Liquid-liquid extraction of zinc from phosphoric acid solution by acid di (2-ethylhexyl) phosphoric

Abstract

Abstract In this work we studied the complexation of Zn2+ in dilute and concentrated phosphoric media. The investigation method used is the liquid-liquid extraction. This method allowed us to define the nature of the zinc phosphoric species and to calculate their stability constants. These are the following entities ZnH2PO4+ and ZnHPO4, whose stability constants are respectively equal to 5.83·10−2 and 5.83·10−5. We also studied at pH and analytical concentration of H3PO4 data the effect of concentration on this complexation. In addition, the sharing data show that the chelate extracted in the organic phase is Z n X 2 , ( H X ) 2 - formed according to the reaction: Z n 2 + + 2 ( H X - ) 2 ⇆ Z n X 2 , ( H X ) 2 - + 2 H + of constant Ke = 5.12·10−3, (X = di (2-ethylhexyl) phosphoric).