The last one:
OPTIONS treatment of waste electrical
AND ELECTRONIC EQUIPMENT
Dusan Piers, Frank Kukurugya, Tomas Havlik
Technical University of Kosice, Faculty of Metallurgy, Department of non-ferrous metals and
Waste Treatment, Letna 9, 042 00 Kosice, Slovak Republic
Abstract
This work is focused on waste from electrical
and electronic equipment (WEEE). Processing of such waste is not
simple and each step of the process there are difficulties. Problems
begin with the characterization of waste material. Chemical analysis is the basis
for further processing, but the complexity and heterogeneity of the material, the whole process
considerably more complex. Those are examples of processing methods and
pyrometallurgic and hydrometallurgical. WEEE is in practice used in
pyrometallurgical methods as part of such charge. copper production, but at
hydrometallurgical methods, it is more a study in laboratory scale, which
putting into practice a few steps missing.
Keywords: WEEE, pyrometallurgic and hydrometallurgical processing
1. Introduction
Electrical and electronic equipment (EEE) are an integral part of our
everyday life. Their technological side is increasing, as reflected in
improving people's lives. On the other hand, say that each device once
complete their life cycle and it becomes redundant or thing. waste.
Recently gradually abandons the constant repair of EEE, which
in the past had great representation, but now applies rapid variation
equipment. It is the result of several factors, such as raising
population's purchasing power, lack of repair, comfort people, or need
possess the latest technology.
In the constantly and rapidly developing new technologies and grow naturally
number of devices on the market. If added to the already mentioned factors from
population, resulting in the increasing amount of discarded equipment, which
accumulate. Waste electrical and electronic equipment is a phenomenon of the last
period (approx. 20 years) and therefore the accumulation is also due to absenteeism
technologies that this kind of waste is managed efficiently process.
For this waste, we must look from a slightly different point of view and not as
waste (unnecessary thing), but as a secondary raw material, which hides
material potential. This secondary material provides us with interesting content
metals (0.1% Au, 0.2% Ag, 20% Cu, 4% Sn), but also substances which may have
hazardous nature (heavy non-ferrous metals, plastics), but the most significant reason
processing is its quantity. In the European Union created a year from 6.5 to 7.5 million.
tonnes of waste. The quantity of waste is growing compared with other wastes
three times faster [1-3].
The European Union adopted Directive 2002/96/EC, which deals with
WEEE. This Directive aims at waste prevention, re-use
and recycling and other forms of exploitation, leading to a reduction in the amount of WEEE
going to landfill. Also divided into ten categories of WEEE. Slovak
Republic implemented the Directive into their own legislation, Law 733/2004
Code, which amended the Act on Waste No. 223/2001 Coll in the seventh section [4].
For these reasons, it should be reasonable and the economic
secondary raw material processed. The concept of process in itself involves many steps. To
beginning the process of entering secondary material and end processing should be
components, for example. metals, which can be used again to manufacture a product, either
sector which came out or in another sector.
2. Material characteristics of WEEE
WEEE processing is very demanding process, which results from the very nature
this waste. In search of technology must begin with characterizing the input
materials. Careful chemical analysis forms the basis for its further processing
and the methods used, but this secondary material is characterized by complexity
and high heterogeneity, which complicates the whole process. The most commonly reported composition
WEEE:
· 40% metals: Cu 20%, 8% Fe, 4% Sn, 2% Ni, 2% Pb, 2% Al, 1% Zn, 0.2%
Ag, 0.1% Au, 0.005% Pd
Of 30% of plastics: polyethylene, polypropylene, polyester
Of 30% of ceramics: 15% SiO2, 6% Al2O3, 9% other oxides [5]
This division is very rough and not individually. Each category of WEEE
obviously has its own composition, but also within one category, the composition can not
identify clearly, rather a range of values in which it is a category
moves. As an example of complexity in Tab. 1 of the composition of personal
computer. It should be noted that this composition does not apply to any computer and that the
composition varies depending on the type, manufacturer, year of manufacture etc.
Tab. The chemical composition of a personal computer [6]
Component Index
[%]
Component Index
[%]
Component Index
[%]
Component Index
[%]
Plastics 22.99
Nickel 0.85
Titanium 0.0157
Cadmium 0.0094
Lead 6.29
Zinc 2.20
Selenium 0.0016
ruthenium 0.0016
Aluminium 14.17
Tantalum 0.0157
Cobalt 0.0157
Niobium 0.0002
Germanium 0.0016
Indium 0.0016
Palladium 0.0003
Yttrium 0.0002
Gallium 0.0013
Vanadium 0.0002
Magnesium 0.0315
Rhodium <0
Iron 20.47
Terbium <0
Silver 0.0169
Platinum <0
Tin 1.01
Antimony 0.0094
Beryllium 0.0157
Mercury 0.0022
Copper 6.93
Gold 0.0016
Bismuth 0.0063
Arsenic 0.0013
Barium 0.0315
Europium 0.0002
Chromium 0.0063
Silicon 24.88
3. Processing methods
WEEE processing methods can generally be divided into pyrometallurgic,
hydrometallurgical or a combination. This preceded by methods
physical pretreatment, which is usually to reduce the size of the input
material, the release of the desired components and concentration of metals.
1.3 Pyrometallurgic method
Pyrometallurgical methods in the treatment of WEEE, such waste may
melt in the plasma furnace, electric arc furnaces, shaft furnace or other
smelting facilities used in the manufacture of copper or lead. Noble metals
in the pyrometallurgical production of copper anode slimes derived from emerging
in the electrolytic refining of anode copper and lead in the pyrometallurgical
refining. Of oxides of WEEE in the pyrometallurgical processing
dissolve in the slag and plastics are burned. Despite the high efficiency of obtaining
precious metals in the pyrometallurgical processing of WEEE, the problems
arise in the processing can be summarized as follows:
· Plastics contained in the electronic components are a source of
air pollution
· The presence of chlorine in plastics can lead to losses in precious metals
form of their chlorides
· Oxides of ceramic parts for electronic components increase the amount of
debris and hence the absolute loss of metals [7]
In Tab. 2 are listed companies in their production processes
use of e-waste as a starting material.
Tab. 2 companies using e-waste as a starting material [8]
Copper ore company [%] Copper waste [%] E-waste [%]
Boliden 70 15 15
Noranda 85 13 2
Union Miniere 0 92.8 7.2
Norddeutsche Affinerie 72.86 27 0.14
2.3 Hydrometallurgical methods
Hydrometallurgical processing is based on suitable treatment entry
waste and their subsequent leaching suitable leaching agent. It is elected
so as to maximize the yield of the desired metal or metal and they are
minimize the dissolution of other undesirable elements. After separation of liquid
and solid phase extraction method treats leachate metals or compounds
from solution [9]. Among the advantages of hydrometallurgical methods compared
pyrometallurgical include:
• here the processing of materials with both low and high
studied metals
Term process taking place at low temperatures
° Range, a higher yield than pyrometallurgical methods
· Lower operating costs and energy consumption [9]
In Tab. 3 are some examples of hydrometallurgical processing
electronic waste.
Tab. 3 Hydrometallurgic method of processing electronic waste [1]
Main process obtained metal processing product
Au (100%), Ni Leaching Aqua Regia Au
Au Au Leaching thiourea complex
Cu, Ag, Au aqueous NaOH Leaching of Cu, Ag, Au
Au (97%) Biolúhovanie in solution with Fe 3 + Au
Au Leaching of CuCl2, NaCl or HCl with HBr Au, metals solution
Pd, Ag (99.5%) Leaching in HNO3, precipitation with KCNS AgCNS, Pd (CNS) 2
Au (95%) Extraction of Cu carrier in 45 to 50% HNO3 Au
Ag, Cu, Zn Leaching solution of FeCl3 in Au, Ag fungus
4. Conclusion
The issue of waste electrical and electronic equipment is still
debated. This is a very broad issue, with many of the
waste is significantly increased. Reasonable and economic should be their
processing and recycling. This requires to know the material, which we
deal with a technology that can be used.
There are several barriers to increasing recycling rates and to:
complexity of the material heterogeneity and low concentrations of elements. But however WEEE
also contains substances that may be hazardous in nature (heavy metals, plastics), but
contains interesting elements such as precious metals (gold, silver) and other non-ferrous
metals (copper, tin), but it's also the quantity that is increasing and it is therefore necessary to
deal with the secondary material and technology to find its processing.
5. Thanks
This work was within the project VEGA 1/2643/05 and APVV-20-
013405.
6. References
1. Krištofová D.: Selected hydrometallurgical Technologies for recycling of
Electronic Waste, Acta Metallurgica Slovaca, 4, Special Issue 1 / 1998, 132-133
2. Steinmann, H. Stopp der E-Schrott-Flut, Umweltschutz, 2000, 12
3. EU-Richtlinie: Kampf den Müllbergen A3 Umwelt, 14, 2001, 1 / 2, str. 66-67
4. Project collection of WEEE [cited 20/02 2007] Available at <http://www.
elektrorecycling.sk / oeez.htm>
5. Decomposition and utilization earn. domotechniky, Techn. Weekly, 2000, 25, 8-9.
6. Exporting Harm [cited 10/18 2005] Available at <http://ban.org/E-waste
/ Technotrashfinalcomp.pdf>
7. Imriš I. et al.: Electronic scrap - a source of precious metals, Metallurgy East -
West '97, 1997, from 191 to 196
8. Berglund, C.: End of life treatment of materials content requirements for
electronics, Stockholm, 2001
9. Krištofová, D.: Metals and the Environment, Environmentally hazardous components
WEEE, Ostrava, 2005, p. 7-18
