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 waterPlastics weathering by sun light and rain water

Pollution of soil and ground water areserious threats to creatures & human health

Elution of hazardous metal speciesand organic additives

Viewpoints in E-waste management

• Environmental aspects– Hazard prevention through stabilization of

hazardous substances—Preparation of insolublematter

– Volume reduction for landfill—Preparation ofmolten slag or sintering pellets

• Economic aspects– There are various efforts on cost-effective collection

and recovery.

– The wider user applications of plastics through acost-effective conversion method are expected.

Various assembly parts andmaterials of E-wastes

Connectors withAu plating

Back cabinet of PSwith a flame retardant

Heat sink of Al

Frame of Fe

Glass-Epoxy resincomposite with Pb&Cu

ABS

Typical Components of E-Waste

Casing

Circuit

board

Devices

Wiring

Thermoplas

tics

PVC

Hazard

ous

metals

Thermoset

ting

plastic

s

Pb

AuAgPd

Sb

FeAlCu

Cu

Cu

potential risk potential value

Economic value of a used cell phone

1000.63810046.0Sum

85.4

3.10

6.87

3.88

0.07

0

0.72

0.55

0.02

0.04

0.02

0.0004

0

0.005

0.03

0.10

0.01

9.79

4.35

40.3

45.5

0.014

0.045

0.003

4.5

2.0

18.5

20.9

Au, 38.9

Ag, 0.44

Pd, 14.6

Cu,0.006

Fe,0.0002

Slag,0

ABS resin

Ratio%

ValueUSD

Ratio%

Weightg

MaterialPrice, USD/g

Cell phone: 0.64 USD value; 13.9 USD/kg upon complete separation

Scope of current recycling business ofE-wastes in Japan

Business environment of collection & resource recovery

A dismantling sector sort various parts bymaterial types and sell them to recyclers.

Under a recycling law forcing collection ofspecific items from general consumers topay a recycling fee.

Large-sized business

Precious metals are the primary targets; Au,Ag, Pd. Other metals such as Cu are treatedin a smelter, and plastics are disposed.

Under an individual contract of a recycler towaste generators like cell phone retailers orcell phone companies.

Small/medium-sizedbusiness

Typical treatment of E-wastes

Collection

Iron scrap

Devises

Cables and batteries

Circuit board

Fluorescence light

Plastic parts

SmelterSteel manufacturerMining company

Glass manufacturer

Molding company

Incineration with heat recovery

Landfill

User

Manual dismantling andsorting by material type

Application examples of recycled resin of good quality

Wastes ProductsTech

Electric appliance manufacturer alsohandle waste plastics for their products.

Waste plastics: the borderline case for recycling

Mixed or dirty plastics

Resin

Incineration ofseparated waste

Fuel

Incineration with heat recovery

UNEP guideline for wasteplastics 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 commerciallyavailable systems

• AIST is assisting to compile it.

Solid fuel• Production: Crushing and pelletization

under 200 °C.

• Limitation: Ash, halogens and nitrogencontents should be controlled.

↑From AIST’s research

Commercial operation of our partner company

Liquid fuel

↑From AIST’s research

Commercial operation of our partner company

• Production: Pyrolysis at ca. 500 °Cfollowed by distillation. Crushing andseparation required for some wastes.

• Limitation: Thermoplastics of PE, PP and PSare the typical feedstock.

Gaseous fueｌ productionunder development

• Two types of gaseous products;syngas and hydrocarbonsdepending on a type of reactor andreaction 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

From AIST’s research

Studies on the treatments ofcircuit boards in AIST

Hydrogen production with halogen treatment usingmolten salt

• Dr. T. Kamo et al., AIST

• Objectives– Hydrogen production from plastics in circuit boards

– Halogens are converted into non-hazardous form suchas alkali metal halides in the presence of metalcarbonates.

• 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

Separation & Conversion

Recycling

User application

Hazard Disposal

None

E-Wastes

Yes

Feasible

Volume reduction

Yes

Not feasible

None

Recycling products

Detoxification

If the obtained material has an end-user application, recycling businesscan be feasible under some conditions.

Hazard prevention is a primary object.