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Method for preparing nano ZrO2 by drying supercritical CO2 liquid

A supercritical and fluid technology, applied in zirconia and other directions, can solve the problems of difficult industrial scale-up, high cost of raw materials, harsh process conditions, etc., and achieve the effects of easy control, good thermal stability, and good monodispersity performance.

Inactive Publication Date: 2008-09-10
SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The precipitation process is the simplest, the raw materials are relatively cheap, and it is easy to realize industrial scale-up; however, serious agglomeration structures may be formed during the drying process of the sediment, so a special drying process must be adopted
In the early days of supercritical fluid drying technology, expensive metal alkoxides were used as precursor raw materials, and alcohols were used as drying media. There were problems such as high raw material costs, harsh process conditions, and difficulties in industrial scale-up.

Method used

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  • Method for preparing nano ZrO2 by drying supercritical CO2 liquid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] (1) Under stirring conditions at room temperature, add ammonia water to a 0.2M zirconyl nitrate aqueous solution, adjust the pH value to 9.5, make a hydrogel, age for 4 hours, filter with suction, and replace the gel with absolute ethanol of water to obtain alcohol gel.

[0019] (2) Supercritical CO with a temperature of 325K and a pressure of 15Mpa 2 The fluid passes continuously through the alcohol gel, CO containing ethanol 2 The depressurization enters the separator with a temperature of 335K and a pressure of 6Mpa, ethanol is precipitated and recovered, and CO 2 Recycling. When ethanol is no longer precipitated in the separator, the pressure of the separator is slowly released to obtain white raw powder.

[0020] (3) Raise the temperature of the original powder to 673K, keep it warm for 2 hours, and cool to obtain ZrO 2 Powder. Its physical properties are listed in Table 1.

Embodiment 2

[0022] (1) Under the condition of stirring at room temperature, add ammonia water to 0.2M concentration of zirconyl nitrate aqueous solution, adjust the pH value to 5.5, make a hydrogel, age for 4 hours, filter with suction, replace the gel with absolute ethanol of water to obtain alcohol gel.

[0023] (2) Supercritical CO with a temperature of 315K and a pressure of 12Mpa 2 The fluid passes continuously through the alcohol gel, CO containing ethanol 2 The depressurization enters the separator with a temperature of 325K and a pressure of 6Mpa, ethanol is precipitated and recovered, and CO 2 Recycling. When ethanol is no longer precipitated in the separator, the pressure of the separator is slowly released to obtain white raw powder.

[0024] (3) Raise the temperature of the original powder to 773K, keep it warm for 4 hours, and cool to obtain ZrO 2 Powder. Its physical properties are listed in Table 1.

Embodiment 3

[0026] (1) Under the condition of stirring at room temperature, add ammonia water to a 0.15M zirconyl nitrate aqueous solution, adjust the pH value to 7.5, make a hydrogel, age for 4 hours, filter with suction, and replace the gel with absolute ethanol of water to obtain alcohol gel.

[0027] (2) Supercritical CO with a temperature of 335K and a pressure of 20Mpa 2 The fluid passes continuously through the alcohol gel, CO containing ethanol 2 The depressurization enters the separator with a temperature of 325K and a pressure of 6Mpa, ethanol is precipitated and recovered, and CO 2 Recycling. When ethanol is no longer precipitated in the separator, the pressure of the separator is slowly released to obtain white raw powder.

[0028] (3) Raise the temperature of the original powder to 873K, keep it warm for 6 hours, and cool to obtain ZrO 2 Powder. Its physical properties are listed in Table 1.

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Abstract

A process for preparing nano-class ZrO3 includes adding ammonia water to the aqueous solution of zirconium oxygen nitrate, regulating pH=5-10, aging, filtering, using alcohol to displace the water in gel to obtain alcohol gel, continuously flowing supercritical CO2 fluid through alcohol gel, separating CO2 containing alcohol, recovering alcohol, cyclic use of CO2 to obtain raw powder, heating to 670-1073 deg.K, holding the temp for a certain time, and cooling.

Description

[0001] Field: [0002] A kind of preparation nanometer ZrO 2 The method, specifically involves a kind of inorganic zirconium salt as raw material, combined with supercritical CO by precipitation method 2 Preparation of ZrO by Fluid Drying 2 nanopowder method. Background technique: [0003] ZrO 2 It has unique mechanical, electrical, optical properties and excellent high temperature resistance, which has attracted extensive attention from the scientific and industrial circles. Partially stabilized tetragonal ZrO 2 It is an important phase change toughening material, which provides a very effective way to improve the fracture toughness of ceramic materials; completely stable cubic ZrO 2 It has oxygen ion conductivity at high temperature and can be used to make electrolytes for oxygen-sensitive components and high-temperature fuel cells; ZrO 2 The refractive index of ZrO is high, combined with low refractive index materials, through reasonable film layer design, high reflec...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G25/02C01G1/02
Inventor 侯相林梁丽萍乔欣刚杜俊民
Owner SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI