Hawk Measurement develops transmitters for flotation cells

Hawk Measurement Solutions has developed a method of monitoring flotation cell performance using acoustic wave transmitters.

Three transmitters combine to monitor the height and density of a cell’s froth layer, as well as the height of the chemical pulp.

The pulp is used to separate the minerals from treated ore slurries so they can be carried by compressed air to the surface of the cell.

Once they are floating on the surface, the minerals will concentrate in a layer of froth.

This froth will eventually overflow into reservoirs around the exterior of the cell called launders.

The height and density of the froth and the height of the pulp therefore need to remain at certain levels so the material always overflows.

These parameters can have a major impact on the performance and therefore profitability of a flotation cell, the company said.

According to the manufacturer, many older flotation cells use a displacement float below the froth layer to measure the pulp height.

However, the slurry can build up on the float and make the readings unreliable.

The measurement solution uses three non-intrusive acoustic wave transmitters set at different frequencies to measure each parameter.

The first transmitter has a very low frequency of five kilohertz to penetrate through the froth and measure the pulp height.

The second transmitter has a higher frequency of 20 kHz and is designed to measure the froth height.

The froth measurements are fed into the pulp inlet’s control loop to maintain constant overflows.

The third transmitter has a frequency of 15 kHz and is designed to measure the density of the froth.

High-density froth will have a greater entrainment of minerals and will therefore be more profitable when concentrated.

All of the transmitters can be mounted above the cell for easy maintenance and service access.

Similarly, the company said the high-powered acoustic wave will automatically clean the sensor face with every measurement pulse to minimise material build-up.


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