3D Imaging Analysis of Mineral Dissolution to Optimize Environmental Friendly Leaching of Metals

Leaching using deep eutectic solvent (DES) can be an alternative solution for environmentally friendly leaching. Two choline chloride (ChCl) based DESs are investigated using two different oxidants for each DES, which are ChCl-ethylene glycol and ChCl-lactic acid with iodine (I2) or hydrogen peroxide (H2O2) as the oxidants. This study attempts a new method of determining leaching dissolution rate by using 3D image analysis from single particle leaching experiment to optimize leaching process through time. X-ray computed tomography (CT) is used to scan the particle to get 3D images, volume and surface area of the particle before and after the leaching. Gold, silver and telluride minerals are used as the target minerals, whereas galena, chalcopyrite and pyrite are used as the gangue minerals. The dissolution rate of these minerals calculated from the 3D image processing are then combined with mineral liberation analysis (MLA) data of a sulphide concentrate. This MLA data provides mineralogical characteristic along with scanning electron microscopy (SEM)-based image to be used in leaching simulation to get mineral recoveries. This method shows that selectivity of each target and gangue mineral dissolution in different solution can be observed and compared. The dissolution rate can also be applied in predicting leaching using different characteristic of ores or concentrates. Batch leaching experiments using all the leaching solutions are also done to compare the leaching simulation result.