This document discusses several key aspects of waste electrical and electronic equipment (WEEE) recycling including: 1) Metals recovery from WEEE faces no major difficulties, with ample recycling capacities and markets available to process over 95% of input metals. 2) Glass recovery from waste electronics like CRTs is challenging due to requirements for highly purified glass and a declining CRT market. 3) Plastics make up around 20% of collected WEEE and include various polymers like ABS, PC, HIPS, and PPO that require further separation and processing. 4) Emerging technologies for WEEE recycling include improved separation methods, thermal treatments, hydrometallurgical extraction, sensing technologies, and

1. Outputs and Markets
S.Gomathy
Assistant Professor(Senior Grade)
KEC

2. Outputs and Markets
• Downstream markets for the outputs of WEEE
recyclers are complex and often consist of further
layers of ‘recyclers’ rather than end markets in
themselves.
• The fact that WEEE processors vary widely in their
outputs adds to this complexity, e.g. some facilities
upgrade the plastics fraction to give a cleaner stream
containing fewer polymer types, but many do not.

3. Metals
 There appear to be no major difficulties concerning the recovery and
recycling of metals from WEEE.
 There are ample capacities and markets available.’2 Metals also
constitute the largest weight of materials in WEEE, around 47%
overall for small mixed WEEE.5
 Current recycling processes are capable of recovering <95% of the
in-feed metals

4. Glass
 The major source of glass in waste electronics is from CRTs,
although this is likely to shift towards glass from flat-panel displays
as the number of CRTs declines.
 CRTs are composed of two main glass types: funnel glass (the back
of the tube), which contains high levels of lead oxide, and panel
glass (the screen), which contains barium and strontium oxides.
 This is difficult for a number of reasons:
• (i) low levels of contamination are required for the production of
new tubes that are difficult to reach with post-consumer recycled
product;
• (ii) there is a declining market for CRTs as they are replaced by flat
panel displays;
• (iii) manufacture of CRTs is now mainly carried out in non-OECD
countries, making the transport of ‘waste’ glass difficult because of
the transfrontier shipment of waste regulations

5. Plastics
 On average plastics constitute approximately 20% of collected
WEEE.
 A number of distinct materials streams are produced from WEEE
recycling
 The composition of plastics from mixed WEEE processing is
complex, containing at least five different polymers in large
amounts and many more used in smaller quantities for specific
applications.
• The major components are:
• Acrylonitrile Butadiene Styrene (ABS)
• Polycarbonate (PC)
• PC/ABS blends
• High-Impact Polystyrene (HIPS)
• Polyphenylene Oxide blends (PPO)

6. Emerging Technologies
Separation
 Efficient separation is a prime requirement for effective WEEE
recycling and can reduce reliance on dismantling.
 Electrostatic separators are good for extracting plastics, but are
limited to relatively small particle size.
 Sand-based fluidised beds for gravity separation are also under
investigation.
 A major advance in separation is likely to come through
sensing methods. Opto-electronic sorting14 is now being
incorporated into research systems.
 The construction sector is developing electromagnetic field
methods for both sensing and sorting

7. Thermal Treatments
• Thermal treatments have the advantages of greatly reducing bulk
and avoiding liquid effluent for the primary recycler, although
ultimately further refining is necessary to extract pure metals.
• partial vacuum methods are being investigated.
• Other thermal routes include encapsulation, using either glass or
binder, to produce low-grade block products for use in construction
Hydrometallurgical Extraction
• Hydrometallurgy is well established for extracting and applying
precious metals
• Processes based on strong acids and hydrogen peroxide have been
developed for WEEE,17 with fluoroboric acid proving useful for
extraction from mixed streams, including products from pyrolytic
processes.

8. Sensing Technologies
 Sensing methods can greatly improve the effectiveness of WEEE
recycling.
 They are crucial to implementation of automated disassembly and
can facilitate great improvements in separation.
 Opto-electronic sorters, which use conventional imaging devices to
discriminate on shape and colour, have been developed for various
industries.
 Augmentation by electromagnetic sensing permits identification of
metals, as well as of rubbers and plastics,23 allowing selective
ejection of the identified items in automated separation processes.
 Laser Induced Breakdown Spectroscopy (LIBS) is a laboratory
technique that is being adapted for on-line operation in separation
processes, and to which enhancements such as pulsing are being
applied.

9. Plastics to Liquid Fuel
 A number of processes have been proposed to use the mixed plastic
fraction as a source of organic chemicals that can be converted to a liquid
fuel.
 The most developed of these is the Catalytic Depolymerisation Process
(CDP)
 The pumps are one of the key parts of the process.
 Heating is carried out in the pump, rather than in the large vessel.
 This ensures that no part of the fluid is heated to the point at which dioxins
are produced (4400 1C).
 The pump uses friction to heat the reactants while bringing together the
reactants and catalyst into intimate contact
 The first operational plant is located in Mexico and can produce c. 500 l
hour1 of diesel.
 A second, larger, plant capable of 1500 l hour1 is planned for Canada.
 The design has been adapted to be modular so it can be easily transported
as standard containers and easily installed on site.
 This also makes it possible to transport the plant to the waste rather than the
other way round.

10. Plastics Containing Brominated Flame Retardents
 A number of attempts have been made to remove BFRs from
plastics to allow recycling of the plastic.
 One such process is the Creasolv process.
 It is based on selective extraction of a targeted polymer from plastic
waste, followed by a cleaning step.
 Impurities, undesired additives (e.g. flame retardants) and toxic
degradation products can be separated effectively to obtain a high-
purity polymer.
 The tar residue from this process is rich in bromine.
 If the bromine level is 410% then it can be used as a feedstock into
the bromine industry, this is a particularly good example of how
refining and purification of a waste stream adds to the value, and
how almost any substance can have value, even toxic substances