Flotation air control upgrade

Common challenges

A common challenge in flotation is that operators do not have sufficient time to continuously adjust the flotation air feed to ensure optimal circuit performance. Manual air regulation is difficult if there are no flow meters available to indicate the amount of air being fed into the cell, and adjusting the airflow based on the observed bubble properties requires skilled personnel, who may not be available if staff turnover is high.

The importance of airflow control

The amount of airflow directly affects flotation performance and so has a major impact on the metallurgical recovery and grade of the concentrate. In addition to bubble/particle interaction, air also helps to control the speed at which concentrate is removed from the cell.

Increasing the air feed produces more bubbles, leading to a greater probability of bubble/particle interaction, which in turn leads to higher recovery overall. However, too much air can lower the concentrate grade and also result in more water being carried out of the cell in the froth layer due to faster-rising bubbles.

Automatic airflow adjustment

Metso Air Control Upgrade makes operators’ work easier by enabling automatic control of the flotation cell air feed. Airflow is controlled by an air mass flow meter and automatic airflow valve. The meter records the airflow rate through the feed pipe, comparing it to the set point (SP) value, and then relays the information to the automatic control valve, which adjusts the flow according to the SP.

• Site and process condition assessment to determine optimum setup
• Piping and compensator
• Automatic control valve for each individual cell
• Airflow meter
• Air isolation valve
• Optional Metso basic and advanced control systems