Summary report - PPlastics recovery from waste electrical...

Plastics Recovery from Waste

Electrical & Electronic Equipment

in Non-Ferrous Metal Processes

Authors:

Frank E. Mark

Dow Europe, [email protected]

Theo Lehner

Boliden Mineral AB, [email protected]

A technical

paper from :

TABLE OF CONTENTS

SUMMARY ………………………………………………………………………………… 2

1. INTRODUCTION ……………………………………………………………… 31.1 WASTE ELECTRICAL AND ELECTRONIC EQUIPMENT (WEEE) ……………… 31.2 PLASTICS INDUSTRY ISSUES…………………………………………………… 31.3 NON-FERROUS METALS INDUSTRY ISSUES …………………………………… 31.4 PROGRAMME OBJECTIVES …………………………………………………… 4

2. WEEE CHARACTERISTICS ………………………………………………… 52.1 ELECTRICAL AND ELECTRONIC (E+E) WASTE ……………………………… 52.2 FEED SUPPLIED TO NON-FERROUS METAL RECYCLING PLANTS ……………… 62.3 WEEE AS A SECONDARY RAW MATERIAL …………………………………… 6

3. NON-FERROUS METALS PRODUCTION ………………………………… 73.1 ZINC FUMING FURNACE …………………………………………………… 73.2 KALDO FURNACE …………………………………………………………… 9

4. INTEGRATED WASTE MANAGEMENT (IWM) OF WEEE ……………114.1 WEEE PRE-TREATMENT ……………………………………………………114.2 WEEE FEED PREPARATION FOR THE TRIAL …………………………………11

5. TRIALS WITH WEEE: PCs ……………………………………………………125.1 RECYCLING OF PC SCRAP IN THE ZINC FUMING FURNACE …………………125.2 PRINTED CIRCUIT BOARD AND CABLE SCRAP RECOVERY AT

THE KALDO FURNACE ……………………………………………………………13

6. RESULTS …………………………………………………………………………146.1 METALS RECOVERY …………………………………………………………146.2 COAL SUBSTITUTION: ENERGY BALANCE FOR THE ZINC FUMING PROCESS …146.3 METALLURGICAL ASPECTS: ZN PRODUCT QUALITY …………………………156.4 EMISSIONS, MATERIAL AND MICRO-ORGANIC BALANCES …………………156.5 DESTRUCTION EFFICIENCY……………………………………………………16

7. ENVIRONMENTAL IMPACT …………………………………………………187.1 EMISSIONS TO AIR ……………………………………………………………187.2 EMISSIONS TO WATER ………………………………………………………187.3 DISPOSAL OF SOLIDS …………………………………………………………187.4 WORKPLACE SAFETY …………………………………………………………18

8. CONCLUSIONS …………………………………………………………………19

9. RECOMMENDATIONS…………………………………………………………20

10. ACKNOWLEDGEMENTS ………………………………………………………20

11. REFERENCES AND WEBSITES ……………………………………………21

1

T E C H N I C A L R E P O R T

1. SUMMARY

A growing range of waste electrical and electronic equipment (WEEE) can now be

used as a feed stream in non-ferrous metal smelting plants. There are significant

environmental benefits, including the complete destruction of all micro-organic

compounds, and economic benefits both for the smelters in recovering valuable

metals, and for society in terms of reducing waste management costs.

The Association of Plastics Manufacturers in Europe (APME) and the Swedish

company Boliden Minerals AB carried out a joint project which demonstrates that the

use of scrap cable and printed circuit boards as secondary raw materials can be

extended to include other E+E equipment such as personal computers (PCs). Plant

performance and workplace safety standards are maintained, and emission levels are

unaffected. In the Boliden plant alone 15,000 tons per year of PC scrap could be

treated in this way.

Emerging requirements to reduce the volume of material going to landfill and

preserve valuable resources can be met more easily with this approach. Metal

recovery rates are high and the plastics content serves a dual function, both as a

reducing agent and as a source of energy for the smelting process.

Since the complete dismantling of WEEE is often neither ecologically nor

economically feasible, the more comprehensive approach of Integrated Waste

Management (IWM) is now preferred. Several different waste treatment methods,

including mechanical recycling, are combined in a way that achieves the optimum

balance of environmental, social and economic requirements. The report demonstrates

how the use of WEEE as a source of secondary raw materials in non-ferrous metals

smelting is a viable component of an IWM approach. It includes a review of

Boliden’s long experience of processing scrap cable and printed circuit boards, and

describes trials conducted with PC scrap.

Plastics Recovery from Waste Electrical & Electronic Equipment in Non-Ferrous Metal Processes.

2


3

1. INTRODUCTION

1.1 Waste Electrical and Electronic equipment

Approximately 6 million tons of waste electrical and

electronic equipment (WEEE) is generated in Western

Europe annually. Although it represents only 4% of the

municipal waste stream, with an average growth rate 3

times greater than that of municipal waste, the quantity of

WEEE generated is expected to double in the next

12 years. Factors contributing to this high rate of growth

are technical developments which shorten product life

cycles and reduction of WEEE inventories through

increased rates of collection.

Disposal of WEEE is considered to present substantially

more environmental problems than is the case with

municipal waste. Currently most WEEE is landfilled and a

small amount recycled or recovered. National directives

are now either in place or being prepared which impose

new requirements regarding the management of WEEE.

Central to this kind of change is a draft European Council

directive on WEEE which will require producers to take

responsibility for certain phases of the waste management

of their products. Among the key objectives of the draft

directive are the minimisation of hazards associated with

WEEE, a reduction in the volume of material going to

landfill and the preservation of valuable resources.

The 6 million tons of WEEE includes 675,000 tons of

plastics waste that is available for collection, and an equal

quantity of non-ferrous metals. The two types of material

are combined within the finished products, often in a

highly complex manner. This provides an opportunity for

the two industries to work together on new and

innovative methods of waste management which meet the

needs of all stakeholders, with a reduced environmental

impact and improved economics. This report describes

joint work carried out by the Association of Plastics

Manufacturers in Europe (APME) and a major non-

ferrous metals refining company, Boliden Minerals AB,

whose world-scale smelting complex is located in

Rönnskär, Sweden.

1.2 Plastics industry issues

From the plastics industry perspective, the first preference

for end-of-life products, when feasible, is re-use.

Individual components can be recovered for re-use by

dismantling. However, the pace of change in product

development of Electrical and Electronic (E+E)

equipment means that the global market for the re-use of

components is somewhat limited. Items that cannot be re-

used need to be treated in a manner which, overall, is both

environmentally and economically sustainable. Where

re-use is not possible, mechanical recycling can be a useful

option. Unfortunately this has severe limitations caused by

the difficulty of achieving acceptable product quality,

limited markets for recycled polymers, innovations in

polymer performance and consumer acceptance. These

limitations apply as much, if not more, to WEEE as to

other plastics waste streams.

Mechanical recycling of older WEEE which contains

plastics can cause a specific problem. Without strict

temperature control during extrusion there is a potential

risk of generating dioxins and furans from some

halogenated flame-retardants.

The extent of these problems differs significantly

depending on the availability of suitable treatment facilities

and of end markets for recycled products. An approach

which achieves optimum results is Integrated Waste

Management (IWM). (In the industrial setting described in

this report, the term Integrated Resource Management

(IRM) is similarly appropriate.) IWM uses a combination

of different recovery methods such as mechanical

recycling, feedstock recycling and energy recovery.

Decisions on which methods to use and in which

proportions need to be made locally, based on a detailed

knowledge of all the relevant factors.

1.3 Non-ferrous metals industry issues

The raw materials used by the smelting industry have

traditionally been of two main types, concentrated and

separated ores, and secondary raw materials or scrap. Scrap

has been traded worldwide for many decades. Its

INTRODUCTION

processing provides a combination of environmental and

economic benefits. For example, only one-sixth of the

energy is needed to produce copper from recycled material

than from ores.

Because of the large range and quantities of non-ferrous

metals present in scrap, this waste stream is an attractive

source of secondary raw materials. A correspondingly

wide range of processes is needed to recover all of the

metal values present. The metals refining industry, which

has long experience of recycling and recovery, is

characterised by a small number of producers who

between them make use of a wide range of technologies.

Figure 1 depicts the various streams involved in the

recycling of metals.

The “Metallurgical Network” in Figure 1 consists of a

number of companies engaged in smelting and refining

which trade with each other in an effort to make optimal

use of their capacities and specialised processes. This

inter-company movement of intermediate process streams

ensures that maximum recovery rates are achieved over a

very wide range of metals.

A third type of feed stream, WEEE, is becoming of

increasing interest to the non-ferrous metals industry. It

contains metals that are capable of extraction, and the

plastics content can play important roles in the smelting

process.

As with plastics recycling there can be potential concerns

about emissions when WEEE is recycled. However,

Boliden Minerals already have considerable experience of

recycling a range of E+E components, in particular printed

circuit boards and all types of cable.

1.4 Programme objectives

Key objectives of this programme were:

• Evaluate optimum methods of recycling waste E+E

material


4

INTRODUCTION


Collect& Sort

ComponentProduction

MetallurgicalNetwork

Components

Assemblies

E+E Products

FeAlCuMg

PbSnZnNi

AuAgPdCd

SbInSeTe

Smelter

H2SO4 Glassy Slag (blasting, road construction)SiO2 Al2O 3 FeO CaO MgO

By-Products

Deposits Hg AsY Ga BrSc Ta ClAm Cd IHg

FIGURE 1: RECYCLING OF METALS FROM WEEE

• Understand the role played by the plastics content of

WEEE during the smelting process

• Understand what types of E+E equipment are suitable

for recycling or recovery

• Develop experience to ensure compliance with the draft

EC directive on waste E+E equipment

• Investigate concerns about the generation of dioxins and

furans from waste/scrap materials when recycling

end-of-life E+E equipment

• Establish additional uses for incremental capacity in the

Boliden smelter

Several trials in Boliden’s Rönnskär smelter were

conducted over a four year period (1995 - 1999), with

additional funding support from APME and the American

Plastics Council (APC).

2. WEEE CHARACTERISTICS

2.1 Electrical and Electronic (E+E) Waste

The amount of waste electrical and electronic equipment

(WEEE) generated in Western Europe has been

researched by SOFRES for APME in several studies. The

total of WEEE for 1998 from all E+E sectors is estimated

at 5.9 million tons. The E+E sectors of interest for the

recovery of non-ferrous metals are shown in Figure 2.

The dark coloured portion of the bars indicates the plastics

content for each of the E+E sectors shown.

More detailed characteristics of E+E waste streams have

been described in an earlier APME report (4).

Typical metals contents of four E+E waste streams are

shown in Table 1. The principal metal present in these

streams is copper, so for purposes of comparison, the levels

of high-value metals present in a typical copper ore are also

shown. The comparison highlights the importance of

maximising the recycling of WEEE, a process which is

facilitated by the presence of plastics in the waste streams.

5

WEEE CHARACTERISTICS

FIGURE 2: E+E WASTE SECTORS SHOWING PLASTICS CONTENT

0 5 10 15 20 25 30 35 40 45

Telecommunications

Office Equipment

Data Processing

Equipment

Brown Goods

Cables

Other Materials

Plastics Content

% of total E+E waste

TABLE 1: TYPICAL METAL COMPOSITIONAL

ANALYSIS OF FOUR E+E WASTE STREAMS

Measured levels of all of these noble and heavy metals can

vary significantly depending on the source, age and

pre-treatment of the waste E+E equipment.

While the total quantity of E+E waste has increased in

recent decades, its percentage of recoverable metals

content has decreased. Some sectors, e.g. brown goods,

are now of questionable value in terms of recovery because

of their low non-ferrous metal content. However, when

used in non-ferrous metal recycling, the plastics content

has value, either as a chemical feedstock to replace the

reducing agents CO and H2, or as fuel. This value of the

plastics content can play a factor in decisions about the

management of E+E waste streams and good scientific data

are required to facilitate this.

The types of feed stream supplied to the various metal

recovery processes depend to a great extent on the supply

and demand situation of the secondary materials. The

amount of secondary materials replacing primary metal ore

concentrates ranges from as high as 50% down to 5-10%

depending on market prices.

2.2 Feed supplied to non-ferrous metal recycling

plants

Non-ferrous metals feed streams have traditionally been of

two main types: a) separated and concentrated ores and b)

secondary raw materials or scrap. Depending on the

process being used, the types of secondary feed used range

quite broadly. Examples of traditional sources of secondary

raw materials for the production of copper, lead, zinc and

precious metals are shown in Table 2.

TABLE 2. SOURCES OF SECONDARY RAW

MATERIALS

There is a complex global market in these secondary

materials which are traded in large quantities. For example,

the globally traded quantity of used printed circuit boards

having a high precious metal content is estimated to be

100,000 tons annually. The amount of cable scrap

recovered in Europe in 1998 is estimated to be in the

range 500,000 - 900,000 tons. The global figure is

approximately 2 million tons (5). Another significant

recycle stream is data processing and telecommunications

equipment with a quantity estimated at between 30,000

tons and 90,000 tons in 1998. Precise data on these

quantities of waste is not available and estimates are

dependent on a number of assumptions.

2.3 WEEE as a secondary raw material

WEEE has become of interest as a new source of

secondary raw material because of its recoverable metals

content and the availability of capacity in the smelting

industry to process it. From a broader systems perspective,

the economics of using these materials can be favourable in

view of the metal values recovered and the avoidance of

landfill and incineration charges. Avoidance of landfill

meets the requirements of the EC draft WEEE directive.

However, other environmental criteria must be satisfied

and one purpose of the work described here was to

investigate this aspect.


6

WEEE CHARACTERISTICS


Copper (Cu) Lead (Pb) Zinc (Zn) Precious MetalsCopper wire scrap Used batteries Zinc ashes/brass Printed circuitElectrical switchgear Solder residue boardsPrinted circuit Cathode ray tubes EAF dust from steel Catalystsboards (Pb glass) mills JewelleryMachine shop Cable shielding Galvanising sludges Photographic filmproduction waste Dross

Keyboards Personal Printed Car Typical Computers Circuit Electronics Copper

Boards OreHigh Value Extractable MetalsAg (%) 0.05 0.009 0.3 0.12 0.00034Au (%) 0.005 0.001 0.008 0.007 0.00001Cu (%) 13 7 25 20 0.8Zn (%) 3 1.2 1.5 1 0.12Pd (%) 0.0020 0.0004 - - 0.04AlTOT (%) 18 11 3 - -Medium - Low Value Extractable MetalsNi (%) 0.6 0.2 0.5 0.3 -Pb (%) 0.3 1.5 - 1 -Metals processed in other facilitiesBi (%) <0.0003 <0.0004 0.17 0.01 -Fe (%)1 3 <0.1 5 5 -Sb (%) 0.3 0.5 0.06 0.08 -

1 Fe remaining after magnetic separation

3. NON-FERROUS METALSPRODUCTION

Non-ferrous metal production sites have highly integrated

plants making them very energy and resource efficient.

Most non-ferrous smelters are large-scale plants operated

by multinational companies such as Boliden Minerals

(Sweden), Norddeutsche Affinerie (Germany), Union

Minière (Belgium), Noranda (Canada) and Outokumpu

(Finland). A typical example, shown in Figure 3, is the

layout of the Rönnskär site of Boliden Minerals AB.

This report assesses the opportunities to use PC wasteadded to the feed stream of the Zinc Fuming Furnace andin a current routine process in which waste printed circuitboards are recovered in the Kaldo furnace. The design andoperation of these two furnaces is described below.

3.1 Zinc Fuming Furnace

Total annual Zinc production in Europe in 1999 was

approximately 2.7 Million tons. Of this total,

approximately 30% is generated from recycled raw

materials. The potential treatment capacity is significantly

higher.

Zinc production in Europe uses the following process

technologies:

Primary Zinc Production

1) Roasting of sulphidic concentrates followed by

hydrometallurgy, leaching the resulting calcine, purifying

the leach liquor and electrowinning zinc.

2) Sintering of sulphidic concentrates, smelting the sinter,

separation at high temperature of lead, liquid slag and

gaseous zinc, refining the zinc by distillation. This process

is known as the Imperial Smelting Process (ISP).

Secondary Zinc Production

3) Recovery of zinc from secondary sources via the

production of zinc oxide, to be supplied to either of the

above processes.

A major secondary source is steel-making dusts which arise

during re-melting e.g. of galvanised car scrap. The dust

may contain impurities. This upgrading is carried out in

rotary furnaces, e.g.Waelz kilns, or in fuming furnaces.

Technologies of types 2 and 3 are also referred to as

pyrometallurgy. The technology applied during this

investigation was No.3. The flow sheet of the Rönnskär

site (Fig. 3) illustrates the many options for entering feed

7

NON-FERROUS METALS

PRODUCTION

SO2 plant

Roasting

Drying

Zinc Fuming

Refining

Precious Metals Plant

H2SO4 plantCopper production

OreConcentrate

.

SecondaryCopper RawMaterials

Smelting Converting Refining Copper

Gas cleaning

LiquidSulphurDioxide

SulphuricAcid

Lead productionElectronic Scrap

Lead Concentrates

NiSO4 plant

Lead

Zinc clinker

Scrap

PalladiumGoldSilver Slime

Selenium Crude Nickel Sulphate

KaldoFurnace

Slag

FIGURE 3: TYPICAL NON-FERROUS METAL REFINING PLANT

materials to non-ferrous smelters. In this study, the zinc

fuming process was chosen for PC waste because it uses

fossil fuel both as a reducing agent and as fuel to recover

zinc from slags.

A fuming plant consists of three separate processes:

1) Fuming furnace

2) Settling furnace

3) Clinker furnace

These are shown in detail in Figure 4.

The fuming furnace is a water-cooled rectangular furnace.

Water cooling is used to generate an autogenous lining of

frozen slag. This prevents attack of the steel shell by the

corrosive liquid slag. The heat is recovered in the boiler.

Hot cooling water from the heat exchangers is fed into the

Skelleftehamn district-heating network connected to the

Rönnskär Smelter. The heat from the off gases is

recovered in the boiler.

Finely ground coal and preheated air is injected into the

liquid slag through submerged injection pipes (tuyeres)

situated along both long walls of the furnace. The injected

coal and air react immediately to form CO gas which

reduces metal oxides such as magnetite (Fe3O4), lead

oxide, and zinc oxide in the slag. Some of the useful resul-

ting metals are in the vapour state, which enables them to

be stripped from the liquid slag. Nitrogen contained in the

injected air assists the stripping of zinc vapour from the

slag.

Directly above the foaming bath of liquid slag, the zinc

vapour is re-oxidised to zinc oxide. The reduction process

also recovers other metals such as lead and arsenic, and in

addition extracts halogens from the slag. The resulting

mixture of oxides (“mischoxide”) is de-halogenated in the

clinker furnace.


8

NON-FERROUS METALS

PRODUCTION


ESP

1 2 3 4 56Storage

Raw FumeHopper

FluorineScrubber

Gas Cooler

Bag House

Ball Mill

103

Rotary Cooler

Clinker Furnace

Cyclone

To WasteWater Plant

Clinker

Granulated Slag

Waste Heat Boiler Economizer

Cooling Tower

Emission Check Points

Mixed oxide to Clinker Plant

Speiss/Matte

Crusher

Ash HopperTransfer of Slag

Revert SlagPCs

EAF dust

Settling

Furnace

Oil +Air

Coal

SlagFumingFurnace

Sampling Points

Lead

Bearing

Dust

Material Hoppers

FIGURE 4: ZINC FUMING PLANT

The cleaned slag is tapped from the fuming furnace into

the settler furnace. Here the remaining copper alloy

droplets and copper sulphide droplets in the liquid slag are

separated into liquid phases. These contain copper and

other precious metals and are either recycled to the copper

smelter or sold for further treatment in specialised

metallurgical plants belonging to the “Metallurgical

Network” highlighted in Figure 1. These two phases, rich

in copper and precious metals, allow for the almost

complete recovery of copper and precious metals

contained in the PC waste added to the furnace.

The geometry and operating parameters of the zinc

fuming plant can be seen in Table 3.

TABLE 3: OPERATING PARAMETERS OF

THE ZINC FUMING PLANT

The total feed to the Zinc Fuming Furnace consists of:

1.Liquid iron-silicate slag from the electric copper

smelting furnace

2.Recycled reverts (solidified slag) e.g. from the transfer of

the liquid iron-silicate slag (No. 1 above) by ladle

3.Internally recycled dust from the fuming furnace (ash

hopper - see Figure 4)

4.Steel making dust (EAF dust) from electric arc furnaces

re-melting galvanised steel scrap

5.E+E waste used for the test campaign

Table 4 indicates the products and their quantities

produced by the zinc fuming plant.

TABLE 4: PRODUCTS FROM THE ZINC FUMING

PLANT

3.2. Kaldo Furnace

There are several similarities in the manufacturing

technologies used to recover non-ferrous metals in the

zinc fuming furnace and the Kaldo furnace. Plastics are

used as fuel, easily oxidisable impurities are dissolved in a

liquid slag and precious and base metals are collected as an

alloy or “Matte” (liquid sulphides). Both processes make

use of the other plants on the site to extract the metals.

Residue streams, such as slags, dusts, sludges or matte, are

usually recycled on-site or processed at other companies,

making use of metallurgical networks (Fig. 1) when

in-house processing capacity is unavailable or trading is

economically more attractive. Through this highly

integrated industry set-up, which avoids the need for

landfilling, the non-ferrous metals industry contributes to

sustainable development by assuring ecologically sound

and economically viable treatment of the residues.

The Kaldo furnace has been specially developed for the

recovery of metals from secondary raw materials. The total

amount of secondary raw materials and lead concentrate

currently processed by Boliden’s Kaldo furnace is

approximately 100,000 tons per year. Most of the

large-scale plants at other major companies such as

Norddeutsche Affinerie (Germany), Union Minière

(Belgium) and Noranda (Canada) have similar capacities.

Kaldo technology has been practised for over 15 years to

recover cable scrap and printed circuit boards. Sound

ecological treatment is assured by means of stringent

emission regulations.

The process is illustrated in Figure 5 on the next page.

9

NON-FERROUS METALS

PRODUCTION

Length 8.1 m District heating: 4-8 MWWidth 2.4 m Capacity: 105 t (batch)Nozzles: 52 Fuming agent: Coal + preheated airFuming cycle: 120 min Coal consumption: 1.5 kg/t ZnOff gas volume: 140-170,000 m3/h Steam generation: 55 tph (40 bar)

Tons per day Zn (%) Pb (%) As (%) Se (%) Cu (%)Mixed Oxides: 120 65 10 0.15 0.02 0.2Slag: 750 1 0.02 <0.005 <0.002 0.5Clinker: 110 75 5 0.01 - 0.1

The analysed material is blended in heaps to improve

integration with the melt and allow for maximum use of

energy and smelting capacities. The material is charged by

front-end loader into a skip hoist. The hoists are emptied

from above under a ventilated cover into the furnace

vessel. The furnace is then tilted back into the operating

position. Oxygen supply to the furnace via a lance is

started. If necessary, an oil-oxygen burner assists in

reaching the ignition temperature. Combustibles

contained in the charge supply heat for melting of the

printed circuit board scrap, additional scrap and fluxes (slag

formers). Off-gases from the furnace are collected in a

water-cooled hood, where additional post-combustion air

also enters. Post-combustion takes place at around

1200°C. Residence time is estimated to exceed 2 seconds.

Steam is produced in the hood and the offtake and is fed

into the smelter’s steam network for in-process use and

energy recovery. The process gases are then shock-cooled

in a venturi scrubber, the dust particle loaded water being

settled in a settler. Water is bled to the central water

treatment plant for metal sulphide precipitation and lime

treatment. The sludge from the scrubber, and also the

sulphide precipitate from the water treatment plant, are re-

circulated to the copper smelter to increase raw material

recovery.

The process produces a metallic copper alloy that is

transferred as liquid to the copper smelter for recovery of

metals (Cu, Au, Ag, Pd, Ni, Se, Zn). Dusts (containing Pb,

Sb, In, Cd) are also generated and these are processed at

other smelters. Slag arising in the process is sent to the

Boliden concentrator for extraction of any remaining

metal value.

The role of plastics from cable insulation is to supply

process heat for the smelting operation. PVC and

crosslinked low-density polyethylene in the cable scrap, as

well as the thermosetting resin in the printed circuit

boards, perform this very valuable function in the Cu

recovery process. Their high heat value provides most of

the process heat needed for secondary raw material

smelting to produce prime grade copper.


10

NON-FERROUS METALS

PRODUCTION


Oxygen

Feed

Furnace Position 2 - Smelting

Furnace Position 1 - Charging

Process encapsulation

connected to bag house

Process gas duct

to venturi scrubber

Furnace Position 3 - Tapping

Oil

FIGURE 5: THE KALDO FURNACE

4. INTEGRATED WASTE MANAGEMENT(IWM) OF WEEE

Integrated Waste Management is a subject which is

discussed widely both in society in general and in the

development of European and national legislation. Within

the EU, several initiatives to describe the system in more

detail exist such as (8). A proposed schematic overview of

IWM, based on the one in Reference 8 (page 20), is

shown in Figure 6.

4.1 WEEE pre-treatment

Waste electrical and electronic equipment is normally

collected through waste management companies or

communities or taken back by the original equipment

manufacturer as outlined in Figure 6. There are no

European (CEN) standards in existence at the time of

writing on important operations such as inspection,

dismantling and sorting of WEEE. The important aspects

are dismantling, removal of valuable parts like printed

circuit boards and removal of hazardous components such

as old Hg switches and NiCd batteries. These steps need

to become standardised operations in any type of WEEE

handling. For most of the articles or equipment the degree

of dismantling needs to be evaluated further. Dismantling

adds significantly to the total cost of treatment and some of

the products generated, such as old housings, have no

material value.

The use of secondary metals in the non-ferrous metals

industry requires all companies either to have shredding

capabilities on site or to receive shredded materials. Partial

dismantling has to be done at the recycling/recovery

operation site to remove parts containing hazardous

elements like Hg-containing batteries, relays etc.

4.2 WEEE feed preparation for the trial

For this test campaign, the PC scrap was collected from

various sources within Scandinavia. Transportation was

mainly by train. The collected scrap was first inspected by

the company Arv. Andersson at its scrap yard in Skellefteå

for the occurrence of known Hg-containing pieces. These

would have to be removed. Figure 7 provides a typical

picture of the PC waste material quality as received.

11

INTEGRATED WASTE

MANAGEMENT (IWM)

OF WEEE

MARKET

(Original use)

E+E

Product

Product to market

Product

Performance

Secondary UseRe-use

MARKET

(Other use)

END-USE-ENERGY

MARKET

SAFE FINAL DISPOSAL

PROCESS

PROCESS

INSPECTION

and eventual

SORTING

Waste from recovery

Waste for disposal

Reject

Open loop

Sorting Residue

RECOVERY

ÒPrevention by source reductionÓ

Closed LoopMaterial for recovery

Waste

FIGURE 6: INTEGRATED WASTE MANAGEMENT (IWM)

A hammer mill shredder with a magnetic iron separator

was used to prepare the bulky material. The plant is

equipped with an automatic sampler to take online

material samples for analysis. After sampling of about

5-10% of the feed, the bulk of the WEEE material was

transferred to the Rönnskär smelter.

No major problems were experienced during crushing and

fragmentation although some printer rolls were hard to

crush. The temperature increase during mechanical

treatment was not greater than that experienced during the

routine treatment of scrap at Rönnskär. The working

environment was checked for heavy metals and dioxins.

All the values were below actual or recommended

hygienic limit values in Sweden.

The fragmented PC scrap was then mixed by front-end

loader with crushed revert slag in a 50:50 mixture. The

proportions were chosen to optimise bulk handling and

silo feeding and avoid any blockages during feeding.

Problems were experienced if insufficient care was taken

to ensure that the material was fragmented into pieces

smaller than ca 30 mm. Especially noticed was the

formation of copper-wire agglomerates and printer

ribbons, which could cause problems during feeding from

the silo.

5. TRIALS WITH WEEE: PCs

Boliden’s technical capability to take the entire shredded

PC scrap into their zinc fuming plant without extensive

dismantling was one of the incentives to start this

programme. Selected removal of critical components

which contain Hg will keep the total chain cost low by

avoiding high pre-treatment costs for material recovery.

5.1 Recycling of PC scrap in the zinc fuming furnace

So far, five campaigns have been run with the aim of

thoroughly exploring the metallurgical, environmental and

economic impacts of this new type of E+E feed. The

testing programme consisted of four major series, outlined

in Table 5.

TABLE 5: TESTING PROGRAMME TRIAL SEQUENCE

The PC feed streams used in these tests arrived from

various sources within Scandinavia and were sampled

according to type, (PC consoles, keyboards and monitors)

for chemical analysis.

TABLE 6: TYPE AND ORIGIN OF FEED STREAMS

The mix containing the PC scrap was transferred by

on-site dumper trucks to the conveyor belt feeder and on

to the silos on top of the zinc fuming furnace. The PC

scrap/slag mixture and pelletised steelmaking dust were

drawn from the two silos and fed by belt conveyor onto

the chute to the fuming furnace. The feeding belts are

equipped with belt weighing devices.

Table 7 gives details of the experimental plan for Test

Series II to IV.The normal charging practice was applied

except for one trial, Trial D. In normal charging, the cold

material is charged during the early part of the fuming

cycle. In Trial D charging was prolonged throughout the


12

TRIALS WITH WEEE: PCs


FIGURE 7: PC MATERIALS AS RECEIVED

Test Series Added to the feed stream TimingI Steel dust and PC scrap 1995II Steel dust and PC scrap April 1996III PC scrap only October 1996IV Steel dust only 1999

Year Country PC Consoles Keyboards & Monitors Age1995 Sweden 12 t 7 t 1980-19911996 Sweden /Norway 53 t 17 t 1980-1990

fuming cycle in order to understand the effect of different

feeding modes.

TABLE 7: EXPERIMENTAL PLAN FOR

PC RECOVERY IN ZINC FUMING PLANT

DURING SERIES II TO IV

In addition to the analysis for metals, heavy metals and

precious metals shown in Table 1 (page 6), an extended

analysis was also performed during two of the above trials,

B and C. The results are shown in Tables 8 and 9.

TABLE 8: FEED STREAM ANALYSIS‡

TABLE 9. METALS ANALYSIS OF PC PARTS

Analysis was carried out for halogen-containing organic

compounds: chlorinated PCDD/Fs, brominated

PBDD/Fs and mixed brominated and chlorinated

PBCDD/Fs. The values found varied quite significantly.

No correlation between the amount of PXDD/Fs and

their source or age has so far been identified. The average

PXDD/Fs content of all the samples of waste E+E plastics

so far investigated by APME have met the following two

German regulations: “German Regulations for Hazardous

Materials” (6) and “The German Chemical Banning

Ordinance” (7). A potentially high content of these

organic compounds may well provide an extra reason for

large-scale handling, automatic fragmentation, Syngas

production and post-combustion, thus minimising the

impact on the internal and external environment.

Furthermore, potentially significant amounts of these

impurities suggest that mechanical recycling of old plastics

from the WEEE should be looked at with great care. The

process shown in Figure 4 has proven to be a sink for

dioxins and halogenated organic compounds, as

demonstrated in section 6.5.

The operators used their normal process mode to carry out

feeding to the furnace. The fuming process did not deviate

from its usual performance. Operating capacity was limited

during one of the campaigns by the capacity of the

subsequent process. When feeding large amounts of PC

scrap, limitations in boiler capacity were experienced. In

these cases the coal feed rate was reduced significantly

while charging the PC scrap/slag mix, indicating a

substantial substitution of coal by plastics.

5.2 Printed circuit board and cable scrap recovery at

the Kaldo furnace

Processing of WEEE has been carried out in the Kaldo

furnace for many years and is a regular commercial

operation, conducted in campaigns between lead flash

smelting campaigns. Similar plants are used for autogenous

smelting of lead concentrates. The length of the

campaigns, and hence the total annual capacity available

for WEEE, is thus determined mainly on economic

considerations. Currently the split is about 50% of the

available time running on lead and WEEE respectively.

The Kaldo plant also makes use of an existing lead kettle

for the recovery of metals from lead sheeted complex

13

TRIALS WITH WEEE: PCs

Trial A B C D EYear 1996 1996 1996 1996 1999Type Base Medium High Prolonged BaseFeed slag (t) 85 85 85 85 85WEEE (t) none 10 20 20 noneEAF dust (t) 5 5 5 5 15

Organic Compounds Trial B Trial CAsh (%) 9.2 7.2Hu (MJ/kg) 31.2 24.4C (%) 65.4 62.7H (%) 6.5 6.5O (%) 12.0 14.1S (%) 0.2 0.2

Metals Trial B Trial CCd (mg/kg) 99 24Tl (mg/kg) <1 <1Hg (mg/kg) 9.5 0.9Sb (mg/kg) 120 63As (mg/kg) 2 <1Pb (mg/kg) 250 280Cr (mg/kg) 41 13Co (mg/kg) 1 1Cu (mg/kg) 200 340Mn (mg/kg) 94 94Ni (mg/kg) 250 58V (mg/kg) <2 <2Sn (mg/kg) 630 5,400Zn (mg/kg) 1,800 1,500

cables. Lead is melted off under hood coverage. The

remaining copper and iron fraction is sent to the copper

smelter. The off-gases from this treatment are ducted to

the gas cleaning devices described earlier.

No specific emission measurements suitable for inclusion

in the report were carried out. The emission levels from

this plant, viewed on an annual basis and shown in

Table 10, are taken from Boliden’s environmental report.

They are based on a total scrap operating time of

3855 hours.

TABLE 10: EMISSIONS FROM THE KALDO

FURNACE (1998)

6. RESULTS

6.1 Metals Recovery

Typical recovery rates exceed 95% of the metal in the feed

stream. Consequently, where spare smelting capacity is

available to process them, feed streams other than those

traditionally used, such as WEEE, are becoming of interest

to the smelting industry. The recovered metals, i.e.

copper, nickel and precious metals, cannot be

distinguished from metals extracted from primary ores.

In addition to the metal values recovered, processing of

these streams provides a significant environmental benefit.

6.2 Coal Substitution: Energy balance for the Zinc

Fuming process

The influence of plastics on the heat balance is best

analysed by means of a comparison with normal operations

(Figure 8). The data show, as does the experience of the

operators, that carbon and hydrogen from the plastics

substituted carbon and hydrogen normally provided by the

coal. By comparing the fuming speed, the generation of

steam, and the specific energy, we conclude that for the

most part the plastics content was used for chemical

purposes.


14

RESULTS


Dust Cu Pb Zn Cd As Hg SO2 F Cl PCDD/Ftpa tpa tpa tpa tpa tpa tpa tpa tpa tpa gpa Eadon1.78 0.03 0.828 0.11 0.002 0.004 0.004 9 0.034 4.24 0.084

In Out In Out

0%

20%

40%

60%

80%

100%

Coal

WEEE

In

Fume Gas

Cold Material (25 12000C)

Heat Losses

Chemical (Zn reduction)

Air

Out

FIGURE 8: INFLUENCE OF PLASTICS ON THE ENERGY BALANCE

IN THE FURNACE SEGMENT

Administrador

Highlight

The effects on batches with PC scrap are well within the

normal operational parameters with regard to fuming

speed, despite a lowered coal feed rate of 1 ton per hour.

The batches with PC scrap have an apparent lower unit

coal consumption per ton of zinc. From this we conclude

that the plastics take part in the reduction of zinc oxide

from the slag. The exact quantity is difficult to define at

low substitution rates.

The left side of Figure 9 illustrates the progressive

reduction in coal usage resulting from Boliden’s efforts to

improve the operational efficiency of the Zinc furnace.

Each data point represents the average coal consumption

rate for one month during a 3-year period.

The section of the graph to the right of the dotted line

shows the individual batch data during the conduct of Test

Series II in April 1996.

It may be possible to detect a positive influence on process

kinetics through early reduction of magnetite by plastics

and the remaining aluminium in the WEEE. According to

the chemical stoichiometry, 1 kg of Al reduces 25 kg of

Fe3O4 and 1 kg of plastic reduces approximately 50 kg of

Fe3O4. Reports in the literature mention a strong positive

influence of H2 on reduction kinetics, compared with CO.

To completely reduce all magnetite in the charge, an

estimated 300-400 kg of Al or 200 kg of plastic would be

required. When aluminium is used, the resulting increase

in the aluminium content of the final slag would be

0.7 - 0.9%, which in some cases may well lead to process

problems.

6.3 Metallurgical aspects: Zn product quality

Zinc fuming rates during the trials were well within the

normal band of operation, in spite of a reduced coal feed

rate. Figures 8 and 9 illustrate the performance of the trial

runs with regard to key parameters. From this we

conclude that a major part of the hydrocarbons contained

in the plastic was used as a reducing agent, i.e. taking part

in the chemical reaction. The standard chemistry

describing this would be a formation reaction of hydrogen

and carbon monoxide from the plastic, which then act as

reducing agents to form zinc metal in the melt.

Once this gaseous zinc leaves the molten bath

it is oxidised to zinc oxide and is recoverable in

the electrostatic precipitator (ESP).

The composition of the product was

continuously monitored and fell well within

the normal range. No deviation in major

elements such as Zn, Pb, Sn, F and Cl, could

be detected. The increased load of halogenides,

especially bromides, could be traced to the

intermediate product called mixed oxides. The

subsequent process of halogen removal in the

clinker furnace has by now adjusted its practice to

accommodate the increased load of halogens introduced

by steel making dust and other feed streams. Halogen

removal is carried out in a long rotary kiln by re-heating

the raw fume together with coke additions to

approximately 1200°C. The rotary kiln can be seen in

Figure 4 (page 8), described as "Clinker Furnace". By

means of this process, halogenides, together with part of

the lead, are separated into a dust which is sent for

processing at a zinc smelter. The clean zinc oxide "clinker"

is processed at Boliden’s 50% owned Norzink plant in

Norway.

The finished product zinc produced in Norway has been

checked for the occurrence of dioxins. The results show

values below detection limits and no influence on levels of

critical impurities such as halogenides could be detected.

15

RESULTS

1

1.2

1.4

1.6

1.8

2

2.2

2.4

2.6

2.8

3

Jan

1993

May Sep Jan

1994

May Sep Jan

1995

May Sep Jan

1996

5 10 15

Batch Number

Tonsofcoalpertonofzincfumed

Monthly averages before the trialsIndividual batch data

during the trial period

FIGURE 9: MONTHLY AVERAGE COAL

CONSUMPTION RATE

6.4 Emissions, Material and Micro-Organic Balances

It is difficult to match mass and component balances on an

industrial scale for elements at very low concentrations

such as the volatile metals and halogens or for

micro-organic components. The major uncertainties are

not with the analytical determination of concentrations

but rather with the difficulty of obtaining reliable

representative samples and making consistent mass flow

measurements. Additional problems arise from a

combination of sampling errors, analytical difficulties and

errors, scarcity of costly assays, and errors in determining

solid and gas flows. The material flow during the fuming

tests was calculated for each batch and is illustrated in

Figure 10, which contains typical compositions of the

different streams around the fuming process. The

important elements, Hg, Br, Cl, F and Sb, were balanced.

Using this elemental analysis, data covering the entire

process, including the input and final output, can be

calculated.

In summary, less than 3% of the halogen content is emitted

through the stack of the zinc refining plant in Norway.

The total halogen content is liberated in the fuming plant

and is neutralised in the gas cleaning section. Metal

sulphide precipitates from the waste water plant are

re-circulated to the copper smelter. After final polishing by

lime precipitation, where fluorine is also precipitated

(as NaF and CaF2), other salts (NaCl, CaCl2, NaBr and

CaBr2 ) are discharged to the sea (Gulf of Bothnia). Of the

antimony added with the WEEE to the fuming process,

over 65% leaves the plant with the raw fume. The overall

potential recovery of Sb is about 40% under these

conditions. The rest is stabilised in a glassy slag or

contained in jarosite in mountain caverns. For mercury the

corresponding figure was approximately 22%, but there

was no special gas cleaning during the trial.

The results of this study suggest that the following

measures should be implemented to deal with WEEE

which contains potentially high amounts of Hg:

• Tighter incoming WEEE control for Hg at the site and

• Establishment of specifications which ensure low Hg

levels or

• Investment in effluent gas treatment (e.g. AC filter)

6.5 Destruction efficiency

One of the objectives of this test programme is to support

the general WEEE waste management strategy and to

show that plastics are recyclable in the form of feedstock.

This has been the subject of many reviews and research

studies because of the potential content of micro organic


16

RESULTS


Fuming

Furnace

Hg

(g)

Br

(Kg)

Cl

(Kg)

F

(Kg)

Sb

(Kg)

70 <2.5 15 1.8 8.3

EAF Dust 20 <2.5 95 0.4

Crushed Slag <5 <2.5 <5 2.5

Hg

(g)

Br

(Kg)

Cl

(Kg)

F

(Kg)

Sb

(Kg)

Slag <80 <40 <80 40 40

Hg

(g)

Br

(Kg)

Cl

(Kg)

F

(Kg)

Sb

(Kg)

Cleaned Slag <80 <40 <80 40 40

Hg

(g)

Br

(Kg)

Cl

(Kg)

F

(Kg)

Sb

(Kg)

Raw fume to Boiler,

Condensation Tower and ESP 70 <2.5 15 1.8 8.3

Hg

(g)

Br

(Kg)

Cl

(Kg)

F

(Kg)

Sb

(Kg)Raw Fume to

the Stack17 0.8 0.6 0.6 0.5

Hg

(g)

Br

(Kg)

Cl

(Kg)

F

(Kg)

Sb

(Kg)

Stack total out 22 3.2 0.9 1.3 0.01

Raw Fume total 24 81 81 73 66

WEEE

FIGURE 10: MATERIAL FLOW AT THE FUMING PLANT

halogenated substances, such as halogenated di-benzo

furans and dioxins (PXDD/Fs) in WEEE. Mechanical

recycling of WEEE with increased detectable levels of

PXDD/Fs will give rise to potential costs of handling and

exposure to recyclates made from these WEEE plastics.

The feedstock recycling technology as shown in this report

will not lead to these kinds of potential risk, if it can be

proven that no equivalent exposure to operators during

feedstock recycling takes place. Equally important is the

fact that the overall destruction efficiency of the process is

guaranteed at a high enough level. Because of this

important issue, dioxin and furan balances have been

carried out and the results of two calculations are shown

here.

In the case of Boliden, the co-treatment of waste PC

equipment and steel dust makes it important to understand

the respective potential contribution of these two

materials. The following short analysis (Figure 11) is based

on the total amount of polyhalogenated dioxins and furans.

FIGURE 11: DIOXIN AND FURAN MASS BALANCE

FOR THE ZINC FUMING PLANT

A more detailed analysis (see Figure 12) has been done for

the critical and regulated 2378 congeners of PXDD/F

which are part of the existing legislation in Germany on

emissions from waste incinerators.

The total halogenated dioxin/furan mass balance shows a

clear destruction of all micro organic compounds from this

family with an efficiency of over 98%. From the total input

of 6.4 g per batch only 0.104 g per batch leaves the fuming

plant. This amount is almost evenly split between the

gaseous emissions and the amount staying with the raw

fume. Since the raw fume is treated a second time at high

temperature in the downstream kiln, which destroys

residual PXDD/Fs on the solid, the destruction efficiency

over both plants is more than 99%.

The method used to calculate the destruction efficiency is

based on a per-batch type of operation, as the long- and

short-term PXDD/F emission results are not very

different. From this it can be concluded that in

determining the dioxin balance, short-term sampling of

two hours for one batch is equally representative as

long-term sampling.

In Figure 12 the equivalent balance for the same batch

using toxic equivalent factors (ITE) is shown.

FIGURE 12: TOXIC EQUIVALENT (I-TE) MASS

BALANCE FOR THE ZINC FUMING PLANT

The ITE results indicate a good level of destruction

efficiency in the zinc fuming plant. An even higher overall

destruction efficiency is achieved because of the

subsequent clinkering process.

17

RESULTS

Input

Feed Quantity (tons) PXDD/F Concentration( g/kg)

Flux

(g/batch)

Slag

Steel Dust

Cold Slag

PC Scrap

86

5

5

5

0

30.6

0

1250

0.0

0.15

0.0

6.25

Total Input 6.4

Output

Quantity PXDD/F ConcentrationOutput

(m3/h) (tons) (mg/kg) ng/m

3Sampling

Time (h)

Flux

(g/batch)

Stack Gas

Raw Fume

130,000

8.48 6.68

182 2 0.047

0.057

Total Output 0.104

m

Input

Feed Quantity (tons) ITE Concentration (mg/kg) I-TE Flux

(g/batch)

Slag

Steel Dust

Cold Slag

PC Scrap

86

5

5

5

-

0.95

-

0.0171

0.0

0.00475

0.0

0.0000855

Total Input 0.00483

Output

Quantity ITE ConcentrationOutput

(m3/h) (tons) (mg/kg) ng/m

3Sampling

Time (h)

I-TE Flux

(g/batch)

Stack Gas

Raw Fume

130,000

8.48 0.078

2 2 0.00026

0.000561

Total Output 0.0008

7. ENVIRONMENTAL IMPACT

7.1 Emissions to air

Measurements of the environmental impact of this type of

feed have been carried out by both the Boliden

measurement team and by an independent certified

laboratory. The results from both laboratories agree within

satisfactory limits. The average emissions for the more

important compounds: CO, NOX, SO2, TOC and O2

were as follows:

TABLE 11. EMISSIONS DURING ZINC FUMING

TESTING

The emissions of other compounds are not shown as they

were not affected by the co-processing of PC scrap. The

concentrations of dust and ten heavy metals (sum of Sb,

As, Pb, Cr, Co, Cu, Mn, Ni, V, Sn) were <11 mg/m3 and

approximately 0.4 mg/m3 respectively.

7.2 Emissions to water

The run-off waters and the process water from the

subsequent scrubbing at the clinker plant, where the raw

fume is dehalogenated, are treated jointly with the waters

from the rest of the smelter site in a central water

treatment plant. Heavy metals are efficiently precipitated as

sulphides. The sulphide sludge is returned to the fluidised

bed roaster of the copper plant. The water is further

treated with lime to precipitate fluorine as fluorspar

(CaF2). After treatment, the cleaned water is discharged to

the sea (Gulf of Bothnia).

7.3 Disposal of solids

Deposits originating from the fuming treatment are minor

amounts of slag and lead. Minor slag volumes are used for

on-site construction and lead is concentrated into the

clinker dust which is shipped for recycling to other non-

ferrous metals producers.

The dusty materials are handled with care due to their

toxic nature and are kept well contained and sealed

according to Swedish government regulations. The Pb

bearing dust was checked for the occurrence of dioxins,

using a combination of three-monthly samples. These

samples represented normal operating practice with the

addition of EAF dust, but without the addition of PC

scrap.

From the balance of dioxins it may be concluded that

dioxins could occur in the lead bearing dust deposits, but

that their concentration is below the values of the German

Chemical Banning Ordinance. No indications are

available that these values are increased by the input of PC

scrap.

Insoluble elements or compounds at the zinc plant

(Norway) end up in the jarosite precipitate and are

disposed in dry mountain caverns. As indicated above, the

final product has been checked for the occurrence of

dioxins. The result shows values below detection limits.

7.4 Workplace safety

Workplace safety was investigated and analysed. The

potential impact on operators of dioxins/furans was

checked by means of a dust-emission sample. The value in

the fuming plant during recycling of PC scrap was found

to be 0.08-0.12 ng/m3, well below the recommended

50 ng TE Eadon /m3 (8 hours working hygienic value).

The potential impact of micro organic compounds during

feed preparation was further checked by personal

monitoring. The results from two different modes of

operation of the fragmentation plant show values below

the proposed German workplace standard. No special

precautions were taken during the handling of the PC

scrap. The level of heavy metals was found to be well

below the hygienic limit values. If necessary the practices

for handling this type of material could be tightened.


18

ENVIRONMENTAL IMPACT


CO NOX TOC SO2 O2

mg/m3 mg/m3 mg/m3 mg/m3 vol %A 10-15 100-160 2 600-1000 12-14B 10-15 160-180 1 945 10-13C 20-50 160-190 2 740 11-12

8. CONCLUSIONS

This successful example of PC co-treatment within the

standard operation of a zinc fuming furnace shows that

other opportunities may exist to use waste plastics as feed

stock or fuel in the non-ferrous metals industry.

The maximum amount tested was 10 t/charge,

corresponding to some 15,000 to 20,000 tonnes per year

of PC scrap. Preliminary tests with continuous feed

indicate no major differences compared with the batch

charging used for this trial. Continuous feed would allow

for approximately 15,000 t per annum of PC scrap to be

treated. The possible influence of an increased halogen

load on the corrosion of gas cleaning equipment must be

assessed in a long-term performance test.

The handling and fragmentation of WEEE falls well

within the broad range of materials already handled at the

Boliden Rönnskär smelting site. At the normal feed rates

studied, co-treatment of PC scrap did not harm the fuming

process. The heat released by the introduction of the

plastic contained in the scrap was compensated by a lower

feed rate of coal.

The influences on the environment are to be considered as

being positive ones, as the process essentially represents an

effective sink for dioxins and heavy metals. No significant

difference in emissions of heavy metals was detected,

except for mercury during the first test run. Several new

requirements, for example the setting of acceptance limits,

and plant improvements such as an active carbon filter for

effluent gas will ensure that the treatment of WEEE

containing potentially higher levels of Hg is dealt with in

an ecologically sound and responsible manner.

No significant increase in dioxin emissions for the trial

batches with PC scrap was detected. The patterns of the

dioxin congeners in the feed and in the stack samples differ

significantly, also stressing the efficient destruction of

micro-organic compounds sometimes contained at a very

low level in old E+E equipment. The exposure of the

employees to micro-organic compounds and toxic

elements does not exceed hygienic limit values. Standard

routines for personal hygiene should be enforced.

Material recycling, comprising mainly dismantling and

material separation, is not charged today at full cost, being

subsidised through cheap labour from the government or

the community. If the level charged for treatment of

WEEE was of the order of €350 to €800 per ton of scrap,

the method described in this report, using the zinc fuming

furnace, would be economic, requiring no further subsidy.

WEEE would be able to compete with other secondary

raw materials. This is due to low costs and high direct

recovery of heavy metals. The inherent extractable metal

content varies considerably within the wide groups

represented by WEEE and the treatment cost is hence

directly related to the market value of the extractable

metals.

19

CONCLUSIONS

9. RECOMMENDATIONS

Current proposals from national environmental protection

agencies call for dismantling of WEEE into separate

components to achieve better environmental performance.

The depth and extent of dismantling is sometimes very

vaguely defined and there is a great lack of sound data,

both socio-economic and scientific. The joint efforts at

Boliden have shown that total dismantling of PCs is not

required. A low content of potentially harmful chemical

elements in the feed, such as Hg or Cd, should be achieved

by selective dismantling. Investment in known and

demonstrated gas cleaning technology may be appropriate.

It is recommended that certain used E+E equipment,

which is known to contain substantial amounts of precious

metals and plastics, be handled in smelting processes of the

types described.

10. ACKNOWLEDGEMENTS

The authors would like to acknowledge the valuable

contribution to the success of their work made by a

number of individuals and organisations:

Project Sponsors

Boliden Minerals AB

Association of Plastics Manufacturers Europe (APME)

American Plastics Council (APC)

Companies

AB Arv. Andersson, Skellefteå, Sweden

Individuals

M.Fisher – American Plastics Council

APME E+E Sector Task Force

M. Frankenhaeuser - Borealis Polymers Oy

P.Peuch – BP/Amoco


20

RECOMMENDATIONS


11. REFERENCES AND WEBSITES

References:

(1) Lehner T. & Vikdahl A. (Boliden) “Trim, slim and

quality”. Paper presented at ‘Copper 95’,

Santiago de Chile, November 1995

(2) Willbrandt, P. “Operational Results of Norddeutsche

Affinerie Copper Smelter” in Queneau. P (Ed.)

‘Symposium: Extractive Metallurgy of Cu,Ni,Co’

Las Vegas, 1993.

(3) Moulins, L.J. & Picard, D. “Precious Metals Recycling

at Noranda Horne - a logical choice”. Paper presented

at ‘Precious Metals 1994’, Vancouver BC.

(4) Vehlow, J. & Mark, Frank E. “Electrical and

Electronic plastics waste co-combustion with

Municipal Solid Waste for energy recovery.” APME

Technical Report No. 8020, February 1997.

(5) Bureau of International Recycling (BIR) “Plastic

Coated Cable Scrap”. Article on website

http://www.bir.org/

(6) Hazardous Substances Ordinance: Gefahrstoffrecht,

Recht-und Verwaltungsvorschriften über gefaehrliche

Stoffe im Arbeits- und Vebraucherschutz, vom 26

Oktober 1993, zuletzt geändert 27 Januar 1999.

(7) Chemicals Banning Ordinance: Verordnung über

Verbote und Beschränkungen des Inverkehrbringens

gefährlicher Stoffe, Zubereitungen und Erzeugnisse

nach dem Chemikaliengesetz (Chemikalien-

Verbotsverordnung - ChemVerbots V) 18 Juli 1996.

(8) Krajenbrink, G.W., Temmink, H.M.G., Zeevalkink,

J.A. & Frankenhaeuser, M. “Fuel and Energy

Recovery”. Consortium Report TNO-MEP -

R 98/220 for European Commission Directorate-

General XVII Energy. January 1999

(9) Lehner T. & Vikdahl A. “Integrated recycling of

non-ferrous metals at Boliden Ltd.Rönnskär Smelter”.

Paper presented at ‘Sulfide Smelting 98’,

San Antonio, Texas 1998.

Websites:

American Plastics Council:www.plastics.org

APME:www.apme.org

Boliden (Sweden):www.boliden.ca

Bureau of International Recycling:www.bir.org

Institute of Scrap Recycling Industries:www.isri.org

Dow Europe:www.dow.com

Noranda (Canada):www.noranda.advancedmaterials.com

Norddeutsche Affinerie (Germany):www.affinerie-hamburg.com

Outokumpu (Finland):www.outokumpu.fi

Union Minière (Belgium):www.um.be

21

REFERENCES

AND WEBSITES

A V E N U E E . V A N N I E U W E N H U Y S E 4

B O X 3 B - 1 1 6 0 B R U S S E L S

A P M E ’ S T E C H N I C A L A N D E N V I R O N M E N T A L C E N T R E

T E L E P H O N E ( 3 2 - 2 ) 6 7 5 3 2 5 8

F A C S I M I L E ( 3 2 - 2 ) 6 7 5 4 0 0 2

F o r d e t a i l s o f A P M E p u b l i c a t i o n s s e eA P M E ’ s w e b s i t e o n h t t p : / / w w w . a p m e . o r g

8036

/GB

/07/

00

Summary report - PPlastics recovery from waste electrical...

Documents

Transcript of Summary report - PPlastics recovery from waste electrical...