Study on Flotation Behavior of Fine Flake Graphite Enhanced by Nanobubbles

Area of Science:

• Mineral Processing and Extractive Metallurgy
• Surface Chemistry
• Nanotechnology Applications

Background:

• Traditional flotation methods struggle with fine graphite recovery due to large bubble sizes and low specific surface area.
• Micro-fine flake graphite presents challenges in efficient separation and collection using conventional techniques.

Purpose of the Study:

• To investigate the enhanced performance of nanobubble flotation compared to traditional flotation for micro-fine flake graphite.
• To analyze the effects of nanobubbles on flotation kinetics, selectivity, and particle size distribution.
• To elucidate the mechanisms behind nanobubble-enhanced graphite recovery.

Main Methods:

• Conducted contrast experiments comparing nanobubble flotation with traditional flotation for Hegang micro-fine flake graphite.
• Optimized flotation parameters including feed fineness (78% -74 μm), pH (10.5), collector (diesel), frother (No. 2 oil), and depressant (sodium hexametaphosphate).
• Evaluated differences in flotation rate, selectivity, slurry particle size, and concentrate particle size.

Main Results:

• Nanobubble flotation achieved a 1.5 percentage point higher final concentrate recovery than traditional flotation.
• The flotation process using nanobubbles was completed 20 seconds faster.
• Nanobubble flotation resulted in a larger average slurry particle size (13 μm increase) and a smaller minimum particle size (2 μm, an 11 μm reduction).

Conclusions:

• Nanobubbles effectively reduce electrostatic repulsion and enhance hydrophobic attraction, stabilizing fine graphite aggregates.
• The presence of nanobubbles increases graphite surface hydrophobicity, significantly promoting the recovery of fine particles.
• Nanobubble flotation offers a superior method for processing micro-fine flake graphite compared to traditional techniques.