Saturday, January 23, 2021

How are batteries recycled? From your home to new products





You may have wondered when your remote control or flashlight batteries ran out and you wanted to throw them away, what happens next? How are batteries recycled?

So, let's see what the process of recycling used batteries involves?


Battery recycling is the process of recycling used batteries from various sources, thus preventing them from being dumped in landfills or the environment.

Almost all batteries used in a household can be recycled whether we are talking about remote control batteries, batteries for children's toys, laptop batteries or car battery.

Batteries contain toxic substances and heavy metals such as lead, nickel, mercury or cadmium. They can contaminate soil and surface water or groundwater if dumped in landfills or in the wild. Therefore, batteries must be recycled in a special battery recycling unit.

Because batteries are of different types and contain different substances, they must be separated before the recycling process begins, as each type of battery has a different recycling process. Once sorted, the batteries are introduced into the recycling process itself, obtaining iron, lead, nickel, cadmium, zinc, lithium and other metals used in the production of batteries.

But let's see more about the path of batteries in the recycling process, from your household to the final products obtained from their recycling.


1. How are batteries collected for recycling?

The process of collecting batteries for recycling starts from your home. As mentioned above, batteries contain environmentally harmfull substances and cannot be thrown directly in the trash. They must be collected and stored separately from household waste. From the household, they can be taken either to the large electronics stores that usually have special containers for storing used batteries, also you can bring them to the retail stores or to a nearby recycling center.Once in the collection centers, the used batteries are sent to a battery recycling factory where are sorted into categories for recycling.


2. What types of batteries can be recycled?

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In principle, any type of battery can be recycled. But the most common in home use are: lead-acid batteries, Li-Ion batteries, Ni-Cadmium batteries (NiCd), Ni-Metal Hydride batteries (NiMH), primary lithium batteries and alkaline batteries.


Lead-acid batteries




Lead-acid batteries are used in motor vehicles (car batteries), for storing energy produced by photovoltaic panels or wind turbines or for back-up power supplies.

 

Lithium-ion batteries (Li-ion) & Primary Lithium batteries


Li-Ion batteries are mainly used for electronics from the smallest (earbuds, watches) to mobile phones, tablets, laptops, cameras or other electronic gadgets. They are also used to power cordless tools and other electrical products. 

Although lithium itself is not in principle harmful to the environment, Li-ion batteries must be recycled as they may also contain metals such as nickel, cobalt or magnesium. Even though these metals are not as polluting as lead, they are considered toxic heavy metals and must be recycled.

Primary Lithium batteries

These batteries must be recycled because the metal lithium in their component is very reactive when it comes in contact with moisture or when the metal tank of the battery is perforated.

As the demand for lithium on the market continues to increase, its recovery through recycling is becoming increasingly important.

Nickel-Cadmium batteries (NiCd)


Nickel-Cadmium batteries are a hazard to the environment if they are not disposed of properly. The harmful effect is so great that the European Union banned the production and use of Nickel-Cadmium batteries in 2009.

To dispose of these batteries, they must be isolated from the other batteries.

Ni-Cd batteries are used for portable electronics, toys, solar garden lamps. Also, special Ni-Cd batteries are used in cordless phones, mobile phones, emergency lighting and other applications. Ni-Cd batteries contain chemical elements such as nickel and cadmium in various compositions and forms that can be recycled.


Nickel-Metal-Hydride batteries




Ni-MH batteries are less polluting than Ni-Cd batteries, but still pose a risk to the environment if disposed in large quantities.

Nickel-Metal-Hydride batteries have similar uses to Li-ion batteries, where more energy is needed such as power tools or some hybrid vehicles.

Ni-MH batteries contain nickel-hydroxide, hydrogen absorbing alloys and pottasium-hydroxide.


Alkaline batteries




Alkaline batteries are currently the most used in household applications, from flashlights, alarm clocks, battery-powered radios to toys.

Due to restrictions on the use of mercury in alkaline batteries since 1996, they have become safe for normal waste disposal (these are considered common waste). Although not a major hazard to the environment, alkaline batteries can be recycled. Alkaline batteries contain materials that can be reused such as zinc, magnesium or iron. Although the recycling process is difficult and dangerous, there are still recycling plants that accept alkaline batteries.


3. The main battery recycling process



The recycling process begins with sorting the batteries by their chemical component. Thus, the batteries are sorted into categories in special containers. The recycling process can become even more profitable for battery recyclers if the batteries arrive at the factory already sorted by category.

Depending on the type of batteries, recycling processes may differ. Next I will detail the recycling process for each type of battery.

Lead-acid batteries recycling process

The batteries are chopped in a hammer mill, turning them into pieces. 

Plastic: The plastic particles are washed, then sent to a plastic recycler that melts them, puts them in an plastic extruder and turns them into small plastic pellets.

These pellets are then reintroduced to the market in various industries that use plastic.

Lead: Lead plates are cleaned, washed, dried and melted in smelting furnaces. The molten lead is poured into ingot molds. After a few minutes, the impurities are concentrated on the surface of the molten lead, floating in the molten lead. Impurities are removed and the resulting lead is left to cool. The resulting lead ingots are then sent to the battery manufacturers where they will be melted again and used to produce new lead plates or other parts for the new batteries.

Sulfuric acid:

Sulfuric acid in lead-acid batteries can be recycled by 2 methods:

Method 1: The acid is neutralized with an industrial compound similar to baking soda. This compound converts the acid to water. The water is treated, cleaned and then tested to meet purity standards for reintroduction into the environment. After the treatment process, the water is poured into the public sewer.

Method 2: Another method of recovering sulfuric acid is to process it and turn it into sodium sulfate, an odorless powder that is used in the production of laundry detergents, in the production of glass and in the textile industry. Also, the acid can be recovered in its original form and reused in the lead-acid battery industry.

Li-ion and Ni-MH battery recycling process

Li-ion batteries are recycled using an ultra-high temperature process. Used batteries are disassembled and melted in UHT furnaces. The resulting materials are separated into metal alloys containing copper, nickel, cobalt and slag, a stony waste containing rare metals. Slag can then be processed to recover lithium, but obtaining a high purity lithium from this compound would require too much cost, so slag is used in the construction industry.

Nickel-Cadmium batteries recycling process

The Ni-Cd battery recycling process is a thermal separation process (TSP). This TSP process is used to recover valuable metals from used Ni-Cd batteries, using limestone and cullet additives. Materials resulting from the process: slag, ingot and flue gas.

The slag contains mainly Ca and Si and the major crystalline phase is CaSiO3.

The ingot has a hight level of Fe (514,000 mg / kg) and Ni (245,000 mg / kg). The ingot can be refined to obtain Ni but the compound can be used in this form as an additive in the steel production process.

Alkaline batteries - the recycling process

As I said, alkaline batteries contain zinc, manganese, zinc-carbon, potasium or mercury. The batteries are pyrolyzed at temperatures of 700°C and the mercury is recovered by distillation.

The other metal components left after distillation are extracted and melted in a furnace at a temperature of 1500°C. Following this process, a molten metal compound containing Fe and manganese is formed, producing a ferromanganese alloy, while zinc vaporizes and can be recovered by condensation.


4. What are the benefits of battery recycling?


In conclusion, battery recycling is a beneficial process. Here are some reasons:

  • The batteries contain harmful chemicals that must not reach the landfill or the environment.
  • Valuable materials are recovered for the production of new batteries, thus reducing the need for the extraction of new materials and automatically reducing the level of pollution
  • Ensures safe storage of batteries, reducing the risk of batteries catching fire or exploding compared to their disposal in landfills or the environment.
  • There is a growing demand on the market for battery recycling
  • Reduce the cost of operating waste for local councils, so less taxes to pay
  • It is very easy to recycle batteries



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