2. Introduction
what is recycling?
Recycling is the process of converting waste
materials into new materials and objects.
The three chasing arrows
of the international recycling logo
3. What’s plastic recycling?
Plastic recycling is the process of recovering scrap or waste plastic and
reprocessing
the material into useful products, sometimes completely different in form from
their original state.
4. Why Plastic Recycling?
-In landfill, both synthetic and
naturally occurring polymers
don’t get the necessary exposure to UV
and microbes to degrade.
-Here they are taking up space and
none of the energy put into making
them is being reclaimed.
-As petroleum prices increase it is
becoming more financially viable to
recycle polymers rather than produce
them from raw materials.
-Reclaiming the energy stored in the
polymers
can be done through incineration,
but this can
cause environmental damage by
release of toxic gases into the
atmosphere
-Recycling is a viable alternative in
getting back
some of this energy in the case of
some polymers.
6. Plastic Fact File
-More than 20,000 plastic
bottles are needed to obtain 1
tonne of plastic.
-It is estimated that 100 million
tonnes of plastics are produced
each year.
-The average European throws
away 36kg of plastics each
year.
-4% of oil consumption in
Europe is used for the
manufacture of plastic
products
-Some plastic waste sacks are
made from 64% recycled
plastic.
9. Plastic Incineration
Incineration of Plastics:
Plastics are the most significant contributors to the energy content - calorific
value - of MSW. Most waste plastics have a high calorific value (CV) – at about
40 MJ/kg - similar to fuel oil.
Polymers, Fuels & Mixed waste plasticsNet calorific Value (Mj/kg)
HDPE/ LDPE/ PP45
Oil40
Coal25
PVC (wide variations between rigid and flexible PVC)22
11. Plastic Recycling Procedure
• Collection of Plastic:
1. House to house collection.
2. Collection at a central point.
3. Collection from street boys.
4. Regular collection from shops.
5. Scavenging or collecting oneself.
12. Plastic Recycling Procedure
• Cleaning & Sorting :
Once the plastic has been collected, it will have to be cleaned and
sorted. The techniques used will depend on the scale of the operation and the type of
waste collected, but at the simplest level will involve hand washing and sorting of the
plastic into the required groups. More sophisticated mechanical washers and solar
drying can be used for larger operations. Sorting of plastics can be by polymer type
(thermoset or thermoplastic for example), by product (bottles, plastic sheeting, etc.), by
colour, etc.
14. Plastic Recycling Procedure
• Size Reducion:
This is to reduce larger plastic waste to a size manageable for small machines,
and to make the material denser for storage and transportation.
17. Plastic Recycling Procedure
• Melting & Extrusion:
At this process plastics are being
heated and melted to induce plastic
behavior and then forced through a die
to form a plastic spaghetti which can
then be cooled in a water bath before
being pelletized.
19. Plastic Recycling Procedure
• Pelletization :
The pelletization process
is used to reduce the
‘spaghetti’ to
pellets which can then
be used for the
manufacture of new
products.
23. Plastic Recycling Procedure
These pellets are used in producing new products using 10-20% of the recycled
plastics and the remaining amount is from new granulas.
25. Plastic Recycling Procedure
The main material of the manufacturing of these products is thermoplastic and
basicly, the main used thermoplastics are:
1. PP or Polypropylene 2. PE or Polyethelyne
26. Recycling Techniques
• Manufacturing Techniques :
The mainly used techniques are :
1. Extrusion
2. Injection Moulding
3. Blow Moulding
4. Film Blowing
27. Recycling Techniques
• Extrusion :
-The extrusion process used for manufacturing new products is similar to
the mentioned operation of the process preceding pelletization, except that the product is
usually in the form of a continuous ‘tube’ of plastic such as piping or hose.
-The reclaimed plastic is forced along the heated tube by an archimedes screw and the plastic
polymer is shaped around a die.
29. Recycling Techniques
• Injection Moulding:
-The first stage of this manufacturing process is identical to that
of extrusion, but then the plastic polymer emerges through a nozzle into a split
mould. The quantity of polymer being forced out is carefully controlled, usually
by moving the screw forward in the heated barrel. A series of moulds would be
used to allow continual production while cooling takes place.
33. Recycling Techniques
• Blow Moulding:
Again the spiral screw forces the plasticised polymer through a die.
A short piece of tube, or ‘parison’ is then enclosed between a split die which is
the final shape of the product - and compressed air is used to expand the
parison until it fills the mould and achieves its required shape. This
manufacturing technique is used for manufacturing closed vessels such as
bottles and other containers.
35. Recycling Techniques
• Film Blowing:
Film blowing is a process used to manufacture such items as garbage bags. It is
a technically more complex process than the others described in this brief
and requires high quality raw material input. The process involves blowing
compressed air into a thin tube of polymer to expand it to the point where it
becomes a thin film tube. One end can then be sealed and the bag or sack is
formed. Sheet plastic can also be manufactured using a variation of the process
described.
37. The Future
Scientists has recently discovered a new genereation of plastics that is
The Biodegradable Plastic
That is a self biodegradable material
38. The Future
Biodegradable plastics are plastics that can be decomposed by the action of
living organisms, usually bacteria.
Two basic classes of biodegradable plastics exist: Bioplastics, whose
components are derived from renewable raw materials, and plastics made
from petrochemicals containing biodegradable additives which enhance
biodegradation.
40. The Future
Despite the huge benefits of the biodegradable plastic, it is still under
researches and its effects on the humans animals and environment are still an
issue of study. However, it can be a strong alternative of recycling process since
it can achieve the same purposes of recycling operation with less or even on
amount of power.
41. Conclusion
Recycling of plastic waste is one of the most important actions currently
available to reduce environmental pollution and impacts on wildlife and
ecosystem.
Developed industrial countries are pressing for sustainable solutions to
plastic recycling and drastic reduction of plastic waste in the marine
environment. There are challenges and technological hurdles in recycling but
it is hoped that the trend of plastic production and disposable waste will be
reversed.
