Fine, liberated, sulphide minerals (<20 microns) are difficult to recover by flotation. Attempts to improve fine mineral recovery including using long conditioning times, high intensity conditioning, split flotation, reducing bubble size and even increasing agitator power have had limited success. These methods are either expensive, non-selective for the valuable mineral, practically ineffective or the benefit is difficult to prove to high confidence.
The ProFlote™ is a statistically proven technology to selectively increase fine mineral flotation recovery; leading to improved total plant recoveries. The technology comprises of a proprietary designed, high strength, rare-earth, permanent, magnet which is encased in a rubber lined stainless steel tube. The resulting strong magnetic field magnetises the fine <20 micron paramagnetic minerals, that then will aggregate in the slurry, the same way two magnets will aggregate when in close proximity.
Minerals that are known to be paramagnetic include: chalcopyrite, bornite, pentlandite, cassiterite and sphalerite that contains iron. ProFlote trials have also shown improvements in gold, silver, PGM minerals and galena (that contains Fe) recovery. Research conducted with CSIRO confirms the magnetic susceptibility of some galena concentrate samples which is contrary to the published literature that reports galena as diamagnetic (not magnetic).
Just as importantly, some of the main minerals, sulfide flotation attempts to reject like siliceous gangue are diamagnetic, or like pyrite, have a negligible magnetic susceptibility. This difference in magnetic properties between the recovered and rejected froth flotation minerals enhances selectivity. The magnetic susceptibility of some of the minerals in a flotation slurry is given in Svoboda (1987) and is reproduced in the table below.
Magnetic aggregation is also a homogeneous process which targets only the very fine paramagnetic minerals. In essence, if two or three 10 micron copper minerals aggregate then they will float with the recovery of a 20 or 30 micron copper mineral, instead of the poor flotation of a 10 micron copper mineral. There has been no statistical tests with ProFlote™ to suggest magnetic aggregation of coarse particles.
As a result, the ProFlote™ technology has no deleterious effect on plant mineral recovery, which makes plant trials a safe, quick and effective way to statistically measure the true extent of the technology's benefit over the trial period.
For more information on the ProFlote™ technology please download the company brochure or alternatively call our office landline.
