INL RESEARCH & DEVELOPMENT

Science

Cold Crucible Induction Melting

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INL Capabilities

INL has designed and built a

Cold Crucible Induction

Melter (CCIM) prototype in an

integrated test bed also capable

of testing an array of offgas

treatment technologies. The

60kW melter can operate over

a range of frequencies from

100KHz to 4MHz. The system

is unique in North America

and is capable of testing solid,

liquid, and slurry feeds with

continuous processing.

Theory of Operation

This melter inductively heats

an electrically conductive

susceptor (graphite in this

case) to start a melt. As

melting propagates through

the feed, the susceptor is

consumed. Water-cooling of

the crucible causes a thin

frozen layer, or shell, to

form inside the melter’s

walls. Thus the CCIM can

achieve melt temperatures

up to at least 3000°C while

maintaining the melt in a

solid containment shell of

the feed composition. The

shell, or “skull,” isolates the

melt from the crucible that is

maintained at ambient

conditions. These conditions

eliminate the need for glasscontact refractory and

concern over material

corrosion and temperature

limitations.

Technology

Advantages

No Refractories— With no

refractory, melts covering a

range of basicity and redox

conditions can be processed

without concern over melter

wear or life expectancy.

Cold crucible induction melting has the potential to significantly simplify and reduce

the cost for stabilizing waste around the world. Future applications include processing

high-purity and corrosive products – like alumina, zirconia, ruby-glasses and customdesign specialty glasses – at temperatures greater than 1,300°C in a wear-free melter vessel.

No Electrodes— With no

metallic or oxide electrodes,

routine operation with melt

temperatures in excess of

2000o

C can be maintained.

Water Cooled— The watercooled crucible is fabricated

out of standard materials and

is protected from corrosion by

the cold shell.

Self-Cleaning— By maintaining the crucible at a much

lower temperature than the

melt itself, the molten material does not bond to the

melter. After cooling, the

residuals can be readily

removed from the melter.

High Purity— Very high

purity melts are attainable

with the melt contained in its

shell (of the same composition) and no refractories or

electrodes present to corrode

and introduce contaminants at

high process temperatures.

This also means that the

melter can be readily cycled

daily from one feed to another

without thermal damage or

loss of composition control.

High-Level Waste

Applications

Within the Department of

Energy and similar worldwide

programs, stabilization of

highly radioactive waste in

glass is recognized as an

The Cold Crucible Induction

Melter is shown with its

protective barrier and external

system connections, including

its offgas system.
INL RESEARCH & DEVELOPMENT

Management Contact

Jay Roach

Manager, Environmental

Engineering Department

Jay.Roach@inl.gov

(208) 526-4974

Technical Contact

Dirk Gombert

Dirk.Gombert@inl.gov

(208) 526-4624

INL R&D

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05-GA50153

extremely durable and long

term waste form.

Problematic Wastes— Many

waste compositions – containing chromium, aluminum,

zirconium, sulfate, or phosphate – are a challenge to

incorporate in glass. These

require significant additives to

process in conventional jouleheated melters and may

increase the glass volume and

create possible process

schedule delays and cost

penalties.

Flexible Operation— The

CCIM allows processing at

much higher temperatures and

provides the needed flexibility

for glass chemists to design

matrices to safely and effectively incorporate much more

waste. Higher processing

temperatures also increase

processing rates and allow for

greater throughput and a

smaller footprint.

Commercial

Applications

High purity and special run

materials do not require the

throughput needed for plate or

bottle glass. Specialty materials do require precise process

control, quality assurance and

flexibility (all possible with

the CCIM), to process small

quantities of custom materials.

Purity with Durability—

The melter design can process

high purity or high temperature materials without crucible damage. In most

applications its design

eliminates the need for

platinum or disposable oxide

crucibles.

Operating Flexibility— By

maintaining the crucible at

near ambient conditions, the

melting process can be started

and stopped without thermal

cycling damage. This not only

allows short duration runs, but

also allows rapid change to

different products without

losing compositional control.

INL Partnering

INL’s team is actively collaborating with colleagues at

the Khlopin Radium and

Electrotechnical Institutes in

St. Petersburg, and at Radon,

as well, in Moscow, Russia.

This collaborative effort

brings together a substantial

capability in electro-thermal

modeling, electrical and

mechanical engineering and

manufacturing. In addition to

R&D for the Department of

Energy complex, INL seeks

opportunities to resolve other

technical challenges for

taxpayers and industry.

Invitation to Tour

Test Bed

We invite you to visit INL’s

melter and see the integrated

thermal test bed facilities that

incorporate fluidized-bed

processing capabilities and

advanced offgas treatment.

View of the melter environment with its specially designed

offgas system.

Demonstration simulating the potential for

encapsulating wastes in a glass matrix.

Idaho National

Laboratory

P.O. Box 1625

Idaho Falls, ID 83415