How intelligent valve control helps mining operations improve flotation performance

Advanced diagnostics and precise valve control help mining operations reduce process variability, improve process stability, and support predictive maintenance.

The flotation process, used to concentrate high-value minerals from low-grade ores, is a key operation in mining. However, it is also highly sensitive to operational variations. Parameters such as pulp level, aeration air flow, and concentrate discharge directly influence froth stability, selectivity, and overall plant efficiency.

Maintaining stable control of these variables is essential for maximizing metallurgical recovery and operational performance. To achieve this, mining companies are increasingly adopting intelligent valve control and diagnostic technologies that improve process visibility and help reduce operational variability.

One example is Valmet's Neles™ ND9000™, an intelligent valve controller with advanced diagnostics that helps operators maintain precise valve control while providing valuable information on valve performance and condition.

When integrated with advanced control practices and predictive maintenance, the technology enables flotation cell valves to function not only as control elements but also as sources of diagnostic information that support real-time process monitoring. Precise valve positioning helps ensure fast and stable responses to process variations, contributing to more consistent flotation performance.

Supporting stable control of critical flotation variables

Maintaining stable flotation conditions requires accurate control of variables that directly affect froth formation and mineral recovery. Variability in control performance can lead to process disturbances that affect plant efficiency and metallurgical results.

Advanced autotuning and fine-tuning capabilities help reduce oscillations, improve interaction between control loops, and increase operational stability. These capabilities support smoother process control and help operators maintain the conditions required for efficient flotation.

Another common challenge is valve stiction, one of the main causes of valve instability in flotation applications. Advanced diagnostic features combined with precise valve control help prevent abrupt movements and ensure smooth, continuous operation. Aeration airflow is one of the most critical variables in flotation, as it directly influences froth formation and stability. Delays in valve response can negatively impact process performance and reduce recovery rates.

The Neles ND9000 helps operators identify deviations between the command sent by the automation system and the actual valve movement, making it possible to detect issues such as pneumatic restrictions, insufficient air pressure, or undersized actuators before they significantly affect the process. "If the ND9000 detects an increase in response time, it can indicate that air flow control is being compromised, allowing the team to act quickly before the process is impacted," explains Ricardo Ferraz, Head of Valve Controls and Actuators LATAM.

Pulp level control is another critical factor in flotation. Even small variations can influence concentrate quality and mineral recovery. By maintaining the valve at the position defined by the automation system, intelligent valve control helps improve flotation cell stability. Adaptive control capabilities further reduce variability and support smoother responses to changing operating conditions.

Using diagnostics to support predictive maintenance

Beyond accurate positioning, intelligent valve diagnostics can help mining operations improve maintenance practices and equipment reliability.

The ND9000 continuously monitors parameters such as position deviation, pressure, and actuator force, providing insights into valve condition and performance. Online valve signature analysis compares current behavior with the commissioning baseline, helping maintenance teams detect degradation and validate maintenance interventions. "Since a large portion of flotation instabilities originate from degraded or improperly adjusted valves rather than the process itself, diagnostics enable early identification of wear, solid buildup, and other issues," says Ferraz.

This information can help maintenance teams identify developing problems before they affect process performance, supporting a transition from time-based maintenance to condition-based maintenance.

From valve performance to process performance

The impact of valve performance extends beyond the valve itself. Stable and responsive control can contribute directly to improved flotation performance and more consistent metallurgical results.

In one major Brazilian mining operation, the intelligent valve controller helped deliver fast response, linear control, and automatic compensation of supply air variations. The result was reduced unwanted oscillations, improved froth layer stability, and increased metallurgical recovery.

According to Ferraz, these improvements were achieved by ensuring that flotation process valves consistently remained at the positions required by the automation system, improve overall process performance.

In addition to reducing level variability and improving froth stability, intelligent valve control can contribute to increased metallurgical recovery, reduced reagent consumption, fewer manual interventions, and a lower risk of unplanned shutdowns. However, the full value is realized when intelligent positioners/valve controllers are used as part of broader process optimization and predictive maintenance strategies. "When the equipment is fully integrated into data-driven control strategies and predictive maintenance guided by diagnostics, it becomes an essential tool for flotation optimization," Ferraz concludes.