Case Studies · Iron & Steel

Arc Furnace High Emissivity Coating: Hot Spots and Shell Cracking Eliminated at Eastman Kodak

Precious-metals recovery arc furnace (9 ft diameter, 12 ft long)·Eastman Kodak, USA

Eastman Kodak's precious-metals recovery arc furnace developed hot and cold spots up to 320°C apart and shell cracks within 1.5 weeks of operation. Its Kala-brick refractory was coated internally with Emisshield and the furnace run at 1,320°C (2,400°F). Over three weeks the exterior held uniform at 150°C with no shell cracking, and the load heated more evenly.

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Uniform 150°C exterior
: No cracking after 3 weeks
: 1,320°C operation

The Challenge

Thermal non-uniformity was cracking the shell and degrading recovery efficiency.

What Was Applied

Internal coating of the Kala-brick refractory to about 10 mil, followed by heat-up at 90°C per hour to 1,320°C and monitoring of temperature uniformity and exterior cracking over three weeks.

Electric arc furnace on a melt shop floor

Why It Worked

A high emissivity lining redistributes radiant energy across the chamber, removing the concentrations that produced hot spots and the thermal gradients that cracked the shell. See How Emissivity Works.

Summary of Results

Metric	Before	After
Exterior temperature variation	Hot spots to 320°C	Uniform 150°C
Shell cracking	Within 1.5 weeks	None after 3 weeks
Load heating	Uneven	Even; better process control and product quality
Precious-metals recovery and maintenance	Baseline	Improved; reduced

Next step

Operating the Same Asset?

Fighting hot spots or shell cracking? Send us the furnace data and thermal images. We project the result from comparable documented installations.

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