Electrokinetic and rheological behaviour of aqueous chlorite dispersions: Effect of ph and solid loading

The association of aluminosilicate clay minerals (e.g., chlorite) with valuable base metal (e.g. nickel, copper) ores may lead to some challenges during their hydrometallurgical processing (e.g., leaching, dewatering). A better understanding of these gangue minerals' interfacial chemistry and particles interactions is essential to device effective strategies for improved processability. This study looks at the electrokinetic and rheological behaviour of aqueous chlorite slurries as a function of pH (2-10) and solid loading (0.001-70 wt. % solid) at 25 degreesC. For the dilute dispersion, the magnitude of negative particle zeta potential decreased with decreasing pH showing an isoelectric point (iep) at pH 2. For concentrated dispersions, however, the chlorite particles displayed lower zeta potential trends with iep at pH 5-6, showing a bifurcation on return pH sweep with iep shift to pH 6.5. Particle interactions measured for concentrated dispersions showed a significant pH dependent behaviour with higher shear yield stress at the isoelectric points and low yield stress at pH 3. The results also revealed a significant solid loading dependent behaviour indicating a strong gel structure at higher solid loading (> 60 wt. %). The interfacial chemistry and particle interactions measured for the chlorite mineral showed pH dependent compliance with the DLVO theory.