Recycling Technologies of Waste Plastics - GEC

Recycling Technologies of Waste Plastics
For Hazard Prevention and Resource Recovery
Yoichi KODERA
National Inst. of Advanced Industrial Science &
Technology (AIST) at Tsukuba
July 8, 2010 UNEP at Osaka

In a scrap yard
Metal corrosion by rain water
Plastics weathering by sun light and rain water
Elution of hazardous metal species
and organic additives
Pollution of soil and ground water are
serious threats to creatures & human health

Viewpoints in E-waste management
• Environmental aspects
– Hazard prevention through stabilization of
hazardous substances—Preparation of insoluble
matter
– Volume reduction for landfill—Preparation of
molten slag or sintering pellets
• Economic aspects
– There are various efforts on cost-effective collection
and recovery.
– The wider user applications of plastics through a
cost-effective conversion method are expected.

Various assembly parts and
materials of E-wastes
Frame of Fe
Glass-Epoxy resin
composite with Pb&Cu
Heat sink of Al
ABS
Connectors with
Au plating
Back cabinet of PS
with a flame retardant

Typical Components of E-Waste
potential risk
potential value
Thermoplastics
Thermosetting
plastics
PVC
Hazardous
metals
Au
Ag
Pd
Fe
Al
Cu
Casing
Sb
Circuit
board
Pb
Cu
Devices
Wiring
Cu

Economic value of a used cell phone
Material
Weight
Ratio
Value
Ratio
Price, USD/g
g
%
USD
%
Au, 38.9
0.014
0.03
0.55
85.4
Ag, 0.44
0.045
0.10
0.02
3.10
Pd, 14.6
0.003
0.01
0.04
6.87
Cu,0.006
4.5
9.79
0.02
3.88
Fe,0.0002
2.0
4.35
0.0004
0.07
Slag,0
18.5
40.3
0
0
ABS resin
20.9
45.5
0.005
0.72
Sum
46.0
100
0.638
100
Cell phone: 0.64 USD value; 13.9 USD/kg upon complete separation

Scope of current recycling business of
E-wastes in Japan
Business environment of collection & resource recovery
Small/medium-sized
business
Large-sized business
Under an individual contract of a recycler to
waste generators like cell phone retailers or
cell phone companies.
Precious metals are the primary targets; Au,
Ag, Pd. Other metals such as Cu are treated
in a smelter, and plastics are disposed.
Under a recycling law forcing collection of
specific items from general consumers to
pay a recycling fee.
A dismantling sector sort various parts by
material types and sell them to recyclers.

Typical treatment of E-wastes
Collection
Manual dismantling and
sorting by material type
Iron scrap
Devises
Cables and batteries
Circuit board
Smelter
Steel manufacturer
Mining company
Glass manufacturer
Molding company
User
Fluorescence light
Plastic parts
Incineration with heat recovery
Landfill

Application examples of recycled resin of good quality
Wastes
Tech
Products
Electric appliance manufacturer also
handle waste plastics for their products.

Waste plastics: the borderline case for recycling
Mixed or dirty plastics
Fuel
Resin
Incineration of
separated waste
Incineration with heat recovery

UNEP guideline for waste
plastics conversion into fuel
• Helps to judge the suitable way to recycle.
• Consider Sustainability in business,
technology and environment aspects.
– Waste composition and generation amounts
– End-user application in the local community
– Technology selection among commercially
available systems
• AIST is assisting to compile it.

Solid fuel
• Production: Crushing and pelletization
under 200 °C.
• Limitation: Ash, halogens and nitrogen
contents should be controlled.
↑From AIST’s research
Commercial operation of our partner company

↑From AIST’s research
Liquid fuel
• Production: Pyrolysis at ca. 500 °C
followed by distillation. Crushing and
separation required for some wastes.
• Limitation: Thermoplastics of PE, PP and PS
are the typical feedstock.
Commercial operation of our partner company

From AIST’s research
Gaseous fuel production
under development
• Two types of gaseous products;
syngas and hydrocarbons
depending on a type of reactor and
reaction conditions.
• Production: crushing and pyrolysis.
• Steam gen. – power gen., or gas
turbine combustion– power gen.
↑Schematic flow of a typical system for producing gaseous hydrocarbons under R&D

Studies on the treatments of
circuit boards in AIST
Hydrogen production with halogen treatment using
molten salt
• Dr. T. Kamo et al., AIST
• Objectives
– Hydrogen production from plastics in circuit boards
– Halogens are converted into non-hazardous form such
as alkali metal halides in the presence of metal
carbonates.
• Procedures
– Molten salt is a key for the effective heat transfer and
formation of inorganic halides.
– Conditions: around 800 °C in the presence of water
– Continuous operation is being developed.

As Summary:Scheme to Decide Types of Treatments
E-Wastes
Hazard prevention is a primary object.
Hazard
None
Yes
Volume reduction
Detoxification
Disposal
Recycling
Feasible
Not feasible
Separation & Conversion
User application
Yes
Recycling products
None
If the obtained material has an enduser
application, recycling business
can be feasible under some conditions.