Resumo

RIBEIRO, Valeria Aparecida Leitão; AFONSO, Júlio Carlos; WILDHAGEN, Glória Regina da Silva  e  CUNHA, José Waldemar Silva Dias da. Liquid-liquid extraction of uranium(VI) from colofanite of itataia (Santa Quitéria, Ceará) by organic extractants in the presence of phosphoric acid. Quím. Nova [online]. 2008, vol.31, n.8, pp. 2159-2164. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422008000800042.

This work describes the liquid-liquid extraction of uranium after digestion of colofanite (a fluoroapatite) from Itataia with sulfuric acid. The experiments were run at room temperature in one stage. Among the solutions tested the highest distribution coefficient (D > 60) was found for 40%vol. DEHPA (di(2-ethyl-hexyl)phosphoric acid) + 20% vol. TOPO (trioctylphosphine oxide) in kerosene. Thorium in the raffinate was quantitatively extracted by TOPO (0.1% vol.) in cyclohexane. Uranium stripping and separation from iron was possible using 1.5 mol L^-1 ammonium or sodium carbonate (room temperature, one stage). However, pH control is essential for a good separation.

Palavras-chave : uranium; solvent extraction; waste management.