Precipitation of Mixed Ni/Co Hydroxides in Hydrometallurgical Processing of Domestic Iron-Rich Laterite Ores

The study presents results on processing ammonium-sulfate solutions obtained after leaching reduced ferruginous laterite ores from the Buruktal deposit in the presence of (NH4)2SO4. We identified conditions for selective hydrolytic precipitation of Fe(III), Ni, and Co hydroxides, considering (NH4)2CO3, NaOH, and Na2CO3 as reagents. The study determined that preliminary iron removal with ammonium carbonate at pH 4.0 enables nearly complete precipitation of mixed Ni/Co hydroxides from ammonium-sulfate solutions at pH 9.3 when using NaOH as the neutralizing precipitant. Under these conditions, the residual Ni concentration in solution remains below 4 mg/L.