DRESSING OF CRYSTALLINE QUARTZ OF NATURAL DEPOSITS Russian patent published in 2015 - IPC C01B33/12 

FIELD: process engineering.

SUBSTANCE: invention relates to cleaning of quartz stock of natural deposits used for production of extra-pure translucent quartz glass applied in production of semiconductor materials, electronics, illumination means and fibre optics. This process comprises mincing of crystalline quartz, drying, optical, magnetic, gravity and thermal-optical separation. Initial 10-60 mm quartz is subjected to mincing by electric pulses in deionised water to grain size smaller than 3 mm. Mineral inclusions are removed from mincing zone. Minced product is sized at screen to classes with separation coefficient of particles 1.2-2. Then, quartz is dried and subjected to optical separation. Here, narrow classification is used in operation of optical separator. Here, separator parameters are selected proceeding from the condition that particles of close sizes feature similar behaviour at free fall in flow to get target fraction of 0.1-0.3 mm without visible foreign inclusions. If required, optical separation is performed several times.

EFFECT: dressing to 0,1-0,3 from initial lumps of 10-60 mm, content of SiO₂>90%, removal mineral inclusions to 1-5 units/kg, no harmful emissions.

7 cl, 1 dwg, 32 tbl, 6 ex