A study has been conducted to compare the floatability of fine zinc sulfide (ZnS) precipitates and sphalerite particles. The floatability of the precipitates was significantly poorer compared to sphalerite particles when xanthate was used as the collector. The floatability was improved by using dodecylamine as the collector, and the difference in floatability between the precipitates and sphalerite particles was reduced. The flotation kinetics of the precipitates was further improved significantly by incorporating a hydrodynamic cavitation tube in a conventional (mechanical) flotation cell. The improved kinetics was attributed to in-situ gas nucleation on the precipitates.