Resource Snapshot (6): Lead

St. Gallen, August 2011. The World Resources Forum Secretariat continues the series "Resource Snapshots" with phosphorus.Ideally, we will shift from importing phosphate rocks to using renewable phosphate fertilizers (such as human excreta and biomass) in the future because this would provide more security to countries that are not rich in reserves.You can learn in less than 2 minutes the key issues of this precious resource.

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Applications and use

Lead is a very soft, highly malleable, low-melting and ductile base metal that is very resistant to corrosion but tarnishes upon exposure to air 1. The primary application of lead is in batteries; currently, the battery industry consumes approximately 71% of the world’s lead, as shown in figure 1. Furthermore, lead is the second densest common metal (after gold), making it an effective sound barrier and shield against X-ray. Hence lead is commonly used in the production of computer and television screens- the addition of lead helps to shield the user from radiation. Lead is also used as the traditional base metal for organ pipes, in electrodes in the process of electrolysis, a colouring element in ceramic glazes and in projectiles2. When lead is mixed with other metals, it can form alloys such as pewter and solder which is important in rubber production and oil refining. However, its use as a petrol additive has declined significantly due to the gradual introduction of lead-free petrol worldwide3.

Mining

Lead metal can be classified as either primary or secondary. Primary lead is produced directly from mined lead ore whereassecondary lead is produced from scrap lead products (such as automobile batteries) which have been recycled4. Total annual production is approximately 8 million tonnes, half of which is primary lead5. It is rare to find pure deposits of lead in nature though. The majority of the deposits are mixtures of minerals6hence lead ore is usually obtained as a byproduct of other metal mining such as zinc, silver or copper- in fact, lead ore is a main source of silver and contributes substantially towards the world's total output. The most common lead ore is galena (PbS), which contains 86.6% lead. Other common varieties include cerussite (PbCO3) and angelsite (PbSO4)7.

Reserves

Total estimated global lead reserves are 85 million tonnes8. The country with the most lead reserves is Australia, followed by the United States, China and Canada- between them, they account for more than half of the world’s primary production of lead9. Other countries that are prominent producers of lead include Mexico, Peru, Russia and Kazakhstan10. It is interesting to note that lead supply can be greatly affected by lead prices- the general trend is that the higher the price of lead, the greater the supply. This is due to the fact that half of the lead consumed comes from recycled lead. For example, when lead prices are high, there is a greater incentive to collect scrap metals which increases the supply of lead.

Recent Price Developments

The sharp increase in the price of lead between 2006 and 2007 was mainly due to a supply deficit of lead at the time11.After that period, lead prices started to fall gradually because global lead supply shifted from a deficit to a surplus at the end of 200712. However, the shift in the balance of lead supply coincided with the global financial crisis which exacerbated the falling prices greatly as seen in the graph below. This is because the automotive industry (which is closely linked to the lead industry as lead is used to make car batteries) was severely impacted by the downturn and base metals prices fell in general as global production contracted. Since mid-2009, lead prices have hovered between USD 1,674/tonne - USD 2,719/tonne, which is a smaller range in comparison to the initial months following the global financial crisis. Although there has been an upward trend in lead prices in the past year, it is unlikely that there will be any substantial price increases as lead inventory levels have been at a record high13.

Environmental problems

Lead and lead compounds are generally toxic pollutants that cannot be broken down; they can only be converted into other forms. Historically, the major sources of lead emissions have been from fuels in motor vehicles (such as cars and trucks) and industrial sources.In the past few decades, several measures have been taken to decrease the amount of lead pollution in the world. For example, leaded gasoline has been banned in most areas of the worldexcept for a few countries in South America, Asia, Eastern Europe and the Middle East which has led to a 94% decrease in levels of lead in the air decreased by between 1980 and 199914. Furthermore, metal plants are collecting sulphur dioxide (a major byproduct of the smelting process in lead processing and the primary cause of acid rain) as it is released and converting it into sulphuric acid15. However, the effort from metal plants to reduce the amount of air pollution from lead processing by filtering the fumes from processing has not been as successful. Lead particles are still reaching the atmosphere- this is an issue that must be tackled in the future as animals and plants that are exposed to lead suffer from an array of health problems16. Furthermore, lead not only accumulates in individual organisms but also in entire food chains, making it a particularly dangerous chemical to have in nature both in the short and long term17.

Social problems

The primary social problem associated with the production, use and disposal of lead is lead poisoning. Like animals and plants, human beings are also affected by lead poisoning. In fact, lead poisoning is the oldest recorded occupational disease18and lead is one out of the four metals that can have the most damaging effects on human health. It can enter the human body through uptake of food (65%), water (20%) and air (15%); lead can even enter a foetus through the placenta of the mother which causes serious damage to the nervous system and the brains of unborn children. The effects of lead on the human body include damage caused to the kidneys, liver, brain and nerves; reproductive disorders; seizures; mental retardation; behavioural disorders; lowered IQ in children; high blood pressure and an increase in heart diseases19.Long term exposure to even the tiniest amount of lead can have detrimental health effects. Hence, the main priority of lead producers with regards to health and safety is to protect their workers from being exposed to lead20.

Alternatives

There are alternatives to lead but they differ depending on the original application of lead. For example, plastics have substituted the use of lead in building construction, electrical cable covering, cans and containers. Other metal oxides such as zinc and titanium oxide have replaced the use of lead in oil and water based paints. More recently, tin has replaced lead in solder for the electronics industry as well as new or replacement potable water systems in the U.S.21- this is due to the health effects of lead poisoning. With regards to the most important application of lead, rechargeable batteries, there have not been any approved substitutes to lead due to safety concerns22.

Outlook

On the supply side, it is predicted that there will still be a surplus of lead in 2011 and 2012. However, forecasts indicate that this will not be a significant surplus, at least in 2011, due to the closure of several lead mines in Australia (following the floods and cyclone Yasi) as well as the reduction in the production of lead in China23. With regards to lead supply in the long term, an article in the New Scientist states that the supply of lead is estimated to run out in 42 years based on the use rates of lead before 200724whereas environmental analyst Lester Brown suggests otherwise- using an extrapolation of 2% growth per year, lead could run out within 18 years25. However, this does not currently pose as a severe issue given then lead recycling rates are extremely high in comparison to other base metals.
On the demand side, China’s Ministry of Environmental Protection has recently ordered almost 1,000 lead-acid battery producers to suspend production temporarily- some even permanently. This will have some impact on the lead industry given that China’s battery production accounts for about 80% of the country’s domestic lead demand as well as 45% of global lead demand26.


WRF Resource Snapshot (6) has been compiled by Natasha Chan. She would greatly appreciate corrections, suggestions or other remarks, which could improve this document. Suggestions for which other resources to choose are also welcome. Natasha can be reached through info@worldresourcesforum.org.