The Large Fraction

According to the EU WEEE (Waste Electrical and Electronic Equipment) directive, 75% to 80% of all discarded electronic appliances in the European Union should now be recycled. One of the reasons for this is to recover the large amount of valuable materials inside these appliances, such as copper and precious metals.

Until now, recycling these products in some parts of the EU often meant manually opening the discarded objects and tediously sorting the materials inside by hand.

However this not only takes a lot of time, it is a tough physical job because the workers usually have to dismantle the appliances, some of which weigh tonnes, with a hammer and a screwdriver whilst on their knees. Also, lots of the valuable materials are lost because they are difficult to separate from the rest of the material.

Central Station
Hellenic Recycling Center S.A. (EKAN), which has a contract through the Greek Ministry of the Environment to serve as a central appliance disposal company in southern Greece, has now adopted an automatic method with which large quantities of electronic scrap can be processed for recycling.

The shredder that has been installed was developed by engineers of the company Erdwich Zerkleinerungssysteme GmbH of Kaufering, Bavaria, Germany. Be it washing machines or motors, the shredding system can “gently process” six tonnes of electronic scrap every hour.

Washing machines, electric ovens and beverage vending machines comprise part of the 25,000 tonnes of electronic scrap that is sent to the EKAN facility in Corinth, Greece, every year.

More than one-third of this material is steel or iron and one-fifth is plastic. However the focus here is on the valuable materials, such as copper, brass, aluminium and stainless steel, which are found in places such as the drum inside washing machines or in the motors, wires and cables. “It is particularly difficult to separate the recyclable materials in large appliances of this kind,” says Norbert Streicher, the project manager at Erdwich responsible for the EKAN installation.

Until the Erdwich installation, the workers at EKAN had been opening the individual appliances tediously by hand in order to remove the various components.

This not only took a long time but was very inefficient; also, the employees were exposed to a high risk of injury when handling these heavy appliances and the fragile materials.

This procedure has now been automated. The Erdwich shredder type HT520/2-2000, which was specially developed for appliances and electronic scrap, can process large appliances, up to a weight of 450 kilograms (992 pounds), at a capacity of six tonnes per hour.

Gentle Nature
“It is very important when handling these appliances that they are opened carefully to prevent the parts being destroyed by toxic substances and to prevent these substances being released,” says Streicher.

The engineers at Erdwich have therefore come up with a shredding method that carefully tears open the appliance thanks to the slow rotating speed and a calm, low-vibration working principle, thereby allowing the parts inside to fall out without being damaged. “At the same time, the method has to be designed so that it is not sensitive to glass, iron and concrete,” says the project manager.

Every ripper shaft is moved separately via a high-quality electro-hydraulic drive and is controlled electrically via an automation device made by Austria-based SPS Automation. “This allows both the speed and also the forward-backwards cycles of the shafts to be carefully adjusted for every application,” says Streicher.

Thanks to the ripper segments that can be exchanged separately, the operator can set the required part sizes and edge lengths of the output individually. For example, a setting of 100 millimetres by 100 millimetres or 300 times 300 millimetres can be selected to suit either downstream machine technology or for subsequent manual sorting.

If the ripper shows signs of wear, the blades can be welded on within the machine, which keeps maintenance costs very low.

Minds and Machines
The electronic scrap delivered to EKAN is initially picked up by grabbers and is transported on conveyor belts to the funnel of the shredder, which has an opening of around 2,000 millimetres by 1,200 millimetres (78 inches by 47 inches).

After the scrap has been gently shredded, a magnet separates the liberated iron and steel material. Then the various materials are sorted manually into two separate cabins. In the first work area, where the iron and steel pieces are sent, the employees pick out the valuable materials, such as copper. The remaining and intact steel and iron is baled and sent to its melting destination.

In the second cabin, trained workers sort the mixed material to remove free and intact pollutants, such as batteries, mercury, condensers and other materials like cables or stainless steel components.

The sorting cabins are attached at a higher level so that the employees can simply throw the collected materials into the respective containers via openings in the floor.

After the manual sorting process, the remaining materials land in a screening station with an integrated separation system. Here, the small mixed and type-sorted plastics, nonferrous metal mixes, copper and stainless steel parts and also the broken glass are separated.

A granulator then shreds the material to a predefined size so that the machine can easily and automatically sort the plastics and metals in a second sorting system. “This ensures that no valuable materials are lost,” says George Tzinis, head of engineering at EKAN. “We have also been able to ensure that no pollutants escape into the environment.”

The collected valuable materials, in particular the increasingly valued copper and also gold, silver and palladium, are sold to highly specialised companies that use these materials to make parts again for new electrical appliances—for households, the entertainment industry and telecommunications. 

This article was submitted by Munich-based Pressebüro Beatrix Gebhardt-Seele on behalf of Erdwich Zerkleinerungssysteme GmbH and EKAN S.A.