Overview of lead recycling
This section provides a brief introduction to lead acid batteries and an
overview of the recycling industry.
The predominant use of lead within the world is in lead acid batteries. Lead
acid batteries are an essential component of the automotive industry for which
there are currently no electro-chemical, economic or environmentally acceptable
or competitive alternatives. World wide it is estimated that between 300 and 350
million lead acid batteries are produced each year (Angus Environmental Ltd,
1993; Behrendt & Steil; Wilson, 1993).
With the continuing growth in urbanisation and private vehicle ownership,
particularly within newly industrialised countries, the steady increase in
demand for automotive batteries is likely to continue, guaranteeing an
international demand for lead (Angus Environmental Ltd, 1993; OECD, 1993). It is
estimated that by the year 2005 approximately 74% of the total lead utilised
within the western world will be in the form of lead acid batteries (Ahmed,
The average life cycle of an automotive battery is approximately 3 to 4
years. Many years ago spent lead acid batteries (batteries which fail to retain
an electrical charge) were disposed of within municipal landfills, with
significant adverse environmental consequences. Therefore, in many
industrialised countries the recycling of lead acid batteries is seen as an
appropriate response to reducing the environmental effects associated with
landfill disposal, while also realising the economic potential that could be
achieved through recycling. Since there is a growing world demand for lead, in
particular in rapidly industrializing countries of the South, it was expected
that these economic benefits would be sustained through the operational lifetime
of the technology (Sancilio, 1995; UNEP, 1995).
Recycled (or secondary) lead is now estimated to constitute about 60% all the
lead produced. This rate is predicted to increase to over 65% by the year 2005.
Over the same period the demand for lead is also expected to increase, but the
level of primary lead production will remain almost static. Therefore, battery
recycling technologies are seen as an increasingly important component in the
production of lead (Ahmed, 1996).
The most common lead recycling process involves the automated breaking and
sorting of batteries into their components, before the lead is extracted at high
temperatures (smelting). Once refined and alloyed with other metals, the
extracted lead is cast into ingots and made available for use in commercial
In addition to the lead content of the battery, other components and
by-products can also be recycled. For example, sulfuric acid reclaimed during
the breaking process can be transformed into other marketable chemical products
(such as detergent additives and fertilizers). Similarly, the propylene cases of
batteries can be shredded and washed to produce clean polypropylene chips
suitable for reconstitution. These may then be formed into other products,
including battery cases (de Feraudy, 1993; Jackson & Tansel, 1994). Some
automotive batteries contain up to 70% recycled plastics and 80% secondary lead
(Worden, cited in Jackson and Tansel, 1994).
However, the recycling process also has the potential for significant
environmental impacts and risks to human health and safety. Generally the more
notable environmental impacts include particulate (including lead and other
heavy metals) and acidic (sulfur dioxide - SO2 and possibly some
hydrochloric acid in the gaseous form, HCl) discharges into the atmosphere
during the smelting and refining processes, the discharge of contaminated
industrial waste and the leakage of acidic electolyte during battery storage.
The growing recognition of such impacts within communities, and by regulatory
authorities, has been paralleled by the tightening of environmental protection
standards and by higher environmental protection costs for recycling plant
operators (Suttie, 1995; Wilson, 1993).
Internal costs, environmental controls and fluctuating lead prices have often
impacted on the viability of any strictly profit-orientated recycling industry
within western societies (Elmer, 1995; Suttie, 1995; Wilson, 1993). Although
lead acid battery consumption within OECD countries continues to rise, there are
few economic incentives for expansion of smelting facilities in developed
nations. In contrast, lead consumption in rapidly industrializing (developing)
countries has been rapidly expanding, often at rates of 10-15% per annum in
volume terms. Many of these countries suffer from a domestic supply-demand gap
for lead. Apart from increased imports of primary lead, this gap has also been
closed by imports of scrap batteries from developed countries. Currently Asian
nations such as Indonesia, India, and Thailand are the principal recipients of
used lead acid batteries. (Elmer, 1995) In this regard, the fear has been
expressed that such North-South shipments of scrap vehicle batteries are fuelled
by lower operating costs of recycling facilities (for instance in terms of
labour, health and environmental costs), which make such operations more
competitive and economically viable (Greenpeace, 1994).
While not yet in force, the Basel Ban Amendment is being voluntarily
implemented by many countries. The Amendment bans the export of hazardous
wastes, including lead acid batteries and lead wastes, from OECD countries to
non-OECD countries. Under the conditions prevailing in many developing
countries, the Basel Ban Amendment effectively encourages the importation of
primary lead in order to bridge the domestic supply-demand gap. Primary lead is
nearly as cheap as secondary lead. In such situations a comprehensive national
strategy is required to reduce waste generation, enhance access to domestic
sources of lead scrap and make recycling environmentally sound and economically
viable (Jha & Hoffmann, 2000).
There are three general categories of lead acid batteries (see Table 2), but
all operate according to the same principles. The major components of the modern
recyclable lead acid battery are the electrodes (typically pure lead oxide and
lead sulfate for the cathode, with the anode being a grid of metallic lead alloy
with various elemental additives that might include antimony, calcium, arsenic,
copper, tin and selenium), the electrolyte (dilute sulfuric acid), the
separators, lead terminals and the plastic or rubber casing. The composition (by
percentage weight) of a typical automotive battery is shown in Figure 1. The
typical lead battery consists of 17% metallic lead, 50% lead oxide/sulfate, 24%
electrolyte, 5% plastics and 4% (and reducing) inert residuals.
An average car battery weights 17.2 kg and contains approximately 6 litres of
sulfuric acid (pH = 0.8) and 9.0 kg of lead - equally divided between anode and
cathode (Basu et al, 1991 cited by Environment Canada 1993). The electrodes (or
plates) are constructed from a grid-like lattice filled with a hardened paste
containing the active material. Grids are cast from a high purity lead and
alloyed with antimony, tin, arsenic and copper to improve their mechanical
properties. A few manufacturers may still use small quantities of cadmium, but
this is rare nowadays.
Direct electrical contact between the plates is prevented by a separator that
allows electric current to flow between the plates when carried by sulfuric
acid. The materials used for separators include plastic (polyvinylchloride,
polyethylene), glass fibres and rubber components (Environment Canada, 1993;
Battery casings are typically constructed from polypropylene, which is also
recyclable. However, previously non-recyclable hard rubber materials (such as
ebonite) were often used. As a consequence, the materials used in battery
construction may vary according to their date and location of manufacture
(Environment Canada, 1993).
Results of the environmental technology assessment
The findings of the assessment team are presented below.
Ahmed, F, 1996: The battery recycling loop; A European perspective. Journal
of Power Sources, 59, 107-111.
Angus Environmental Ltd, 1993: An Overview of the Metal Recycling Industry in
Canada. Canada Centre for Mineral Technology, Ontario.
Behrendt, H. and H. Steil (ndated): Lead - Acid Batteries: State of
Environmentally Sound Recoery and Recycling. Unpublished Manuscript.
Elmer, J.W., 1996: The Basel Convention: Effect on the Asian secondary lead
industry. Journal of Power Sources, 59, 1-7.
Environment Canada, Hazardous Waste Division, Office of Waste Management,
1993: Guidelines for the Management of Used Lead Acid Batteries in Canada.
Environment Canada, Quebec.
De Feraudy, H., 1993: Recycling the plastic components in today's lead acid
battery. Journal of Power Souces, 42, 315-318.
Frias, C., M. Garcia and G. Diaz, 2000: New Clean Technologies to Improve
Lead-Acid Battery Recycling. Unpublished manuscript, Tecnicas Reunidas, S.A
(R&D Centre), Sierra Nevada 16, 28830 San Fernando de Henares, Madrid,
Greenpeace, 1996: Lead Overload: Lead Battery Waste and Recycling in the
Philippines. Greenpeace International, Manila, The Philippines.
Jackson, H. and B. Tansel, 1994: Recycling analysis of lead acid batteries.
Journal of Resource Management and Technology, 22 (2), 96-99.
Jha, V. and U. Hoffmann, Achieving objectives of Multilateral Environmental
Agreements: A package of trade and positive measures - elucidated by results of
developing country case studies. UNCTAD/ITCD/TED/6), United Nations Conference
on Trade and Development, Geneva, 2000.
OECD, 1993: Lead Risk Reduction. Organisation for Economic Cooperation and
Development, Waste Management Policy Group, Paris, France.
Sancilio, C., 1995: COBAT: Collection and recycling spent lead acid batteries
in Italy. Journal of Power Sources, 57, 75-80.
Suttie, A., 1995: Lead recycling via rotary furnaces. Third International
Symposium. Recycling Metals and Engineered Materials, Point Clear, Alabama, USA,
November, 1995, Minerals, metals and Materials Society, AIME, USA.
United Nations Environment Programme, 1996: Environmental and Technological
Issues Related to Lead Acid Battery recycling: A Workbook for Trainers. United
Nations Environment Programme (UNEP), Industry and Environment, Paris.
United Nations Environment Programme, 1983: Fundamentals of Battery
Manufacturing. UNEP Design Manual II: Pollution Control Facilities for Small
Battery Plants. United Nations Environment Programme (UNEP), Regional Office for
Asia and the Pacific.
Wilson, D.N., 1993: New approaches to the collection of scrap batteries.
Journal of Power Sources, 42, 319-329.