Danilevskaya L. A., Senior Researcher, danilevs@krc.karelia.ru; Skamnitskaya L. S., Senior Researcher, camnits@krc.karelia.ru; Institute of Geology, Karelian Research Centre of RAS (Russia).

By way of example of the Eastern Hizovaara (North Karelia) deposit quartz-muscovite metasomatites, on the basis of 102 individual samples, taken from seven boreholes, the ore types geological-mineralogical characteristics and processing specifics have been studied. Quartz-muscovite metasomatites with muscovite content of at least 18 %, accounting for 70 % of total rock mass, are of a commercial interest, being represented by light-gray fine-and-medium-grained schistosity rocks with varying content of rock-forming minerals: quartz — 10–71 %; muscovite — 8–42 %; plagioclase — 1.5–28 %; kyanite — 2–13.5 %; biotite — 0.1–8 %. Small technological samples processing experiments established easy dressability with regard to muscovite. With respect to the technology, starting material after crushing is deslimed by -0.1 mm size fraction, +0.1 mm size fraction is subjected to gravity concentration (on concentration tables) by the flow sheet that includes rougher operation and two cleanings of middlings. Muscovite concentrate contains 95.6 % muscovite, recovery being 83%. A possibility of producing quartz concentrates of variable grade as fine-grain muscovite by-products has been shown under laboratory conditions on the basis of two large samples. Mineralogical-technological specific properties of quartz were studied both area-wise and depth-wise of the deposit in order to estimate a possibility of higher-grade quartz concentrates production from muscovite cycle tailings. Mineral inclusions' specialties were determined with respect to quartz morphotypes. Special features of a combined processing technology with application of gravity concentration and flotation are described. Prospects for possible use of produced quartz products are indicated: concentrate to be produced from the deposit South-East area ore, with size of 0.315–0.1 mm and impurities content of 236 ppm, may be used to produce metal silicon of special grades; concentrate from North-West area ore, with size 0.2–0.1 mm (1465 ppm impurities), complies with the requirements to raw material for production of ferrosilicon of high grades.

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