Three technologies for recovery of nickel from Polish laterites were validated at Łukasiewicz Research Network – Institute of Non-Ferrous Metals (Łukasiewicz-IMN).
The first technology covered the application of hydrochloric acid. In a series of operations comprised of leaching and subsequent precipitation steps, it allowed to obtain nickel and magnesium concentrates as well as to recover hydrochloric acid.
The second one was dedicated to the production of the solution containing nickel and magnesium using sulphuric acid. Both technologies included also iron removal step, essential for further material processing.
Both technologies were validated at Łukasiewicz-IMN facilities using 50 dm3 – 1 m3 leaching tanks and suitable chamber-membrane filtration presses. Sulphate solutions from second technology were subjected to solvent extraction tests. Tests were performed using a laboratory system for continuous solvent extraction composed of 8 mixer-settler units (0.5 dm3 and 1.5 dm3 each). The single test took ca. 8 hours and 15 test were done to validate the technology.
It was found that it was possible to recover over 90% of nickel contained in laterites during leaching. Solvent extraction tests allowed to recover almost 100% of nickel contained in the solution and to reduce magnesium content over 20-times.