Have you wondered why batteries run out? The most common forms of non-rechargeable batteries used are the Zinc-Carbon battery and Zinc-Chloride battery. The other types of non re-chargeable batteries include Alkaline-Manganese and Primary Button Cells. Inside them an irreversible chemical reaction produces the ‘charge’. Over a period of time, impurities pile up which prevent further reactions or the chemicals themselves are fully consumed. This renders them useless but keeps them potentially hazardous. Since these cells use heavy elements, both metallic and non-metallic, any leakage of the contents causes pollution. It makes soil and water poisonous and if burnt, these chemicals also lead to air pollution. Even without leakage, they form a massive amount of non-biodegradable waste causing considerable damage.
There are three principal kinds of rechargeable batteries—Nickel-Cadmium (NiCd), Nickel-Metal Hydride (Ni-MH) and Lithium –Ion (Li-Ion). They have a long life and can be recharged several times. However due to accumulation of by-products inside the cell they eventually run out. They, too, have a potential leakage problem and are thus hazardous as well.
Despite being ‘dead’, these batteries can be regenerated. Since dead batteries are potentially problematic, the best solution is to recycle them and reuse the materials in productive manner.The chemicals used can be extracted and reused in multiple ways. The components inside the cells can be reused to make more cells. The metals extracted are essentially pure and can be used in various ways. The secret is to extract them in the correct manner and before they start causing damage. Thus the extraction involves categorizing batteries on the basis of material, age and battery type.
Battery manufacturers have to use pure chemicals to enhance the life of the batteries. Thus the metals and non-metals extracted can be readily re-used. Some of the most important products extracted are
- Ferromanganese Concentrate: Iron is extracted from this more easily and profitably than natural iron-manganese ore. The iron extracted is twice the purity of the ore and since less power is consumed and less slag produced during extraction, this is highly prized by the iron and steel industry.
- Zinc concentrate: The zinc found from the dead batteries is around 40% pure. It is used for making other cells and industrial electrolysis processes.
- Mercury: Very pure Mercury can be extracted from cells, especially button cells used in watches, cameras and MP3 players. Mercury is extremely valuable and used in thermometers and other metric instruments. It is also used in fluorescent lighting.
- Silver: Silver is also used in many rechargeable batteries. The extracted silver is very pure and an be used for other cells as well as ornaments.
- Nickel: Nickel extracted is mainly used by the steel manufacturers.
- Cadmium: Cadmium is mostly used to make new batteries.
- Lead: Lead is also reused by the battery industry for new cells.