Institute of Mining, Far East Branch, Russian Academy of Sciences, Khabarovsk, Russia:

E. D. Shepeta, Senior Researcher, Candidate of Engineering Sciences, elenashepeta56@mail.ru
L. A. Samatova, Head of Laboratory, Candidate of Engineering Sciences
O. V. Voronova, Researcher

Processing of low-grade tungsten ore and waste governs a cardinally new strategy of beneficiation. This article discusses possible processing of low-grade scheelite ore and waste of the Vostok-2 and Skrytoe deposits by X-ray radiometric and X-ray absorption separation. In tests of the highly contrast material, it was succeeded to remove 60–65 % of tailings before the stage of deep processing. Recovery of WO₃ in flotation feed made 95 % in case of ore and 84–87 % in case of mining waste, while concentration of WO₃ reached 2.3–3 relative units. The tests were carried out on the industrial separators SRF-2–200RRS and TOMRA COM Tertiary XRT. The studies of transparent polished sections by the mineralogical and petrographic analyses revealed the main difficult-to-treat associations of scheelite with pyroxene, amphibole, chlorite and biotite. It is observed that scheelite occurs in the form of disseminated shots in quartz veins, in quartz zones of hedenbergite skarn and at the quartz–sulfi de interfaces. The crystals of scheelite in the associations reach 0.03 mm to 2(3) mm in size. In terms of the low-contrast scheelite–quartz–amphibole and scheelite–carbonate ore of the Skrytoe deposit, the concentration of 1.5–1.7 relative units is reached, the separation efficiency makes 81–85 %. The mentioned ore features high content of calcite (15–9 %) and low content of scheelite. The sheelite grains are mainly 0.03–0.15 mm in size. To improve contrast properties of mineral surfaces, it is proposed to use high-energy acoustic vibrations. The tests were conducted on the machine UZDN-2T: working frequency was 22 kHz, average acoustic intensity I_uz = 15 W/cm², size grade of the test material was –3+2 mm. Efficient mineral dissociation was observed in specimens with vein-impregnated texture and in marmorized limestone, selective recovery of scheelite was reached at the quartz–scheelite interface. The processing circuit proposed in this article for low-grade tungsten ore and mining waste includes preliminary concentration by means of X-ray absorption separation and treatment of second stage milling sand by high-frequency acoustic vibrations.

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