Evaluating cationic extractant systems containing Versatic 10 on the solvent extraction of metals from an Ni lateritic sulfuric solution

Abstract

The solvent extraction of Ni, Co, Cu, Ca, Mn, Mg, and Zn was evaluated in this work using Versatic 10 and its mixture with D2EHPA, Cyanex 272, Cyanex 301, LIX 84-I, and LIX 860N-IC. The aqueous phase reproduces a liquor obtained by applying a sulfation-roasting-leaching process in an Ni lateritic ore after precipitation of Fe, Al, and Cr. Tests were conducted at 40 °C, A/O ratio = 1, and [extractant] = 0.5 M. It was found that Cu, Ni, Co, Zn, and Mn can be separated from Ca and Mg by Versatic 10 at pH 6.5. Similarly, Cu, Zn, Co, and Ni can be separated from Mn, Ca, and Mg by Versatic 10 + Cyanex 301 at pH 1.5, whose antagonism on Mn extractions favors Co/Mn and Ni/Mn separation at pH 1–2. Synergism was verified on Ni extractions with Versatic 10 + LIX 84-I and Versatic 10 + LIX 860 N-IC systems. Cu, Ni, and Co are preferentially extracted over Zn, Mn, Ca, and Mg by Versatic 10 mixed with LIX 860 N-IC and LIX 84-I at pH 4 and 5, respectively. Stripping tests using Ni electrolyte solution (50 g/L Ni + 1 M H2SO4) from the loaded Versatic 10 + LIX 860 N-IC resulted in the recovery of 80% Ni, 70% Co, and 42% Cu. These four organic systems may have potential applications in direct SX operations. Conversely, Versatic 10 + D2EHPA and Versatic 10 + Cyanex 272 preferentially extract some impurities over Co and Ni. At pH 3, Zn, Ca, Cu, and Mn can be removed over Co and Ni using Versatic 10 + D2EHPA; synergism was found to Mn extractions. Versatic 10 + Cyanex 272 separated Zn, Cu, and Mn at pH 3.5 leaving Co, Ni, Ca, and Mg in the raffinate; synergism was found to Ca extractions. Targeting the extraction of impurities over Co and Ni, Versatic 10 + D2EHPA is superior to Versatic 10 + Cyanex 272, with potential application to treat liquors obtained from the dissolution of MHP.