Amorphous silica effects on copper flotation: A kinetic and selectivity investigation

Amorphous silica has been recently recognized for its adverse effects on copper flotation, but its impact remains poorly understood. This study investigates the effects of varying amorphous silica content on the kinetics and selectivity of copper flotation. Results show a significant reduction in chalcopyrite from approximately 99 % to 86 % with increasing amorphous silica content, attributed to increased pulp viscosity and slowed flotation kinetics. The classical first-order kinetic model provided the best fit for the flotation kinetics data, revealing that higher amorphous silica content prolongs the time required to achieve ultimate recovery. Results also show that amorphous silica deteriorated flotation selectivity and increased gangue recovery via entrainment, with complex variations depending on amorphous silica content. A small amount of amorphous silica was identified to significantly impair flotation kinetics and selectivity, leading to a deterioration in overall flotation performance.