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The present work reports distribution of platinum(IV), iridium(III) and rhodium(III) from HCl, H2SO4 and HNO3 (0.1-6 mol L-1) media using Cyanex 471X diluted with toluene. Detailed studies have been conducted to evaluate the effect of different variables influencing the extraction such as equilibration time, temperature, diluent and concentration of extractant. An assessment of the loading capacity, regeneration power and stability of extractant has been made. The extraction behaviour of associated metals namely gold, silver, iron, nickel, cobalt, chromium and copper has been investigated and the conditions for their binary separations involving platinum metals have been optimised. The stoichiometric composition of the extracting platinum and iridium species have been identified. Based on the extraction data separation schemes have been designed to recover platinum, iridium and rhodium from synthetic mixture and real sample. [ABSTRACT FROM AUTHOR]

Abstract: The extraction of indium(III) and gallium(III) along with the associated metal ions from hydrochloric acid medium by bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) has been studied. The extraction profiles of indium(III) and gallium(III) have been investigated as a function of type and molarity of the acid, nature of organic diluent and concentration of the metal ion and the extractant. The extracting species have been identified as In(OH)R2, Ga(OH)R2 and H+GaCl4·2R. It has been possible to strip In(III) and Ga(III) from the organic phase by appropriate molarity of HCl. Conditions for a number of binary and ternary separations of analytical interest have been optimized. The developed conditions have been extended to recover pure In(III) from sphalerite and galena and Ga(III) from bottom ash and electronic waste. Loading capacity of the extractant was evaluated and the results reveal that Cyanex 272 can hold indium(III) up to one-fifteenth and gallium(III) up to one-twentieth of its molar concentration. The hydrolytic stability and regeneration capacity of the extractant has been assessed. [Copyright &y& Elsevier]