CN100417597C - Method for preparing nano ZrO2 by drying supercritical CO2 liquid - Google Patents

Abstract

The present invention relates to a method for preparing nano ZrO2 by drying supercritical CO2 liquid. Ammonia water is added in a zirconyl nitrate water solution, and the pH value is adjusted to 5 to 10; after aging and suction filtration, water in gel is displaced by alcohol so as to prepare alcogel. The supercritical CO2 fluid continuously passes through the alcogel, alcohol in a CO2 separator containing alcohol is separated and recycled, so CO2 can be circularly used, and initial powder can be obtained when no alcohol is separated from the separator. The temperature of the initial powder is raised to 673 to 1073 K, and ZrO2 powder is obtained via thermal insulation and cooling. The present invention has the advantages of low production cost, simple process, easy control and easy industrialization realization.

Description

Supercritical CO 2Fluid drying prepares nanometer ZrO 2Method

Affiliated field:

A kind of preparation nanometer ZrO ₂Method, relating in particular to a kind of is raw material with inorganic zirconates, by the precipitator method in conjunction with supercritical CO ₂Fluid drying prepares ZrO ₂The method of nano-powder.

Background technology:

ZrO ₂Have unique mechanical, electricity, optical property and good resistance to elevated temperatures, thereby caused the extensive concern of scientific circles and industrial community.Partially stabilized cubic ZrO ₂Be important phase toughness material, for the fracture toughness property of improving stupalith provides a kind of very effective approach; Completely stable cube of ZrO ₂At high temperature have the oxygen ion conduction characteristic, can be used to make the ionogen of oxygen photosensitive elements and high-temperature fuel cell; ZrO ₂Specific refractory power higher, combine with low-index material, by the design of rational rete, can make highly reflecting films; In addition, ZrO ₂Weak acid, the weakly alkaline on surface, the negative ion transport properties of cube fluorite structure and good high-temperature and chemical stability make it also obtain to use widely at catalytic field as catalyzer and solid support material.

The nanotechnology that grows up the 1980s makes nanometer ZrO ₂Material presents some novel characteristics again on the basis of traditional performance.As important 26S Proteasome Structure and Function pottery, particle diameter that powder raw material is small and high specific surface area can reduce sintering temperature effectively, obtain to have the microstructural sintered compact of nanometer, enhance product performance.At catalytic field, specific surface area that nano material is high and abundant surface imperfection can significantly improve its adsorptive power and catalytic activity.Therefore, ZrO ₂The preparation of nano-powder is one of the focus in nano materials research field in recent years always.

ZrO ₂The preparation of ultrafine powder has the precipitator method usually, hydrothermal method, microemulsion method and sol-gel method etc.Prepare nanometer ZrO at present ₂The report of powder is also a lot, obtains precipitation of hydroxide as the patent of invention CN 01128448.X " preparation method of nano zirconium oxide powder " of Hou Shuen application by zirconium saline solution, filters, washing, dehydration, dry, calcining, obtains ZrO ₂Powder wherein adopts the azeotropic distn dehydration, and colloidal solution is dry in water distilling apparatus; The patent of invention CN 01111426.6 " production process of serial zirconia ceramic powder " of ten thousand lucky high people's applications is raw material with the zirconates, by the cryogenic freezing treatment process, prepares and does not have the ultra-fine ZrO of reunion ₂Powder; The patent of invention CN 99100053.6 " preparation method of the weakly agglomerated nano zirconium oxide powder of surface doping " that application such as smooth is thanked to by Peking University then prepares nano zirconium oxide powder with the zirconium tetrachloride vapor phase hydrolysis.

Precipitator method technology is the simplest, and raw material is also cheaper, is easy to realize the industry amplification; But in sedimentary drying process, might form serious aggregate structure, therefore must adopt special drying process.The supercritical fluid drying technology adopts expensive metal alkoxide to make forerunner's raw material in early days, and there is the raw materials cost height in alcohols as drying medium, the processing condition harshness, and problems such as difficulty are amplified in industry.

Summary of the invention:

The purpose of this invention is to provide that a kind of raw material is cheap, technology is simple, be easy to the nanometer ZrO that industrialization is amplified ₂Production method.

The present invention prepares nanometer ZrO ₂Method comprise the steps:

(1) under the stirring at room condition, ammoniacal liquor is added in the Zircosol ZN aqueous solution of 0.15-0.3M concentration, regulate the pH value to 5-10, make hydrogel, ageing, suction filtration, the water with in the dehydrated alcohol displacement gel gets alcogel;

(2) with the supercritical CO of temperature 305-345K, pressure 9-35Mpa ₂Fluid by alcogel, contains alcoholic acid CO continuously ₂Step-down enters the separator of temperature 305-355K, pressure 6-9Mpa, and ethanol is separated out recovery, CO ₂Recycle when no longer including ethanol in the device to be separated and separating out, with the slow release of separator, obtains the former powder of white;

(3) former powder is warming up to 673-1073K, is incubated 2-10 hour, cooling obtains ZrO ₂Powder.

Compared with prior art the present invention has following advantage;

1, is raw material with inorganic zirconates, reduced production cost;

2, with CO ₂Substitute organic solvents such as ethanol commonly used and carry out supercritical fluid drying, service temperature significantly reduces, and technology is simple, easily control;

3, be easy to realize industrialization;

4, present method synthetic ZrO ₂Powder has that particle diameter is little, monodispersity can good, characteristics such as specific surface area is high, pore volume is big, Heat stability is good.

Embodiment:

Embodiment 1:

(1) under the stirring at room condition, ammoniacal liquor is added in the Zircosol ZN aqueous solution of 0.2M concentration, regulate pH value to 9.5, make hydrogel, ageing 4 hours, suction filtration, the water with in the dehydrated alcohol displacement gel gets alcogel.

(2) with the supercritical CO of temperature 325K, pressure 15Mpa ₂Fluid by alcogel, contains alcoholic acid CO continuously ₂Step-down enters the separator of temperature 335K, pressure 6Mpa, and ethanol is separated out recovery, CO ₂Recycle.When no longer including ethanol in the device to be separated and separating out,, can obtain the former powder of white with the slow release of separator.

(3) former powder is warming up to 673K, is incubated 2 hours, cooling obtains ZrO ₂Powder.Its physical properties sees Table 1.

Embodiment 2:

(1) under the stirring at room condition, ammoniacal liquor is added in the Zircosol ZN aqueous solution of 0.2M concentration, regulate pH value to 5.5, make hydrogel, ageing 4 hours, suction filtration, the water with in the dehydrated alcohol displacement gel gets alcogel.

(2) with the supercritical CO of temperature 315K, pressure 12Mpa ₂Fluid by alcogel, contains alcoholic acid CO continuously ₂Step-down enters the separator of temperature 325K, pressure 6Mpa, and ethanol is separated out recovery, CO ₂Recycle.When no longer including ethanol in the device to be separated and separating out,, can obtain the former powder of white with the slow release of separator.

(3) former powder is warming up to 773K, is incubated 4 hours, cooling obtains ZrO ₂Powder.Its physical properties sees Table 1.

Embodiment 3:

(1) under the stirring at room condition, ammoniacal liquor is added in the Zircosol ZN aqueous solution of 0.15M concentration, regulate pH value to 7.5, make hydrogel, ageing 4 hours, suction filtration, the water with in the dehydrated alcohol displacement gel gets alcogel.

(2) with the supercritical CO of temperature 335K, pressure 20Mpa ₂Fluid by alcogel, contains alcoholic acid CO continuously ₂Step-down enters the separator of temperature 325K, pressure 6Mpa, and ethanol is separated out recovery, CO ₂Recycle.When no longer including ethanol in the device to be separated and separating out,, can obtain the former powder of white with the slow release of separator.

(3) former powder is warming up to 873K, is incubated 6 hours, cooling obtains ZrO ₂Powder.Its physical properties sees Table 1.

Embodiment 4:

(1) under the stirring at room condition, ammoniacal liquor is added in the Zircosol ZN aqueous solution of 0.3M concentration, regulate pH value to 8.5, make hydrogel, ageing 4 hours, suction filtration, the water with in the dehydrated alcohol displacement gel gets alcogel.

(2) with the supercritical CO of temperature 335K, pressure 30Mpa ₂Fluid by alcogel, contains alcoholic acid CO continuously ₂Step-down enters the separator of temperature 345K, pressure 6Mpa, and ethanol is separated out recovery, CO ₂Recycle.When no longer including ethanol in the device to be separated and separating out,, can obtain the former powder of white with the slow release of separator.

(3) former powder is warming up to 1073K, is incubated 5 hours, cooling obtains ZrO ₂Powder.Its physical properties sees Table 1.

Table 1ZrO ₂The physical properties of nano-powder

Claims (1)

1. supercritical CO ₂Fluid drying prepares nanometer ZrO ₂Method, it is characterized in that comprising the steps:

(1) under the stirring at room condition, ammoniacal liquor is added in the Zircosol ZN aqueous solution of 0.15-0.3M concentration, regulate the pH value to 5-10, make hydrogel, ageing, suction filtration, the water with in the dehydrated alcohol displacement gel gets alcogel;

(2) with the supercritical CO of temperature 305-345K, pressure 9-35Mpa ₂Fluid by alcogel, contains alcoholic acid CO continuously ₂Step-down enters the separator of temperature 305-355K, pressure 6-9Mpa, and ethanol is separated out recovery, CO ₂Recycle when no longer including ethanol in the device to be separated and separating out, with the slow release of separator, obtains the former powder of white;

(3) former powder is warming up to 673-1073K, is incubated 2-10 hour, cooling obtains ZrO ₂Powder.