Improving the representation of hot flotation testing through the application of a novel, double batch flotation machine

Hot batch flotation tests are often applied to reduce risks in plant trials as they combine the benefits of matching complex plant feed stream compositions with the high precision of lab scale batch flotation testwork. One of the weaknesses of hot flotation tests is the sequential nature of the testwork, where ageing of pulp samples can influence metallurgical performance. When present this interference could at best generate inconclusive results, and at worst, inaccurate conclusions. To improve the reliability of test data, CP Kelco has developed a novel, double batch flotation machine for conducting parallel hot flotation tests on live flotation streams. Hot flotation tests with a sensitive Ni cleaner feed stream, principally containing pyrrhotite, pentlandite, magnesite and talc, were used to demonstrate the principles and potential of the device. Parallel tests with the double flotation machine were shown to afford reproducible Ni recovery-grade curves, while sequential tests conducted with a 30 min ageing period showed a marked change in Ni recovery-grade curves. In this study, selectivity curves have been beneficial in identifying the sources of the changes caused by ageing, which appear to be due to an increased recovery of pyrrhotite.