TOMRA Sorting Recycling: Addressing the challenges of aluminium recycling
By TOMRA Recycling
Demand for aluminium has risen steadily over recent years and is predicted to increase further over the next two decades, with both the European car industry and construction industry likely to remain major end users of this highly versatile metal. In the car industry, the need to lightweight vehicles is driving up demand for aluminium, in particular wrought aluminium alloys for use in electric vehicles as the industry shifts away from internal combustion engines which use cast alloys. And, with Europe’s construction industry under increasing pressure to reduce its CO2 emissions and become more energy efficient, demand for aluminium from this sector is also likely to rise further still as it is such a lightweight, energy efficient and infinitely recyclable material.
We’ve already witnessed European plastics manufacturers committing to increasing the amount of recycled content of their products in order to reduce their carbon footprint and now we’re seeing the same thing happen in the aluminium industry, where aluminium producers are marketing high recycled content aluminium to demonstrate their environmental credentials and their commitment to reducing CO2 emissions.
It’s clear that the end markets for high quality recycled aluminium already exist and that demand is only likely to rise further in the future. The challenge for European scrap metal processors, along with the growing number of aluminium producers who are investing in equipment to sort the scrap material themselves, is how to produce a consistently high quality, high purity furnace-ready aluminium product. To achieve this, and optimise the use of scrap in their furnaces, the infeed material needs to be cleaned of heavy metals, of aluminium-plastic compounds and of other light material, such as magnesium. Being able to rely on a repeatable quality furnace material is key for the aluminium industry.
Removing contaminants to produce high-purity aluminium
One of the major sources of scrap aluminium is Zorba – a mixed non-ferrous material generated by eddy-current separators in end of life vehicles (ELV) and Waste Electronic & Electrical Equipment
(WEEE) recycling. Zorba consists primarily of aluminium (typically 70-80%) and other non-ferrous metals like copper, brass and zinc, as well as magnesium generated by eddy-current separators. Additionally, Zorba can contain non-metallic contaminants such as rubber and foil. In Europe, magnesium makes up between 1-2% of a typical scrap aluminium fraction and is regarded as an unwanted contaminant in the scrap mix. Secondary aluminium smelters ideally like the aluminium from Zorba to contain very low magnesium, typically well below 0.5% by weight.
Similarly, the increasing volume of aluminium-plastic compounds, as well as contaminating plastic and non-metallic materials in Zorba make it difficult for processors to produce high-purity aluminium scrap. Historically, both the magnesium and the aluminium-plastic compounds would have ended up in the aluminium fraction, reducing the quality of the aluminium product and, subsequently, reducing its market value.
Until two years ago, processors could sell this lower quality material to China, but since China closed its borders it has become increasingly difficult to sell Zorba that has not been cleaned. Consequently, there is a now a surplus of Zorba in Europe. With an excess amount of Zorba sitting in yards across Europe, the issue of quality becomes even more significant. Selling it on without cleaning it simply isn’t a sustainable solution, especially if you want to get a good price for the material. Only those recyclers who are able to process the material and recover a consistently high-quality aluminium product will be able to sell it on to end customers in domestic markets.