The characteristics of plastics-rich waste streams
FROM END-OF-LIFE ELECTRICAL AND ELECTRONIC EQUIPMENT
January 2006
Prepared by :
Dr. Frank E. Mark
A Technical Report
prepared by:
The characteristics of plastics-rich waste streams
FROM END-OF-LIFE ELECTRICAL AND ELECTRONIC EQUIPMENT
January 2006
Prepared by :
Dr. Frank E. Mark
Dow Chemical Europe
Abstract
The results from numerous studies on the plastics fractions obtained from waste electrical and electronic equipment have
been analysed and an assessment made of their suitability for recycling or other forms of recovery. In view of the challenge
to ensure the suitability for mechanical recycling by removal of various substances, it is concluded that it is prudent to explore
the benefits or other end-of-life recovery options such as chemical feedstock recycling and energy recovery.
Summary
The implementation of the European Directive on Waste Electrical and Electronic Equipment (WEEE Directive) will result in
the collection for treatment of a significant proportion of the estimated 7M tonnes of end-of-life equipment from this
sector. While the vast proportion of this consists of metals, other materials such as glass, rubber and plastics are also part of
such equipment. Of the E&E equipment covered by the Directive, it is estimated that 715 000 tonnes of plastics waste was
generated (W. Europe, 2003) and this can be expected to increase over time with the dynamic growth of this market sector.
Because the primary driving forces for any WEEE treatment operation are the removal of any hazardous materials and
the recycling of metals, it is not clear to what extent any plastics can be recovered for recycling into similar or alternative
applications.
Plastics-rich streams with a content of > 95 % compounded plastics can be achieved by manual dismantling but this is usually
at a prohibitive cost. The alternative is multi-step mechanical separation. The quality and the characteristics of this plasticsrich stream (WEEP) derived from the shredder depends very much on the market sector supplying the input material and the
various categories collected as described by the WEEE Directive.
In addition, economic pressures on the shredder operators are leading to a further recovery of metals from the shredder
residue (SR). This further refining results in a plastics-rich residue which, as such, does not meet the appropriate specifications
for any of the potential applications, whether for mechanical recycling, use as an alternative fuel or as a feedstock for chemical
processes.
This paper considers the options of treating such plastics-rich fractions to enable the best use to be made of their intrinsic
properties while ensuring environmental regulations are strictly observed. Potential outlets include their use in other
industries such as power generation, cement and steel production. The plastics industry is committed to stimulate all such
developments which can improve the overall life-cycle impacts of its materials, in line with the principles of Responsible Care®
and Product Stewardship.
It has been shown that the SR user requirements from the power generating industry, cement manufacturers and steel
producers can be met with pre-treatment steps such as mechanical or thermal refining processes in combination with using
plastics waste from the packaging market sector.
While the amount of inert materials in the recyclate is usually low ( < 3 wt %), the content of heavy metals, metals and
halogens is high enough to require that specific attention is given to the properties of the WEEP stream and the specific
customer specifications. Plastics-rich streams produced by a traditional mechanical shredding/ separation plant cannot meet
the high purity requirements without a post refining step using a wet separation. After such a step the WEEP has an improved
quality with respect to inerts, metals, halogens and heavy metal content. However, the disadvantage of such a plastics
refining step is that more than 50 % has to be subsequently disposed of in a landfill or find an alternative outlet. Recycled
materials sold as granulate for plastics processing are generally of a good quality with respect to processing and physical
properties. Nevertheless, they still need to demonstrate they meet the low concentration levels of various substances as
required by the EU Directive on the Restriction of Hazardous Substances (RoHS) , the EU Directive on Penta- and Octa-bromodiphenylether (EC 2003/11) as well as any other specific national legislation such as the Dioxin Ordinance in Germany.
The above considerations mean that, currently, there is no single practical technology or solution which will enable the
plastics-rich light shredder fractions to make any significant contribution by mechanical recycling to the overall ambitious
recycling targets of product categories required for compliance with the WEEE Directive.
It is concluded that, rather than the current major focus on recycling, it is in fact the appropriate combination of mechanical
recycling, feedstock/chemical recycling and energy recovery, that best suits the needs of the market and the public at large,
which will offer the most sustainable approach to achieving cost efficient compliance with the spirit of the EU WEEE Directive.
6
Table of contents
List of abbreviations
1. Background
8
1.1 Current handling at End of Life (EoL)
8
1.2 WEEE collection
8
1.3 End of Life plastics mixtures investigated
10
1.4 End of Life plastics processing input streams
11
1.5 Output streams
12
1.6 End of Life Plastics output streams
13
2. Sampling and analysis of EoL plastics
13
2.1 Reproducibility of analytical methods
13
2.2 Analytical product characteristics
15
3. Characteristics of WEE Plastics
16
3.1 WEEE Recycled Plastics product quality
16
3.2 WEEE Recycled Plastics quality for mechanical recycling
18
3.3 Physical/Chemical Properties
19
3.4 Regulated Substances
20
4. Conclusions
22
5. References
23
6. Appendix
24
Table I: Reproducibility and reliability of physical and chemical methods
24
Table II: Comparison of the plastics medium density fractions from WEEP
25
7. Acknowledgements
26
Abbreviations
AD
Dispensers, Automated equipment
MD
Medical devices
COE
Cooling/Refrigeration equipment
MCI
Process control
Cd
Cadmium
MR
Materials recycling
Cr
Chromium
MSWI
Municipal solid waste incineration
CE
Consumer electronics
MPW
Mixed plastics waste
CRT
Cathode ray tube
n.a.
Not available
DM
Dismantling
N-FE
Recovery in non ferrous metals industry
EoL
End of Life
Pb
Lead
E&E
Electrical and electronic
PBB
Polybrominated Biphenyls
EET
Power tools
PBDE
Polybrominated-di-phenylethers
ELV
End of life vehicles
PC
Personal computer or polycarbonate
PCB
Polychlorinated Biphenyls
ESR
Shredder residue from E&E goods
QC
Quality control
ER
Energy recovery
RCP
Chips, granulated WEEP
FE
Ferrous metals recovery
RoHS
Restriction of certain hazardous substances
FR
Feedstock recycling
SEP
Plastics/plastics separation
Fr-Br
Bromine containing flame retarded plastics
SD
Shredding
Hg
Mercury
SHA
Small household appliance
HS
Hand sorting
SR
Shredder residue: generally mixed
HSL
Hand sorting in the laboratory
HSI
Hand sorting on an industrial scale
TCA
Analytical determination by combustion
HIPS
High impact polystyrene
TLS
Play, recreational, sports equipment
ITE
Information technology equipment
TCE
Telecommunication equipment
IND
Industrial equipment
WEEE
Waste electric and electronic equipment
WEEIP
Waste E&E plastics from industry
LAGA
Technical working group of the states in Germany
WEEP
Mixed plastics from E&E
LIE
Lighting equipment
WID
European Waste Incineration Directive
LHA
Large household appliance
auto/white goods
1. Background
1.1 Current handling at End of Life (EoL):
The physical and chemical composition of end of life (EoL) post consumer plastics is of paramount importance
for any customer using recycled plastics as well as for operators of plastics processing equipment to avoid
difficulties during the product manufacturing operation. The characteristics of EoL plastics are extremely difficult
to define due to the diversity of the various electrical and electronic sectors. The numerous applications, the
different life-times and the specific requirements of the individual OEM’s (Original Equipment Manufacturers)
all impose different requirements for the virgin plastics to meet. Nevertheless this report attempts to provide
such a characterisation, with emphasis on providing a qualitative and quantitative description of the plastics to
be found in plastics-rich waste streams.
The report covers the following stages of waste or product characteristics
• WEEE collection/categories
• WEEE mixtures collected
• WEE plastics separation from mixtures
• WEE plastics mixtures as potential sales products
• WEE plastics refining
• WEE plastics recycling products
The appropriate knowledge of EoL characteristics is extremely important for waste owners, recyclers and users
of recycled plastics from E&E. But the physical requirements for a feedstock or energy recovery plant are
generally different and less critical. This is due to the fact that operating units are not influenced so much by
the amount of metals and heavy metals as they are equipped with emission control units in order to comply
with legislation relating to emissions from industrial installations. This often includes high temperature
thermal processing to produce an inert slag whereby metals and heavy metals are immobilized before either
being landfilled or incorporated into a beneficial application of a larger inert mass such as road construction.
Any hazardous organic chemicals contained in the WEEE are safely destroyed in high temperature units as
demonstrated in the numerous industrial trials undertaken and reported by PlasticsEurope.
1.2 WEEE collection:
The national collection schemes of WEEE in Europe are currently being implemented, but not all in the same
way. There will therefore be a number of different types of plastics containing waste streams. In order to
minimize overall costs, a certain standardization has been developed to collect a minimum of 4 to up to the
6 or 7 streams of the 10 official categories of the EU WEEE Directive.
8
Table 1: Different possible collection baskets
Minimum EU WEEE type
Germany
UK
1. cooling equipment
LHA
LHA
2. CRT containing
SHA
SHA
3. gas discharge lamps
CE
ITE,TCE
4. oil containing
ITE
LE
5. others
others
EET
...
TLS
Different collection schemes will lead to different WEEE mixtures. The two possible routes to derive high quality
plastics-rich streams from these WEEE mixtures are:
I: Hand sorting / dismantling of housings to produce a high plastics content stream followed by some
decontamination prior the shredding process
II: Shredding (with or without decontamination) and post separation of metals, inert and plastics materials
The ongoing technical programme undertaken by PlasticsEurope is shown in Table 2. The E&E plastics specific
programme started in 1996 and covers most categories which are today regulated via the WEEE Directive. The broad
range of countries covered within these studies means the information can be considered as representative for
the whole E&E sector. The results for Europe are as a whole typical for today’s physical and chemical
characteristics of WEEE. The country specified in the table refers to the country of the origin of the waste.
Table 2: PlasticsEurope / APME E&E Technical programme overview
Ref. Source
Year
Sector
Country
Literature Ref.
1
1997
CE, IND, SHA
Germany
(1,2)
2
1997
CE
Germany
(1,2)
3
1997
IND
Germany
(2)
4
1999
ITE
Sweden
(3)
5
2001
CE
Germany
(4)
6
2001
CE
Netherlands
(4)
7
2001
CE
Switzerland
(5)
8.1
2003
SHA, CE, ITE
Switzerland
(6)
8.2
2003
COE
Switzerland
(6)
9
2004
SHA, ITE, CE, IND
Germany
(7)
10
2004
COE, ITE, CE
Netherlands
(8)
9
1.3 End of Life plastics mixtures investigated:
Table 3 gives another overview of the WEEE plastics covered and the different sectors as shown. The fact that
not all categories have been covered is understandable as the content of plastics in the categories LIE and MD
is not high and the existing collection systems in the past did not collect the WEEE. However, judging by the
amounts of plastics sold into the sectors investigated, it can be concluded that over 90% of the market is
described here.
Table 3: WEEE categories covered in the PlasticsEurope programme
CATEGORIES / SECTORS
Ref.
Source
LHA
SHA
ITE
TCE
CE
1
X
X
X
X
2
X
LE
EET
X
IND
X
X
4
10
MD
X
3
X/PC
5
X/TV
6
X/TV
7
X/TV
8
TLS
X
X
X
X
X
9
X
X
X
X
10
X
X
X
X
1.4 End of Life Plastics processing input streams:
The process sketch below shows the input-output relationship and should define the difference between WEEP
and high rich plastics fractions from SR or ESR by the maximum content of inert materials, especially metals
and the minimum plastics content of > 95% or < 95% respectively.
FIGURE 1:
Simplified schematic
diagram for WEEP Production
WEEP
“Light plastics”
Plastics-rich
stream
WEEP or ESR
from I: or II:
Input WEEE
WEEP
“Medium density
plastics”
WEEP
“Heavy plastics”
Metals,...Residues
Some of the more modern mechanical processing plants have two or even more outlets of plastics-rich streams.
The post processing of these streams by identification, density separation, electrostatic separation and colour
sorting (11) has been investigated by the American Plastics Council (http://www.plasticsresource.com). Other
studies and their results have been presented at the Identiplast conferences organized by PlasticsEurope / APME
(12). The results for the higher plastics-rich streams will be shown here as the aim is to achieve the highest
possible quality for the customer. Table 4 summarises the plastics-rich streams going to analytical testing after
separation.
11
Table 4: Input and output streams
Ref.
Source
Output
streams by
Input
type
Input examples of
equipment
Amount
sampled, t
Plastics
type (main)
Separation /
identification
Process control
7.1
n.a.
TCA
3
II
SR
4
II
ESR
PC, CPU, monitors
175
HIPS, ABS
GSL
8
II
ESR
Kitchenware
6
PP, HIPS, ABS etc.
GSI
9
II
ESR
Telephone, PC
50
PP, ABS, HIPS, etc.
GSL
10
II
ESR
CE, IT, household
290
HIPS, ABS, etc.
n.a.
1
I
ESR
PC, monitors, printers
140
n.a.
TCA
2
I
ESR
Vacuum cleaners
120
n.a.
TCA
5
I
WEEP
TVs, monitors
1
HIPS, ABS, PS
TCA
6
I
WEEP
TVs, monitors
1
HIPS, ABS, PS
TCA
7
I
WEEP
TVs, monitors
12
HIPS, ABS, PVC
HSI
Total
~ 750 t
Note: Plastics identification is possible using other techniques than thermal analytical (TCA) analysis by combustion. Gravity separation
(GS) has been done at different size levels either in the laboratory (GSL) or at large industrial scale (GSI). In addition hand sorting after
identification (HSI) has been carried out. There are a number of spectroscopic techniques that can be used to identify both plastics resins
and additives.
1.5 Output streams:
The main output streams for the recycling operations today are the following:
• precious metals (gold, silver, platinum,..)
• non-ferrous metals (Cu, Al, Zn, Ni,..)
• ferrous (stainless steels)
• alloys (brass,..)
The financial returns for selling these materials are the main driver of the operations. Plastics output streams
are currently mostly not recovered, but landfilled together with the other residue streams. Some export of
plastics scrap takes place.
12
1.6 End of Life Plastics output streams:
The resulting product quality characteristics are determined by major specification criteria relating to metals,
heavy metals, halogens and minimum polymer content. The target is to guarantee the required properties
which can be achieved via the two routes, I (hand sorting) and II (shredding). The medium density fraction has
been selected to show the final achievable quality for recycled plastics.
Further refining has to be done in order to achieve a low enough inert, low metal and low heavy metal
content as required. Shredding a specific high polymer stream such as housing materials can achieve such a
product fraction as shown later. In several cases (5,6 and 7) some hand sorting was needed to achieve the
required quality.
2. Sampling and analysis of EoL plastics
2.1 Reproducibility of analytical methods:
As described above, the user of recycled WEEP will require a certain minimum plastics quality. The meaningfulness of these data depends on the quality of the analytical work and the representative sampling.
Reproducibility of the sample treatment method as well as the analytical reproducibility has been shown to be
good for heterogeneous materials (see table 5). This is indicated by the Relative Standard Deviation (RSD) value
and the uncertainty figure shown for the repeatability of the analytical method. These two parameters are
useful for judgment of any customer value.
Table 5: Reproducibility and reliability of physical and chemical methods for a typical sample (8.1)
Ref. Source
Sample (1) Sample (2)
Sample (3)
Mean
value
RSDa
[%]
Uncertainty of
analytical
determination
[%]
8.1
Ash content
wt%
5,88
6,20
4,65
5,58
15
not available
Halogen (total Cl, Br)
wt%
3,28
3,8
3,5
3.5
18
10
Heavy Metals (all WID) mg/kg
1113
1753
1031
1299
30
11
Metals (Cu, Pb, Zn)
1226
2038
1387
1550
27
10
mg/kg
a : RSD = Relative Standard Deviation [%]
When the processing operations resulted in one or more residue streams, all residue streams were analyzed.
However it was the residue stream with the highest plastics fraction which was used and analyzed in depth in
order to understand the characteristics of the plastics-rich fraction and its potential for the mechanical
recycling material route.
13
The amount of plastics-rich streams investigated and covered in this report is sizeable and consequently should
lead to meaningful analytical results for the characterization. The important steps are sampling (A1), size
reduction (B1) or other pretreatments (C1) as well as the physical and chemical analysis which needs to be
conducted according to good laboratory practice. These methods and procedures have been described in detail in
the references (2,3) as the stages A1 and B1 are not yet standardized.
Table 6: Key compositional properties of WEEP streams
Ref.
Source
Plastics, wt%
Heavy Metals, wt%
Metals, wt%
Halogens, wt%
1
95
5.0
0.08
1.4
3.2
2
95
4.0
0.25
1.8
3.1
3.1
90
0.6
8.5
6.8
n.m.
0.3
0.5
6.8
8.2
3.2
Inert, others wt%
4
92
0.32
0.23
0.4
n.m.
5
97
<2.5
0.023
5.5
<1.0
6
97
<1.5
0.02
3.0
1.2
7
51
n.a.
~0.02
n.a.
48*
7.1
99
~2.0
<1
n.a.
After separation of non plastics
8
90
0.7
3
4.1
6
Note: 3.1 means sample before gravity separation, 3.2 after plastics refining, *mainly wood. The table figures do not add up to 100% as
other compounds, chemical species or metals / heavy metals can be in the WEEP. These have not been analyzed. The fact that Cu, Pb are
separated out from the heavy metals group is due to the fact that they are valuable for the N-Fe industry from a recovery standpoint.
The heavy metals characterized in column 3 and legislated are: Cd, Hg, Sb, As, Pb, Cr (total), Cr (VI), Cu, Co, Mn, Ni, V, Sn, Zn, Tl.
The last column in the table above indicates the amount of inert or other materials. This has to be understood
to not only include metals and non volatile heavy metals but also fractions which could be separated, such as
wood.
14
In general it can be concluded that most of the SR or ESR output streams of conventional simple recycling
operations are not suitable for extrusion or other plastics processing operations. Polymer consistency and the
quality of recycled material can be optimized through gravity separation to a limited extent. But other waste
polymers generated from these unit operations also need a market outlet, which will significantly impact the
overall economics. High polymer consistency and polymer content with, for example, HIPS/ABS can be achieved
from selected E&E applications such as TV and monitor housings, because of the large market share of one polymer.
Another source of high polymers content mixture can be sourced from refrigerators or cooling appliances EoL
processing plants. The two streams are a PU foam powder and a thermoplastics stream with HIPS, PP and ABS.
The quality of the raw or refined PU containing SR has been described, including the removal of ozone depleting
substances (13). The quality of the raw thermoplastics mixture: PP, HIPS, ABS in a ratio of around 45/ 45/ 10 wt%
is such that it needs to be also post treated (i.e. by removal of metals and heavy plastics and inerts) in order
to achieve a minimum plastics mixture quality. If required, additional processing can be used to separate the
individual plastics with some yield loss.
2.2 Analytical product characteristics:
The qualities of the three different plastics streams (low, medium and high density) are compared with respect
to the content of heavy metals and halogens. Reproducibility of the sample treatment method as well as the
analytical reproducibility has been shown to be good for heterogeneous materials (e.g. 8.1). This is indicated by
the Relative Standard Deviation (RSD) value and the uncertainty figure shown for the repeatability of the
analytical method in Table I (see appendix). These two parameters are useful for the judgment of any customer
value.
15
3. Characteristics of WEEE Plastics
3.1 WEEE Recycled Plastics Product Quality:
The high plastics content in WEEP and plastics-rich fractions of SR or ESR does not automatically deliver a high
quality for users. The minimum requirements shown should be part of any meaningful customer specification.
Especially the high content of heavy metals in the intended product ranging from 0.3 to 5 wt% requires a
careful decision as to its marketability. The metal content is low enough in most cases not to damage extrusion
equipment, but quality control on the recyclers side is required to sell that kind of material. Most extrusion
machines cannot tolerate a metal content of >1 wt% and risks of machine damage are very high. As regards
the concentration of halogens, this varies greatly due to the flame retardant requirements for the different
product categories and specific WEEE sectors.
The further refining of the WEEP to reduce the content of inerts and metals or even halogens is technically
implemented today on a larger scale, using mainly gravity separation. The economics and the practical usefulness
of this effort depend in the future on the markets for these recycled plastics and associated prices which can
be achieved to cover the significant costs of upgrading. The economics have been investigated (11). The quality
aspect of these higher purity recycled plastics is equally important to the market as they determine the price
level the materials can be traded for.
The plastics separation as shown below has been carried out either at technical or laboratory scale. The results
are therefore not strictly comparable. It is understandable that a larger pilot-scale separation using minimum
3 to 5 tonnes, will have a lower efficiency, producing more scrap and less product. The separation quality at
laboratory scale is thus normally different, which therefore influences the results of the analytical testing of
heavy metals and halogens.
Plastics which can be used for mechanical recycling through a melt processing step have to meet a number of
minimum specifications. The characteristics of plastics in WEEE can be described with the following minimum
number of criteria as indicated in table 7.
16
Evaluation of the quality of the pellets:
The quality parameters of the pellets as received during the different stages of the trial are shown in the table
below:
Table 7: Specification items for plastics recycling product (A), fuel (B), feedstock (C) use
(A)
(B)
(C)
Minimum Plastics
content wt%
> 98%
> 50%
> 80%
Maximum Inert
content wt%
< 2%
< 50%
< 20%
Maximum Metal
content wt%
<1%
tba
tba
B,C depends very much on the
type of operation
RoHS
Directive*
tba
tba
Depends on the residue/
product use
n.a.
May be
limited due
to corrosion
tba
Limited due to
excessive corrosion
n.a.
Destruction in B,C proven,
handling procedure
important
Maximum Heavy Metal
content wt%
Maximum Halogen
content wt%
Maximum regulated
organic content wt%
Comments
B,C more due to economic reasons
EU Directives
RoHS* +
2003/11*
n.a.
Due to technical mostly
operational reasons
Note: n.a.= not applicable for the use considered, tba = to be agreed,
*The RoHS directive applies only to the electrical and electronic sectors covered under the WEEE Directive.
Other sectors are currently not regulated except for the penta and octa PBDE restriction according to EC 2003/11 which applies for all
market sectors.
17
The minimum plastics content and the maximum inert and metal content are interrelated. A level of 95 wt%
for the minimum plastics content is most likely to cause problems in the extrusion and plastics processing line.
A high plastics content of > 98 wt% is therefore required. The heavy metals considered for recovery technologies
are the emission related 13 heavy metals regulated in the European Waste Incineration Directive
(see Appendix Tables Nr. I and II). The total metal content has not in all cases been consistently characterized.
The economically recyclable metals Cu, Pb, Zn have been considered in all cases and also Al in some cases. Total
halogens covers Cl and Br in all cases. Where significant amounts of F have been anticipated the F content was
also determined by analytical means. To the general public, halogens are often mis-understood generically to
be substances of concern subject to regulations.
In the case of plastics from WEEE it is of interest to differentiate the substances of concern between heavy
metals and micro organic compounds such as dioxins. The following analysis is done by using these six
characteristic values to describe the WEEP and its suitability for recovery.
3.2 WEEE Recycled Plastics quality for mechanical recycling:
The materials produced from WEEP by the typical mechanical operations (8,9) are mixtures of different polymers
and as such very difficult to market –due to the different thermoplastics processing behaviours- even when
they can perform according to a given customer’s specification. The plastics mixtures derived from WEEE
according to the future collection categories will still have a wide ranging polymer composition. This broad
polymer composition coupled with the limited polymer compatibility between certain thermoplastics like HIPS
and ABS will lead to rough surface appearance and even possibly delamination. As a result of this processing
issue, the WEEP product mixture consisting of chips is currently further refined by gravity separation by selected
operators to achieve a better homogeneous polymer matrix. Selected streams as shown in the table below have
been post refined as well as gravity separated in order to achieve a more valuable WEEP fraction.
Table 8: Refined WEEP mixtures
Ref.
Light plastics
PO (PP, PE)
4
18
Medium density
plastics
HIPS, ABS, PC/ABS
Heavy plastics
PVC, PA, PBT, PC
11
Residues
(Inerts, wood)
89
5
98
<2
6
98
<2
7
0
94
4
8.1
3
46
51
<2
8.2
5
70
9
35
30
20
25
15
10
6
43
26
rest
Note: Nomenclature 8.1 means first sample of this fraction from source 8, PO stands for the various polyolefine types (PP,PE)
As expected, the polymer separation process can produce in principle three different polymer mixtures which
are defined as light, medium and heavy plastics. The major group consists of polyolefins (polyethylenes and
polypropylenes), HIPS/ABS and a mixture of PVC and higher engineering polymers such as PC, PA, PBT etc.
The quality characteristic is described by the purity of these three fractions (see below) and the polymer
composition. Polymer content and composition of these three fractions have not been investigated.
In order to achieve a sufficient enough polymer compatibility from the plastics mixture to enable recycling,
a large amount of residual WEEP has to be disposed into landfill or to be used as a source of energy. The residual
fraction of 15 wt% (Ref. 9, in Table 8) and the other non recyclable materials of 51 wt% (Ref. 8, in Table 8) have
therefore to find end uses along with the main product.
The final sales product quality should have the characteristics meeting the major specification criteria: metals,
heavy metals, halogens and minimum polymer content. As mentioned above, the guarantee of meeting the
required specification properties can be achieved via the two routes of I: hand sorting and II: shredding, where
the post refining step is necessary to achieve this quality level. The medium density fraction has been selected
to demonstrate the final quality which is currently achievable.
3.3 Physical/Chemical Properties:
The ultimate highest purity and polymer homogeneity which can be achieved with multiple stage mechanical
separation technology is shown below. The mechanical shredder residue route II is compared with the quality
of pure plastics achieved by hand sorting.
The medium density fraction of ESR containing HIPS and ABS mainly from two different recyclers (8 & 9) are
shown. The production technologies are different but the feed streams are very similar. The recyclates produced
from the density range fraction of 1.12-1.22 kg/l would almost have the quality of hand sorted plastics from
housing.
Table 9: Comparison of medium density plastics fraction (WEEP)
Ref. Source
WEEP
WEEP WEEP from
from Pellet from
ESR 9
ESR 8
ESR 8
<1.12 kg/l
8.1
WEEP from
ESR 9
1.12-1.22 kg/l
WEEP
WEEP
from ESR 9 housing
> 1.22 kg/l
Ash content
wt%
5,58
2.2
3.7
5.1
19.5
2.3
Halogen (total Cl, Br, F)
wt%
3.53
0.24
2.0
4.5
10.5
6.2
Heavy Metals (all WID)
wt%
0.59
0.073
< 0.14
< 0.12
0.54
0.20
Metals (Cu, Pb, Zn)
wt%
0.16
0.04
< 0.012
0.175
0.48
0.05
19
The housing fraction of TVs and monitors from Germany and the Netherlands has been compared in a previous
paper (2) which also made a comparison with the housings from personal computers. It was found that
antimony (Sb) concentrations for the PC’s were lower, which can be explained by the different requirements
for flame retardancy.
The material homogeneity of housings (HIPS, ABS with a minor amount of PVC) has been very good as
confirmed by the relative small deviations between the two sources. The comparison of WEEP obtained from
the housing fraction with that received from ESR is shown Table Nr. 9. From the standpoint of a buyer using
the WEEP chips for extrusion and compounding, the material thermoplastic processing quality seems sufficient
for further use. The specifications between the seller and the buyer needs, however, also to confirm the
compliance of the recycled plastics in relation to regulated substances.
3.4 Regulated Substances:
The quality of secondary raw materials is currently not very well prescribed by customers or by the market in
general. European and national eco-label guidelines mostly contain product restrictions for the four heavy
metals: Hg, Cd, Cr (VI) and Pb which are also banned as hazardous heavy metals in the RoHS Directive.
Maximum limits for the three heavy metals Hg, Pb, Cr(VI) have been set at 1000 mg/kg and for Cd 100 mg/kg
for each heavy metal as agreed by the relevant European Technical Adaptation Committee (TAC). These limits
are critical and difficult to meet without blending virgin or high quality post industrial or post consumer recyclates into the WEEP. The German Chemical Banning Ordinance does limit the Cd content to a maximum of
100 ppmw which will pose an even larger problem for WEEP. A careful and ongoing quality control is therefore
required to make sure that this limit is not exceeded.
The regulated substances today are PCBs in most developed countries, the penta - and octa - PBDEs covered
in the EU Directive 2003/11/EC (on restrictions on the marketing and use of penta-and octabromodephenyl
ether) and the RoHS Directive. For substances “banned” from EEE by the EU RoHS Directive, practical limits of
0.1% by weight PBBs and PBDEs in "homogeneous materials" for recycling and use have been suggested but
are not yet final. A product made from recycled plastics could contain some of these restricted substances.
20
Table 10: Limit values for material recycled into products for the E&E sector
The most important criteria are today as follows:
Legislation
Limits, mg/kg
PCB
5
50
EU 2003/11
1000
EU RoHS
Directive
1000
German Chemical
Banning Ordinance
< 1 micro g/kg
< 5 micro g/kg
PCB sum 6 PCBs
PCB equivalents
Penta/Octa PBDEs
PBDEs
PBBs
4 PBDD/Fs
8 PBDD/Fs
In Germany the PBDD/Fs (dioxins and furans) are regulated substances through the Chemical Banning
Ordinance. Limits exist as shown above in Table 10.
The content of regulated and other micro pollutant substances such as PXDD/Fs in chips has been investigated
in the majority of the various E&E waste sources covered here. A trend between Br content and a higher
PBDD/Fs content has been confirmed by many analyses of old WEEP. The number of Br containing flame
retarded compounds is rather large and hence the above statement applies mainly to historical WEEE where
PBDEs were used in the majority of cases. This relation does not lead to the conclusion that Br containing waste
plastics will contain automatically a significantly high content of PBBD/Fs in either old or new WEEP. The
occurrence of PBDD/Fs is believed to be mostly linked to the use of the old versions of PBDE flame retardants.
Nevertheless recycled materials from WEEP in chip form which are marketed today and being processed
further in moulding equipment will go through additional thermal stress cycles. This can lead to a further
increase in PBDD/Fs concentrations depending on the stability of the flame retardant product and the level
of process control. It is therefore recommended that unless quality control monitoring of the extrusion,
compounding or molding processes can confirm the legal levels of PBBD/F’s are not being exceeded, then recycling
of bromine containing WEEP coming from mixed post consumer articles should not be mechanically recycled.
The content of PCBs has been analyzed for a number of shredded WEEE plastics-rich fractions whereby concentrations of around 50 mg/kg in SR or ESR were confirmed as real. This suggests that suitable process controls
and PCB measurements should become also part of normal Q/C procedures for recycling operators processing
plastics from WEEE.
21
4. Conclusions
The quality of post consumer plastics from electrical and electronics varies to a very large extent as a result of
the different requirements for the various market sectors. The critical criteria determining the suitability of
post-consumer recycled plastics for new applications are the content of metals, heavy metals, halogens and
the presence of regulated organic compounds, such as dioxins.
The reduction of metals, heavy metals and brominated flame retardant compound concentrations from post
consumer WEEP can be achieved by using the best available identification and separation technologies. For large
scale operation it has been demonstrated that raw post consumer plastics products in the form of flakes can be
processed by wet/gravity separations. The degree of separation required to guarantee a high quality plastics product
for sale is significant and a large amount of waste is consequently produced. The cost of such a separation
system is also significant and is only economically justified in the case of high value plastics products.
Such a high amount of waste from separation already brings a heavy burden to the operator of the recycling plant
under current conditions. In the future costs will increase as landfill of plastics waste in Switzerland and Germany,
for example, are no longer allowed. Further developments in plastics recovery technologies are desirable.
The product quality of the refined plastics can become borderline with respect to meeting the German
Chemical Banning Ordinance on dioxins/furans and heavy metals such as Cd, Pb, Cr (VI) and Hg which
are restricted as a consequence of the European Directives: RoHS, the Penta- and Octa- PBDEs and ELV.
The final product quality produced from commercial recyclate has therefore to be assessed by the producer/
compounder to ensure it does not exceed the limit values of PBDD/Fs and penta- and octa- PBDE concentrations.
In view of the challenge to mechanically remove metals, heavy metals and halogens from E&E plastics
to comply with legislation, it is prudent to explore the benefits of other EoL options such as chemical
feedstock recycling and energy recovery.
In the final analysis it is the combination of mechanical recycling, feedstock/chemical recycling and energy
recovery, that best suits the needs of the market and the public at large, which will offer the most
sustainable approach to achieving cost efficient compliance with the spirit of the EU WEEE Directive.
22
5. References
(1) Recycling of Br from plastics containing Fr-Br in state of the art MSWC facilities, APME TEC Nr. 8040
APME PlasticsEurope previously APME: Technology Reports see www.plasticseurope.org, 2002
(2) Plastics Recovery from Waste Electrical & Electronic Equipment in non-Ferrous Metal Processes, APME TEC
Nr. 8036, 2000
(3) Feedstock recycling of electrical and electronic plastics waste (depolymerisation and conversion into syncrude),
APME TEC Nr. 8024, 1997
(4) Electrical and electronic plastics waste co-combustion with Municipal Solid Waste for energy recovery,
APME TEC Nr. 8020, 1997
(5) APME Internal Report on Project with company DRISA, 2001
(6) APME Internal Report on Project with company IMMARK, 2003
(7) Co-combustion of ESR at MHKW, July 2004, APME TEC Report in preparation
(8) Recovery of EoL Plastics from Electrical and Electronic Markets in an integrated precious metals smelter,
PlasticsEurope TEC Report in preparation
(9) Recycling of plastics from E&E products, Kunststoffe, 2/2004, pages 76 - 78
(10) Recovery of used plastics from E&E, Kunststoffe, 9, 2002 Sept. Vol. 92, pages 22 - 27
(11) Development of Hydrocyclones for Use in Plastics Recycling, American Plastics Council, Feb. 1999
(12) Identiplast Conference Summary: 2005, 2003, 2001, 1999 and 1997 APME, www.plasticseurope.org
(13) Fact sheets from European Diisocyanate and Polyol Producer Isocyanate and Polyol Producer Association,
ISOPA, www.isopa.org
23
6. Appendix
Table I: Reproducibility and Reliability of physical and chemical methods
Source 8.1
Sample (1) Sample (2) Sample (3) Mean value
Uncertainty
of analytical
determination
[%]
Ash content
%
5,88
6,20
4,65
5,58
15
not available
Chlorine (total Cl)
%
1,8
2,5
1,9
2,07
18
10
Bromine (total Br)
%
1,48
1,30
1,60
1,46
10
10
mg/kg
53
52
58
54,3
Cadmium (Cd)
5,9
b
mg/kg
3,4
0,3
< 0,2
< 0,2 - 3,4
Antimony (Sb)
mg/kg
4.570
4.210
5.920
4.900
18
10
Arsenic (As)
mg/kg
10
6
10
8,7
27
16
Lead (Pb)
mg/kg
530
648
499
559
14
10
Chromium (Cr total) mg/kg
33
53
52
46
24
9
Copper (Cu)
mg/kg
76
530
58
58 - 530 b
n.d. c
10
Cobalt (Co)
mg/kg
34
19
22
25
31
12
Manganese (Mn)
mg/kg
100
115
97
104
9,3
9
Nickel (Ni)
mg/kg
81
55
42
59
34
7
Vanadium (V)
mg/kg
<1
<1
3
< 1 - 3b
n.d. c
11
Tin (Sn)
mg/kg
190
270
183
214
23
10
Zinc (Zn)
mg/kg
620
860
830
770
17
a
mg/kg
< 0,6
< 0,6
< 0,6
RSD = Relative Standard Deviation [%]
No mean calculated due to the strong differences between the three determinations
c
Not calculated since this element was not detected in any of the three analysis
b
< 0,6
n.d.
11
c
Mercury (Hg)
Thallium (Tl)
24
RSDa [%]
n.d.
15
10
c
16
Table II: Comparison of the plastics medium density fractions from WEEP
Source 8.1
WEEP
from
ESR 8
WEEP
WEEP from
Pellet from
ESR 9
ESR 8
< 1.12 kg/l
WEEP from
ESR 9
1.12-1.22 kg/l
WEEP
WEEP
from ESR 9 housing
> 1.22 kg/l
Ash content
%
5,58
2.2
3.7
5.1
19.5
2.3
Chlorine (total Cl)
%
2,07
0.1
0.58
0.69
5.2
3
Bromine (total Br)
%
1,46
0.14
0.88
3.8
5.2
3.2
mg/kg
54,3
71.5
110
36
25
46
0.02
0.2
0.5
0.1
0.05
Cadmium (Cd)
b
Mercury (Hg)
mg/kg
< 0,2 - 3,4
Antimony (Sb)
mg/kg
4900
397
<6
690
170
19260
Arsenic (As)
mg/kg
8,7
2.0
3
2
12
42
Lead (Pb)
mg/kg
559
83.7
430
76
1700
195
Chromium (Cr total) mg/kg
46
29.7
16
17
150
31
31.7
240
78
1900
18
b
Copper (Cu)
mg/kg
58 - 530
Cobalt (Co)
mg/kg
25
15.3
4
<1
<1
n.a.
Manganese (Mn)
mg/kg
104
27.5
35
29
54
7
Nickel (Ni)
mg/kg
59
47.7
41
38
120
31
1.0
<1
<1
2
n.a
b
Vanadium (V)
mg/kg
<1-3
Tin (Sn)
mg/kg
214
21.7
< 10
23
49
120
Zinc (Zn)
mg/kg
770
288
550
210
1200
293
Thallium (Tl)
mg/kg
< 0,6
0.5
< 0.2
0.2
0.7
n.a.
a
RSD = Relative Standard Deviation [%]
No mean calculated due to the strong differences between the three determinations
c
Not calculated since this element was not detected in any of the three analysis
b
25
7. Acknowledgements
This summary review covers almost 10 years of activity by industry related to the end of life aspects of
products from the electrical and electronic sector. It would not have been possible without the contribution of a
number of individuals such as Rainer Martin (BAYER), Theo Lehner (Boliden), Juergen Vehlow (ITC/FZK), Mike
Fisher (APC), Harre Kayen (ECVM) and Lein Tange (EBFRIP) who were (or are) representatives of various
industry associations. A special recognition is also appropriate for the financial support provided by the
Association of Plastics Manufacturers in Europe and the American Plastics Council (APC), now part of the
American Chemistry Council, for the financial support given to demonstrate technologies for the recovery of
plastics. The characterisation information presented in this report is just a small part of this comprehensive
technical activity.
Dr. Frank E. Mark - fmark@dow.com
Design by morris-chapman.com
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