All about how permanent-magnet engineering is tackling more than one aluminum casthouse challenge

Aluminum casthouses are facing a growing operational challenge of increasing the use of recycled metal without compromising melt quality, recovery rates or production efficiency. As manufacturers look to incorporate more post-consumer recycled (PCR) aluminum, processing lightweight scrap, machining chips and other low-density materials has become increasingly important. Such materials are difficult to introduce into conventional melting furnaces, making efficient scrap feeding and submergence essential to improving recycling performance.

The challenge extends beyond scrap preparation. Maintaining consistent temperature and chemical composition throughout the molten metal bath is critical to producing specification-compliant aluminum. Equipment used for circulation and stirring must therefore support effective heat transfer and metal movement while limiting process interruptions and excessive metal loss.

Conventional mechanical pumps, although widely used, rely on immersed rotating components that can deteriorate through exposure to molten aluminum, dross accumulation and contact with refractory debris.

Against this backdrop, Zmag America, Ltd. operates in a specialized segment of aluminum casthouse technology, developing magnetic engineering solutions for molten metal circulation, furnace stirring and scrap recovery.

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From magnetic engineering to molten-metal applications

Zmag's technological foundation lies in the industrial application of magnets and magnetic circuits. Its company history traces its roots to work in magnetic engineering and the commercialization of eddy-current separation technology, which is used to recover non-ferrous metals from mixed material streams. The company subsequently expanded its focus to molten-metal applications, developing its patented zPMC™ (Zmag Permanent Magnetic Circuit) as the technological foundation for equipment that stirs, circulates and submerges material in molten aluminum.

The distinction between permanent-magnet and conventional electromagnetic systems is central to understanding Zmag's approach. Rather than relying on a conventional electromagnetic stirring arrangement, its zPMC technology uses a permanent magnetic circuit to generate the magnetic field responsible for moving the molten metal. The resulting movement is often described by the company as a virtual impeller, allowing the systems to generate circulation without depending on conventional immersed mechanical impellers.

In an August 2025 interview with AL Circle, Eishin Takahashi, President of Zmag America, identified limited familiarity with the technology as one of the barriers to wider adoption in the United States. He observed that “Globally, aluminum producers tend to be conservative and feel more comfortable with equipment and processes they are already familiar with.”

MagStir targets furnace homogenization

One of Zmag’s principal offerings is MagStir, a non-contact stirring system designed for aluminum melting and holding furnaces. It uses the company's permanent magnetic circuit to generate movement within the molten bath, supporting the homogenization of temperature and alloy composition.

The system is available in different configurations for furnaces with capacities ranging from 15 to 200 metric tons, according to Zmag. Its non-contact operating principle removes the need for an immersed mechanical stirring component, making it an alternative for casthouses seeking to improve melt circulation without introducing additional moving parts into the molten-metal environment.

MagStir's application history extends beyond the United States. New Zealand Aluminium Smelters (NZAS) installed the technology in a casting furnace, subsequently extending its use to additional furnaces. A technical case study published in 2017 examined the installations and reported improvements in temperature control during furnace preparation. The technology has also been installed at Rio Tinto-operated Boyne Smelters in Queensland, Australia, where a MagStir unit was fitted to a casthouse furnace in 2019.

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MagPump offers an alternative to mechanical circulation

While MagStir focuses on stirring, MagPump extends Zmag's magnetic engineering approach to molten-metal pumping and circulation. The system is designed to fit into a standard pump well without requiring furnace modification. Unlike conventional mechanical pumps, it does not use a physical impeller and is marketed as a nearly hands-free alternative with no consumable parts and minimal downtime.

Its application was examined at the TANDEM Division of US-based secondary aluminum producer TST Inc. in Fontana, California. During a seven-week trial, MagPump replaced an existing mechanical pump in a furnace used for aluminum production.

The findings described smooth operation and reduced disturbance to the molten-metal surface. TST's plant management also reported that the system avoided the splashing experienced with conventional pumping arrangements as the furnace metal level fell during draining.

The technology was also presented at the TMS 2023 Annual Meeting and Exhibition, where its application in side-well, multi-chamber furnaces was discussed. The presentation showcases its potential for additional operations, including gas injection and scrap submergence, alongside its primary role in metal circulation.

Typhoon addresses difficult-to-process aluminum scrap

Zmag's third major product, Typhoon, focuses on scrap submergence and chip melting. The system is designed to introduce lightweight aluminum scrap and machining chips beneath the molten-metal surface, rather than allowing these materials to remain at the top of the bath. Its magnetic circuit generates a vortex-like movement that draws the material into the melt, supporting heat exchange and recovery during remelting.

A recent installation at Neuman Aluminium's Marktl facility in Austria provides a strong example of the technology's application. Neuman incorporated a Typhoon chip-submergence system into a furnace modernization project to expand its ability to process low-density post-consumer scrap. The targeted material included lightweight fractions with a bulk density of approximately 375 kg/m³, which had presented challenges for conventional furnace charging and melting.

The operating results exceeded the initial expectations. Neuman had set a target of processing one metric ton per hour while continuing to melt solid charge materials in the same furnace. During operation, the Typhoon system processed almost twice the planned scrap quantity within the expected time, without disrupting normal furnace operations.

The company also reported low operator involvement and no negative impact on melt or finished-product quality.

The Typhoon system operates at 5-15 kW, including its air-cooling blower, and can submerge up to five metric tons per hour of machining chips, according to the published technical account. Its vortex intensity can also be adjusted to suit operating requirements, allowing the system to maintain molten-metal movement when scrap or alloying material is not being charged.

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Operating in a competitive technology landscape

The market for aluminum furnace stirring, molten-metal circulation and scrap-submergence equipment includes several established industrial suppliers. However, their offerings do not all represent direct equivalents to Zmag's permanent-magnet technology.

ABB supplies its AL-EMS electromagnetic stirring system for aluminum melting, holding and alloying furnaces. Its technology has been deployed across a substantial global installation base, with the company reporting more than 430 installations. In April 2026, ABB announced a further order from Arconic for a fifth stirrer at its Hungarian casthouse, following earlier installations at the same facility.

Presezzi Extrusion Group, through its Melting Technology division and North American presence, also operates in the furnace-stirring segment. Its portfolio includes the L.E.C. (Low Energy Consumption) Stirrer, designed for melting and holding furnaces, alongside equipment for aluminum remelting and complete casthouse operations.

Pyrotek has a broader presence across aluminum casthouse equipment, including electromagnetic pump systems and its LOTUSS (Low Turbulence Scrap Submergence) technology. Its EMP systems use electromagnetic forces to circulate molten aluminum and support metal transfer and scrap charging, while LOTUSS uses a circulation pump and refractory well to submerge lightweight scrap. Pyrotek's UK operations also include EMP Technologies Ltd., which is involved in the design, sale and installation of metal-melting and circulation systems incorporating electromagnetic pumps.

Rockwell Automation, meanwhile, operates in the adjacent industrial automation segment rather than offering a like-for-like permanent-magnet stirring product. Its work in the aluminum sector includes furnace and ladle-shop control systems, as demonstrated by its modernization project for Mozal Aluminium's casthouse operations.

It is evident that the aluminum producers seek to incorporate more challenging recycled feedstock, the ability to manage molten-metal movement without relying on conventional immersed mechanical components could become an increasingly relevant consideration.