METHOD OF OBTAINING SYNTHETIC SiO (SILICON DIOXIDE) Russian patent published in 2015 - IPC C01B33/18 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of obtaining synthetic SiO₂ from ash, formed as a result of burning an organic fuel (coal or brown coal, peat, lignite, oil shales, wood, wastes of animal breeding, poultry farming, and agriculture) which contains SiO₂, Al₂O₃, Fe₂O₃, K₂O, CaO, MgO, rare and rare-earth elements. The method includes mixing an initial raw material - ashes with ammonium fluoride in a quantity of 1.2-1.4 of a stoichiometric value, mixture heating, exposure in the heated condition until the formation of ammonium hexafluorosilicate is completed, sublimation and precipitation of volatile ammonium hexafluorosilicate in a condenser, its following dissolution in water, interaction of the obtained solution with ammonia water to form a sediment of synthetic SiO₂, extracted by filtration, with a mixture of ash with ammonium fluoride directly before heating being subjected to mechanic-activation for 5-15 minutes with supporting the ratio of the supplied power of mechanical energy to the specific surface of the mixture in a range of 0.0133-17 W × kg × m^-2.

EFFECT: reduced duration of the stage of heating the mixture of ash with ammonium fluoride and extraction of volatile ammonium hexafluorosilicate due to the acceleration of a chemical reaction between solid bodies by the mechanic-activation of the mixture of the initial raw material and the chemical reagent with the reduction of power consumption.

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