Pacific Fertiliser has supplied gypsum to an Aluminium Smelter decommissioning project.
The project used the high quality gypsum for treating leachable fluoride concentrations in waste to chemically fix any leached fluoride to form the stable precipitate calcium fluoride.
The concept of “gypsum fixing” is commonly used within the aluminium smelting industry for the treatment of fluoride containing waste.
Gypsum has been previously used for this purpose at the Tomago Aluminium Wallaroo Landfill. Gypsum was used as the preferred calcium source, when compared to calcium chloride and calcium carbonate as it was found to be more effective at reducing leachable fluoride concentrations with minimal pH change.
