In mineral processing, flotation is often carried out in several stages rather than a single step. Rougher, scavenger and cleaner flotation are three common stages, each serving a different purpose in the flotation circuit.
Rougher flotation is usually the first major flotation stage after grinding and reagent conditioning.
Its main purpose is to recover floatable valuable minerals from the feed slurry and produce a rougher concentrate.
Feed Slurry → Rougher Flotation → Rougher Concentrate + Rougher Tailings
Scavenger flotation further treats the rougher tailings.
Its purpose is to recover additional floatable valuable minerals that remain in the tailings after rougher flotation.
Rougher Tailings → Scavenger Flotation → Scavenger Concentrate + Final Tailings
Depending on the process design, scavenger concentrate may be returned to an earlier flotation stage for further processing.
Cleaner flotation further processes the concentrate produced by rougher flotation.
Its main purpose is to remove more unwanted gangue and improve concentrate quality.
Rougher Concentrate → Cleaner Flotation → Final Concentrate
Some flotation circuits may use multiple cleaning stages depending on ore characteristics and concentrate requirements.
| Stage | Typical Feed | Main Purpose |
|---|---|---|
| Rougher | Flotation feed | Initial recovery of valuable minerals |
| Scavenger | Rougher tailings | Recover additional valuable minerals |
| Cleaner | Rougher/intermediate concentrate | Improve concentrate quality |
These stages work together as part of the overall flotation circuit rather than as separate processes.
Flotation machines can be configured for roughing, scavenging and cleaning, but equipment configuration may vary according to the requirements of each stage.
Important factors include:
Therefore, flotation equipment should be selected according to the complete mineral processing flowsheet.
When selecting a flotation machine or flotation cell, information such as ore type, processing capacity, feed characteristics, flotation process and concentrate requirements should be considered.
These conditions help determine the appropriate flotation machine type, cell volume, number of cells and circuit configuration.
Rougher flotation provides the initial recovery, scavenger flotation further treats rougher tailings, and cleaner flotation further upgrades the concentrate.
Understanding the role of each stage helps mineral processing plants configure suitable flotation equipment and flotation circuits.
