Process/Manufacturing - Metallurgy

Gases and chemicals are used in the metallurgical industry in production of aluminium and steel. Oxygen boosts temperature in smelting ovens, and argon and nitrogen remove impurities from the liquid metal. Gases are also used in the surface treatment of metals.

Oxygen is added when fusing metal or in the melt treatment of metal (oxyfuel burners, oxygen lances or nozzles/pluggers) to raise the temperature in the melt. Argon and nitrogen are added to the melting baths to refine or "purify" the metal of undesired elements. The impurities are transported to the surface. In addition, the effectiveness is increased by energy transmission from the oxyfuel flame to the melted metal. CO₂ can be used for the same purpose and can also produce a cooling effect round the injection nozzles.

Argon and nitrogen are used as inert atmosphere in the surface treatment of metal to prevent oxidation.

Acids are also used in the surface treatment of metals (bating).