Separation of Mo(VI) and Fe(III) from the acid leaching solution of carbonaceous Ni–Mo ore by ion exchange

• Mo(VI) can combine with SO42 − to form heteropoly acids in acid sulfate solution.
• The heteropoly acids can excite in the [H+] range of 0.1–1.0 mol/L.
• S/Mo more ratio range is 1.7–0.3 in the heteropoly acids.
• Optimal pH range to adsorb the heteropoly acids with resin anion is 0.30–0.74.
• Resin anion can effectively separate Mo(VI) from Fe(III) in acid sulfate solution.

The separation of Mo(VI) and Fe(III) from the acid leaching solution of carbonaceous Ni–Mo ore by ion exchange was studied. The leaching solution was a sulfate solution with pH 0.68, which contained Mo(VI) 10.63 g/L, Ni(II) 2.38 g/L, Fe(III) 11.42 g/L and so on. Experiments confirmed that Mo(VI) can combine with SO42 − to form heteropoly acids in acid sulfate solution, the Mo(VI) existing in the leaching solution was in the form of the heteropoly acid anions with S/Mo mol ratio 1.7–0.3, which can be adsorbed with resin anion. The molybdenum and nickel were respectively recovered from the leaching solution by means of the technological process of direct adsorbing Mo with anion exchange resin D314, purifying with CaCO3 to remove impurities Fe, Al, Si and P from the effluent under the conditions pH 4.01, temperature 80 °C, stirring for 1 h, and then recovering nickel from the purified solution using Na2CO3 as the precipitant to produce basic nickel carbonate. It was found that the heteropoly acid anions can excite in the [H+] range of 0.1–1.0 mol/L and, the optimal pH range for it adsorbed from the leaching solution with the resin is 0.30–0.74.