Curious about the process of recycling batteries?
In today’s fast paced world where mobility and convenience are sometimes taken for granted, batteries play very important roles in our lives. They power many of our wireless appliances (eg. tv remote controls, alarm clocks) and allow us to work and multi-task on the go (e.g. cell phones and laptops).
But have you wondered what happen to these batteries once they get exhausted and cannot be used further? Better getting to the answer of this question, you will first need to understand the different types of batteries and their general utility.
Types of batteries
There are three main types of batteries.
The first one is the wet-cell battery which contains lead acid. It is used mainly in powering vehicles and by the various industries.
The second variety is the dry-cell non-rechargeable (primary) battery which is the regular battery used in households. This variety of battery can be further classified into the following:
- Zinc Carbon – generally used in less power-consuming gadgets like watches, shavers, clocks, and radios.
- Zinc Chloride – also used in less power-consuming gadgets.
- Alkaline Manganese – used in mp3 players. This variety is slightly more leak-proof when compared to the above two and also has a longer life.
- Primary Button Cells – can be further categorized into (i) Mercuric Oxide, used for small applications like pacemakers and hearing aid, (ii) Zinc Air, as an alternative to mercuric oxide, (iii) Lithium, used in cameras and watches and (iv) Silver Oxide, used in electronic applications like watches, calculators, toys etc.
The third variety is the dry-cell rechargeable (secondary) battery also commonly used in the home. This variety of battery can be further classified into:
- NiCd or Nickel Cadmium – used mainly in powering lap-tops, cordless and cell phones, and some varieties of toys.
- NiMH or Nickel Metal Hydride – variety of batteries which are less harmful to the environment and have a longer life.
- Li-Ion or Lithium Ion – batteries with a larger energy storage capacity when compared to the above two batteries.
The main advantage of using rechargeable batteries is that it reduces the number of batteries that need to be produced and disposed of. However, safe disposal is needed for rechargeable batteries because 80% of them contain nickel cadmium, a carcinogen.
The chemical composition of batteries is what contributes to high levels of toxicity in the environment. Chemicals like cadmium are harmful to humans, as well as other animal and plant life. In the landfills, heavy metals that leak from the dead batteries can mix with ground soil and cause irreversible damage to the ecosystem thereby affecting plant and animal life. At the incinerators, the burnt batteries release toxic gases containing the heavy metals.
Therefore, it is extremely important to control battery waste management and ensure that most of the used batteries, if not all, get absorbed back into the manufacturing cycle.
The Process of Recycling Batteries
Described below is the process of recycling batteries process:
Collection: This part of the recycling batteries process involves the collection of used batteries (both non rechargeable and rechargeable ones) from households, offices, industries, etc. In some areas, the local recycling agencies actually collect used batteries for recycling. In other areas where local recycling agencies do not offer collection services, you might have to get in touch with regional-based battery retailers who have collection schemes to get your used batteries recycled.
Check out the recycling collection centres that take in unwanted batteries.
Sorting: Depending upon the composition, age, and condition of the disposed batteries, recycling agencies need to sort out the batteries before sending them for recycling.
Reprocessing of batteries: The technical process of recycling batteries involves recovering the various component materials (e.g. heavy metals, plastic) from the disposed batteries. This process is more established for batteries containing nickel-cadmium, nickel hydride, lead, and mercury, whereas the systems for recycling nickel-hydride and lithium are newer.
In the process of recycling batteries, the battery first needs to be separated into its components (e.g. plastic, acid and heavy metal). In some instances, the combustible components of the batteries (e.g. plastic) are burnt away. At other times, whole batteries are crushed, such as by a high-speed hammer or shredder. Liquid nitrogen is used to freeze lithium-based batteries before crushing them.
The battery acids or other liquid electrolytes in the crushed batteries are drained away and neutralized to become water, or processed into compounds such as carbonates or sulfates that can be used in other industrial manufacturing processes. The remaining parts of the crushed batteries are then passed through suitable liquids that allow the various components (e.g. plastic, metal) to be separated based on their density. The lighter plastics (that form the casing etc) and other impurities float to the surface, where they could be scooped away for plastic recycling or for disposal. The heavier metal compounds sink to the bottom where they could be collected. The metallic compounds might then be separated into the various metal elements (e.g. nickel, cadmium etc) using their different melting points.
Zinc Carbon and Zinc Air batteries are sometimes recycled by steel manufacturers, as zinc can be used in steel manufacturing to protect steel from rust. The metallic parts of waste zinc-batteries are fed into the molten steel mill furnaces. The zinc fumes from the batteries are then captured by a vacuum baghouse for recovery, while the remaining metal components are used in making low-grade steel (i.e. rebar).
Nickel-Cadmium, Nickel Metal Hydride, and Lithium Ion batteries are recycled via a High Temperature Metal Recovery (HTMR) process. The metallic compounds extracted from waste batteries are passed into a molten metal bath in a furnace. By controlling the temperature of the molten metal bath, metals with lower melting points (e.g. zinc, lithium and cadmium) can be separated from the other metals with higher melting points.
Batteries that are made up of mercury as their chief metal compound are recycled by employing the vacuum-thermal technique. Heat is applied to the contents of the battery such that the mercury vaporizes, is captured, condenses and ultimately solidifies (as the temperature decreases) in a designated container. The extracted mercury can be reused into the manufacturing cycle. With legislations in place to limit the sale of certain mercury-containing batteries in various countries, the quantity of mercuric oxide batteries that need to be recycled is decreasing.
Interesting facts about recycling batteries (or not)
Here are some interesting recycling batteries facts and statistics.
- 50 times more energy is needed to make batteries compared to the amount of energy the batteries can give out. So do use your batteries carefully. Read about the Reduce, Reuse and Recycle Principles of waste management.
- Battery waste is generated at the rate of 20,000 to 30,000 tons per annual while the amount recycled is only around 1,000 tons per annual, which means that a lot of battery waste is currently occupying landfill space somewhere on the planet or being burnt away and contributing to air pollution and our carbon footprint. So if you must use batteries, do be sure to recycle them after you are done with them.
Read more about the battery recycling challenges in Singapore as well as the efforts we are taking in battery recycling.
Where To Send Unwanted Batteries
If you take in unwanted batteries for recycling, I would love to share your service with my readers.
Anyone intending to get ride of their unwanted batteries will definitely find your service information very useful.
Please share with us the following details:
- location of battery collection centre(s)
- type / condition of batteries that would be rejected/accepted by collection centre(s)
- any fees incurred / reimbursement given for using the recycling service
- any additional service(s) provided (e.g. free transportation of unwanted batteries to collection centre)
- contact(s) for queries
Note that regrettably, we are unable to provide links to external webpages.
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