Method for producing nano silicon dioxide and nano calcium carbonate by using rice hull ash and flue gas of biomass power plant

Abstract

The invention relates to 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 the following steps: adding the rice hull ash, obtained by combustion in the biomass power plant for power generation, into 10-20% sodium hydroxide solution by weight, fully reacting the mixture at the temperature of 95-1,000 DEG C for 3-4 hours, and performing filtration; adding water into filtrate to dilute the filtrate, controlling sodium silicate in a system to be 8-15 percent by mass in silicon dioxide, heating to 60-800 DEG C, adding a dispersing agent, continuously feeding the flue gas of the biomass power plant under a normal pressure condition, fully stirring to react for 2-4 hours to obtain the nano silicon dioxide; mixing the filtrate and washing liquor, adding a calcium hydroxide solution at the temperature of 5-700 DEG C, and fully stirring to react for 0.5-2 hours to obtain the nano calcium carbonate. The particle sizes of the silicon dioxide product and the nano calcium carbonate product which are obtained by the method are extremely small and can both reach the nano level.

Description

technical field [0001] The invention relates to a method for producing nano-materials by recycling waste residue and waste gas of a biomass power plant, in particular to a method for producing nano-materials by utilizing waste rice husk ash after burning rice husks for power generation in a biomass power plant and flue gas when burning rice husks. Methods of silicon oxide and nano calcium carbonate. Background technique [0002] At present, there are many methods for recycling rice husk ash as renewable resources, such as patent CN1756719, which uses rice husk ash and carbon dioxide as raw materials to produce silica. In this method, the leaching rate of silica is low, about 70%, and two The synthetic reaction of silicon oxide is carried out under pressurized conditions, the operation is difficult, and the equipment investment is large; the patent CN1762802 uses rice husk ash to cook with alkali under high temperature and pressure to produce water glass, and then reacts wate...

AI Technical Summary

Problems solved by technology

In the above-mentioned each method, or rice husk ash adds soda ash under the normal pressure condition, produces water glass and then cools down and directly precipitates silicon dioxide, and the industrialization of this method is difficult

Or rice husk ash and caustic soda are used to produce water glass under high temperature and high pressure conditions, the dissolution rate of silicon dioxide is low, and in the process of preparing silicon dioxide by acidification of water glass, the silicon dioxide is obtained by directly acidifying sodium silicate. Acid and silicic acid aggregates are precipitated and separated from the system. In fact, the aggregation process of silicic acid is a process in which the particles grow gradually, that is, through the process of sol, gel, and precipitation. If the particles are allowed to aggregate and grow naturally, in fact Difficult to reach nano-silica with very small particle size

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