Method for preparing Nano carbon white from fly ash based on gas phase sol gel method

A sol-gel method, nano-silica technology, used in chemical instruments and methods, inorganic chemistry, non-metallic elements, etc.

Inactive Publication Date: 2007-02-21
JIANGSU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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  • Method for preparing Nano carbon white from fly ash based on gas phase sol gel method
  • Method for preparing Nano carbon white from fly ash based on gas phase sol gel method
  • Method for preparing Nano carbon white from fly ash based on gas phase sol gel method

Examples

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example 1

[0019] Such as figure 1 , grind the fly ash sample with a mortar, soak it in 4mol / L nitric acid, stir it continuously for 2 hours with an electric mixer, filter it with suction, wash it, and dry it in a vacuum oven for 8 hours, and put it in a muffler furnace at a high temperature of 800°C Burn for 4 hours to remove residual combustible substances such as charcoal. The burnt fly ash was put into 4mol / L nitric acid solution and stirred with an electric mixer for 1 hour to remove impurities such as iron and aluminum, and obtained silica by washing, suction filtration and vacuum drying. Put 3g of sodium fluoride and 5g of silicon dioxide into a four-neck flask, add concentrated sulfuric acid dropwise, the rate of concentrated sulfuric acid is controlled at 40 drops / min, the gas generated is passed into concentrated sulfuric acid to dry, and the temperature of the oil bath is controlled at 140°C , the gas is then fed into a 4.5g / L sodium dodecyl sulfate (SDS) solution for hydroly...

example 2

[0021] Such as figure 2 , Obtain the silicon dioxide needed for the experiment in the same way as example 1. Put 5g of sodium fluoride and 15g of silicon dioxide into a four-necked flask, add concentrated sulfuric acid dropwise, the rate of concentrated sulfuric acid is controlled at 30 drops / min, the gas generated is passed into concentrated sulfuric acid for drying, and the temperature of the oil bath is controlled at 100°C , the gas is then passed into a 5.5g / L sodium lauryl sulfate solution for hydrolysis, the pH of the solution is kept at 6.3, a sol is formed, the aeration is stopped, the sol is placed in a beaker, sealed, and gelled in a 60°C water bath. Wash the gel with distilled water until the conductivity of the filtrate is less than 50 μs / cm, dry in an oven at 80°C, and burn in a muffle furnace at 350°C to obtain nano-silica. Its specific surface area is 151.27 / m 2 g -1 .

example 3

[0023] Such as image 3 , Obtain the silicon dioxide needed for the experiment in the same way as example 1. Put 8g of sodium fluoride and 25g of silicon dioxide into a four-neck flask, add concentrated sulfuric acid dropwise, the rate of adding concentrated sulfuric acid is controlled at 10 drops / min, the generated gas is passed into concentrated sulfuric acid for drying, and the temperature of the oil bath is controlled at 180°C , the gas is passed into a 2.5g / L sodium dodecyl sulfate solution for hydrolysis, the pH of the solution is kept at 1.85, a sol is formed, the ventilation is stopped, the sol is placed in a beaker, sealed, and gelled in a water bath at 25°C. Wash the gel with distilled water until the conductivity of the filtrate is less than 50 μs / cm, dry it in an oven at 100°C, and burn it in a muffle furnace at 450°C to obtain nano-silica. Its specific surface area is 631.78 / m 2 g -1 .

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Abstract

This invention relates to a sol-gel method for preparing nanoscale white carbon black from fly ashes, NaF and concentrated H2SO4. The method comprises: (1) dissolving fly ashes in HNO3, and sintering at a high temperature to obtain SiO2; (2) dropping concentrated H2SO4 onto SiO2 and SiF4 to generate SiF4 gas, introducing SiF4 gas into solution of sodium dodecyl sulfate, Sodium dodecyl sulfonate and cetyltrimethyl ammonium bromide, hydrolyzing to obtain sol and then gel, and calcining to obtain nanoscale white carbon black. The obtained nanoscale white carbon black has diameters of about 20nm, and a specific surface area of 58-631 m2/g. Besides, the nanoscale white carbon black is semi-transparent white, and has such advantages as high purity, no obvious aggregation, high dispersibility and high activity. The method has such advantages as mild reaction conditions, easy control of the techniques and simple process.

Description

technical field [0001] The invention relates to a method for preparing nanometer white carbon black, in particular to a method for preparing nanometer white carbon black by using fly ash, sodium fluoride and concentrated sulfuric acid as main raw materials, adding a surfactant, and adopting a gas-sol-gel method. Background technique [0002] White carbon black is the general term for white powder amorphous silicic acid and silicate products, mainly refers to precipitated silica, fumed silica, ultrafine silica gel and aerogel, and also includes powdered synthetic silicic acid aluminum and calcium silicate etc. Silica has many unique properties, such as high temperature resistance, acid and alkali resistance, non-combustibility, tasteless, odorless, good electrical insulation and high dispersibility. Therefore, it has been widely used, such as reinforcing agent, mixing agent, thixotropic agent, anti-settling agent, defoaming agent, etc. There are many methods for synthesizin...

Claims

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Application Information

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IPC IPC(8): C01B33/113C01B33/157
Inventor 倪良蒋银花胡莹海张莉王学宝
Owner JIANGSU UNIV
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