Induced crystallization of goethite precipitate from nickel sulfate solution by limonite seeding

The goethite process has gained renewed attention due to the generation of environmentally acceptable sludge in hydrometallurgical processing of nickel. Goethite precipitation at low pH (2.1 to 2.5) contributes to minimizing the loss of nickel, but results in iron precipitates with poor filterability. In this paper, crystallization induced by natural limonite seeds was used to improve the filterability of iron precipitates. The X-ray Diffraction, Scanning Electron Microscopy and Laser Particle Size Analysis show that limonite seeds could induce the growth of goethite crystals and reduce the generation of amorphous iron phases at low pH. The limonite particles of size range − 74 + 37 μm were the most suitable for inducing goethite crystallization. A smaller specific surface area of goethite particles by limonite seeding and hot acid washing contributed to a decrease in the adsorption on to the precipitates.