Batteries are made from important resources and chemicals, including lead, cadmium, zinc, lithium and mercury. Each battery placed in the bright red recycling box will be taken apart and many of the materials will be recovered and used to make new batteries or something else. If you put your batteries into a rubbish bin they will be taken to landfill sites and the resources lost.
Recycling batteries is good for the environment. It keeps them out of landfill, where heavy metals may leak into the ground when the battery casing corrodes, causing soil and water pollution. If batteries are incinerated with household waste, the heavy metals in them may cause air pollution.
All types of battery – disposable and rechargeable – can be recycled, including:
AAA and AA cells
Sizes C and D
Button batteries (e.g. watch or hearing aid batteries)
Mobile phone batteries
Most shops selling batteries and many local authorities will have containers that collect batteries for recycling. Schools, libraries and workplaces will also have containers – look out for the bright red box saying “Recycle your batteries here”. Alternatively, type your address into the location finder on this page to find the nearest locations to where you live.
There are many techniques for recycling the different types of batteries – and new and more effective techniques are being developed all the time. ERP has produced a battery recycling processes factsheet which you can download here to find out more.
There are three main types of battery – disposable dry-cell, rechargeable dry-cell and wet-cell. All types of battery can be recycled. Most batteries contain toxic heavy metals, such as nickel, cadmium or mercury. Recycling batteries is good for the environment. It keeps them out of landfill, where heavy metals may leak into the ground when the battery casing corrodes, causing soil and water pollution and endangering wildlife. If batteries are incinerated with household waste, the heavy metals in them can cause air pollution. Recycling batteries recovers the valuable metals and saves energy by reducing the need for raw materials.
There are many types of disposable household batteries such as alkaline, zinc-carbon, zinc-air and button cells. Zinc-carbon and zinc-chloride batteries are used in low energy use appliances such as clocks and radios. They are often found in products sold with disposable batteries inside, as they are cheap. Alkaline batteries are used in equipment such as MP3 players, torches or toys. They are less prone to leaking than zinc-carbon and zinc-chloride batteries and are longer lasting. Button cell batteries contain mercury, silver, lithium or other valuable heavy metals as their main component. Mercuric oxide button cells are used for hearing aids, pacemakers and photographic equipment. Zinc-air batteries are an alternative to mercuric oxide button cells. They may be used in hearing aids and radio pagers. Silver oxide button cells are a type of alkaline battery and are used in electronic watches and calculators. Lithium button cells are used in watches and photographic equipment.
First batteries are sorted and shredded. Lead batteries are separated and treated in a specialised recycler. Nickel cadmium, nickel metal hydride and lithium ion batteries are treated by a separate process. Silver oxide button cells are also taken for special treatment. The remaining zinc-chloride, zinc-air, alkaline and lithium button cells and other button cell batteries are recycled by the OxyreducerTM process, which involves treating them at very high temperature in a rotating hearth furnace. Button cell batteries containing mercury are usually recycled using a vacuum-thermal treatment, in which the mercury vaporises. The mercury condenses and eventually solidifies when temperatures are reduced and can then be re-used.
An increasing number of consumer electronics contain rechargeable batteries. The main types of rechargeable batteries are nickel-cadmium, nickel-metal hydride and lithium-ion batteries. They have a long life, but need to be disposed of eventually. Rechargeable battery technology is developing rapidly.
Nickel cadmium (NiCd) batteries are used for cordless power tools, medical equipment, alarm systems and emergency lighting. The EU has banned nickel cadmium batteries for other applications, as cadmium is very hazardous to human health and there are effective alternatives for all other uses. Nickel-metal hydride (NiMH) batteries were developed as a less environmentally harmful alternative to nickel cadmium and tend to have a longer life.
Lithium-ion and lithium ion polymer (Li-Ion) have a greater energy storage capacity than NiCd and NiMH batteries. They are found in cameras, MP3 players, laptops, sat navs and mobile phones. They have to be very carefully transported, however, as there is a risk that they can start fires.
When rechargeable batteries are spent, they can be recycled. Nickel-metal hydride batteries are reprocessed by mechanically separating the individual materials (plastic, hydrogen and nickel) within a vacuum chamber to prevent hydrogen escaping. The output is a product with high nickel content which can be used in the manufacture of stainless steel. Nickel cadmium (NiCd) batteries can be reprocessed through a thermal technique, which recovers cadmium and iron-nickel for steel production. Lithium-ion and lithium ion polymer (Li-Ion) batteries are reprocessed through pyrolysis (heat treatment). The process focuses on maximizing the recovery of cobalt and other metals such as copper from the batteries for resale. The remaining products can then be used in smelting works, cement factories and also as road building materials.
The most common type of wet-cell battery is lead-acid. They are used to power vehicles, including cars, and in industry for standby power.
Lead-acid battery recycling is well established in the UK, the current recycling rate is around 90%. Different materials, such as lead, plastics and acid, are separated prior to processing or the batteries are processed whole through heat treatment in a furnace. The lead and other metals are then recovered at the end.