Refining & Roasting

Gases for Refining and Roasting in the Non-Ferrous Metals Industry

Technologies include: removing contaminants with gases such as oxygen, hydrogen, chlorine and sulphur hexafluoride (SF₆); using nitrogen or argon as inert carrier gases; stirring using gases; oxygen-rich roasting atmospheres; and other industrial gases applications. These offer significant financial benefits for refining, degassing and roasting in the non-ferrous metals industry.

Offerings applicable to refining and roasting.

Refining - Oxygen Injection

Oxygen is used via an oxidation process to remove sulphur and other contaminants such as antimony and bismuth from copper, lead, nickel or zinc. Using oxygen rather than air drives the reaction faster, resulting in increased productivity.

Refining - Hydrogen Injection

Hydrogen or hydrogen / nitrogen mixes can be used to remove dissolved oxygen or to control the generation of metallic oxides in many copper and nickel baths. This method brings productivity and efficiency benefits.

Refining - Sulphur Hexafluoride Injection

Injection of sulphur hexafluoride (SF₆) or chlorine, in an inert gas (nitrogen or argon), into molten aluminium or copper removes hydrogen and other undesirable elements that cause porosity, inclusions or pinholes in the final product. Reducing hydrogen and alkali metal content, and promoting flotation of oxides and non-metallic inclusions, produces more consistent, higher quality metal. In addition, SF₆ degassing eliminates the maintenance associated with other degassing approaches that typically cause emission problems and corrosion of equipment and plant structures.

Refining - Stirring

Gas injection to stir molten metal improves homogeneity of both alloy composition and temperature. This increases yield, decreases alloy requirement, reduces production rejects and produces a higher product quality and consistency.

Refining - Inerting

Using nitrogen to displace the oxygen above a molten bath reduces the formation of oxides at the melt surface providing a higher yield and improved quality.

Roasting - Oxygen Enrichment

Oxygen is injected into zinc roasters to increase productivity, reduce flue gas volume and increase sulphur dioxide concentration. In addition oxygen has been shown to stabilise production when the quality of the concentrate varies.

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