ITP Metal Casting: Advanced Melting Technologies: Energy Saving ...

Another project sponsored by the ITP Metal Casting is developing integrated retrofit
technologies for clean aluminum melting systems by focusing on immersion heating coupled
with metal circulation systems. 49 This is being achieved through substitution of conventional
radiant burner method with immersion heating in reverberatory furnaces. The program will
enable cost-effective retrofits to a range of existing furnace sizes, reducing economic barrier to
implementing new applications.
4.2.3 Infrared Heating
Infrared heating is currently being employed by the forging industry; this technology can also be
used for die heating and heat treatment in the metal casting industry. It offers a method for
reducing time and energy costs of die preheating. A study conducted by ORNL indicated that the
surface of the die can be heated to 300°C (572°F) in less than 20 minutes. 50 An infrared panel
heater can bring the furnace to full power in a matter of seconds, saving energy to maintain a hot
furnace while idle (Exhibit 20). 51 The rapid heating could also reduce heat-treatment cycle time
and increase product throughput.
Infrared radiation is often supplied by high-intensity quartz heat lamps, producing radiation of
around 1 micron wavelength. This radiation melts metals with uniform heat distribution. The
high-density infrared technology can achieve a heating rate of 50 to 400°C/sec (120 to
750°F/sec). 52
Source: Oak Ridge National Laboratory
Exhibit 20: Electric infrared flatbed furnace
(used for both laboratory and industrial testing)
Recently, DOE funded a study on surface treatments on refractories used in aluminum
processing. 53 High-density infrared processing will be used to apply corrosion-resistant, high
emissivity coatings on refractories so as to reduce its porosity.
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