Influence of coal particles on froth stability and flotation performance

• Froth half-life time for high hydrophobic particles was very long.
• Maximum froth height for moderate hydrophobic fine particles was very high.
• Froth half-life time for hydrophilic fine particles was very short.
• High hydrophobic fine particles greatly decreased coarse particles’ recovery.
• Moderate hydrophobic fine particles greatly increased coarse particles’ recovery.

Solid particles have significant effect on flotation froth. In this research, the effects of coal particles of different size and hydrophobicity on froth stability and flotation performance were studied. The froth stability was measured in both the froth formation and froth decay processes by maximum froth height, froth half-life time and water recovery. The results show that fine particles of moderate hydrophobicity contributed most to maximum froth height in the froth formation process and were most favorable for flotation. Fine hydrophilic particles stabilized the froth in the froth formation process but the froth half-life time was very short due to the high water solid ratio. High hydrophobic particles of both fine and coarse size fractions greatly increased the froth half-life time in the froth decay process. But the froths were very rigid and the maximum froth heights were very low. The presence of fine hydrophobic particles was very unfavorable for the recovery of coarse particles.

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