Message Board Thread - "Slag Emissivity"

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Slag Emissivity Eddie Hindmarsh 5/19/2004
A client has requested me to check the temperature of molten slag and molten copper (separately)being tapped from an electric furnace. The emissivity of the slag according to them is .75, however this gives a temperature much lower than they expected. Has anyone any idea what it could be, and also what the emissivity of molten copper would be, both at approx. 1300deg. C
Eddie Hindmarsh
Re:Slag Emissivity Thermasearch 5/23/2004
I have been working as a consultant with Nucor Steel to install a fixed set of ir spot radiometers that give the emmisivity of the pouring molten steel and the subsequent change when comming to the slag state. The equipment is installed in a dirty, dusty and hot environment and works well after fiding best placement. It is now used to give the operators moment of slag start. Emissivity is displayed to the third decimal and temperature readings are as accurate as calibration will allow with known E and millisecond corrected temp data.

Contact me for further data.

Re:Slag Emissivity raffar 12/9/2004
The emissivity of both can be almost anything. Liquids change emissivity with surface conditions (turbulence), as shown in the graph. The laboratory emissivity of the material poured was 0.5; we measured the values shown on line.
Metals change emissivity with small concentrations of alloying materials. Changes are often quite large.
You can see all of this on our website, under the links for liquids, metals, and powder metallurgy.


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