Amines iron complexes, solvent extraction

In acid leaching, sulphuric acid is used in a complex ion-exchange or solvent extraction process to produce yellowcake of very high purity. Various metals (such as vanadium, arsenic, nickel, iron, copper, etc.) may be leached in this process. Chemicals involved in this process include sulphuric acid, ammonium nitrate, sodium chloride, amines, alcohols, kerosene, and ammonia. Considerable process water has to be derived from reclaim water of the tailings and returned to the mine for preparing the slurry. 

The antimony(V) chloride complex can be extracted into DIPE from 1-10 M HCl [1] about 99% extraction is obtained in 5-7 M HCl. It is convenient to extract Sb(V) from 2M HCl (94% extraction) since Fe(III) is not extracted under such conditions. Iron(III) can be separated by extraction from 6-7 M HCl before the Sb(III) is oxidised to Sb(V). The chloride complex of Sb(V) can be extracted with non-polar solvents in the presence of amines, e.g. tribenzylamine or tridodecylamine. The antimony(III) can be extracted with 20% TBP from 2M HCl and 1 M MgCbiS]. 

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