METHOD FOR PRODUCING NANO SILICON DIOXIDE AND NANO CALCIUM CARBONATE BY USING RICE HULL ASH AND FLUE GAS OF BIOMASS POWER PLANT

Provided is a method for producing nano silicon dioxide and nano calcium carbonate by using rice hull ash and flue gas of a biomass power plant. The method comprises: adding the rice hull ash into a sodium hydroxide solution, fully reacting at the temperature of 95-100 °C for 3-4 hours, and performing filtration; adding water into a filtrate to dilute the filtrate, controlling sodium silicate in a system to be 8-15 wt% in silicon dioxide, heating to 60-80 °C, adding a dispersing agent, continuously feeding the flue gas of the biomass power plant under a normal pressure condition, stirring to react for 2-4 hours to obtain the nano silicon dioxide; mixing the filtrate and a washing liquid, adding a calcium hydroxide solution at the temperature of 50-70 °C, and stirring to react for 0.5-2 hours to obtain the nano calcium carbonate. The particle sizes of the silicon dioxide product and the calcium carbonate product which are obtained by the method are extremely small and can both reach the nano level.