FURNACE BASICS
This is the temperature at which pure aluminum melts.
What is approximately 660°C (1,220°F)?
In a typical natural-gas-fired furnace, this is mixed with fuel to produce combustion.
What is air?
This is the layer of oxidized aluminum that forms on the surface of molten metal.
What is dross?
The furnace isn't reaching temperature. One of the first things an operator should verify on a gas-fired furnace is this.
What is fuel supply/burner operation?
This should never be allowed to contact molten aluminum.
What is water/moisture?
This furnace component contains the molten aluminum during the melting process.
What is the hearth/main chamber?
This is the visible result of fuel burning in the furnace.
What is the flame?
This gas is especially important in aluminum because too much can produce porosity during solidification.
What is hydrogen?
A dirty or restricted burner can cause this to decrease.
What is heat output/combustion efficiency?
This PPE protects an operator's eyes and face from molten-metal splash and furnace hazards.
What are appropriate safety glasses and face shield?
This material lines the inside of many aluminum furnaces and is designed to withstand high temperatures.
What is refractory?
Too much of this can cause excessive oxidation and unnecessary heat loss.
What is excess combustion air?
This operation removes unwanted oxide and other material from the surface of the molten aluminum.
What is skimming?
If the furnace temperature reading suddenly jumps or becomes erratic, this component may need inspection.
What is the thermocouple?
Wet scrap entering a furnace can cause this extremely dangerous event.
What is a steam explosion?
This device is used to measure the temperature of molten aluminum.
What is a thermocouple?
Too little combustion air can result in incomplete combustion and increased production of this dangerous gas.
What is carbon monoxide?
Water contacting molten aluminum can rapidly turn into this, potentially causing a violent explosion.
What is steam?
Excessive dross production may indicate excessive temperature, excessive turbulence, or excessive exposure of the molten metal to this.
What is oxygen/air?
Before charging scrap into a furnace, operators need to verify that the material is dry and free from this hazard.
What is moisture/water contamination?
A furnace that repeatedly loses heat through damaged or deteriorated lining may experience this problem.
What is heat loss/poor thermal efficiency?
This ratio describes the amount of combustion air supplied compared with the amount theoretically required to burn the fuel.
What is the air-to-fuel ratio?
Excessive turbulence while charging or transferring aluminum can increase this undesirable reaction at the metal surface.
What is oxidation?
The furnace is consuming more fuel than normal, recovery time is increasing, and the outside of the furnace is unusually hot. This furnace component should be investigated.
What is the refractory?
When working around molten aluminum, this principle is critical: never assume something is dry simply because it appears to be.
What is treating unknown material as potentially hazardous until it is verified safe and dry?