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Recycling of rechargeable batteries


By Engr. Saud Khan

WE THE humans of 21st century are living in the electronic era, where electronic items are playing a vital role in our daily life. Today batteries are an integral part of our life; they are used to power electronic devices like watches, cell phones, power tools and general household appliances. The alkaline battery (primary battery) was the first type of battery invented and is still widely in use. You can find them in various sizes from AAA, AA, C and D. However they do not last very long; typically after a short time of use they are fully discharged and need to be thrown out. To overcome the short life of primary batteries, scientists developed rechargeable batteries in which chemical reaction is reversible and, therefore, they can be recharged from an electric source. The lead-acid battery is one of the oldest rechargeable batteries and it is primarily used in cars/automobiles. A rechargeable battery provides service for long periods but eventually it reaches the end of its useful life and becomes waste. These batteries contain a corrosive liquid or semi-liquid electrolyte that is either a strong acid or a strong base. In addition these batteries contain metals, such as cadmium, lead and lithium, which generally are toxic and harmful to the environment.
Nowadays there is enormous discussion on renewable energy sources like solar and wind energy systems, and other eco-friendly gadgets and devices. The level of safety to the environment of these products is often highly praised. Although they do not emit harmful fumes or do not shake the balance of an ecosystem, the rechargeable batteries that are used in these green machines and devices still carry an inherent danger to nature. Many of the elements used in manufacturing batteries are in fact toxic pollutants, and have their own negative effects not only on the environment but also on human health. The major problem to human health is caused by heavy metals such as toxicity caused by mercury, cadmium lead and nickel i.e. it includes dysfunction of vital organs and metabolism disorder problems. In fact rechargeable batteries are an essential part of renewable electricity system e.g. the solar energy obtained from sunlight is converted into electric energy instantly but there are chances that the user may not utilize electric energy fully or he may need electricity during night time. To overcome this problem, a solar panel is put on charging rechargeable batteries from where (through UPS) smooth electricity is available for 24 hours.
The inherent danger from batteries is the leakage of toxic metals from waste dumps that can result in water and air contamination. Environmental agencies have become aware of the increasing environmental
concern from the disposal of batteries containing toxic heavy metals; therefore, the need for recycling toxic batteries is highly emphasized. Recycling helps lessen the amount of waste that goes into landfills, helps reduce the amount of toxic chemicals absorbed into the earth and, in some cases, significantly reduces manufacturing costs and energy consumption. The recycling process starts by removing the combustible material, such as plastics and insulation, with a gas fired thermal oxidizer. The cells are then chopped into small pieces, which are heated until the metal liquefies. Non-metallic substances are burned off and the different alloys settle according to their weights and are skimmed off like cream from raw milk.
There are numerous directives and guidelines adopted by the European countries on the management of waste batteries and now they are moving towards legislation where strict penalties will be imposed if found incompliance. The situation in Pakistan is also no so encouraging, sometime ago SEPA (Sindh Environmental Protection Agency) had demolished around 150 units in Hyderabad where worn out lead batteries were being recycled illegally. The lead from old batteries was extracted through furnaces situated in residential areas. Health and environmental experts consider the practice of lead extraction through melting a highly hazardous practice as it can cause lead poisoning to humans while the process also generates over 3000 carcinogens. SEPA has estimated that there are over 1000 such shops and small units working in Gadap Town, Garden, Orangi Town, Baldia Town and some other low-income localities of the Karachi city where lead is extracted from the used batteries and there are thousands of people involved in the business. In short the demand for new batteries is increasing every year on the other hand scrap merchants are finding worn out batteries a lucrative business. It will be unrealistic that the manufacturers of new batteries would stop producing them any time soon, but if we have a solid plan for recycling, we will probably survive long enough to invent a true clean and green rechargeable battery for our green technologies.
The Writer Is Electrical Engineer At The Chashma Nuclear Power Plant-2 Via technologytimes.pk