Institute of Geology, Karelian Research Centre RAS (Petrozavodsk, Russia):
Skamnitskaya L. S., Senior Researcher, skamnits@krc.karelia.ru
Svetova E. N., Senior Researcher, Candidate of Geological and Mineralogical Sciences, enkotova@rambler.ru

Institute of Geology, Komi Research Center, Uralian Branch of RAS (Syktyvkar, Russia):
Shanina S. N., Senior Researcher, Candidate of Geological and Mineralogical Sciences, shanina@geo.komisc.ru

This paper covers the results of the mineralogical and process study of the vein quartz of the Fenkina-Lampi deposit, conducted with the aim of expanding the applications for this raw material and developing an advanced processing technology that would take into account the specific features of quartz contamination by fluid inclusions. The vein quartz varieties are investigated by vacuum decrepitation, optical absorption spectroscopy, optical and electron microscopy, microprobe analysis, gas chromatography and inductively coupled plasma atomic emission spectrometry. The advanced purification technology for quartz, using magnetic separation, flotation, UHF processing, thermal shock and chlorination, enabled obtaining quartz concentrates with the total content of impurity elements of 96 and 107 ppm, which is above the requirements for high-purity quartz products. It is shown that a significant part of the Al, Na, Ca, and K impurities remaining in quartz may be associated with the composition of salt solutions of fluid inclusions and the presence of «captive» minerals. The quartz is characterized by high gassing in the high-temperature range (600–1000 °C), which makes it less suitable as a raw material for high-quality fused glass. This should be taken into account when developing the processing technology for this quartz. The respective advanced purification operations should incorporate innovative solutions to release the impurity elements trapped by the finest fluid inclusions.
The research was conducted under the financial support from the federal budget for the fulfillment of the state assignment set for the Institute of Geology of the Karelian Research Center RAS.

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