SEPARATION OF COPPER, IRON AND ZINC FROM COBALT AND NICKEL IN MINARA PROCESS LIQUOR BY SYNERGISTIC SOLVENT EXTRACTION: PILOT PLANT OPERATION

摘要

The Minara Process liquor was taken from its Murrin Murrin Nickel Operation after iron precipitation before copper removal. It contained 126 g/L Ni, 8.1 g/L Co, 0.17 g/L Cu, 1.83 g/L Zn and 0.002 g/L Fe. The primary and most important objective of the project was to obtain raffinate solutions containing <0.3 ppm Cu and Fe from which a high quantity cobalt product containing <50 ppm Cu and Fe could be achieved. This has been successfully achieved and confirmed by ICP-MS. For the A/O ratios as high as 7:1 and as low as 1.5:1, the target Cu and Fe concentrations of <0.3 ppm in the raffinates were consistently achieved. This means that there is a wide operating window of A/O ratios. It was found that there is a reasonably wide operating pH window to meet these requirements. The pH in EX2 should be controlled to pH >3.7 (or best between pH 3.7-4.0) and that in EX1 to pH <3.7 (or best between 3.5-3.7).