copper bus bar enables the recovery of not only copper but the precious metals
silver, gold and palladium at recovery rates of 95%. There are now equally efficient
processes for recovering cobalt from the lithium-ion batteries. For the other critical metals
such as tantalum, gallium, indium, neodymium and praseodymium, there is a need for basic
research on the quantities involved and on the issue of whether these metals can be
recovered at reasonable expense despite the probably low absolute quantities.
5 LED lights
In recent years white LEDs have increasingly been used for lighting. These new lights have
many benefits. For instance they currently provide very energy-saving lighting due to a high
luminous efficacy of 50-80 lm/W. Their light is of high quality with a color rendering index of
80-90 and a continuous spectrum. They have a long service life of up to 50,000 hours, good
switching stability and start-up time (period between the beginning of the current flow through
the LED and reaching their maximum light intensity) and are very shockproof and vibrationresistant.
In addition, their small design permits new design solutions. This enables a wide
range of applications, such as in the automotive industry. With constantly rising values for
luminous efficacy due to technological advances and the ability to produce LEDs with white
light, they are also of interest for room lighting.
The basic design of an LED is similar to that of a semiconductor diode. Diodes are electronic
components which only allow electrical current to pass in one direction. In a semiconductor
diode the diode chip contains adjacent layers of an n- and p-doped semiconductor. An ndoped
semiconductor can be imagined as a substance in which individual electrons can
function as charge carriers. In contrast, in a p-doped semiconductor this is the missing
electrons ("holes").
41