| 简介 |
FIELD : chemistry.
SUBSTANCE : invention relates to production of synthetic silicon dioxide (SiO2) of ash from burning organic fuel (black or brown coal, peat, lignite, combustible shale, wood, wastes from livestock sector, poultry farming, agriculture), containing SiO2, Al2O3, Fe2O3, K2O, CaO, MgO, rare and rare-earth elements. Method involves mixing ashes with ammonium fluoride, heating mixture, holding in a heated condition before fluorination with formation of ammonium hexafluorosilicate, raising temperature of mixture to 290-300 °C, holding for 35-45 minutes, leaching with water at temperature +20-100 °C, dissolving in water and reacting obtained solution with ammonia water for precipitation of synthetic SiO2, separated by filtration. Mixing ashes with ammonium fluoride is primarily performed by mechanical activation.
EFFECT : technical result consists in reduction of duration of step of separating ammonium hexafluorosilicate from mixture, use of low temperatures, low cost of equipment and power consumption.
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