Aluminum casthouses are being pushed to raise their use of recycled metal without sacrificing melt quality, recovery rates or production efficiency. As producers take in more post-consumer scrap, lightweight fractions, machining chips and other low-density materials become harder to handle: such material is difficult to introduce into conventional melting furnaces, which makes efficient scrap feeding and submergence central to recycling performance.
The difficulty is not confined to scrap preparation. Temperature and chemical composition must stay consistent throughout the molten bath to hit specification, so circulation and stirring equipment has to support heat transfer and metal movement while limiting process interruptions and excessive metal loss. Conventional mechanical pumps, though widely used, depend on immersed rotating components that degrade through contact with molten aluminum, dross accumulation and refractory debris.
Magnetic circuits in place of immersed impellers
Zmag America, Ltd. works in a specialized corner of casthouse technology, developing magnetic engineering solutions for molten metal circulation, furnace stirring and scrap recovery. The company traces its roots 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 foundation for equipment that stirs, circulates and submerges material in molten aluminum.
The distinction from conventional electromagnetic systems matters. Instead of an electromagnetic stirring arrangement, zPMC uses a permanent magnetic circuit to generate the field that moves the metal. Zmag describes the resulting movement as a virtual impeller, obtaining circulation without immersed mechanical impellers. In an August 2025 interview with AL Circle, Zmag America president Eishin Takahashi named limited familiarity with the technology as a barrier to wider US adoption, observing that aluminum producers globally tend to be conservative and more comfortable with equipment and processes they already know.
MagStir for furnace homogenization
MagStir is a non-contact stirring system for melting and holding furnaces. Its permanent magnetic circuit moves the bath to homogenize temperature and alloy composition. Zmag offers configurations for furnaces of 15 to 200 metric tons; because there is no immersed mechanical stirring component, casthouses can add circulation without putting further moving parts into the molten-metal environment.
The installation record extends beyond the United States. New Zealand Aluminium Smelters fitted the technology to a casting furnace and later extended it to additional furnaces; a technical case study published in 2017 examined those installations and reported improvements in temperature control during furnace preparation. Rio Tinto-operated Boyne Smelters in Queensland, Australia, had a MagStir unit fitted to a casthouse furnace in 2019.
MagPump as a mechanical-pump alternative
MagPump applies the same engineering approach to pumping and circulation and is designed to fit a standard pump well without furnace modification. It has no physical impeller and is marketed as a nearly hands-free option with no consumable parts and minimal downtime.
TST Inc., a US secondary aluminum producer, examined the system at its TANDEM Division in Fontana, California. Over a seven-week trial, MagPump replaced an existing mechanical pump in a production furnace. The findings described smooth operation and reduced disturbance to the molten-metal surface, and 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, alongside potential roles in gas injection and scrap submergence.
Typhoon and difficult scrap
Typhoon addresses scrap submergence and chip melting by drawing lightweight scrap and machining chips beneath the surface rather than letting them sit on top of the bath. Its magnetic circuit produces vortex-like movement that pulls material into the melt, supporting heat exchange and recovery during remelting.
At Neuman Aluminium's Marktl facility in Austria, the system was incorporated into a furnace modernization intended to widen the plant's ability to process low-density post-consumer scrap, including lightweight fractions with a bulk density of about 375 kg/m³ that had challenged conventional charging and melting. Neuman had targeted one metric ton per hour while the same furnace continued to melt solid charge; in operation the Typhoon processed almost twice the planned scrap quantity within the expected time without disrupting normal furnace operations, with low operator involvement and, the company reported, no negative effect on melt or finished-product quality. According to the published technical account, the system runs at 5–15 kW including its air-cooling blower and can submerge up to five metric tons per hour of machining chips, with an adjustable vortex intensity that can keep metal moving when no scrap or alloying material is being charged.
A crowded field with few direct equivalents
Several established suppliers compete in furnace stirring, molten-metal circulation and scrap submergence, though their offerings are not all direct equivalents to permanent-magnet technology.
- ABB supplies its AL-EMS electromagnetic stirring system for melting, holding and alloying furnaces, reporting more than 430 installations; in April 2026 it announced a further order from Arconic for a fifth stirrer at a Hungarian casthouse.
- 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 and complete casthouse equipment.
- Pyrotek covers a broader range of casthouse equipment, including electromagnetic pump systems and LOTUSS (Low Turbulence Scrap Submergence), which uses a circulation pump and refractory well to submerge light scrap; its UK operations include EMP Technologies Ltd.
- Rockwell Automation sits in adjacent industrial automation, supplying furnace and ladle-shop control systems, as in its modernization project for Mozal Aluminium's casthouse.
The common thread is that recirculation and submergence remain essential as recycled feedstock becomes more demanding. Whether permanent-magnet systems displace immersed mechanical components will depend on how quickly casthouses accept an unfamiliar route to a familiar problem; the case for them rests on taking wear-prone parts out of the melt rather than on a different metallurgical result.