BATTERY RECYCLING DAY
If we trace what is in our garbage can, we realize that there is quite a lot of waste – especially a lot of plastic. However, there is waste that cannot end up in any of the 4 primary sections (mixed, plastic / metal, glass, paper) – e.g. batteries. What to do with them and why, what they consist of, and whether they can be simply not thrown away, but reused, writes Julian Kubisztal, PhD.
„Save the date” is a series of articles that have been written to celebrate various unusual holidays. The authors of the presented materials are students, doctoral students and employees of the Faculty of Science and Technology of the University of Silesia.
Since 2015, September 9th is an annual Battery Recycling Day. This date was chosen not by accident, because on this day in 1737, the Italian physician from Bologna Luigi Galvani was born. Galvani’s groundbreaking work on the effect of electric current on the reaction of crafted frog muscles inspired Alessandro Volta, who in 1800 developed the first galvanic cell. A single galvanic cell is a system of two electrodes immersed in an electrolyte, in which chemical energy is converted into electricity. The latter allows us to power various electronic devices, including telephones, watches and remote controls. Currently used electrochemical energy sources can be divided into irreversible galvanic cells (so-called disposable batteries that are unusable after discharge) and reversible galvanic cells (so-called accumulators which can be recharged multiple times). In everyday language, the word battery describes both one cell and a sequence of galvanic cells.
The usefulness of batteries and accumulators in everyday life is undeniable, but the materials and chemicals used in their production can seriously threaten humans and the environment. Used batteries and accumulators are specific waste containing toxic elements such as lead, cadmium, nickel, lithium, caustic acids and alkalis. We should remember to never throw used batteries and accumulators together with other waste but, to dispose them into special containers intended for this purpose. Batteries that end up in ordinary waste containers may corrode, causing leaks of toxic compounds into the environment. For instance, one button battery used in wristwatches can contaminate about 1 m3 of soil and several hundred litres of water.
Companies that recycle batteries and accumulators can recover up to 99% of all their components. There are currently three methods of recycling batteries and accumulators.
The mechanical method consists in grinding waste in special mills and separating components with characteristic physical properties (density, size, magnetic properties). It prepares used batteries for further processing in hydrometallurgical and pyrometallurgical procedures.
The hydrometallurgical method consists in acidic or alkaline leaching of a properly prepared battery mass. It is followed by a series of physicochemical operations that separate and concentrate valuable components or waste in the appropriate phases.
The pyrometallurgical method consists in melting the battery at high temperatures. All carbon compounds are burned during the process and the battery metals form an alloy. Its components can be recovered using hydrometallurgical techniques.
Recovered raw materials include paper, plastic, and metals such as iron, aluminium, copper, cobalt, nickel and manganese. Recovered materials can be used for production of new batteries and accumulators or in other technological processes. Thanks to recycling, we not only solve the problem of waste, but also reduce the economic and environmental costs of extracting and producing new raw materials.