Proceeding new eu legislation _weee_ compliant recovery pr…

New EU Legislation (WEEE) Compliant Recovery Processes
Roland Martin, Brigitte Simon-Hettich, Werner Becker
MERCK KGaA, Frankfurter Strasse 250, D-64293 Darmstadt, Germany ABSTRACT
used for LCDs have a thickness of 0.4 to 1.1 mm. Liquid Crystals are used as mixtures typically Sustainability from synthesis to final disposal of containing up to 25 single compounds, sometimes products will become essential in future. Due to even more. The mixtures are composed of chemi- considerable annual LCD growth rates their waste cally quite similar compounds some of which only will increase, too. Although being not hazardous, differ in their alkyl or alkoxy side chains by varying new legislations in Europe (‘WEEE’ directive) and numbers of carbon atoms (so-called homologous Japan (‘Recycle Law’) require LCD reuse, recyc- compounds). The quantity of LCs in LCDs now- ling or recovery. Merck presents two economical and ecological recovery processes. In incinerators Over 95% of the laptop computer, notebooks and metallurgy processes LCDs substitute used and monitors use a backlight unit some consisting raw materials with recovery rates of almost 100%, of gas discharge lamps still containing mercury. an example for Product Stewardship and Respon- Calculations (1) show that the content of LCs in an LCD with areas ≥ 100 cm2 is ≤ 0,1 %, and in relation to an LCD module or even to an electronic INTRODUCTION
device fare below 0,1%. As an example a Laptop with a 15-inch screen and a weight of 2.5 to 1,5 kg Although most of the LCD applications, in parti- cular notebook PC, LCD monitors and TV sets are typically long-life products the disposal or recycling LCD PANEL WEIGHT ESTIMATION FOR 2008
at their end of life needs to be considered under new EU directives and an integrated product policy In 2004 about 70 Mio LCD monitors (2) will be (IPP). Hence, in total about 152.000 tons of LCD sold, and their number is expected to increase to panels for the 3 most weight-relevant applications about 130 Mio in the year 2008, representing a will be sold worldwide in the year 2008. Conse- CAGR of about 17 % (comparison for CRT moni- quently, several years later - depending on the tors: 2004: 65 Mio; 2008: 12 Mio). Likewise note- different life times - corresponding amounts of LCD book PCs will increase from 45 Mio in 2004 to 78 waste need to be recycled or to be disposed of, but Mio, in 2008 (CAGR = 15 %) and LCD TVs from 10 no economical and ecological recovery processes Mio in 2004 to 56 Mio in 2008 (CAGR = 54 %). In the same period CRT TVs will increase only mar- ginally from 155 Mio in 2004 to 165 Mio - in 2008 but by no means be replaced completely by LCD DEFINITIONS AND COMPONENTS OF LCDs
TVs, even not in the more distant future. The average area diagonals of LCD monitors, The definition of ‘LCD’ or ‘LCD panel’ describes notebooks and LCD TVs and the corresponding the sandwich composed of the two glass plates weight of the LCD are contained in the table below, with attached polymers (for example polarizers, together with an estimation of the weight of LCDs color filters, optical compensators and protective worldwide in the year 2008. The definition of ‘LCD’ films) and the sealed liquid crystal mixture in or ‘LCD panel’ is given in the next paragraph. A between the two glass plates. This definition does 17-inch LCD with glass of 0.8 mm thickness not include the backlight unit, the printed circuit weights approximately 400 g at an area of appro- board, the cables and the frame. These are part of ximately 139 inch2. From these figures the areas of 15 inch (108 inch2) and 30 inch (385 inch2) LCDs Polarizers are usually composed of polycarbo- were calculated assuming an aspect ratio of 4:3 for nate. Their thickness is typically about 200 nm. 15 inch and 17 inch for the notebook respective The orientation layer consists of a polyimide, which monitor LCDs and of 16:9 for the 30” TV-LCD. is about 30 to 100 nm thick. The ITO–electrode is also about 30 to 80 nm thick and the glass plates followed the national regulations for animal welfare Year 2008
Notebooks
as well as the worldwide acknowledged principles monitors
of ‘Good laboratory practice’ (GLP). The toxicological test methods carried-out at Merck such as the determination of the acute oral toxicity, the assessment of effects on skin and eye and of the bacterial mutagenicity are described in detail in a corresponding brochure (1), as are Since most of the environmental pollutants enter the environment via wastewater, the aquatic compartment is in the focus of eco-toxicological testing. Aquatic organisms used for a first indica- tion of environmental effects of chemicals are i.e. fish, water flea, algae and bacteria. These are exposed to the test compounds dissolved in the test medium and the results are expressed as Fig. 1 LCD panel weight for 3 top applications
median lethal concentration (LC50) or median effect concentration (EC An estimation for sold LCD weight panels in the did not show any adverse effects on water flea (daphnia), algae and bacteria up to the limit of water solubility (4). Factors such as chemical stability, adsorption and SAFETY OF LIQUID CRYSTALS (LCs)
biodegradability influence the concentration and Merck and its Japanese competitors perform toxi- fate of chemicals in the environment. Degradability cological tests (3) with liquid crystals already in the of LCs by bacteria was assessed in ready bio- development stage as precautionary measures degradability tests, which are stringent tests pro- according to the principles of ‘Responsible Care’ viding limited opportunity for biodegradation. and ‘Product Stewardship’. Toxicological testing is Depending on the structure, LCs showed biodegra- part of the product market introduction strategy for Liquid crystals marketed have no acutely toxic Toxicity is the capacity of a chemical to cause or mutagenic properties and are therefore classi- adverse effects, i.e. functional or structural chan- fied as non-hazardous materials according to EU ges, to a living organism. Toxicity is dependent on the dose administered, as already Paracelsus Furthermore, eco-toxicological investigations (1493-1541) found: ‘All substances are poison, revealed that LCs also are not harmful for aquatic only the dose makes that a substance is not a organisms. This is in agreement with the poison’. Toxicological studies are designed to re- statement of the German Federal Environmental veal such hazardous properties and to provide To find possible hazardous properties, acute LEGISLATION AND CLASSIFICATION
toxicity studies, skin and eye irritation studies and bacterial mutagenicity tests were performed with many liquid crystals (1,3). Additionally, information 2002/96/EC on ‘Waste of Electrical and Electronic on skin sensitization, long-term and aquatic toxicity Equipment (WEEE)’ and 2002/95/EC on the (4), biodegradability and bio-accumulation is avail- ‘Restriction of the Use of Hazardous Substances in able for a few LCs. Data from these studies are Electrical and Electronic Equipment (RoHS)’ on used in human health and hazard evaluation, 27th January 2003. The member states have to environmental risk assessment and serve as basis implement the directive into national law by 13th for classification and labelling of the substances. August 2004 and establish a collection system Merck has committed itself to perform toxi- cological tests with liquid crystals already in the development stage as precautionary measures WEEE Directive
according to the principles of ‘Responsible Care’ The purpose of the WEEE directive is the pre- and ‘Product Stewardship’. It is part of our sales vention of electronic and electrical waste and in policy that acutely toxic or mutagenic substances addition, the reuse, recycling and other forms of would not be introduced into the market (6). All recovery of such waste so as to reduce the dis- toxicological studies were preformed according to recent international guidelines (OECD, EU) and For the categories 3 and 4 (IT, telecommunication and consumer equipment) the targets of 75% for ‘Recycling’ means the reprocessing in a pro- recovery and 65% of component, material and duction process of the waste materials for the ori- substances reuse and recycling per appliance ginal or for other purposes. But this excludes ener- have to be achieved by 31st December 2006. gy recovery, which means the use of combustible With respect to LCDs WEEE requires that those of waste as a means of generating energy through a surface > 100 cm2 and all those back-lighted with direct incineration with or without other waste but gas discharge lamps have to be removed from collected electrical and electronic waste. ‘Recovery’ means any of the applicable opera- To fulfil the targets of the WEEE directive of tions provided in Annex IIB of the Directive 75% for recovery and of 65% for reuse and recyc- ling per appliance a recovery is required for LCDs ‘Disposal’ means any of the applicable opera- (7). In the future, at least in Japan and Europe tions provided in Annex IIA of the Directive LCD monitors will have to be recovered or 75/442/EEC (the collection, sorting, transport and treatment of waste as well as its storage and RoHS Directive
In the future at least in Japan, Europe and may The purpose of the RoHS directive is a restric- be in China due to the legislation LCD monitors tion of hazardous substances in electronic and have to be reused, recovered or recycled. There- electrical equipment in order to contribute to the fore a ‘Recycling’ or ‘Recovery’ process is of high protection of human health and the environment. From 1st July 2006 on, new electrical and electro- nic equipment put on the market may not contain lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE). Liquid Crystals mixtures supplied by Merck do not contain any of the substances mentioned in the
RoHS directive in detectable amounts (5).
European Waste Classification
The EU Directive 2000/532/EC of 3rd May 2000 established a harmonized list of waste with code numbers and a definition for hazardous waste with detailed criteria: one or more substances classified as very toxic, carcinogenic or mutagenic at a total concentration of ≥ 0,1 % and classified as terato- Fig. 2 LCD
genic at a total concentration of ≥ 0,5%. LCD with separated glass plates and plastic foils Applying these criteria to LCDs proves that those without the backlight are no hazardous waste Reuse of LCD Modules
according to the EU Directive 2000/532/EC and The reuse of LCD modules is possible as re- can be classified in the European Waste Cata- placement for out of order LCD modules and wide- logue under the waste code number 16 02 16 ly used at least in Third World Countries. In future, (components removed from discarded equipment this will be only a marginal proportion due to the other than hazardous components). This is in rapid development of higher performance LCDs. accordance with the directive of the Association of the German Federal States for Recovery/ Recyc- Evaluation of a Recycling Process for LCs
ling/ Disposal of used electronic devices with tech- An evaluation of a ‘Recycling’ process for reuse nical requirements and a classification for LCDs, of the LCs in LCDs shows no economical benefit. An LC Mixture typically contains up to 25 or more components. Theoretically, reclaiming the LC REUSE, RECYCLING & RECOVERY
mixtures from waste LCDs would yield a mixture containing a huge variety of LCs from all LC pro- Basic considerations
ducers. For reuse, LCs have to be extremely pure To fulfil the targets of the WEEE directive of (´electronic grade´). Therefore, this reclaimed mix- 75% for recovery and 65% for reuse and recycling ture of in the worst case up to about 500 different per appliance a recovery is required for LCDs. In LCs would have to be separated into the single future the ratio between LCD and LCD module or components and be purified afterwards. The costs Laptop PC will increase due to the reduced weight for quantitative separation and purification are higher than those for newly synthesized LCs, not considering the complex patent situation.
LCD Recovery Process: Incineration
At the high temperatures during the incineration (see Figure 3) of aggressive and hazardous in-dustrial waste the wall of the incinerator will be corroded soon. Additives containing silica are widely used to generate a thin silica layer to pro-tect the wall. Many trials in practice have shown that LCDs can be used as a substitute for silica containing materials. In addition, the plastic foils of the LCDs are used during the incineration process to produce heat energy. A calculation demonstrates that the
Fig. 4 Metallurgy Process
energy of the plastic foils is sufficient to melt the Due to the substitution of the raw material by FINAL REMARKS
LCD glass and heat generation from the LCD plas- tic foils this process is considered a ‘Recovery Pro- Merck KGaA is a member of the Responsible Care cess’ with a recovery rate of approximately 99%. Initiative of the Chemical Industry in Europe and feels responsible for its products and the environ-ment from the development until the final recycling, recovery or disposal. Therefore, apart from the intensive toxicological and eco-toxicological testing carried-out by Merck for numerous liquid crystals (1,3) and the self-commitment not to introduce acutely toxic or mutagenic substances into the market (5) Merck has engaged itself into this subject of LCD recycling resp. recovery. This is particularly remarkable since liquid crystals repre-sent only a minor quantity and cost share of the Fig. 3 Incineration Process

LCD Recovery Process: Metallurgy Processes
REFERENCES
Some metallurgy processes (see Figure 4) for [1] Merck brochure ‘Toxicological and Ecotoxico- the production or purification of metals with high logical Investigations of Liquid Crystals’, Sept. temperatures are using melting sand in order to separate the noble metals from the base metals. [2] Merck Internal Data Base ‘MIDAS’, status Q3, To avoid the formation of metal oxides, reduction 2004 and The DisplaySearch Monitor, June to agents - like carbon containing products - have to [3] H. Takatsu et al. ‘Investigation Activity and Many trials in practice have shown that the Data on Safety of Liquid Crystal Materials’, Mol. glass of LCDs can be used as a substitute for the Cryst. and Liq.Cryst., Vol.364, pp.171-186 melting sand or Silica containing materials and the plastic foil of the LCDs can be used as a substitute [4] B. Simon-Hettich et al., ‘Ecotoxicological pro- perties of LC compounds’, Journal of the SID, [5] Merck KGaA Statement under www.merck.de / considered a ‘Recovery Process’ with a recovery liquid crystals & display materials / safety [6] www.umweltbundesamt.de/uba-info-daten- [7] R. Martin et al., ‘Safety of Liquid Crystals and Recycling of Liquid Crystal Displays’, Procee-dings Displays and Vacuum Electronics, pp. 139-142, May 3-4 (2004)

Source: http://www.ecotic.ro/uploads/original/44ae9b13c8690c85315fa88cd9bc39f438b52a1e.pdf