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Recycling Potential of Rare Earth Elements and Cobalt in WEEE-Batteries

Diploma Thesis 2013 135 Pages

Engineering - Industrial Engineering and Management

Excerpt

Table of contents

Kurzfassung

Abstract

List of figures

List of tables

List of appendices

List of abbreviations

1. Introduction
1.1. Preface
1.2. Objectives

2. Background information
2.1. Rare earth elements
2.2. Cobalt
2.3. WEEE-batteries
2.4. Nickel cadmium batteries
2.5. Nickel metal hydride batteries
2.6. Lithium-ion batteries

3. Materials and methods
3.1. System boundaries
3.2. Calculation model
3.3. Data acquisition
3.4. Data estimation and uncertainties
3.5. Theoretical recycling potential
3.5.1. Material composites
3.5.2. Battery systems
3.5.3. Battery mass fraction
3.5.4. WEEE generation
3.6. Recycling path
3.6.1. WEEE collection
3.6.2. WEEE treatment
3.6.3. Battery sorting
3.6.4. Battery recycling

4. Results
4.1. Theoretical recycling potential
4.1.1. Theoretical recycling potential of rare earth elements
4.1.2. Theoretical recycling potential of cobalt
4.2. Recovered amounts
4.2.1. Recovered amounts of rare earth elements
4.2.2. Recovered amounts of cobalt

5. Discussion
5.1. Qualifying the research results
5.2. System analysis
5.3. Recommendations
5.4. Future developments of the Li-ion battery market

6. Conclusion and outlook

References XCV

Appendix CXIII

Kurzfassung

Die stetig wachsende weltweite Nachfrage nach Seltenen Erdelementen (SEE) und Kobalt sowie die diesbezüglich aktive chinesische Exportpolitik haben zu einer erhöhten Aufmerksamkeit gegenüber einem Recycling dieser Metalle geführt. Die Wichtigkeit von SEE und Kobalt für die europäische Wirtschaft wurde durch die Klassifizierung dieser Metalle als kritische Rohstoffe für die Europäische Union in einem von der Europäischen Kommission beauftragten Expertengutachten weiter betont. Während SEE als besonders anfällig gegenüber Angebotsrisiken eingeschätzt werden, wird Kobalt als wirtschaftlich bedeutsamer beurteilt. 2010 machte die Batterieproduktion einen Anteil von 8 Prozent des weltweiten SEE-Verbrauchs und 27 Prozent des weltweiten Kobaltverbrauchs aus. Eine Rückgewinnung von SEE und Kobalt aus Batterien könnte also deutlich zu einer Reduzierung der Angebotsrisiken und einer Preisstabilisierung beitragen. Der Verbrauch von SEE in der Batterieherstellung lässt sich ausschließlich auf Nickel-Metallhydrid-Akkumulatoren (NiMH) zurückführen, die zu etwa 10 Prozent SEE beinhalten. Der Kobaltverbrauch geht hauptsächlich auf den Anteil von circa 14 Prozent in kobaltbasierten Lithium-Ionen-Akkumulatoren (Li-Ion) zurück. In kleineren Anteilen enthalten auch Nickel-Cadmium (NiCd) und NiMH-Akkumulatoren sowie auf Nickel-Mangan-Kobaltoxid und Nickel-Kobalt-Aluminiumoxid basierende Li-Ion-Batterien Kobalt. Da die meisten Li-Ion- und NiCd- sowie viele NiMH-Batterien mit den Geräten entsorgt werden in denen sie als Energiequelle genutzt wurden, enthalten Elektro- und Elektronikaltgeräte (EAG) ein beträchtliches Potential an SEE und Kobalt.

In der vorliegenden Diplomarbeit wird die Bedeutung von SEE und Kobalt für Batterien aus EAG untersucht und das theoretische Recyclingpotential sowie die tatsächlich zurückgewonnene Menge dieser Metalle aus EAG-Batterien quantifiziert. Dabei stützt sich die Untersuchung in erster Linie auf EAG ausgewählter Gerätearten die im Jahr 2011 in privaten Haushalten angefallen sind. Die für das im Rahmen dieser Arbeit entwickelte Berechnungsmodell benötigten Daten wurden durch Literatur- und Marktrecherche, Anlagenbesuche, Experteninterviews und praktische Untersuchungen ermittelt. Die Ergebnisse zeigen, dass von 41,7 ± 7,2 Tonnen SEE in EAG-Batterien aus privaten Haushalten derzeit keine SEE im Sinne eines funktionellen Recyclings zurückgewonnen werden. Von den 364,3 ± 63,7 Tonnen Kobalt in EAG-Batterien aus privaten Haushalten werden 47,8 ± 13,7 Tonnen separat zurückgewonnen. Als eine hauptsächliche Ursache für die niedrigen Rückgewinnungsquoten wurde die niedrige Sammelrate von batteriebetriebenen EAG ausgemacht. Um die dem Recycling zur Verfügung stehende Menge von EAG-Batterien zu erhöhen, sollte das bestehende EAG-Bringsystem durch ein Holsystem ersetzt und die Menge von illegal ausgeführten EAG durch flankierende Maßnahmen reduziert werden. Außerdem sollten die derzeit mengenbasierten Recyclingquoten von Batterien und EAG im Hinblick auf kritische Rohstoffe überarbeitet werden. Obwohl Recyclingtechnologien existieren, die eine separate Rückgewinnung von SEE und Kobalt aus Batterien erlauben, werden sie aus Gründen mangelnder Wirtschaftlichkeit in vielen Fällen nicht in industriellem Maßstab umgesetzt. Eine Untersuchung der aktuellen Marktentwicklung von in Elektro- und Elektronikgeräten eingesetzten Batterien ergab, dass NiCd- und NiMH-Batterien in zunehmendem Maße von Li-Ion-Batterien ersetzt werden. Gleichzeitig wird das bisher dominierende kobaltbasierte Li-Ion System von kobaltreduzierten und ‑freien Batteriesystemen abgelöst. Da auf Batterien derzeit nur das chemische Hauptsystem angegeben wird und recycelnde Betriebe große Schwierigkeiten haben, das chemische Subsystem zu bestimmen, sollten Batteriehersteller dazu verpflichtet werden, das chemische Subsystem auf der Batterie zu markieren.

Abstract

The continuously growing world demand of rare earth elements (REE) and cobalt and the active Chinese export policy regarding these materials led to an increased interest in REE and cobalt recycling in recent years. The importance of REE and cobalt to the European economy was further emphasized in 2010 when an expert group chaired by the European Commission classified REE and cobalt as critical raw materials for the European Union. While REE were characterized as most exposed to supply risk, cobalt was classified as being of greater economic importance. In 2010, battery production accounted for a share of 8 per cent of worldwide REE consumption and 27 per cent of worldwide cobalt consumption, showing that a recovery of secondary REE and cobalt from batteries could contribute significantly towards confining supply risks and stabilizing prices. The REE consumption in the battery industry is solely due to the application of REE in nickel metal hydride (NiMH) batteries, which contain approximately 10 per cent REE. Lithium-ion (Li-ion) batteries based on lithium cobalt oxide (LiCoO2, LCO), which contain circa 14 per cent cobalt, account for the majority of cobalt consumption. Minor amounts of cobalt are also contained in nickel cadmium (NiCd) and NiMH batteries as well as in Li-ion batteries based on lithium nickel manganese cobalt oxide (NMC) and lithium nickel cobalt aluminium oxide (NCA). Since the majority of Li-ion and NiCd batteries and a large amount of NiMH batteries is disposed of along with the devices they were employed in as energy sources, a huge potential of REE and cobalt is inherent in waste electrical and electronic equipment (WEEE).

This thesis inquires about the role of REE and cobalt in WEEE-batteries and assesses the total contained quantities and the actual recovered quantities of REE and cobalt contained in WEEE-batteries. Thereby, the investigation focused on WEEE-batteries of a group of selected equipment types which did arise as waste from the German consumer sector in 2011. For the investigation, a calculation model was developed and furnished by data acquired through literature and market research, plant visits, expert interviews and experimental surveys. The results show that from a theoretical recycling potential of 41.7 ± 7.2 tons of REE in WEEE-batteries, no REE are currently recovered in the sense of a functional recycling. Of the 364.3 ± 63.7 tons of cobalt contained in WEEE-batteries, only 47.8 ± 13.7 tons were separately recovered. The low collection rate of battery powered WEEE was identified as a main causal factor. To increase the collected amount of WEEE-batteries, a kerbside collection system complemented with measures to decrease illegal WEEE exports should be realised and current quantity based recovery quotas should be amended with regard to critical materials. Regarding recycling processes that allow for a separate REE and cobalt recovery, it was found that technologies exist but are often not implemented due to insufficient economic feasibility. Research on the market trends of batteries built-in electrical and electronic equipment (EEE) showed that NiCd and NiMH batteries are increasingly superseded by Li-ion batteries. At the same time the previously dominant cobalt based LCO system is replaced by cobalt‑free and ‑reduced Li-ion battery systems. Since only the main chemical system is labelled on Li-ion batteries at present and recyclers face considerable efforts to identify and separate Li-ion batteries into chemical subsystems, battery manufacturers should be compelled to mark the chemical subsystem on the battery casing.

List of figures

Figure 1: Recycling path of REE and cobalt in EEE-batteries

Figure 2: REO consumption and waste generation by market sector and REO disposal routes in 2008

Figure 3: Structure of NiCd and NiMH batteries

Figure 4: Structure of Li-ion batteries

Figure 5: Calculation model part I

Figure 6: Calculation model part II

Figure 7: Umicore battery recycling process

Figure 8: RWTH Aachen/Accurec/UVR-FIA recycling process for NiMH batteries

Figure 9: RWTH Aachen/Accurec/UVR-FIA recycling process for Li-ion batteries

Figure 10: Hydrometallurgical recycling process for NiMH batteries

Figure 11: Recycling path and losses of REE

Figure 12: Recycling path and losses of cobalt

Figure 13: Estimation of collected spent Li-ion batteries in the EU

List of tables

Table 1: Rare earth oxide prices in 2010

Table 2: Characteristics of rare earth elements

Table 3: Cobalt applications

Table 4: Specifications of general purpose primary batteries

Table 5: Specifications of button cell primary batteries

Table 6: Specifications of secondary batteries

Table 7: Equipment types analysed in this work

Table 8: Data sets and data indicators used in the calculation

Table 9: Methods used for data acquisition

Table 10: Material composition of NiCd, NiMH (AB5) and Li-ion (LCO) batteries [wt.-%]

Table 11: Average REE and cobalt content in batteries [wt.-%]

Table 12: Market share of Li-ion battery types placed on the market in 2011 [%]

Table 13: Share of battery systems applied in WEEE in Germany in 2011 [%]

Table 14: Battery mass fraction of equipment types [wt.-%]

Table 15: Average total lifetime

Table 16: Average unit weight [g]

Table 17: Estimated WEEE generation in Germany in 2011

Table 18: Amounts of EEE placed on the market and WEEE collected in 2011 (only B2C)

Table 19: Amount of WEEE collected as percentage of WEEE arising in the EU27 in 2005

Table 20: Estimated collection rate [wt.-%]

Table 21: Estimated separation rate of WEEE-batteries [wt.-%]

Table 22: Status quo recovery of single elements from waste batteries

Table 23: Comparison of pyro- and hydrometallurgical metal recovery processes

Table 24: Recycling rates and final products of LCO batteries in the Val’Eas process

Table 25: REE content in WEEE-batteries in Germany in 2011 [t]

Table 26: Cobalt content in WEEE-batteries in Germany in 2011 [t]

Table 27: Recovered amounts of REE in Germany in 2011 [t]

Table 28: Recovered amounts of cobalt in Germany in 2011 [t]

Table 29: REE content in EEE-batteries sold in Germany in 2011 [t]

Table 30: Cobalt content in EEE-batteries sold in Germany in 2011 [t]

List of appendices

Appendix 1: WEEE categories, equipment groups and collection groups in the EAR system

Appendix 2: Material composition of general purpose primary batteries [wt.-%]

Appendix 3: Material composition of button cell primary batteries [wt.-%]

Appendix 4: Material composition of selected secondary batteries [wt.-%]

Appendix 5: Components of NiMH batteries [wt.-%]

Appendix 6: Components of LCO batteries [wt.-%]

Appendix 7: Research on material composition of NiCd batteries [wt.-%]

Appendix 8: Research on material composition of NiMH batteries I [wt.-%]

Appendix 9: Research on material composition of NiMH batteries II [wt.-%]

Appendix 10: Research on material composition of NiMH batteries III [wt.-%]

Appendix 11: Research on material composition of NiMH batteries IV [wt.-%]

Appendix 12: Research on material composition of Li-ion batteries I [wt.-%]

Appendix 13: Research on material composition of Li-ion batteries II [wt.-%]

Appendix 14: Research on material composition of Li-ion batteries III [wt.-%]

Appendix 15: Survey on battery systems applied in EEE

Appendix 16: Share of battery systems applied in EEE sold in Germany in 2011 [%]

Appendix 17: Sales of EEE to consumer market in Germany [1,000 pcs]

Appendix 18: Battery sorting facilities in Germany

Appendix 19: Battery recycling companies (non-lead acid)

Appendix 20: Literature review on NiCd, NiMH and Li-ion battery recycling methods I

Appendix 21: Literature review on NiCd, NiMH and Li-ion battery recycling methods II

Appendix 22: Literature review on NiCd, NiMH and Li-ion battery recycling methods III

Appendix 23: Literature review on NiCd, NiMH and Li-ion battery recycling methods IV

Appendix 24: Literature review on NiCd, NiMH and Li-ion battery recycling methods V

Appendix 25: Literature review on NiCd, NiMH and Li-ion battery recycling methods VI

List of abbreviations

List of chemical symbols and formulas

Abbildung in dieser Leseprobe nicht enthalten

List of other abbreviations

Abbildung in dieser Leseprobe nicht enthalten

1. Introduction

1.1. Preface

Following the events at the end of the last decade, several economic, political and ecological issues led to an increased interest in the recycling of rare earth elements. Namely, shortages of REE on the world market due to an active Chinese export policy, including taxes, export quotas, a ban of new mining licenses until 2015 and the closing of minor mining operations, caused prices to skyrocket in 2010 (Schüler et al., 2011). This was intensified by a growing world demand, particularly for neodymium used in high-strength permanent magnets (BGS, 2012). The current supply shortage of REE on the world market is expected to continue for some elements (e.g. neodymium, lanthanum, dysprosium) and to abate for others (e.g. cerium) due to market trends in rare earth employing technologies and the (re-)opening of mining and production sites, e.g. in Mountain Pass, California or Mount Weld, Australia (EC, 2010b).

Besides REE, an expert group chaired by the European Commission defined cobalt as critical raw material for the European Union. While REE were characterized as most exposed to supply risk, cobalt was classified as being of greater economic importance (EC, 2010a). The exposure to supply risk originates from a concentration of cobalt mining and refining activities (cf. chapter 2.2) and the limited possibility of a substitution of cobalt (EC, 2010a).

In addition to REE and cobalt, graphite (in this work often addressed with its element name carbon) is listed as critical metal by the expert group of the European Commission. Although graphite reserves are abundant, production is dominated by China with Europe only having minor reserves (EC, 2010b). Of 1,120,000 t world mine production of graphite in 2008 circa 4 per cent relate to a use in the battery industry. A recycling of graphite is technically feasible in some cases, but generally not practised due to low prices on the world market (USGS, 2012c). Its burning characteristic to react with oxygen to carbon dioxide and thus being lost in pure form poses a further issue. Consequently, graphite recycling from batteries is not being discussed in more detail in this work. Other metals contained in batteries, such as aluminium, cadmium, copper or lithium, were not classified as critical metals by the expert group and their recycling is thus not investigated extensively in this study. For most of these metals a recycling is already in place (cf. table 22). In the case of lithium, significant research has been carried out on recycling methods (cf. appendix 20 – 25, (LiBRi, 2011), (LithoRec, 2011)) and a realisation in industrial scale seems to be merely inhibited by current low lithium prices on the world market.

In 2010, battery production accounted for a share of 8 per cent of worldwide REE consumption and a share of 27 per cent of worldwide cobalt consumption (EC, 2010b). The REE consumption in the battery industry is solely due to the application of REE in NiMH batteries which contain on average 10 per cent REE. NiMH batteries are the current standard rechargeable batteries on the retail market and are widely used in small battery powered household appliances. The cobalt consumption is largely caused by the application of cobalt in Li-ion batteries employing lithium cobalt dioxide as active material, since this battery system employs on average 14 per cent cobalt. Historically, Li-ion batteries based on lithium cobalt dioxide were the most widespread type of Li-ion batteries but are currently superseded by other Li-based battery systems employing less or no cobalt. Lithium cobalt dioxide batteries are mostly used to power EEE, especially energy intense IT and consumer electronics. Besides Li-ion batteries based on lithium cobalt dioxide, some other Li-based battery systems as well as NiMH and NiCd batteries apply small amounts of cobalt in their electrode material (cf. chapter 3.5.1). In addition to the growing market of battery powered EEE, the increasing number of electric bicycles and automobiles is contributing towards a rising demand of NiMH and more so Li-ion batteries.

This data shows that battery recycling with regard to REE and cobalt recovery could contribute significantly towards closing the raw material cycle for these elements. Whereas the recovery of iron, nickel, manganese, zinc and lead from spent batteries is a common standard, recycling processes for the recovery of REE and cobalt has just lately been implemented. Academic literature on the topic of REE and cobalt recovery from spent batteries is comparatively abundant (cf. appendix 20 – 25) but few approaches have been tested on a pilot plant scale and a transfer to industrial size is often curbed by an insufficient economic feasibility.

1.2. Objectives

The aim of this diploma thesis is to describe the role of REE and cobalt in batteries from electrical and electronic equipment, to assess the theoretical recycling potential of REE and cobalt and to depict the current recycling situation of REE and cobalt from WEEE-batteries in Germany. In addition, possible recycling processes of WEEE-batteries which include the recovery of REE and cobalt shall be presented. The theoretical recycling potential represents the total amount of REE and cobalt contained in batteries of WEEE which is accruing in one year.

In order to define the scope of these aims, the following objectives were formulated:

1. Qualitative description of the application of REE and cobalt in WEEE-batteries

2. Quantification of the theoretical recycling potential of REE and cobalt in WEEE-batteries arising in Germany based on quantifications of the:

a. REE and cobalt content in batteries
b. application of battery systems in WEEE
c. battery mass fraction of WEEE
d. WEEE generation

3. Qualitative description of the recycling path of REE and cobalt in WEEE-batteries, including:

a. WEEE collection
b. battery separation
c. battery sorting
d. battery recycling

4. Qualitative description of possible battery recycling processes which recover REE and cobalt

5. Quantification of the actual amount of recovered REE and cobalt from WEEE-batteries in Germany based on quantifications of the:

a. WEEE collection rate
b. battery separation rate
c. battery sorting rate
d. recovery rate of REE and cobalt

The work is mainly drawing on data gained through literature review, market evaluation, plant visits and interviews.

Source: Author’s illustration

Abbildung in dieser Leseprobe nicht enthalten

Figure 1: Recycling path of REE and cobalt in EEE-batteries

The flow chart in figure 1 above depicts the way of primary and secondary REE and cobalt as constituting elements in EEE- and WEEE-batteries and illustrates the steps along the recycling path of REE and cobalt that are incorporated in the present work. The first part of the REE and cobalt life cycle begins with the use of REE and cobalt as raw materials for battery production and continues with the application of batteries in EEE, the use of EEE by consumers and the subsequent arising of end of life EEE as WEEE. The second part of the REE and cobalt life cycle includes the collection of WEEE in official collection systems, the separation of WEEE-batteries during WEEE treatment, their subsequent sorting into battery systems and in a final step the recovery of REE and cobalt from WEEE-batteries. During all these steps along the recycling path, losses of REE and cobalt occur and reduce the amount of REE and cobalt which can be used as secondary raw material in the industry.

As a background, information on the characteristics of REE and cobalt as well as an overview of battery systems employed in EEE is given in chapter 2. Due to their relevance concerning REE and cobalt, NiCd, NiMH and Li-ion batteries are investigated in more detail. In the first part of chapter 3, the boundaries related to the quantification are specified, e.g. regarding the disambiguation of used terms or the scope of investigated equipment types. Following, the calculation model chosen to quantify the theoretical and actual recoverable amounts of REE and cobalt is presented. The calculation model is consisting of two parts, the calculation of the theoretical recycling potential of REE and cobalt and the calculation of the actual recovered amounts of REE and cobalt. In the two adjacent parts, the methods used for data acquisition and the procedure regarding data estimation and uncertainties are laid out. Chapter 3.5 and 3.6 contain the necessary data for conducting the calculation of the theoretical recycling potential and the actual recovered amounts of REE and cobalt in WEEE-batteries. Chapter 3.5 consists of the quantification of the average REE and cobalt content in batteries, the average application of battery systems in WEEE, the average battery mass fraction of WEEE and the WEEE generation in Germany in 2011. In chapter 3.6, the recycling path of WEEE-batteries is described, including the collection of WEEE, the separation of WEEE-batteries, the sorting of the batteries and the subsequent battery recycling. For each step along the recycling path, the related process efficiencies are quantified. In chapter 3.6.4 are possible recycling processes for NiMH and Li-ion batteries described, which would allow for a recovery of REE and cobalt. The results of the calculation of the theoretical recycling potential and the actual recovered amounts of REE and cobalt in WEEE-batteries are presented in chapter 4. In the first part of the following chapter 5, the results are analysed and compared to findings of other studies. Subsequently, the various steps along the recycling path are shortly discussed, problems are pointed out and recommendations to increase the amount of recovered REE and cobalt are given. Due to the rapid technology developments concerning Li-ion batteries and their crucial role regarding the recycling potential of cobalt in WEEE-batteries, the expected future developments of the Li-ion battery market are outlined. At this point, a quantification of the REE and cobalt content in batteries applied in EEE sold in 2011 in Germany is undertaken. In the final chapter 6, a conclusion of the present thesis is given and areas requiring further research are formulated.

2. Background information

In this chapter, the necessary background information for this thesis is presented. That includes general information on the investigated critical elements REE and cobalt as well as on the object of investigation, WEEE-batteries. For all types of WEEE-batteries, information on characteristics, application and market prevalence is displayed. Since NiCd, NiMH and Li-ion batteries are of particular importance to this study, they are described in more detail.

1.

2.

2.1. Rare earth elements

“Rare earth elements” is a collective term for the elements scandium, yttrium, lanthanum and the elements following lanthanum in the periodic table, the so called lanthanides. In contrast to their name, REE are not particularly rare to find in the earth’s crust. Though, they seldom appear in concentrations worth mining. In minable concentrations, they occur mostly in the minerals bastnaesite and monazite and can only be mined together. Their production in pure form is very cost-intensive (EC, 2010a). But as especially light rare earth elements (LREE) inhibit similar chemical characteristics, for cost reasons they are often used as a composition of several elements (Erdmann et al., 2011b). This composition is also addressed as mischmetal. A typical mischmetal consists of approximately 50 per cent cerium, 25 per cent lanthanum, 15 per cent neodymium and to a smaller amount of praseodymium and other REE (Gupta & Krishnamurthy, 2007). REE can be classified into light rare earth elements and heavy rare earth elements (HREE), with prices for LREE being expected to decrease in the medium term and prices for HREE being expected to increase in the short term and stay constant in the long term (RolandBerger, 2011). Table 1 gives an estimate of the average price of rare earth oxides (REO) in 2010.

Table 1: Rare earth oxide prices in 2010

Abbildung in dieser Leseprobe nicht enthalten

Source: (USGS, 2012a)

The following table 2 lists characteristics and typical applications of REE. A common application is in the production of high-strength permanent magnets. These are an essential component of wind turbines, disk drives in computers and loudspeakers. A total of 2.5 g of REE (mainly Nd) in notebook magnets has been estimated by Buchert et al. (2012). In electrical and electronic equipment REE are commonly used in the luminescent material in visual display units, such as LCD screens used in laptops and television sets (Buchert et al., 2012). In NiMH batteries they serve as alloying element for the production of hydrogen storage alloys which act as active material in the negative electrode (cf. chapter 2.4).

Table 2: Characteristics of rare earth elements

Abbildung in dieser Leseprobe nicht enthalten

Source: Based on (Liedtke & Elsner, 2009), (Greenpeace, 2011), (Öko-Institut, 2011)

The Production of REE is limited to a few countries, with china being the largest producer. From an estimated 133,000 tons REO world mine production, 130,000 tons have been mined in China in 2011 (USGS, 2012c). At present, there is no significant production of REO in the EU, making the EU highly dependent on imports (BGS, 2012). According to Erdmann et al. (2011a), Germany had a demand of 3,000 tons of REO in 2008, whereas the actual consumption is expected to be considerably higher due to imports of products that contain REE.

So far, only minor quantities of REE have been recycled from old scrap. Graedel et al. (2011) and Erdmann et al. (2011a) estimate the worldwide end of life recycling rate (EOL-RR)[1] at below 1 per cent. The recycled content (RC)[2] for REE is rated between 1 and 10 per cent for some elements (La, Ce, Pr, Nd, Gd, Dy) and below 1 per cent for others (Y, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu) (Graedel et al., 2011). While recycling of REE from luminescent appliances or battery alloys was just initiated lately, REE are recycled since a while from permanent magnet production scrap. Reasons for the low recycling rate are the dispersed application, until recently relatively low prices, the tendency of moving into the slag when pyrometallurgically treated and the high costs and complexity of a hydrometallurgical treatment.

However, since the recent increase in prices a lot of research and development on REE recycling has been done. An overview of a multitude of academic papers dealing with REE recycling is given in appendix 20 – 25. On an industrial scale, there has been only a few recycling activities so far worldwide. Dowa Holdings has built a recycling plant in Kosaka, Japan, which reclaims precious metals such as gold, indium or antimony from WEEE and is trying to develop a recycling process for neodymium from WEEE magnets (Tabuchi, 2010). The recycling from NiMH batteries started recently in Europe with a cooperation of Umicore and Rhodia (Umicore & Rhodia, 2011). A more detailed description is given in chapter 3.6.4. Rhodia also developed recycling processes for the recovery of REE from magnets (i.e. neodymium, praseodymium, dysprosium and terbium) (Rhodia, 2011a) and low-energy light bulbs (Rhodia, 2011b). Rhodia collects the REE concentrates generated at previous recycling steps from its partners and refines these at its two dedicated facilities in La Rochelle and Saint-Fons, France. Both recycling units became operational in the first quarter of 2012. In Japan, JOGMEC’s Metals Mining Technology Group developed a process to extract REE from hybrid electric vehicle batteries, though it has not yet been implemented in industrial scale (JOGMEC, 2010).

As many REE exhibit similar characteristics, a substitution between REE is possible in several cases with only minor performance losses. In many applications, REE can be replaced by other metals, though they are generally less effective (USGS, 2012c). Further information on REE and their recycling can be drawn from Goonan (2011) and Schüler et al. (2011). Figure 2 displays the REO consumption and waste generation per market sector and the disposal routes of REO in 2008. Tables with similar findings can be found in Erdmann et al. (2011b) and RolandBerger (2011).

Figure 2: REO consumption and waste generation by market sector and REO disposal routes in 2008

Source: (Goonan, 2011)

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2.2. Cobalt

Cobalt is a hard, lustrous, brittle metal with a greyish-silvery colour and the atomic number 27. It has ferromagnetic properties and retains its strength at high temperatures, which makes it an important alloying metal for very hard superalloys with useful magnetic characteristics (BGS, 2012). Examples are the production of turbine blades or jet engines. In Li-ion batteries it is commonly used as cathode material in the form of lithium cobalt dioxide. In NiMH and to lesser amounts in NiCd batteries it is added to the nickel hydroxide electrode to increase performance (Rydh & Svärd, 2003) (Zhang et al., 1998a). Besides its use in metal alloys and secondary batteries, cobalt is added to a wide range of chemical compounds and as a pigment to glass, enamels and pottery to give it a distinctive deep blue colour (BGS, 2012).

Table 3: Cobalt applications

Abbildung in dieser Leseprobe nicht enthalten

Source: (Angerer et al., 2009)

In 2010, the world mine production of cobalt was 89,500 tons with the Democratic Republic of Congo being the largest producer of mined cobalt with 53 per cent of the world total (USGS, 2012b). Other major producers of mined cobalt are China, Russia, Zambia and Canada holding together a share of 26 per cent of the world total. The world production of refined cobalt metal increased from 59,700 tons in 2009 to 76,400 tons in 2010 with China being the largest producer with 43 per cent of the world total (USGS, 2012b). According to Erdmann et al. (2011a), the German cobalt demand amounted to 2,604 tons in 2008.

The price of cobalt metal on the world market is highly volatile. The average price (purity min. 99.80 per cent, free market, Rotterdam) of 84.89 US-dollar per kg in 2008 (DERA, 2011) fell to 38.60 US-dollar per kg in 2011 (DERA, 2012).

The worldwide end of life recycling rate for cobalt was stated to lie at around 68 per cent in 2011 (Graedel et al., 2011). In 2009, Ketterer et al. (2009) estimated the worldwide recycling rate for cobalt at 22 per cent. Some years earlier, the recycling rate for Germany was estimated to range between 20 and 25 per cent (BGR, 2007). The recycling rate of cobalt for the U.S. is estimated to be 24 per cent in 2011 (USGS, 2012c). The recycled content is assumed to lie at 32 per cent (Graedel et al., 2011). To date, major sources for the recovery of cobalt are cobalt containing alloys and catalysts (Buchert et al., 2009) and recently Li-ion batteries. Citing the Cobalt Development Institute, Angerer et al. (2009) states that 8 per cent of the cobalt applied in battery alloys in 2003 in the European Union has been recycled. Existing recycling plants for the specific pyrometallurgical recovery of cobalt from spent batteries already reach recovery rates of over 95 per cent (Wendl, 2009). Academic research has examined the possibility of recovering cobalt along with cadmium and nickel from NiCd batteries, but as cobalt forms only a minor constituent, cobalt yields were comparatively low (Nogueira & Delmas, 1999), (Reddy & Priya, 2006).

2.3. WEEE-batteries

Batteries are devices to provide electrical energy by converting previously stored chemical energy. They consist of one or more electrochemical cells which can be classified into two main types: primary cells and secondary cells. Primary cells, also called primary batteries, are designed to be used only once and subsequently be discarded. Secondary cells, or secondary batteries, are rechargeable batteries to be used several times. Their electrochemical system allows a reversion of the chemical reactions by inducing an electric current into the cell.

WEEE-batteries are batteries contained in waste electrical and electronic equipment and are classified as waste batteries according to Directive 2006/66/EC (Batt.Dir., 2006). WEEE-batteries are portable batteries (DE: Gerätebatterien; cf. (BattG, 2009)). Portable batteries are batteries that can be carried in one hand and are sealed (Batt.Dir., 2006). This excludes industrial and vehicle batteries. WEEE-batteries can be grouped into two types, one being standardized retail batteries that are designed to be replaced by the customer. These batteries are in most cases primary batteries. Examples for this type are alkaline or NiMH round cell general purpose batteries in clocks, flashlights or radio sets. The other being WEEE-batteries specially designed for the device. While the single battery cell may be of a standardized industrial size, the battery pack is custom build, fitting only to a particular product line. Contrary to the first type, they occur in a wide range of sizes and can be relatively large. With the exception of button cells, the second type is generally rechargeable and made to be loaded with special charging equipment. Devices employing this type are for example power tools, portable PCs or mobile phones.

Rechargeable WEEE-batteries can be divided according to their chemical system into NiCd, NiMH and Li-ion batteries. While NiCd batteries dominated the previous decade in quantity and scope of applications, they are increasingly replaced by NiMH and Li-ion batteries. NiMH batteries are in their presence on the market and their technical performance to be seen as a transitory technology (Weyhe, 2013). The market penetration of NiMH batteries was promoted by EU legislation restricting the use of cadmium due to its toxic properties (Batt.Dir., 2006). In Germany, the law on batteries (BattG, 2009) implemented the EU legislation into national law and limited the use of NiCd batteries to security applications, medical devices and electrical tools. NiCd batteries exhibit positive properties concerning resilience, low temperature durability and cost-effectiveness, are fast loadable and enable a high current supply. Negative properties are the toxicity of the contained cadmium, the low energy density and the memory effect[3]. NiMH batteries exhibit moderate characteristics concerning price, resilience and energy density besides having a high self-discharge rate and inhibiting the lazy battery effect[4]. Li-ion batteries provide a high energy density, a high voltage and a low self-discharge rate, but are expensive, to some degree toxic, inhibit safety risks and need special recharging techniques (GRS, 2012b). The mentioned characteristics of Li-ion batteries apply primarily to conventional LCO batteries. Recently developed Li-ion batteries show different properties in several aspects (cf. chapter 2.6).

The tables below list the characteristics for common electrochemical systems of primary and secondary batteries. Primary systems are further distinguished into batteries for general purpose, implying cylindrical or prismatic shapes, and button cells, which have a squat cylindrical form and are used to power small portable electronic devices, such as wrist watches, pocket calculators or hearing aids. The figures of batteries sold and returned in 2009 in Germany are derived from the German Federal Environment Agency (UBA, 2011). They indicate numbers for the main electrochemical systems of portable batteries, not including industrial and automotive batteries that primarily employ lead acid systems. In 2009 a total of 37,298 tons of portable batteries have been placed on the market and 16,556 tons of spent batteries have been returned. Since 2009 the amount of the various battery systems sold changed. Due to a rising energy density the overall mass of batteries declines while the use of batteries in electrical and electronic equipment increases, leading to more batteries with less weight. Especially Li-ion batteries gain market share. In 2011, an amount of 6,089 tons of Li-ion batteries has been reported to be placed on the market from companies associated with the GRS foundation (GRS, 2012a) and circa 6,500 tons were placed on the German market in total (Wiaux, 2012). Zinc carbon batteries in particular lose market share and are replaced by alkaline batteries (UBA, 2011).

Table 4: Specifications of general purpose primary batteries

Abbildung in dieser Leseprobe nicht enthalten

Source: Based on (Duracell, 2006), (EPBA, 2007), (Tadiran, 2010), (UBA, 2011), (GRS, 2012b) and (Duracell, 2012)

[...]


[1] Graedel et al. (2011) defines the EOL-RR as the recycled EOL metal (old scrap) divided through the metal content of EOL products. If not otherwise noted, it refers to functional recycling and includes recycling as a pure metal as well as recycling as an alloy.

[2] Graedel et al. (2011) defines the recycled content as the fraction of secondary (scrap) metal in the total metal input of metal production.

[3] The memory effect describes the loss of capacity due to recharging with low currents or if the battery has not been completely discharged before. It can be remedied by completely discharging the battery, preferably two to three times in a row (GRS, 2012b).

[4] Similar to the memory effect, the lazy battery effect occurs when the battery is permanently or partially recharged. It also can be remedied in the same manner as the memory effect (GRS, 2012b).

Details

Pages
135
Year
2013
ISBN (eBook)
9783656743859
ISBN (Book)
9783656743842
File size
2.7 MB
Language
English
Catalog Number
v280865
Institution / College
Technical University of Berlin – Institut für Technischen Umweltschutz - Fachgebiet Abfallwirtschaft
Grade
1,0
Tags
Rare Earths Elements Cobalt Recycling WEEE Batteries Waste Waste Electrical and Electronic Equipment Seltene Erden Kobalt Elektroaltgeräte Batterien NiMH LCO REE LiCoO2 Rare Earths

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Title: Recycling Potential of Rare Earth Elements and Cobalt in WEEE-Batteries