Reversing Corrosion In Metal

[Photon Guy]

From what I know, when you melt down rusty metal the rust floats to the top. However, I heard that with smelting there are chemical procedures to actually reverse the rusting effect, that after melting down the metal they will somehow turn the rust back into its natural form. Rust forms when oxygen combines with the metal so supposedly there's ways to remove the oxygen from the rust. This reversal process I believe involves the use of chemicals.

[chenbeier]

Adding coal (carbon) is the normal way.

[studiot]

3 hours ago, Photon Guy said:

From what I know, when you melt down rusty metal the rust floats to the top. However, I heard that with smelting there are chemical procedures to actually reverse the rusting effect, that after melting down the metal they will somehow turn the rust back into its natural form. Rust forms when oxygen combines with the metal so supposedly there's ways to remove the oxygen from the rust. This reversal process I believe involves the use of chemicals.

At room temperatures the normal chemical process is the combination of iron with oxygen, rusting as you rightly say.
This chemical process is called oxidation.
Since the bulk of the planetary surface iron is near room temperature, it has largely been oxidised over time so the ores are largely oxides of iron (there are more than one).

The reverse process is called reduction (which means the removal of oxygen).
The chemical which effects the reduction is called the reducing agent.

Reduction is largely accomplished by heating the iron to several hundred degrees centigrade in the presence of carbon monoxide.
The heating is carried out either electrically or by burning the coal (as coke).
If the coal or coke is starved of oxygen in the burning/heating process carbon monoxide is given off.

The final temperature of the iron that melts and leaves the furnace is over 1200 degrees centrigrade.