Recycling batteries is one of the most important recycling practices. Recycling glass or paper is essential, due to the cost efficiency or forest protection. In addition to the reasons listed above, recycling batteries has one more crucial reason: batteries contain toxic chemicals. Releasing these chemicals into the environment (for example, when batteries end up in a landfill) can cause significant water and soil pollution. Scientific studies [1] have demonstrated that mercury, cadmium and lead of the batteries present the major environmental problems.

How do batteries work?

A battery stores energy in the form of chemical energy and transforms this chemical energy into electricity, when connected to an electrical circuit. An electrical circuit is basically a flow of electrons in one direction, or a flow of positive ions in the opposite direction. These charges (electrons or ions) flow through a conductive path, for example, a wire. Such a wire thus forms an electric circuit.

Any battery consists of three main parts: a cathode (+), and anode (-) and an electrolyte to separate them. When the battery is not connected to an electrical circuit, the electrolyte prevents cathode and anode from exchanging charges. However, when we install a battery into a circuit, there is an external path – this circuit – following which electrons can reach the cathode. Therefore, an electrical current starts flowing through the circuit. The chemical reactions in the battery define the amount of charges this battery can produce. Some batteries – the disposable ones – can only transform chemical energy into electrical energy. Therefore, they can only used once. Other batteries – rechargeable – also work in an opposite direction, when electrical energy from an external source can be transformed back into chemical energy. Therefore, such batteries are multiple-use, and are thus better for the environment.

Recycling process

Currently, all types of batteries can be recycled. Most of them are even 100% recyclable, meaning every part of the used battery ends up as a part of a new product (usually a battery as well). Some batteries – like car batteries – always end up at a recycling facility, due to the fact that recycling is much more energy- and cost-efficient. But the batteries that we use in our everyday life – for example, in a TV remote – still often finish their life cycle in a landfill.

Lead battery recycling

Let us briefly describe the procedure of battery recycling on an example of lead acid batteries. After their arrival at a recycling facility, the batteries are crashed into small pieces. The next step is to separate the different components of these small pieces. To do that, battery pieces undergo a special procedure, as a result of which lead and other heavy metals fall to the bottom of a special vat, while the plastic pieces float. Therefore, there are now three separate material components, all separated from each other: lead and other metals, plastic and acid.

The lead pieces proceed to hot furnaces, where they melt. When the lead melts, impurities float on its surface, which allows to clean the lead from these impurities. The cleaned lead then goes back to battery manufacturers. Plastic pieces also end up back at the battery manufacturer, to become parts of new batteries again. Old battery acid mostly undergoes a neutralization procedure, as a result of which it turns into water.

You can find more detailed information about recycling procedures for this and all the other battery types here.

[1]  Bernardes, A. M.; Espinosa, D. C. R.; Tenorio, J. A. S. “Recycling of batteries: a review of current processes and technologies”. Journal of Power Sources. 130 (1–2): 291–298. doi:10.1016/j.jpowsour.2003.12.026.

Aluminium is probably the easiest material to recycle. Recycling aluminium is even easier than recycling glass! The whole process basically implies just re-melting the metal. It can then be further used to manufacture new products. Recycling is, therefore, much less energy-consuming than creating new material from scratch.

Creating new aluminium requires conducting a process called electrolysis of aluminium oxide (Al₂O₃). Electrolysis uses electricity to catalyze chemical reactions that would not happen under normal conditions. Apart from that, someone first has to refine aluminium oxide from the natural material – bauxite. Bauxite, which is the most important ore of aluminium, only contains from 30% to 60% of it. The whole procedure is rather cumbersome and expensive. On the other hand, recycling aluminium requires only 5% of the energy used to make it from the raw ore. For this reason not only conscious consumers, but also profit-oriented corporations are trying their best to enforce separate collection of aluminium and its consequent recycling.

History

Due to the advantages presented above, aluminium recycling is one of the oldest recycling practices. The first attempts to recycle this metal appeared as early as in the 1900’s. The practice became even more wide-spread during World War II. However, recycling reached its peak popularity in 1960’s, when beverage cans appeared on the counters. Up to this day, cans for various drinks are the most popular usage of aluminium. Consequently, they are also the most recycled.

Just like glass, aluminium does not deteriorate during recycling, therefore, it can be recycled indefinitely. The quality of the recycled product will not be any worse than that of the initial product. Therefore, recycled metal has the same usage as the newly manufactured one: beverage cans, bicycle tires, computers, kitchen ware and many other products which require a light strong material. Moreover, aluminium is a key component of some computer hardware and various types of wiring, due to its high thermal conductivity.

Aluminium recycling process

As with any other recycling process, the first stage of it is a consumer throwing his beverage can or chocolate foil into a recycling bin. On the next stage that aluminium is collected and taken to a recycling plant, where it is cleaned and sorted. Special machines usually cut beverage cans into small pieces. This helps to decrease the volume they occupy, and also makes it easier for separating machines.Usually cleaning the metal from inks and admixtures happens during the melting stage, however, some products require additional cleaning.

At the next stage the pieces turn into aluminium blocks. This helps to prevent oxidation during the melting stage, as aluminium easily turns back into its oxide, when exposed to oxygen. The resulting blocks then undergo spectroscopic analysis. As a result of this analysis and according to the desired goal admixtures like copper or zinc may find their way into the mixture. Only at this stage the substance proceeds into the furnace, where it finally melts.In case of beverage cans the melted mass turns into big blocks – ingots – each consisting of approximately 2 million cans. Special machines subsequently roll the ingots out, giving them additional flexibility and strength. The obtained aluminium sheets are ready for creating new drink cans, food packaging and, most importantly, chocolate wrapping!