RATES OF CAPTURE OF SMALL PARTICLES IN FLOTATION.

The absolute rate of flotation was determined by a new experimental technique that depends on allowing single bubbles to rise through a very dilute suspension of particles. Measurements were made of the rate of capture of particles 10 - 50 mu m in diameter by bubbles 0. 5 - 1. 0 mm in diameter. The particles comprised narrow-range fractions of quartz or spherical glass micro-beads, all previously rendered strongly hydrophobic by surface methylation. It was concluded that angularity or roughness of quartz particles ensures easy rupture of the wetting film, even when the barrier is strengthened by addition of low concentrations of surfactant or when the contact angle is reduced from 87 degree to 30 degree .