Aluminum casthouses are being asked to absorb more recycled metal without surrendering melt quality, recovery rates or production efficiency, and the fractions that make that hardest — lightweight scrap, machining chips and other low-density material — are precisely the ones conventional melting furnaces handle least gracefully. Zmag America, Ltd. is promoting a family of permanent-magnet devices as one route to the problem, on the argument that molten-metal movement can be generated without immersing rotating hardware in the bath.
The difficulty has two connected halves. Introducing low-density scrap demands submergence, because material that sits on the bath surface melts slowly and is exposed to oxidation; holding a large bath at uniform temperature and composition demands circulation. Circulation and stirring equipment must therefore support heat transfer and metal movement while limiting process interruptions and excessive metal loss. Conventional mechanical pumps, though widely used, rely on immersed rotating components that deteriorate through exposure to molten aluminum, dross accumulation and contact with refractory debris.
A magnetic circuit instead of an impeller
Zmag's technical foundation sits in the industrial application of magnets and magnetic circuits. The company traces its history to magnetic engineering and the commercialization of eddy-current separation, used to recover non-ferrous metals from mixed material streams, before extending into molten-metal applications. Its patented zPMC (Zmag Permanent Magnetic Circuit) is the technological base for equipment that stirs, circulates and submerges material in molten aluminum.
The company's central distinction is between a permanent magnetic circuit and a conventional electromagnetic stirring arrangement. In Zmag's equipment the permanent circuit generates the field that moves the metal; the resulting motion is described by the company as a virtual impeller, delivering circulation without an immersed mechanical impeller. The claim's significance is mainly about wear and intervention: if the moving part in the melt disappears, so does one route to degradation.
MagStir, MagPump and Typhoon
MagStir is a non-contact stirring system for aluminum melting and holding furnaces, using the permanent magnetic circuit to generate movement in the bath and support homogenization of temperature and alloy composition. Zmag offers it in configurations for furnaces from 15 to 200 metric tons. Its non-contact principle removes the need for an immersed mechanical stirring component, which the company presents as an option for casthouses that want better melt circulation without adding moving parts to the molten-metal environment.
The installation record reaches beyond the United States. New Zealand Aluminium Smelters (NZAS) fitted the technology to a casting furnace and later extended its use to additional furnaces; a technical case study published in 2017 examined the installations and reported improvements in temperature control during furnace preparation. A MagStir unit was also installed in a casthouse furnace at Rio Tinto-operated Boyne Smelters in Queensland, Australia, in 2019.
MagPump carries the same approach into pumping and circulation. It is designed to fit a standard pump well without furnace modification and, unlike conventional mechanical pumps, uses no physical impeller; it is marketed as a nearly hands-free alternative with no consumable parts and minimal downtime. At the TANDEM Division of US secondary producer TST Inc. in Fontana, California, a seven-week trial replaced an existing mechanical pump in a production furnace. The findings described smooth operation and reduced disturbance to the molten-metal surface, and TST plant management reported that the system avoided the splashing seen with conventional pumping as the furnace metal level fell during draining.
The technology was also presented at the TMS 2023 Annual Meeting and Exhibition, where its use in side-well, multi-chamber furnaces was discussed; the presentation set out potential further roles, including gas injection and scrap submergence, alongside metal circulation.
Typhoon addresses scrap submergence and chip melting, introducing lightweight scrap and machining chips beneath the molten surface instead of leaving them at the top of the bath. Its magnetic circuit generates a vortex-like movement that draws material into the melt, supporting heat exchange and recovery during remelting. The most detailed public example is a recent installation at Neuman Aluminium's Marktl facility in Austria, where the system was incorporated into a furnace modernization intended to widen the plant's ability to process low-density post-consumer scrap, targeting lightweight fractions with a bulk density of roughly 375 kg/m³ that had challenged conventional charging and melting.
Neuman had set a target of one metric ton per hour while the same furnace continued to melt solid charge. In operation the Typhoon system processed almost twice the planned scrap quantity within the expected time, without disrupting normal furnace operations, and the company reported low operator involvement and no negative impact on melt or finished-product quality. According to the published technical account, Typhoon operates at 5–15 kW including its air-cooling blower and can submerge up to five metric tons per hour of machining chips; vortex intensity is adjustable, so the system can keep metal moving when no scrap or alloying material is being charged.
Familiarity as the real constraint
Adoption is not purely a technical question. In an August 2025 interview with AL Circle, Eishin Takahashi, president of Zmag America, named limited familiarity with the technology as a barrier to wider use in the United States, observing that aluminum producers globally tend to be conservative and more comfortable with equipment and processes they already know.
A crowded field with few direct equivalents
Suppliers of furnace stirring, molten-metal circulation and scrap-submergence equipment are well established, though not all offerings are direct equivalents. ABB supplies its AL-EMS electromagnetic stirring system for melting, holding and alloying furnaces, with more than 430 installations reported globally; in April 2026 it announced a further order from Arconic for a fifth stirrer at its Hungarian casthouse, following earlier units at the same site. Presezzi Extrusion Group, through its Melting Technology division and North American presence, offers the L.E.C. (Low Energy Consumption) Stirrer for melting and holding furnaces alongside remelting equipment and complete casthouse operations.
Pyrotek covers a broader equipment range, including electromagnetic pump systems and its LOTUSS (Low Turbulence Scrap Submergence) technology: the EMP systems use electromagnetic forces to circulate molten aluminum and support metal transfer and scrap charging, while LOTUSS relies on a circulation pump and refractory well to submerge lightweight scrap. Pyrotek's UK operations include EMP Technologies Ltd., which designs, sells and installs metal-melting and circulation systems built around electromagnetic pumps. Rockwell Automation, by contrast, sits in the adjacent industrial automation segment rather than offering like-for-like permanent-magnet stirring, with furnace and ladle-shop control work that includes a modernization project for Mozal Aluminium's casthouse.
The competitive picture suggests the permanent-magnet route will be judged on the same terms as its electromagnetic and mechanical rivals: whether it holds bath uniformity, handles difficult scrap and avoids unplanned downtime on a given furnace. Because the evidence so far is concentrated in individual installations and case studies rather than broad comparative data, the case for non-contact circulation rests on plant-level results — and, as the company's own account acknowledges, on how quickly casthouses become willing to run equipment that differs from what they already know.