Hawk Measurement Systems offers flotation cell optimisation for mining operations.
One of the most important process operations in a mining concentrator is the flotation cell area. Profitability of the mining concentrator plant is largely attributable to this area of the process.
Most of the older flotation cells use a displacement float to measure the pulp height through the froth. This is an extremely important measurement in the process to make sure the liquid pulp does not overflow the launders. When this happens the flotation cell does not produce, which is very costly to the process.
Problems affecting the displacement float include slurry build-up and high agitation.
Acoustic Wave Transmitter
Hawk has developed very low frequency acoustic wave transmitters that are non-intrusive and can penetrate through the froth to measure the pulp height.
The Hawk sensors are mounted above the froth and pulp height eliminating maintenance or mechanical problems. Typically, the transmitter can be mounted at walkway height for easy serviceability.
The low frequency level transmitter can be supplied ready for connection to the typical 2-wire loop power supply used for the displacement float transmitter that it replaces. Remote mounted transmitters are also an option.
Froth Height Measurement Transmitter
Hawk also provides as an option, non-intrusive transmitters to measure the froth height. Continuous measurement of the froth height provided as feedback to the control loop for the inlet ‘Dart Valve’, allows a floatation cell to maintain constant overflowing of froth to the launder, even when the ore body type may produce variations to frothing consistency.
Small changes in the pulp height to keep the froth overflowing at all times will enhance the efficiency of the flotation cell and consequently increase profitability. Hawk transmitters will reliably measure froth height even when froth density changes.
Relative Froth Density Measurement Transmitter
Hawk also provides a third type of transmitter to measure relative froth density. Higher density froth will have greater entrainment of mineral going over the launder.
Currently, density measurement is not widely used due to the degree of difficulty in making an effective online density measurement in each flotation cell. Bubbler type pressure transmitters have been commonly used, though they have high maintenance costs due to their intrusive installation.
Non intrusive transmitters that penetrate partly through the froth give an output proportional to density. Data from the froth height transmitters is used with the froth penetration (density) information.
Monitoring of the deviation between froth height and froth penetration allows the control system to track relative froth density non-intrusively.
Relative density data can be used to actively control density through a feedback loop, regulating forced air flow into the flotation cell. Air input is currently largely controlled manually by onsite operators.