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

Improved Refractory for Coreless Induction Melters of Cast Iron
Today many cast iron manufacturers use induction melting for cast iron. However, the current
melting practices and refractories result in rapid refractory destruction. Research should examine
new materials for refractories that will last longer. Research should also develop new melting
systems that help increase the refractory campaign life. The combination of new
refractories and
new melting systems that dramatically improve refractory campaign life would significantly
reduce energy use in iron melting operations.
Wider Applicability of Induction Furnaces
Current aluminum furnaces are limited in their utility because they are prone to forming excess
oxidation film during the melting process. In addition, the melting of aluminum scrap requires
that a heel of molten metal be left at the bottom of the furnace to promote coupling and only
clean scrap be used because of the limited off-gas cleaning system and the lack of refining
capabilities in the induction furnace design.
Research and development to limit the formation of oxide films offers significant potential for
energy savings. Also, R&D is needed to combine induction melting with some chemical energy
and refining capabilities to promote induction melting in ferrous casting shops. This would
enable ferrous casters to refine their metal during
melting and reduce the amount of virgin
materials.
This could reduce the cost of steel production in these furnaces. Finally, there is a need
to better educate the metal casting industry on best practices in induction melting, including how
to properly pack these furnaces to ensure better coupling during melting.
Scrap Preheating
Scrap/ingot preheating has the potential to reduce energy by 10 to 20% in batch melting
operations. Preheating systems, such as a second furnace or a shaft above the furnace, are the
most promising. Research is needed to develop a comprehensive energy transfer model
linking
the furnace operation with gas generation and scrap/ingot preheating. The model should use
natural gas, carbon and oxygen, and provide for heat transferring to the scrap and ingot.
Research must also focus on the design of efficient scrap/ingot preheating systems for batch
melting operations. The design should consider the space limitations that exist in smaller casting
facilities and the charging requirements, and ensure efficient heat transfer. Most importantly,
the
design should offer reliability and require minimal maintenance.
Improved Stack Furnace Design
The rapidly rising energy costs today warrant the need to improve the design and structural
materials utilized in the construction of stack furnaces. This would limit the maintenance
required in operating a stack furnace and make it a viable alternative
to the reverberatory furnace.
There is also a need to reduce the size of the stack furnace to enable its installation in smaller
facilities that may not have the ceiling room to accommodate these melting systems.
38