TUC validated heap leaching in WP6 by taking also into a series the results of a series of activities in WPs 3, 4 and 5, involving:
– Larger column leaching tests of low-grade laterites (Ni content 0.5-0.7 %wt), using a 5 kg feed and sulphuric acid as leaching medium.
– Sequential leaching tests (i.e the PLS obtained from the first leaching column was used as leaching medium in the second column), based on the results of single tests using ores of various grade, in order to increase the content of Ni and Co in the pregnant leaching solution (PLS)
– PLS purification was carried out by precipitation and SX; mineralogical analyses and SEM studies were carried out in the precipitates and leaching residues
– Finally, the leaching residues were valorized through alkali activation for the production of alkali-activated materials (AAMs)