Preparation and uses of the metals

Thallium is likewise recovered from flue dusts emitted during sulfide roasting for H2SO4 manufacture, and from the smelting of Zn/Pb ores. Extraction procedures are complicated because of the need to recover Cd at the same time. There are no major commercial uses for T1 metal world production in 1983 was estimated to be 5-15 tonnes p.a. and the price ranged from 60 to 80 per kg depending on purity and amount purchased. 

The huge difference in scale between the production of A1 metal, on the one hand, and the other elements in the group is clear from the preceding section. The tremendous growth of the A1 industry compared with all other non-ferrous metals is indicated in Table 7.3 and A1 production is now exceeded only by that of iron and steel (p. 1072). 

Production of A1 metal involves two stages (a) the extraction, purification and dehydration of bauxite, and (b) the electrolysis of AI2O3 dissolved in molten cryolite Na3AlF6. Bauxite is now almost universally treated by the Bayer process this involves dissolution in aqueous NaOH, separation from insoluble impurities (red muds), partial precipitation of the trihydrate 

No further cryolite is actually needed once the smelting process is in operation because it is produced in the reduction cells by neutralizing the Na20 brought into the cell as an impurity in the alumina using AIF3  

Brazil, Norway and Czechoslovakia (5% each). In addition to this primary production, recycling of used alloys probably adds a further 3-4 million tonnes pa to the total A1 metal consumed. 

Some uses of A1 and its alloys are noted in the Panel from which it will be seen that many of 

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