Glass Melting Technology: A Technical and Economic ... - OSTI

Plasmelt has assembled a world-class group of scientists, engineers, and experienced R&D
managers to execute the High Intensity Plasma Melting Project. This team, along with the
combined efforts and experience of the cost share partners, AGY and J-M, give the project a very
high probability of success.
Development history
Plasma melting technology has not been extensively investigated for high quality glass melting
since it involves a significant paradigm shift from the traditional glass melter design—even
though such shifts represent potentially high reward. Commercial development of high intensity
melters has generally relied on traditional technologies (gas, electric, enhanced mixing). The
high-intensity melter system proposed here is small with a highly concentrated energy source
that reportedly achieves arc temperatures in excess of 20,000 o K. Different melter designs and
procedures must be developed to make the best use of this high-temperature energy source, a
departure from the approaches currently used by most glass companies. The paradigms
surrounding the design and operation of traditional glass melting must be challenged in order to
realize real step function changes in efficiency and throughput.
The process presented here is a hybrid of typical plasma torch designs, and represents a departure
from the better-known single torch transferred or non-transferred configuration. The dual torch
design applies the anode and cathode through two separate torches, i.e., an anode torch and a
cathode torch. This approach is commercially available, and has been applied in both typical
metal torch and graphite torch configurations. The dual torch configuration allows for better
heat distribution and better process control by permitting fine adjustment of the heat transfer
between joule and plasma heating. Though it is offered commercially by several manufacturers,
the dual torch design is more specialized and has not been applied as extensively as single torch
systems. The work by J-M clearly demonstrates its processing potential, as well as the potential
for success. This dual torch design uses no glass contact electrodes and avoids several adverse
chemical reactions in the glass that might otherwise result from the use of submerged metallic or
graphite electrodes.
The design and operation of a technology that is new to the glass industry requires significant
investment in time and resources in order to conduct the required advanced research. The lack of
expertise with plasma technology within glass companies further adversely impacts the
acceptance of plasma technology by them. Today, most US glass companies are risk-averse, are
more short-term oriented, and are capital-constrained. Therefore, it is highly unlikely that any
one company will invest the resources required to perform the research to develop a technology
that is a departure from their current technology base, and may be seen as high-risk due to
unfamiliarity in the technology.
Project goal and scope of work
Develop an efficient 500 lb/hr transferred arc plasma melting process that can produce high
quality—glass suitable for processing into a commercial article.
Design, construct, and operate a 500-lb/hr melter that is generically suited to many specialty
glass segments across the glass industry. Initially, E-glass will be melted at the 500-lb/hr level,
and glass marbles produced. These marbles will be subsequently re-melted and processed into
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