| Abstract |
Critical shortage of aluminium raw materials in Russia justifies the high-priority of domestic relatively low-grade bauxites processing methods improvement. This type of bauxites occur in the Vezhayu-Vorykvinskoye deposit in the Timan province, that is significantly ferruginate, and characterized by a high silica modulus. Grade of bauxites, and, consequently, profitability of their processing, may be considerably increased, if ferruginate impurities could be separated, and titanium and silica minerals, carbonates and sulfides could be removed. More general way for modification of many varieties of bauxites, permitting to remove up to 70 % of silica, is chemical beneficiation with preliminary roasting. A significant hindrance with respect to processing of bauxites is high content of non-magnetic oxides – gothite-hydrogoethite and hematitehydrohematite. A supposition is made, that gothite and hematite transformation into ferromagnetic phases may provide for separation and selective recovery of aluminium and ferruginate components. This will increase aluminium concentrate grade and open up the possibility for production of additional ferruginous middling. Using up-to-date methods of mineralogical studies, the effects of low-temperature pyrolysis and exposure to radiation by accelerated electrons upon phase composition and magnetic susceptibility of ferruginous bauxites were studied for the first time. It is shown, that after heating and holding during 60 minutes in the temperature interval of 180–600 °С, magnetic susceptibility of this type of bauxites is considerably reduced. Exposure to radiation during heating, on the contrary, leads to strengthening of magnetic properties, contributing to separation of alumina and ferruginous components of bauxites. With that, the task of rare and rare-earth elements’ phases selective recovery is accomplished.
The authors are indebted to the Shared Use Center of the Komi Republic Institute of Geology Scientific Center of the Ural Branch of the Russian Academy of Sciences, the Institute of Mining Affairs and the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences for assistance in performance of the analytical works.
This work was performed with the financial aid for the Ural Branch of the Russian Academy of Sciences Projects (Project No. 15-11-5-3). |
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