Collaboration between firms sees Italian aluminium recycling levels increase

A collaboration between Centro Rottami, Indinvest LT and TOMRA has seen an increase in aluminium recycling levels.

Italian scrap recycler Centro Rottami has been handling aluminium scraps for a decade using TOMRA separating units in order to supply a nearby foundry, run by metal manufacturer Indinvest LT, with the recycled matter. This repurposed aluminium is then turned into 85 per cent recycled content billet.

Clean aluminium at Centro RottamiThe Centro Rottami plant currently processes approximately 1,500 tonnes of aluminium, along with 1,000 tonnes of ferrous scrap on a monthly basis. The infeed aluminium is largely sourced from old window profiles, which require separation in order to produce pure aluminium fractions, due to contaminants such as plastic, rubber, copper, brass, zinc, and steel.

The recycling company has three TOMRA FINDER and three TOMRA X-TRACT sensor-based sorters at present, with which the separation is completed. First, the infeed material is shredded and pre-sorted using both magnets and eddy current separators, before following two lines. Material dropped by the eddy current separator is processed by the FINDER unit, which recovers metals such as stainless steel, and uses technologies such as SUPPIX® and Z-TECT in order to detect the desired material and deliver increased purity levels from the recovered fractions.

The three X-TRACT units are used to purify the aluminium ejected by the eddy current separator. They use X-ray transmission technology to detect the remaining contaminants and sort them by their respective atomic density. Through this process, shredded aluminium is distinguished from heavier metals, such as copper and brass, ready to be processed into green billet by Indinvest LT’s production plant.

Located next to Centro Rottami’s facility, the Indivest foundry houses five extrusion lines, with a total production capacity for 60,000 tonnes of extruded profiles per annum. The alloys produced must meet certain specifications, with Indivest developing a specific melt recipe to create the finished blends. The alloys are created from a mixture of primary aluminium, post-production scrap from the metal manufacturing company’s own plant, and the post-consumer scrap supplied by Centro Rottami. The higher the quality of the scrap, the less the amount of raw material that has to be used will be.

Aluminium retains its surface characteristics when recycled, making it a 100 per cent reusable resource. Additionally, the recycled alloy saves up to 95 per cent of the energy that would be required to produce primary aluminium from bauxite if the associated reduction in carbon dioxide emissions is considered.

Italy ranks first in Europe for recycled aluminium production, achieving 70 per cent recovery, exceeding the objective set by the European Union of 50 per cent recovery by 2025.

Gennaro Del Prete, Technical Director at the Centro Rottami plant, commented: "We started out as a scrap iron shredder then five years ago we decided to specialise in aluminium refining, a move which has been possible thanks to TOMRA's technologies.

"In 2019, we purchased two more TOMRA X-TRACT units because the aluminium market demands ever-increasing quantity and quality. We then combined the three machines into a single line, subdividing the material to be screened for further sorting to achieve the highest quality recovered aluminium from the shredding process. This move was also made to take advantage of synergies with Indinvest, an aluminium smelter whose plant is adjacent to ours."

"Being able to guarantee a constantly high purity aluminium is essential to establishing trust with foundries. Thanks to TOMRA, we have achieved the highest possible quality alloy materials which meet the quality requirements for the production of new aluminium profiles."

Ezio Porreca, Casthouse Manager for Indivest LT, said: "For around five years, Indinvest has been buying post-consumer scrap from Centro Rottami.

“Thanks to Centro Rottami’s use of the TOMRA X-TRACT units, we’ve been able to significantly increase the use of post-consumer material in the melting furnaces from around 20 per cent scrap to around 40 to 50 per cent. This has not only allowed us to reduce our use of primary material, but has also led to energy and gas savings of 5 per cent, which is significant given our production volumes.

"By using cleaner recycled aluminium our production has increased significantly. If not properly cleaned, recycled aluminium can still contain some contaminants such as paint, plastic and other material, which, in turn, form slag in the furnace. Using the clean material from TOMRA, we have far fewer pollutants and don’t need to clean the furnace as frequently. Cleaning the furnace involves opening the door and dropping the temperature from 1100 degrees to 800 to 900 degrees. Getting it back to 1100 degrees requires time, gas and electricity."

Roberto Antichi, President of Indinvest LT, said: "For us, the concept of collaboration is very important. We started this project together and thanks to our synergies you can clearly see that it has paid off."

"Two years ago, we created a billet called Creal, containing 85 per cent post-consumer aluminium with mechanical and, above all, surface results comparable to those of primary aluminium created by aluminium manufacturers from bauxite.”

"Recent years have shown us that our recycled aluminium is well received by the market and is increasingly in demand. Especially now, with the 2030 Paris Agreement mandating a reduction in CO2 consumption, all customers are pushing for the production of profiles with recycled material."