Batteries and accumulators returned to shops and other collection points are shipped to Akkuser Oy’s specialised processing plant where they are first sorted. This is important, as each type of battery and accumulator requires a different kind of processing procedure in order for the materials contained in them to be recycled into new raw materials as thoroughly as possible. In total, more than 50% of the raw materials contained in batteries and accumulators can be reutilised as industrial raw materials.
The majority of batteries on the Akkuser processing line are alkaline batteries – they comprise approximately 80% of all batteries and accumulators recycled in Finland. First, the line workers separate other battery types from the alkaline batteries. Recognising the different battery types requires experience and a good eye, as they can sometimes look confusingly similar.
When other fractions have been separated from alkaline batteries, alkaline batteries are crushed, and magnetic iron is first separated from the crushed material (less than 25%). The remaining “black mass” is delivered to a zinc smelting plant or a chemical treatment process.
In Finland, the magnetic iron collected from the alkaline batteries through the recycling process is refined into raw materials for construction equipment, cars, tools, etc. Zinc can be recycled for use by the construction, automotive and pharmaceutical industries, for example.
In the future, it may be possible to produce fertiliser from all alkaline batteries recycled in Finland thanks to technology developed by the Finnish company Tracegrow Oy. Tracegrow Oy’s fertiliser products, which are suitable for organic farming, can utilise the manganese in the black mass, in addition to the zinc.
Read more about their story on our #Kierrossa-blog.
Lithium primary batteries are carefully separated from alkaline batteries. It is imperative that their terminals have been taped over, as they may cause a fire if they short-circuit. This is why Akkuser stores them outside under a separate shelter.
From there, the batteries are delivered to Riihimäki to undergo a high-heat treatment process by Fortum. The process is designed for hazardous waste, and the flue gases generated from processing the waste are carefully processed as well. The process is less harmful to the environment than incinerating the waste with normal mixed waste.
Button cell batteries are mechanically separated from others and divided into large and small batteries. The small batteries are often so-called silver oxide batteries, containing 2–4% silver. They are delivered from the processing plant to a precious metal refinery for recovery. Larger lithium button cell batteries are transported with other lithium batteries for high-heat treatment intended for hazardous waste, as the materials cannot be safely recovered by any other means.
Lithium batteries that are used in a variety of devices, such as smartphones, laptop computers and hand tools, are processed at the Akkuser recycling plant in a two-stage crushing process that enables safe handling of the ignition-prone and volatile Litties.
The fractions resulting from the process contain significant amounts of ingredients such as cobalt (25–30% concentrate) and copper (15–20% concentrate) that are reutilised as industrial raw materials. Cobalt is an important raw material for batteries while copper is needed in the electronics industry, among others.
The smaller lithium batteries contain significant amounts of cobalt, which is delivered to the world’s largest cobalt refinery in Kokkola. There, the recycled cobalt is refined for use as recycled raw material in industry. Not only does recycling cobalt save energy, it also saves pristine cobalt, which is mined primarily in the Congo area under primitive conditions.
A separate process is currently being developed in Finland for low-cobalt and cobalt-free lithium batteries that are used in tool and electric vehicles, for example. Depending on their type, the batteries contain materials such as copper, nickel, manganese, aluminium and iron. These batteries currently comprise only a relatively small portion of all recycled batteries and accumulators, but their amount is expected to increase significantly in the near future.
Nickel-metal hybrid batteries and accumulators, such as rechargeable small batteries that resemble alkaline batteries as well as many hand tool batteries, are crushed after sorting at the processing plant. Different ingredients can be separated from the crushed material magnetically and with other mechanical means.
The most important metals recovered from nickel-metal hydride batteries are nickel and cobalt (approx. 35% in total). Nickel is used for applications such as manufacturing stainless steel, whereas the rare cobalt is used for manufacturing batteries for various devices, especially smartphones and electric cars.
Box-shaped, sealed lead gel batteries contain 65–90% lead, which is extremely harmful to the environment but easy to recycle. Lead-acid batteries are delivered through domestic collectors, such as Akkukierrätys Pb Oy, to lead-acid battery recycling plants for processing, where the lead is recovered and used primarily for manufacturing new lead-acid batteries. The process also involves neutralising the acids contained in the batteries.
Nickel-cadmium batteries used in devices such as old cordless tools are delivered from Nivala to suitable recycling plants, where the materials contained in them are separated in a multi-stage process.
The ferro-nickel (60%) contained in nickel-cadmium batteries is reutilised in the manufacturing of steel and the cadmium (15%) is used for applications such as the manufacturing of new batteries. Using recycled nickel saves up to 75% of energy when compared to mining pristine material.
Statistical information on recycling batteries and accumulators in 2020 can be found here.