Purlex process

Solvent extraction is applied either directly to the weakly acidic leach hquor (the method is known as the Purlex process in South Africa, and the Amex process in the USA) or to the strongly acidic eluate obtained from a preliminary ion-exchange treatment of the leach liquor (known as the Bufflex process in South Africa, and the Eluex process in the USA). In the Purlex process, a 5 /(i solution of a tertiary amine in kerosene is typically used to treat a leach liquor containing up to 1 g of uranium per litre (although concentrations as low as 0.04 g 1 may be encountered) at a pH value of 1 to 2. A modifier such as isodecanol (2-5%) is usually incorporated into the organic phase to prevent the formation of a third phase and to inhibit the formation of an emulsion. The extraction of uranium(VI) is usually considered to proceed according to reactions such as ... 

Bufflex [from Buffelsfontein (South Africa), extraction] A process for extracting uranium from its ores, using a solution of an amine (Alamine 336). It was developed in South Africa, and was later replaced by Purlex. See also Eluex. 

Purlex An improved version of the Bufflex process for extracting uranium from its ores. Operated in South Africa. 

Amine systems achieve higher uranium purity than organophosphorus systems (due to the greater selectivity of amines for uranium) and have lower extractant losses due to their lower aqueous-phase solubility. SX is applied either directly to the weakly acidic leach liquor (also known as the Purlex or Amex process, Vaal River West, South Africa) or to the strongly acidic eluate from an ion-exchange preconcentration treatment of the leach liquor (the Bufflex or Eluex process, Vaal River South, South Africa) (Nicol et al. 1987). A more modem variation (such as at Southern Cross Resources Uranium One, South Africa) is to treat the ore by pressure leaching followed by SX. 

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