Co-precipitation study of nickel and cobalt from ammoniacal leach liquor of laterite ore

In ammoniacal medium, the co-precipitation of nickel and cobalt in presence of iron and manganese is a known fact in hydrometallurgy. It always results in the form of loss of these valuable metals from leach liquor. To address and encounter this problem, the behavior of nickel and cobalt co-precipitation with iron and manganese in ammoniacal medium was investigated here. During precipitation, the effect of oxygen purging at ambient temperature and pO₂ at elevated temperature was studied. The results showed that it is possible to avoid the loss of cobalt and nickel by selective in-situ precipitation of iron and manganese at ambient temperature and pressure. However, pO₂ found an important role on cobalt precipitation but has little effect on nickel. It was also observed that after a long duration of atmospheric precipitation, nickel and cobalt gets coprecipitated with manganese and identified as asbolan type phase (Co,Ni) Mn₂O₄(OH).XH₂O by the XRD.