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

3.4 Selecting Appropriate Melting Technology
Industrial operations have to address a broad range of considerations that have a direct effect on
their “bottom line” when faced with the choice of melting technologies. These factors include:
• Space availability (floor space & height) • Capital investment
• Type and variety of alloys to be melted • Quantity of the metal required
• Fluctuations in metal demand during operation • Alloying requirement
• Quality of the metal • Operating costs, especially in labor
• Quantity of dross/slag • Reliability of the equipment
• Emissions and environmental considerations • Durability of the furnace
• Maintenance requirements
Since each foundry may attribute a different priority to each one of these factors, there is no
“one-size-fits-all” decision in the selection of melting technologies. Energy efficiency is not
necessarily the only significant criterion in selecting melting equipment. Where energy costs are
high (e.g., in Europe), energy efficiency has been an operating priority for many years. For
example, stack furnaces are more common than reverberatory furnaces for melting aluminum in
Europe. However, in the United States, 95% of aluminum is melted in gas reverberatory
furnaces, which operate with energy efficiency of 20-30% but require lower capital cost and
provide easier operation and maintenance than stack melters.
A furnace design must meet some requirements to provide for an efficient melting process.
These requirements include the ability to produce high-quality metal, to accurately control bath
temperatures, to minimize metal losses, and to meet environmental concerns, while maintaining
high energy efficiency. Although the cost of fuels, metals and labor are constantly changing
variables, energy efficiency will always be an important consideration, especially in the face of
the current trend of rapidly rising energy costs. Improving efficiency of melting, while
addressing all other aspects of the operation, is critical in keeping the metal casting industry
competitive. 12
4. Current and Emerging Melting Technologies and
Practices
This section of the report describes different types of melting technologies that are currently used
in the metal casting industry. It discusses their benefits, technical barriers, and scale-up issues,
and examines advances in furnace technologies that improve energy efficiency and reduce melt
loss. Non-conventional melting technologies are included even though their practical application
may be limited, as they offer alternative approaches and add to our knowledge base in the
melting technology field. Additionally, the more practical energy-saving opportunities are
described, such as retrofits for existing furnace systems, changes in fuel source, and best
practices.
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