FINNISH company Numcore Oy says it is now possible to increase the efficiency of flotation processes using real-time 3D images derived from measurement devices based on impedance tomography.
These 3D images provide insight into the inside of pipelines and tanks used by the processing industries. Applications include concentration plants in the mining industry.
According to Numcore Oy, the technology opens up new possibilities to control flotation processes, where bubbles of air are blown into a mixture of ore, water and chemicals, so the mineral particles cling onto the bubbles, and the mineral-bearing froth can then be collected from the surface.
Problems emerge if the froth cannot carry the load of mineral particles or the process otherwise becomes disturbed. The froth bed then disappears, and restarting the process wastes valuable time.
Numcore measurement devices use electric conductivity distribution to monitor the size and quantity of air bubbles and the solid matter content of the froth bed. It is possible to detect changing situations and respond by modifying parameters to prevent problems in the process.
The technology provides real-time information, continually providing the operator with factual data on what is happening in the flotation cells.
Since operators can ‘look’ inside the process, it is possible for them to maintain an optimal mix all the time.
Numcore has worked in close partnership with Outotec. Its sensors are used at two concentration plants.
Depending on the diameter of the pipeline or tank, Numcore measurement devices are realised either as a flow-through sensor or as a probe-type sensor for installation inside large pipelines or tanks.
By supplying a weak alternating current to the electrodes of the sensor, it is possible to measure conductivity differences between the phases, for example for liquids, inside pipelines and tanks, as different substances show different conductivity values. The actual image is created by means of inverse calculation.
The CoreApus flow-through sensor are suited for analysing material flows inside pipelines of less than one metre in diameter. For larger processing tanks, the probe-type CoreHydra sensor can analyse a larger area.