Probing the interaction between air bubble and sphalerite mineral surface using atomic force microscope

Area of Science:

• Surface science and colloid chemistry
• Mineral processing and materials engineering
• Nanoscale force measurements

Background:

• Air bubble-solid surface interactions are crucial in mineral froth flotation.
• Understanding these forces at the nanoscale is key to optimizing flotation processes.

Purpose of the Study:

• To directly measure interaction forces between air bubbles and sphalerite mineral surfaces.
• To investigate the influence of hydrophobicity and hydrodynamic conditions on bubble-mineral attachment.
• To validate experimental findings with theoretical models.

Main Methods:

• Utilized an atomic force microscope (AFM) bubble probe technique for direct force measurements.
• Examined sphalerite surfaces with varying hydrophobicity (conditioned vs. unconditioned).
• Applied Reynolds lubrication theory and augmented Young-Laplace equation for theoretical analysis.

Main Results:

• Hydrodynamic and surface forces critically govern bubble-mineral interaction and attachment.
• Hydrophobic disjoining pressure is stronger for conditioned sphalerite, enabling attachment at higher velocities.
• Increased salt concentration weakens electrical double layer forces, facilitating bubble-mineral attachment.

Conclusions:

• Direct force measurements provide fundamental insights into bubble-mineral interactions in froth flotation.
• The AFM bubble probe technique is a versatile method applicable to various mineral systems.
• Findings contribute to the understanding and optimization of mineral processing technologies.