Article featured in the Aluminium International Today
A turnkey project from Hertwich Engineering for Aluminium Foundry France demonstrated how modern furnace technology can enable circularity, energy efficiency and a competitive advantage. Günther Wimroither and Leon Hensel report.
As governments introduce stricter CO₂ regulations and carbon pricing schemes, aluminium producers are under pressure to decarbonise their operations while still maintaining productivity and product quality. Recycling plays a central role in this transformation, but the challenge lies in processing contaminated scrap streams efficiently and sustainably.
A recently completed greenfield recycling casthouse supplied by Hertwich Engineering to Aluminium Foundry France illustrated how furnace and casthouse technology can enable operators to reduce CO₂ emissions, increase recycling yields and move towards net zero targets.
A fully integrated recycling casthouse in the heart of Europe
The project involved the engineering, delivery, supervision of installation and commissioning of a complete aluminium recycling casthouse located in the north of France, in close proximity to major European scrap sources and extrusion plants.
All major equipment across the process chain was supplied by Hertwich Engineering, which included:
- melting and holding furnaces,
- vertical direct chill (VDC) billet casting machine,
- a continuous homogenising plant,
- sawing, weighing and packing equipment.
This fully integrated approach ensures optimal interaction between individual equipment and related process steps and allowed a fast and reliable ramp-up of production. The backbone of the casthouse is the advanced automation system developed by Hertwich Engineering.
From the start of mechanical installation to start of production (SOP), the entire casthouse was brought into operation in six months to produce its first saleable billets. The result can be seen as proof of highly professional overall project management and coordination by Aluminium Foundry France and the excellent collaboration of all parties involved.
Once fully ramped up, the facility is designed for an annual capacity of around 80,000 tons of finished extrusion and forging billets.
Designed for challenging scrap streams
The casthouse was engineered to process a range of aluminium scrap qualities, with a focus on locally available contaminated recycling material. The melting and casting route consists of:
- an Ecomelt PS preheated shaft melting furnace for contaminated scrap,
- a single chamber melting furnace for quasi-clean scrap,
- a holding and casting furnace for alloying and melt conditioning,
- a Hertwich VDC casting plant equipped with inline melt treatment and gas-assisted mould technology for premium billet quality.
After casting, all billets are inspected using a helical ultrasonic testing station before they are cut to final length. The billets are then passed through a continuous homogenising furnace, followed by cooling in a billet cooling station including a turbo-cooling section, before final weighing and packing into bundles ready for shipment.
Preheat shaft furnace
At the heart of the project lies a key differentiator: the Ecomelt PS150 melting furnace with preheat shaft, with a melting capacity of 150 tons per day. This furnace type enables the use of contaminated scrap, such as:
- old window profiles with paint, lacquer and plastic contents of up to 20%,
- coated sheet scrap.
As a side effect those kinds of contaminated scrap are usually available in the market at a substantially lower price compared to clean process scrap. During the preheating process, the organic components of the scrap undergo pyrolysis, thereby releasing combustible gases. Instead of flaring these gases or losing their energy content, the PS150 furnace is designed to capture and reuse the pyrolysis gases as supplementary fuel for the regenerative burners in the main chamber.
To achieve this, Hertwich uses a proprietary custom furnace preheat shaft design incorporating:
- sophisticated hot gas circulation systems,
- special gas control flaps and
- a sophisticated automation system.
The automation continuously balances the ratio between natural gas and pyrolysis gas depending on scrap composition and operating conditions. This allows stable furnace operation while reducing natural gas consumption.
Compared to conventional furnace concepts, this approach can reduce fossil fuel usage by up to 50%, which directly translates into significantly lower CO₂ emissions per ton of aluminium produced.
Submerged melting
In addition to energy savings, the PS150 furnace employs submerged melting technology. Scrap melts by contact with liquid metal instead of melting in the atmosphere, which:
- reduces oxidation,
- minimises dross formation
- improves metal recovery.
By increasing aluminium yield during melting, the furnace further strengthens the environmental and economic performance of the recycling process. Higher yield means less primary aluminium is required to compensate for losses, which is another important contributor to CO₂ reduction along the aluminium value chain.
Hydrogen-ready
In addition to the fuel-saving capabilities, all gas-fired furnaces of the plant are hydrogen-ready, enabling a future switch to a CO₂-emission-free fuel source.
Circular economy
One of the advantages of this casthouse concept is its ability to close the material loop locally. By processing post-consumer and post-industrial scrap sourced from the surrounding region, the customer has established a circular economy model with
- reduced reliance on primary aluminium,
- shorter transport distances for scrap and finished bullets,
- greater resilience against volatile raw material markets.
This local recycling approach not only lowers Scope 1 and Scope 3 emissions, but also provides long-term supply security, which is an important factor for extrusion companies and downstream customers alike.
A blueprint
The project demonstrated that modern recycling casthouse technology is no longer just an environmental add-on, but a strategic investment into competitiveness. As CO₂ emissions become increasingly regulated, monitored and priced, aluminium producers around the world must adapt their operations accordingly.
Equipment solutions like the Ecomelt PS furnace with pyrolysis gas utilisation allow operators to :
- process lower-grade scrap, more widely available scrap,
- reduce dependency on fossil fuels due to reduced specific energy consumption,
- lower CO₂ emissions per ton of output,
- improve metal yield and operational efficiency.
For casthouse operators seeking to align profitability with sustainability, such technologies can make a decisive difference.
Conclusion
Achieving net zero in aluminium production requires more than incremental improvements; it demands fundamental changes in how scrap is processed and energy is used.
The recycling casthouse supplied by Hertwich to Aluminium Foundry France shows that, with the right technology, it is already possible to combine high productivity, excellent billet quality and substantial CO₂ savings in a single integrated solution.
For the aluminium industry, this represents not just a path towards compliance with future regulations, but an opportunity to secure long-term comp
