In April 2001, US Geo Specialty Chemicals (that operates gallium plants in Germany and France) announced it was planning to spend A$77million to upgrade the plant. Forty employees would be involved to process 11 million tonnes of bauxite liquor to produce 100 tonnes of gallium.
On May 8th 1997, it was announced gallium chloride production would be suspended after only 28 months in operation in response to an over-supply in the world market with twenty jobs lost. In July it was placed on a care and maintenance status following further falls in the world price.
Gallium is used in light emitting diodes as gallium arsenide and phosphide (and potential in visible diode lasers). It can be used as replacement for mercury in thermometers and dental amalgams. World production of gallium is around 100 tpa. Nearly all the world's gallium is sourced as a by-product of alumina production by extraction from the caustic liquor produced in processing bauxite.
Rhodia Pinjarra, formerly Rhone-Poulenc, operated a $50m facility 5km south of Alcoa's Pinjarra alumina refinery established in 1989. It used liquor pumped from the refinery which is returned after processing. The company extracted the gallium as a 15 per cent solution of gallium chloride (ie. equivalent to 200 gms of gallium per litre) involving a series of steps including counter current organic solvents extraction and further extraction using an ion exchange resins.
Production capacity was about 30 tpa as gallium (ie. one-third of then world demand of 90 tonnes). Only a small proportion of the gallium contained in bauxite liquors produced in the state is extracted by Rhone-Poulenc.
The gallium chloride was exported to Salindres in France where Rhone-Poulenc extracts the metal.
There is an extensive deposit at Mt Weld in Western Australia.
Rhone-Poulenc Chimie proposes the production of rare earths adjoining the galium plant in Pinjarra by processing monazite co-produced by the state's titanium mineral producers. The project will cost A$60m and employ 60 persons. It involves extracting the rare earths as a nitrate concentrate at up to 15 000 tpa. Processing produces radioactive waste for disposal in the Goldfields region (Mt Walton).
The Western Australian rare earth plant will process monazite to three commodities:
|rare earth nitrates for export|
|phosphates for use in fertiliser manufacture, and|
|waste, for disposal at the Government's Intractable Waste Disposal Facility 90km North of Koolyanobbing in the Goldfields.|
|Mixing the monazite with hot caustic soda to dissolve phosphates from the mineral, leaving rare earth hydroxides.|
|Filtering hydroxides from the solution, allowing the remaining phosphates to be used for agricultural fertiliser. The caustic soda will be recycled. Tricalcium phosphate will be stored, on a temporary basis, in the evaporation ponds before the material is sold to fertiliser manufacturers.|
|Reacting the rare earth hydroxides with nitric acid and barium salt, then filtering the solution to remove insoluble radioactive elements - thorium, uranium, radium - and other inert materials. Wash waters will be stored in evaporation ponds on site.|
|Exporting the resulting rare earth nitrates.|
|Transporting low level radioactive waste, in the form of a moist clay-like insoluble material, to the State Government's Intractable Waste Disposal Facility at Mount Walton East in the Coolgardie Shire.|