The effect of hydrophobicity on the froth phase behavior

The influence of glass beads of various degrees of hydrophobicity on the detachment rate of particles and recovery has been investigated in a continuous flotation system. The detachment characteristic of particles in the froth phase is defined by a detachment rate constant, and the recovery in the froth phase is evaluated. It is shown that detachment rate constants for particles of weak hydrophobicity (corresponding to a contact angle of almost equal 50) decrease sharply as the froth height increases. While those for particles of intermediate hydrophobicity (corresponding to a contact angle of almost equal 66) increase as the froth height increases. Strongly hydrophobic particles (corresponding to a contact angle of almost equal 83), on the other hand, exhibit the lowest value of the detachment rate constants, with froth height having little effect on it. Froth recovery for particles of intermediate hydrophobicity indicates that substantial particle detachment occurs in the froth phase. Froth recovery decreases from 99% to 70% when the froth height increases from 2 to 36 cm. Under the same experimental conditions the froth recovery decreases from 100% to 83% for the particles of weak hydrophobicity and from 100% to 99% for those of high degree of hydrophobicity. The results of concentrate enrichment ratio versus froth height shows that particles with intermediate hydrophobicity demonstrate the highest enrichment ratio.