Study on floatation separation of iridium in potassium iodide-tetrabutyl ammonium bromide-water system

The separation behaviors and conditions of iridium from other metal ions were studied in potassium iodide-tetrabutyl ammonium bromide-water system.The results showed that IrⅣ could form water insoluble ternary complex(2) with tetrabutyl ammonium bromide and potassium iodide in aqueous solution.This ternary complex floated on water phase,and the liquid-solid two-phase was formed with clear interface.When the concentrations of tetrabutyl ammonium bromide and potassium iodide were 8.0×10-4 mol/L and 6.0×10-3 mol/L,the flotation rate of IrⅣ was up to 97.6 %.Meanwhile,RhⅢⅣⅥ,WⅥ,VⅤ,CeⅢ,SnⅣ,MoⅥ,UⅥ,GaⅢ,CrⅢ,MnⅡ,AlⅢ,FeⅡ,ZnⅡ,CoⅡ and NiⅡ were not floated in this system,realizing the quantitative separation of IrⅣ from these metal ions.BiⅢ,SbⅢ and HgⅡ had high flotation rate in this system.PbⅡ and CuⅡ could react with KI to form water insoluble PbI2 and CuI,so IrⅣ could not be separated from PbⅡ,CuⅡ,BiⅢ,SbⅢ and HgⅡ.The synthetic water sample was separated by this method with satisfactory results.