Aluminium casthouses are under pressure to use more post-consumer recycled metal while protecting melt quality, recovery and productivity. Lightweight scrap, machining chips and other low-density feeds are difficult to charge into conventional melting furnaces, so efficient feeding and submergence have become more important. Circulation and stirring must also maintain temperature and composition throughout the bath without adding excessive downtime or metal loss.
Zmag America is targeting those tasks with permanent-magnet systems rather than conventional immersed mechanical equipment. The company's patented zPMC circuit generates a magnetic field that moves molten aluminium; Zmag describes the resulting flow as a virtual impeller because it can circulate metal without a physical impeller in the bath. Rather than using a conventional electromagnetic stirring arrangement, the zPMC design uses a permanent magnetic circuit to generate the field that moves the metal. Zmag's background includes magnetic engineering and eddy-current separation for non-ferrous recovery before it moved into molten-metal applications.
Non-contact stirring for furnace homogenisation
MagStir is a non-contact stirring system for melting and holding furnaces. It uses the permanent-magnet circuit to promote temperature and alloy homogenisation and is offered for furnaces from 15 to 200 metric tons. Because it has no immersed mechanical stirring element, it is presented as a way to improve circulation without adding moving parts to the molten-metal environment. New Zealand Aluminium Smelters installed the system in a casting furnace and later extended it to other furnaces; a case study published in 2017 reported better temperature control during furnace preparation. Rio Tinto's Boyne Smelters in Queensland, Australia, fitted a MagStir unit to a casthouse furnace in 2019.
Pumping without a physical impeller
MagPump extends the same concept to pumping and circulation. It is designed to fit a standard pump well without furnace modification, uses no physical impeller and is marketed as requiring little manual attention, with no consumable parts and minimal downtime. At TST Inc.'s TANDEM division in Fontana, California, a seven-week trial replaced an existing mechanical pump in a production furnace. The trial was described as running smoothly and causing less disturbance to the molten-metal surface; plant management also said the system avoided the splashing seen with conventional pumping as the furnace metal level dropped during draining. The technology was presented at TMS 2023 in connection with side-well, multi-chamber furnaces, and possible uses include gas injection and scrap submergence as well as circulation.
Vortex submergence for lightweight scrap
Typhoon addresses scrap submergence and chip melting. It introduces lightweight scrap and machining chips below the surface instead of letting them float, using a magnetic circuit to create a vortex that draws material into the melt and supports heat exchange and recovery. At Neuman Aluminium's Marktl plant in Austria, the system was part of a furnace modernisation aimed at low-density post-consumer scrap, including fractions with a bulk density of about 375 kg/m³. Neuman set a target of processing one metric ton per hour while continuing to melt solid charge in the same furnace. During operation, Typhoon processed almost twice the planned scrap quantity within the expected time without disrupting normal operations, and the company reported low operator involvement and no negative effect on melt or finished-product quality. The system operates at 5–15 kW including its air-cooling blower and can submerge up to five metric tons per hour of machining chips, with adjustable vortex intensity.
Competing routes to molten-metal movement
Zmag is not alone in supplying furnace stirring and circulation equipment. ABB's AL-EMS electromagnetic stirring system is used in aluminium melting, holding and alloying furnaces and has more than 430 installations, according to the company. In April 2026, ABB announced an order from Arconic for a fifth stirrer at its Hungarian casthouse after earlier installations there. Presezzi Extrusion Group's Melting Technology division offers the L.E.C. low-energy-consumption stirrer for melting and holding furnaces, along with remelting and casthouse equipment. Pyrotek supplies electromagnetic pump systems and LOTUSS low-turbulence scrap submergence, which uses a circulation pump and refractory well for lightweight scrap; its UK operations include EMP Technologies. Rockwell Automation works in adjacent furnace and ladle-shop control systems rather than offering a like-for-like permanent-magnet stirrer.
The comparison matters as casthouses try to incorporate harder recycled feeds. Zmag argues that avoiding immersed mechanical components can reduce maintenance and process disruption, but adoption may depend on producers becoming more familiar with permanent-magnet equipment. In an August 2025 interview, Eishin Takahashi, president of Zmag America, identified limited familiarity with the technology as a barrier in the United States, noting that aluminium producers globally tend to prefer equipment and processes they already know.