The different effects of bentonite and kaolin on copper flotation

• Bentonite and kaolin caused different issues in copper flotation.
• Bentonite reduced the amount of froth and decreased copper recovery.
• Kaolin enhanced froth stability and decreased copper grade.
• Bentonite caused high pulp viscosity reducing bubble and particle mobility.
• Kaolin had little effect on pulp viscosity and moved to the froth.

Clay minerals impose deleterious impacts on mineral processing. In this study, bentonite consisting primarily of montmorillonite and kaolin consisting primarily of kaolinite, were used to characterise the effect of clay minerals on copper flotation. It was found that bentonite and kaolin caused different issues in the process of flotation. Increasing the proportion of bentonite reduced the amount of froth on the top of slurry and decreased the copper recovery. On the other hand, increasing the kaolin content mainly decreased the copper grade with little effect on copper recovery and the bubbles on the top of froth became smaller with higher froth stability. The different roles of bentonite and kaolin in the flotation were associated with their unique properties. The findings in this study suggest that to mitigate the negative effect of clay minerals, different approaches might be applied according to specific problems caused by different clay minerals.