Page 32 from: June / July 2011

32 June/July 2011

Electronic scrap shredder takes care of business
On the face of it, the concept of

‘gentle’ shredding appears to be a

contradiction in terms. However,

German engineering firm Erdwich

Zerkleinerungssysteme has devel-

oped a shredder which carefully

opens up the electronic scrap

handled at EKAN in Greece to

prevent damage to its contents.

SSome 75-80% of all discarded electronic appliances must be recycled under EU law.
The recycling of these items, which contain

large amounts of valuable materials such as

copper and precious metals, remains to a large

extent a manual job in many countries.

EKAN, the central disposal company in south-

ern Greece and the country’s largest recycler of

electronic scrap, had been relying on manual

methods until the recent introduction of a more

automated system via which large volumes of

e-scrap can be processed for recycling. The asso-

ciated shredder was developed by Germany’s

Erdwich Zerkleinerungssysteme – a machine

and plant engineering company which concen-

trates on three core business areas: the recycling

and reprocessing of valuable materials; destruc-

tion of all types of special wastes; and the shred-

ding of waste to reduce its volume.

Focus on valuable materials
Some 25 000 tonnes of electronic appliances are

received every year at the Hellenic Recycling Cent-

er (EKAN) in Corinth, Greece. In material terms,

more than a third is iron and a fifth is plastic. How-

ever, the focus is on reclaiming valuable materials

such as copper, brass, aluminium and stainless steel

that are found, for example, in the drum of a

washing machine or in the motor and cables.

‘It is particularly difficult to separate the recyclable

materials in large appliances of this kind,’ explains

Norbert Streicher, Project Manager at Erdwich.

Until recently, EKAN’s workers had been engaged

in the tedious process of opening up the indi-

vidual appliances by hand in order to remove the

various components. This was not only time-

consuming but also very inefficient; moreover,

the employees were exposed to a high risk of

injury when handling these heavy appliances and

their fragile materials. However, this procedure

has now been automated following the installa-

tion of an Erdwich HT520/2-2000 shredder which

was specially developed for electronic scrap. It can

process large appliances weighing up to 450 kg at

a rate of six tonnes per hour.

Slow rotating speed
‘When handling these appliances, it is very

important that they are opened carefully to pre-

vent the parts from being destroyed by toxic

substances and to prevent these substances from

being released,’ says Mr Streicher. The engineers

at Erdwich devised a new shredding method

that carefully tears open the appliance thanks

to its slow rotating speed and a steady, low-

vibration working principle, as a result of which

the parts inside 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,’

Mr Streicher explains. Each ‘ripper’ shaft is moved

separately by an electro-hydraulic drive and is

controlled electrically through an SPS automation

device. ‘This allows both the speed and also the

forward-backward cycles of the shafts to be care-

fully adjusted for every application,’ he adds.

Given that the ripper segments can be

exchanged separately, the operator can set the

required part sizes and edge lengths of the out-

put individually. Furthermore, if a ripper shows

signs of wear, the blades can be welded on

within the machine to keep maintenance costs

very low, according to Erdwich.

E – S C R A P By Kristin Haertling

After shredding, valuable materials and potential pollutants are manually sorted in two separate cabins.

The heart of the Erdwich-built system is a shredder that carefully
tears open the electronic appliances to prevent interior parts being
destroyed by toxic substances and the release of those substances.

03 -s a 3 1 -06-11 10:11