The EU has a number of schemes, initiatives and directives that all promote the idea of recycling materials wherever possible. Achieving the circular economy – a society in which nothing is wasted or disposed of until its potential value has completely depleted – is one of the EU’s key objectives in the 21st century.
Businesses have long understood the benefits of drawing the most value from assets as possible. The only difference is that now it has become an important issue for wider society, with the competitive advantage provided by asset utilisation replaced with economic and environmental responsibility.
Effective materials recovery is critical in ensuring that the recycling process for waste electrical and electronic equipment (WEEE) is as effective as it can be.
In a typical electronic application, there will be hundreds of resources with little reusable value and many components made of high-value materials. Recycling plant managers will naturally want to recover as many valuable materials as possible with little waste mixed in.
This means that companies need to invest in quality handling and processing equipment to ensure they can extract as much value from the WEEE as possible.
WEEE recovery is a particular challenge compared with other materials recovery applications. Gough Engineering has worked on a number of applications: for example removing nails from construction pallets so the material can be reused, and sorting plastics so they can be shredded and used as feedstock for masterbatches.
But in WEEE recovery, there are bigger challenges to face. Irregular-shaped products will pass through the processing line, meaning that handling equipment needs to be adaptable to a number of potential products.
High rates of valuable material recovery are only possible through specialised screening and separation equipment during recovery operations. In most applications where screening is necessary, there is a risk that blocked mesh or ‘screen blinding’, will affect throughput rates.
For example, one stage in the recycling process of a standard refrigerator involves the unit itself being shredded down to separate insulation foam, electronic matter, metals, plastics and gases. From there, each component goes its separate way.
The foam, for instance, is ground into a powder to release the gases contained within it, and the resulting polyurethane powder then moves on via a conveying system to another part of the plant for handling.
“High rates of valuable material recovery are only possible through specialised screening and separation equipment during recovery operations.”
When this powder is being screened, it may accumulate and block the mesh, a phenomenon known as screen blinding. This is not an uncommon occurrence and, in our experience of material processing, can be prevented by using screens that include an ultrasonic pulse and a vibratory motor.
But it is also vital that no valuable WEEE or metals are mixed in with the foam ahead of the grinding process. To ensure this, plant managers must use a screening and separating system that can effectively sort the shreds of polyurethane from steel fragments or gold-containing circuitry.
This is just one example of electronics recovery. More commonly, the recovery process is exclusively about extracting precious metals from the circuitry. Recently, Gough worked with a customer to supply handling equipment for their WEEE recycling plant.
The customer uses the heat and ultraviolet light properties of plasma to smelt and separate the precious metals contained within WEEE, and then convert the catalyst material into an inert, safe and reusable product.
By using this method, the customer manages to generate a much higher recovery of materials, with more than 98% typically recovered. This includes gold, silver, palladium, copper, iron and tin. The process also destroys all the hazardous elements from the WEEE.
Gough designed the handling equipment to fit within the materials handling needs and layout of the plant. Each recycling plant will require something different from its screening and separation systems, whether it is due to the flammability of processed items or granularity. The layout of the plant may also influence the handling systems if processes are carried out on different levels.
By consulting with a materials management specialist, plant managers can determine the best equipment to maximise the value of their operations and the space that they have available.
The EU calculates there will be more than 12 million tonnes a year of WEEE across Europe by 2020. By investing in the right equipment to sort waste and recover valuable materials effectively and efficiently, recycling plant managers can be rewarded with lower output and input costs, less downtime and a greater contribution to that circular economy.
Stephen Harding is managing director of recycling materials management specialist Gough Engineering