Effect of single pellet properties on its strength and leaching performance for three types of nickel laterites ores

Heap leaching is a widely used extraction method for low-grade minerals including nickel and cobalt. Agglomeration of fine mineral particles as a precursor to heap leaching is an important means of enhancing leaching rates and metal recoveries. Single pellet leaching behaviour of three nickel laterite ores: siliceous goethitic (SG), goethitic (G) and saprolitic (SAP) was investigated to access the effect of pellet properties (binder type, binder content, porosity and dryness) on its stability, initial leaching rate and maximum Ni recovery. The Ni leaching rate was found to be directly related to the pellet dryness and the highest rate was obtained at an intermediate degree of dryness due to the better wetting and diffusion of acidic lixiviant into the pores in between the particles. Furthermore, in addition to the observation of significant effect of porosity and binder type on the pellet's mechanical strength, which in turn determines the pellet stability during acid leaching, the ore mineralogy is also noted to play a very important role