Scientific publications

The results of mineralogical-technological study of high-silica rocks of Central Karelia are discussed with a view to assessing the potential of using these rocks as natural material for producing quartz concentrates for various applications. Weakly transparent vein quartz, pebble quartz from Paleoproterozoic conglomerates and volcanogene-sedimentary silicites were subjected to optical and electron microscopy, microprobe analysis, X-ray fluorescence and diffraction analysis, atomic emission spectrometry. Technological studies of the silicites showed they can be enriched to produce quartz-feldspatic concentrate meeting the requirements to feedstock for fine ceramics (Fe2O3 ≤ 0.2 %, K2O+Na2O ≥ 8 %, K2O/Na2O = 2). Owing to low Li, B and P content, quartz concentrates made from pebble quartz conglomerates fulfill the requirements for raw material for highgrade ferrosilicon production. Processing experiments were carried out, showing that the quartz concentrate of the –0.315 + 0.1 mm fraction obtained from weakly transparent vein quarts, with 34.6 ppm total impurity content meets the requirements for high purity quartz products of some grades (TU 5726‑002‑11496665‑97) and is suited for extra pure fused glass utilizable in the manufacturing of semiconductor materials, electronics, lighting engineering, means of fiber-optic communication.