Interactions of clay minerals in copper–gold flotation: Part 1 – Rheological properties of clay mineral suspensions in the presence of flotation reagents

• Kaolinite and bentonite suspensions follow Newtonian or pseudoplastic fluids.
• Bentonite has a stronger effect on the viscosity of suspensions than kaolinite.
• pH modifiers alter the rheology of clay mineral suspensions differently.
• PAX and Interfroth 6500 alter the rheology of clay mineral suspensions similarly.
• The effect of pH modifiers on the rheology is more pronounced.

Clay minerals are often associated with copper, gold and other valuable minerals and place a widespread problem in mineral flotation. This paper is one of a series addressing the problem caused by clay minerals in copper–gold flotation. This study seeks to understand the rheological behaviour of kaolinite and bentonite suspensions at natural pH and how the pH modifier, collector and frother normally used in copper–gold flotation affect the rheological properties. It was found that kaolinite and bentonite suspensions may follow Newtonian flows or non-Newtonian flows with pseudoplastic characteristics depending on the solid concentration. Bentonite has a stronger effect on the viscosity of suspensions than kaolinite. The pH modifier, collector and frother have a potential to alter the rheological behaviour of kaolinite and bentonite suspensions and the effect of the pH modifier is more pronounced.