Lead-acid storage batteries (LABs) are widely used on a mass-scale in all parts of the world. They act as power sources in a wide-range of equipment and appliances used by households, commerce and industry. LABs finds application in all modes of modern transport including cars, trucks, buses, boats, trains, rapid mass-transit systems, recreational vehicles etc.
During power-cuts, lead-acid batteries provide emergency power for critical operations such as air-traffic control towers, hospitals, railroad crossings, military installations, submarines, and weapons systems. Every telephone company in the world, including mobile telephone service providers, uses lead-acid batteries as backup power to the telecommunications systems.
There are two types of battery: primary cells which cannot be recharged and secondary cells which can be recharged. Batteries are normally split into three categories, depending on their use: consumer or portable, automotive and industrial. All automotive batteries and 95 percent of industrial batteries are lead-acid secondary cells whilst over 95 percent of all consumer batteries are primary cells.
Lead-acid batteries contain sulphuric acid and large amounts of lead. The acid is extremely corrosive and is also a good carrier for soluble lead and lead particulate. Lead is a highly toxic metal that produces a range of adverse health effects particularly in young children. Exposure to excessive levels of lead can cause damage to brain and kidney, impair hearing; and lead to numerous other associated problems. On average, each automobile manufactured contains approximately 12 kilograms of lead. Around 96% lead is used in the common lead-acid battery, while the remaining 4% in other applications including wheel balance weights, protective coatings and vibration dampers.
Lead is highly toxic metal and once the battery becomes inoperative, it is necessary to ensure its proper collection and eco-friendly recycling. A single lead-acid battery disposed of incorrectly into a municipal solid waste collection system, and not removed prior to entering a resource recovery facility for mixed MSW, could contaminate 25 tonnes of MSW and prevent the recovery of the organic resources within this waste because of high lead level.
The most common and most efficient method for the collection of used lead-acid batteries (ULABs) is through the battery retailer where a discount is given against the purchase price of a new battery provided the customer returns the used battery. In some countries a deposit has to be paid when a new battery is purchased and is only returned to the customer when the battery is returned to the retailer for recycling.
In several parts of the world, reconditioned lead-acid batteries are offered for sale. In the Caribbean islands there is a thriving second-hand auto trade and thousands of used Japanese cars are imported into the region every year to be broken up for spares. Many of these vehicles have a used lead acid battery, which is removed from the vehicle and shipped to Venezuela for recycling. Another collection mechanism is through rag-pickers who scavenge for discarded materials that can be reused or recycled. Rag-pickers scour waste dumps, strip abandoned vehicles and wrecks and even collect batteries that have been used for standby power in domestic houses.
Advantages of Battery Recycling
The lead-acid battery recycling sector has a well-established infrastructure in many parts of the world, especially North America and Europe. Recycling of lead-acid batteries, provided it is done in an environmentally sound manner, is important because it keeps the batteries out of the waste stream destined for final disposal. Lead from ULABs placed in unlined landfills can even contaminate the groundwater.
Recycling prevents the emission of lead into the environment and also avoids the energy usage associated with manufacturing lead from virgin resources. Obtaining secondary lead from used lead-acid batteries can be economically attractive, depending upon the market price of lead. Recovery of lead from batteries is easier and requires significantly less energy than producing primary lead from ore.
Recycling also reduces dispersal of lead in the environment and conserves mineral resources for the future when undertaken in an environmentally and socially responsible manner. It needs to be mentioned that recycling of used lead acid batteries is not a simple process that can be undertaken in small scale enterprises. Certain control measures should to be taken to prevent adverse impacts to people and the environment.