Study of froth behaviour in a controlled plant environment – Part 1: Effect of air flow rate and froth depth

• A device is developed to determine the recovery of collection and froth zones in a controlled plant environment.
• Air rate has a positive effect on recovery of particles in both the collection and froth zones.
• Deep froth causes the weakly composite particles to drop out of the froth.
• Froth recovery is a strong function of particle size.

This paper presents the results of a thorough investigation into the froth recovery measurements in a controlled plant environment using a device that allows direct collection of dropback particles from the froth phase.Experiments were performed at the Northparkes concentrator (NSW, Australia), using a feed taken from the head of the cleaner scavenger bank. The feed slurry had a relatively higher copper grade varying from 5.2% to 6.8%. Experiments were performed to investigate the effect of important flotation parameters such as air flow rate and froth depth, on the froth performance. The size of the particles in the relevant streams was analysed to acquire in-depth knowledge about the froth dropback mechanism. The results suggested that the froth recovery could be as low as 70%, although it was relatively easy to achieve the values in the range 75–85% by the correct choice of operating variables. It was found that the air flow rate has a positive impact on both collection (pulp) and froth zone recoveries. However, the effect was more prominent in the froth zone. It appeared that the froth recovery is a strong function of particle size.