Institute of Chemistry and Chemical Technology SB RAS (Krasnoyarsk, Russia):
Zashikhin A. V., Researcher, Сandidate of Engineering Sciences, obog2006@ya.ru

The paper covers the recovery of flattened free gold from heavy gravity concentrates. A significant grade improvement through preliminary centrifugal impact crushing has been proposed and experimentally substantiated for gravity concentrates (primary gold concentrates) in the presence of galena. Images are shown (Hitachi TM4000 electron microscope) indicating the sizes of characteristic particles of refractory gold, which are morphologically comparable to mica; changes in their shape as a result of crushing have been traced. Three main types of particle shapes are proposed, caused by isometrization of flattened particles. Measurements of the free fall velocities of flattened gold particles before and after crushing are used to demonstrate the technological feasibility of their targeted charging to make them equal-falling with galena particles. As a result of the analysis of experimental data, a particle size limit has been established, below which the technical solution used in the work for the centrifugal impact crushing shall require improvement. In view of the poor availability of gold particles, it is proposed to use model mixtures of balls of narrow grain sizes of a tin-lead alloy, which are freely available on the market, for the experimental crushing, processing, and classification studies. The work was aimed to substantiate the possibility of using simple, reliable, and environmentally friendly solutions to increase the processing efficiency for refractory gold-bearing raw materials, expanding the applications of centrifugal impact crushing.
The work was carried out within the framework of the state assignment of the Institute of Chemistry and Chemical Technology of the Siberian Branch of the Russian Academy of Sciences (project No. 121031500206-5) using the equipment of the Federal Research Center «Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences».

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