Physico-chemical nature and leaching behaviour of goethites containing Ni, Co and Cu in the sorption and coprecipitation mode

Goethite (c¢-FeOOH) samples containing Ni, Co and Cu in coprecipitation and sorption mode were synthesized and characterized in terms of chemical composition, surface area, phase constituents, crystallinity and structural disorder (by XRD) and crystal size and morphology (by TEM).
Dissolution behaviour of Fe in Ni-, Co- and Cu-bearing goethite samples in sulfuric and sulfurous acid leaching systems have been compared with the behaviour of a pure goethite sample and correlated with the physical characteristics of the samples. Minor elements interfere with the dissolution of iron in sulfurous acid leaching. Elements in the sorption mode are easily leachable compared to the coprecipitation mode. In the latter case these may be present as a part of the goethite structure or as
occluded oxyhydroxide. The implications of these results are discussed for acid leaching of manganese nodules.