Leaching of metals with microemulsions containing bis-(2-ethyhexyl)phosphoric acid or tributylphosphate

The leaching of metals from oxide materials with sodium bis-(2-ethylhexyl)phosphate (NaDEHP) microemulsions containing extractants bis-(2-ethylhexyl)phosphoric acid (DEHPA) or tributylphosphate (TBP) was studied. It was shown that the microemulsions exist in a wide range of NaDEHP and water concentrations; the hydrodynamic diameter of microemulsion droplets was less than 10 nm. Nanostructured fluids (extractant-containing microemulsions) provide the leaching of metals. It was shown on the example of copper recovery from CuO, the extraction into DEHPA- or TBP + CH3COOH-containing microemulsions took place; copper recovery into solutions of the extractants in kerosene was not observed. The leaching of copper, cobalt, nickel and iron from an oxidized cobalt-copper concentrate with DEHPA- and TBP + CH3COOH-containing microemulsions demonstrated low iron extraction in comparison with non-ferrous metals extraction. The DEHPA-containing microemulsion with concentration of the extractant CDEHPA = 0.174 mol/L demonstrated 72.1% of copper recovery for 5 h of the leaching; at the same time recovery factors of Co, Ni and Fe were 6.0, 5.9% and 0.5%, respectively.