Real-Time Control in the Flotation Circuit: The Key to Stable Recovery
Tuesday 25 Nov 2025
The flotation process is an unstable step in mineral processing. Small changes in feed density, pulp level, air flow, or reagents can quickly cause problems like overflowing cells, unstable froth, or lower recovery.
To avoid these issues, operators need reliable, real-time information to keep the process under control.
Why Particle Size and Slurry Density Matter
For flotation to work well, the mineral particles need to be ground to the right size.
- If they are too coarse, valuable minerals stay locked with waste and won’t float.
- If they are too fine, they may not attach to bubbles properly or get carried into the froth with waste (the gangue).
The material that ends up “in between” – not clean concentrate and not pure tailings – is called middlings. Middlings lower recovery and are often sent for regrinding or recycling to improve separation.
In flotation slurry density is a powerful indicator for grind size. Because density is closely linked to particle size, measuring it in real time gives operators an early signal of changes in the grinding and flotation feed.
Developments in Flotation Control
- Smarter Froth Monitoring
Modern camera systems can “see” what’s happening in the froth, tracking bubble size, speed, and even color. This data helps adjust air flow automatically, improving cell stability without constant operator input. - More Sensors, Better Decisions
Plants are moving towards integrated monitoring, tracking not only slurry density, but also pH, reagent use, and pulp levels in real time. This combination of data makes advanced control strategies more effective. - Non-Nuclear Density Measurement
Many plants are moving away from nuclear sensors due to safety and regulation challenges. Non-nuclear ultrasonic sensors, like Rhosonics’ SDM ECO, now provide a safe, reliable, and accurate alternative.
How Rhosonics Adds Value
| Problem in Flotation | Old Approach | With Rhosonics Sensors |
|---|---|---|
| Variable feed & middlings | Slow reaction, efficiency loss | Real-time density data for early action |
| Unstable froth | Manual adjustments | Data-driven control with automation |
| Fluctuating pulp levels | Risk of overflow or starving cells | Inline monitoring for stable operation |
| Nuclear safety concerns | Regulatory complexity | Safe ultrasonic sensors (non-nuclear) |
Conclusion
Maintaining stable process conditions is critical for efficient flotation. With the right instrumentation and integrated automation stable process conditions can be maintained at all times, yielding optimized results.
Rhosonics’ SDM ECO give operators the insights they need to prevent middlings, stabilize flotation cells, and maximize recovery, all without the safety and regulatory issues of nuclear devices.

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