MAGNETIC FLUID SEPARATION OF ALLUVIAL GOLD FROM PLACER BENEFICIATION PRODUCTS

The process of separation in a ferrofluid is recommended for gold separation from placer beneficiation products. The process of magnetic fluid separation is based on the ponderomotive force of the inhomogeneous magnetic field appeared in ferrofluids in addition to the pushing gravity force. The horizontal component of this force in a separation medium participates in the movement of bodies along an equipotential surface across the working area – to the separation cell walls and towards the central plane of the pole gap, and the longitudinal component participates in the movement along the working area. In order to improve the technological parameters of the process, it is recommended to limit the transverse displacements of the bodies by vertical partitions installed in the separation medium along the separator pole gap. The theoretical study results regarding particle motion in the separator working area suggest that the wall effect is manifested in the appearance of a flow opposite to the direction of particle motion. This increases the hydrodynamic drag force and reduces the speed of particle movement. It is shown that the decrease in the time of light concentrate fraction presence in the separator working area with vertical walls promotes an increase in the productivity of the process with respect to the initial feed and heavy fraction productivity (gold extraction into the heavy fraction). The mathematical methods of experimental design were used to perform investigation tests of competing methods of separation on artificial mineral mixtures and heavy gold-bearing concentrates isolated from placer sands. It has been proved that the transition from ferrofluid volume separation to separation using the developed method increases the unit productivity by 9 %, and the gold extraction into the heavy fraction from 84,34 to 91,77 % due to light fraction losses reduced from 15,46 to 7,96 %. Heavy fraction yield lowered by 11,6 rel.% made it possible to obtain a material containing over 800 kg per ton of gold.

gold recovery, magnetic fluid separation, vertical partitions, comparative tests, increased productivity

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