CN1259240C - Method for preparing nanometer metal oxides by direct liquid phase precipitation - Google Patents

Abstract

The invention provides a method for preparing nanometer metal oxides by direct liquid phase precipitation, which is characterized in that it comprises the following steps: preparing an ethanol solution of a metal salt, preparing an ammonia water ethanol solution, mixing the two fully under stirring, and preparing the obtained The metal hydroxide precipitate is washed with ethanol, and the washed precipitate is dried and roasted to obtain loose nano-metal oxide powder; the filtrate produced in the whole process is distilled to recover ethanol, and ammonium chloride by-product is obtained at the same time , The recovered ethanol can be recycled. The invention adopts ethanol as the main reaction medium and washing liquid, effectively eliminates the agglomeration phenomenon generated in the preparation process, and makes the final nanometer metal oxide powder have good dispersibility. The method has easy-to-obtain raw materials, simple operation, low production cost, high efficiency, basically realizes "zero discharge", easy control of process parameters, easy realization of large-scale industrial production, and certain versatility.

Description

Method for preparing nanometer metal oxides by direct liquid phase precipitation

technical field

The invention belongs to the technical field of new materials, in particular to a method for preparing nanometer metal oxides by direct liquid phase precipitation.

Background technique

Nano-metal oxides are a new type of high-function fine inorganic materials with a particle size between 1 and 100nm. Due to the miniaturization of their particles, they have special functions such as heat, light, electricity, magnetism, mechanics and chemistry that are different from conventional materials. . It has important application value and broad application prospects in fine chemical catalysis, daily chemical industry, new ceramic materials, new refractory materials, high-quality and special functional engineering materials, and the manufacture of electronic devices. In recent years, the preparation of nano-metal oxides has become a hot topic in materials science.

So far, the methods for preparing nanometer metal oxides mainly include physical methods and chemical methods. Physical methods include mechanical pulverization, evaporation condensation, ion sputtering, etc. These methods require high energy consumption. Chemical methods are divided into gas-phase method, liquid-phase method and solid-phase method. The gas-phase method has complex equipment, while the solid-phase method is a heterogeneous reaction. Therefore, the liquid-phase method is currently the main method for preparing nanometer metal oxides. The liquid phase method also includes: (1) sol-gel method; (2) precipitation method (uniform precipitation method, direct precipitation method, supergravity reaction precipitation method, ultrasonic precipitation method, etc.); (3) hydrolysis method (alcohol salt hydrolysis method , microwave hydrolysis); (4) hydrothermal method; (5) microemulsion method and so on.

As we all know, the easiest and most industrialized way to prepare metal oxides is the direct liquid phase precipitation method, but due to the existence of agglomeration, uniformly dispersed nano metal oxides cannot be prepared in this process, as Tadao Sugimoto said in "FINE PARTICLES "One book (page 2) pointed out: "Under normal circumstances, the direct reaction of metal salt solution and alkali cannot produce uniformly dispersed particles, so it is necessary to overcome agglomeration." Therefore, to overcome agglomeration is to use direct liquid phase precipitation to prepare nano The bottleneck that needs to be solved by metal oxides.

In the direct liquid phase precipitation method, agglomeration phenomenon exists in almost any operation step. The agglomeration of particles is generally divided into soft agglomeration and hard agglomeration. Soft agglomeration is mainly caused by van der Waals force and Coulomb force between particles, and the agglomeration can be eliminated by some chemical action or by applying mechanical energy. In addition to the van der Waals force and Coulomb force between particles, there are also chemical bonds in the hard aggregate of powder. Therefore, the structure of hard aggregates is not easy to be destroyed in the subsequent processing, which leads to the deterioration of material properties. It is generally believed that the formation of hard agglomerates is related to the non-bridging hydroxyl groups, structural coordination water and adsorbed water contained in the hydroxide precipitated colloidal structure. Among them, the adsorbed water mostly exists in the form of capillary water between particles, and as the liquid continues to evaporate , voids appear in the precipitated particles, and a large number of menisci are formed in the voids, so capillary contraction presses the particles together. The greater the surface tension of the liquid in the precipitation, the stronger the capillary contraction, the easier it is for the precipitation to form a stronger binding force between the particles during the drying process, and the more serious the aggregation between the particles is, the adsorbed water on the surface of the particles and the particles Due to the hydrogen bond between the particles, the particles are combined more tightly. With the further removal of water, the non-bridging hydroxyl groups of adjacent colloidal particles can spontaneously transform into bridging hydroxyl groups; and part of the structural coordination water in the precipitation is excluded. , thus forming hard agglomerates, and this hard agglomeration may be further strengthened in the subsequent firing process.

In order to eliminate the hard agglomeration produced by the direct liquid phase precipitation method, people have done a lot of work, which is still in the exploration stage. Anti-agglomeration can be carried out in two steps: the first step is to control the agglomeration of particles in the process of forming colloidal precipitation, such as polymer protection method, and there are few researches in this area; the second step is to use such as organic Washing, azeotropic distillation, freeze drying, spray drying, supercritical fluid drying and other methods control the agglomeration of precipitates.

In the existing liquid-phase methods for preparing nanometer metal oxides, some have complex technological processes, some have high equipment and technical requirements, some have high raw material costs, some have long production cycles, some have low yields, and some produce pollution. , Some cannot fundamentally eliminate the agglomeration phenomenon produced in the preparation process, resulting in poor dispersion of the product, which limits its application in industrial production. Moreover, there are not many general methods suitable for preparing different kinds of nanometer metal oxides in the existing methods, and most of them are about the preparation method of a specific oxide.

Contents of the invention

The purpose of the present invention is to provide a kind of simple operation, low cost, high efficiency, no agglomeration of products, no environmental pollution, easy to realize industrialized production, and a method for preparing nanometer metal oxides with certain versatility.

According to the method for preparing nanometer metal oxides by direct liquid phase precipitation method of the present invention, it is characterized in that comprising the following steps:

1) select metal salt to be the metal chloride that can be dissolved in ethanol, the metal chloride that has crystal water or the metal chloride that has crystal water plus the metal nitrate that has crystal water,

2) preparing metal salt ethanol solution, dissolving the metal salt with water with a volume percentage of ≤25%, and then diluting with ethanol to a metal salt ethanol solution with a concentration range of 0.05mol/L to 1mol/L,

3) prepare the ammonia water ethanol solution, dilute the concentrated ammonia water with ethanol, and prepare the ammonia water ethanol solution with a concentration of 0.05mol/L～4mol/L,

4) Fully mix the prepared metal salt ethanol solution and the ethanol solution of ammonia water under stirring, and the reaction temperature during mixing can be controlled within the range of 5°C to 70°C,

5) Control the pH value at the end of the reaction in the range of 5 to 11, so that the metal hydroxide is completely precipitated,

6) the reaction solution is filtered to separate the metal hydroxide precipitate from the mother liquor,

7) washing the isolated metal hydroxide precipitate with ethanol to no chloride ion,

8) drying the washed metal hydroxide at 30°C to 120°C for 1 to 6 hours,

9) Calcining the dried metal hydroxide at 500° C. to 1000° C. for 1 to 4 hours to obtain loose nanometer metal oxide powder.

In this method, ethanol is used as the main reaction medium to replace a large amount of water molecules in the direct liquid precipitation method reaction system, and its effect is as follows: (1) reduce surface tension, weaken capillary action; , to reduce the formation of hydrogen bonds between particles, these two effects make hard agglomeration difficult to occur, and fundamentally eliminate the agglomeration phenomenon. In addition, using ethanol as the main medium reduces the solubility of hydroxide and increases the relative supersaturation of the precipitate, which is conducive to explosive nucleation and the formation of a homodisperse colloidal system. For some hydroxides with high solubility, the loss can be reduced by reducing their solubility.

Substituting organic solutions such as methanol, propanol, and isopropanol for ethanol can basically achieve the same effect. However, compared with ethanol, methanol is more toxic, while other alcohols are expensive, and the solubility of metal salts in them is small.

According to the present invention, the metal salt can be selected from at least one metal ion in groups II _A to _VA , III _B to VII _B and lanthanides of the periodic table of elements.

According to the present invention, the nanometer metal oxide is an oxide containing at least one metal element in the Periodic Table of Elements II _A to V _A , III _B to VII _B and Lanthanide, such as zirconium oxide, doped Y ₂ O ₃ zirconia, MgO-doped zirconia, magnesia, titanium oxide, tin oxide, aluminum oxide, etc.

According to the present invention, the preparation method of the metal salt ethanol solution is to dissolve the metal salt with a small amount of water to increase its solubility in ethanol, and then dilute it to the required concentration with ethanol.

According to the present invention, the concentration of the metal salt ethanol solution is 0.2mol/L-0.5mol/L.

According to the present invention, the temperature of the precipitation reaction is room temperature, and the energy consumption is minimum at this time.

According to the present invention, the pH at the end point of the precipitation reaction can be controlled within the range of 5.5-11. For hydroxides with a small solubility product, the pH at the end point of the precipitation reaction can be controlled within the range of 5.5-9, which can make the precipitation complete; for hydroxides with a large solubility product, the pH at the end point of the precipitation reaction can be controlled at 8-9. 11 to ensure complete precipitation.

According to the present invention, the said washing with ethanol can further remove the adsorbed water.

According to the present invention, the drying process can be an ordinary oven with a temperature of 100°C to 120°C and a drying time of 1 to 3 hours; a vacuum drying oven can also be used with a temperature of 30°C to 100°C and a drying time of 2 to 3 hours. 5h.

According to the present invention, the temperature of the calcination process depends on the specific oxide, the range is 500°C-1000°C, and the calcination time is 1-4h. In this process, due to the proper pre-precipitation treatment (ethanol is both the reaction medium and the washing liquid), loose nano-oxide powders are directly obtained.

According to the present invention, the ethanol is dehydrated ethanol, 95% ethanol or recycled ethanol.

According to the present invention, the recovered ethanol is the ethanol obtained by distilling the filtrate produced in the whole preparation process, including the mother liquor, and ammonium chloride by-product is obtained during the process of distilling and recovering ethanol, basically realizing "zero discharge".

According to the method for preparing nanometer metal oxides with direct liquid phase precipitation method of the present invention, has the following prominent features:

1. In the present invention, ethanol is not only the main medium of the precipitation reaction but also the washing liquid, thereby eliminating the agglomeration phenomenon caused by the adsorption of water in the preparation process, making the metal hydroxide precipitate easy to filter and wash, and under optimal conditions The final nano-metal oxide powder obtained under the method is soft and does not need to be ground.

2. The ethanol used in the whole process of the present invention can be distilled and recycled, and the by-product ammonium chloride can be obtained at the same time, and "zero discharge" can be basically realized, which can be called a green chemical synthesis method.

3. The present invention has easy-to-obtain raw materials, simple operation, no need for complex equipment, low cost, high efficiency, easy control of method parameters, easy realization of large-scale industrial production, and certain versatility.

Description of drawings

Fig. 1 is the transmission electron micrograph (TEM photo) of nano zirconia obtained by the method of embodiment 1 provided by the present invention.

Figure 2 is the XRD spectrum of the nano-zirconia obtained by the method of Example 1 provided by the present invention.

Fig. 3 is a TEM photograph of nano-zirconia doped with Y ₂ O ₃ obtained by the method in Example 2 provided by the present invention.

FIG. 4 is a TEM photo of MgO-doped nano-zirconia obtained by the method of Example 3 provided by the present invention.

Fig. 5 is the TEM picture of the nano magnesium oxide obtained by the method of embodiment 4 provided by the present invention.

Figure 6 is the XRD spectrum of the nano-magnesia obtained by the method of Example 4 provided by the present invention.

FIG. 7 is a TEM photo of nano-titanium oxide obtained by the method of Example 5 provided by the present invention.

Fig. 8 is the XRD spectrum of nano-titanium oxide obtained by the method of Example 5 provided by the present invention.

Fig. 9 is a TEM photograph of nano-tin oxide obtained by the method of Example 6 provided by the present invention.

Figure 10 is the XRD spectrum of the nano-tin oxide obtained by the method of Example 6 provided by the present invention.

Figure 11 is a TEM photo of the nano-alumina obtained by the method of Example 7 provided by the present invention.

Figure 12 is the XRD spectrum of the nano-alumina obtained by the method of Example 7 provided by the present invention.

Detailed ways

The specific implementation manner of the present invention will be described below with reference to the accompanying drawings and through a series of embodiments.

Example 1

The method for preparing nano zirconia by direct liquid phase precipitation method comprises the following steps:

1) Prepare a zirconium salt ethanol solution, weigh a certain amount of ZrOCl ₂ 8H ₂ O and dissolve it in 12% water by volume, then add ethanol to form a ZrOCl ₂ ethanol solution with a concentration of 0.5mol/L,

2) Dilute the strong ammonia water with ethanol to prepare a 2mol/L ammonia ethanol solution,

3) under sufficient stirring, the ammoniacal ethanol solution is dropped into the _ZrOCl ethanol solution to generate white ZrO(OH) _{Precipitation} , the reaction temperature is room temperature,

4) dropwise until the solution pH is 6.8, the reaction ends, ZrO(OH) _{Precipitation} is complete,

5) the reaction solution is filtered to make ZrO(OH) _{Precipitation} is separated from the mother liquor,

6) ZrO(OH) ₂ precipitation is washed with ethanol to no chloride ion,

7) Place the washed ZrO(OH) ₂ precipitate in an oven and dry it at 115°C for 2 hours,

8) Place the dried ZrO(OH) ₂ precipitate in a muffle furnace, and bake it at 600°C for 2 hours to obtain white dispersed nano-zirconia powder.

The yield rate of this embodiment is 93.8%. Analysis of Fig. 1 and Fig. 2 shows that the average particle diameter of the product is 14nm, and it is monoclinic crystal form.

Example 2

The method for preparing doped Y ₂ O ₃ nanometer zirconia by direct liquid phase precipitation method comprises the following steps::

1) Prepare a metal salt ethanol solution, weigh a certain amount of ZrOCl ₂ 8H ₂ O and a certain amount of Y(NO ₃ ) ₃ 6H ₂ O, so that the Y ₂ O ₃ molar percentage of the final product is 3%, and they are Dissolve in 10% water by volume, then add ethanol to prepare a _ZrOCl ethanol solution containing Y(NO ₃ ) ₃ at a concentration of 0.48mol/L,

2) Dilute the strong ammonia water with ethanol to prepare a 2mol/L ammonia ethanol solution,

3) Under full stirring, the ammonia water ethanol solution is dropped into the ZrOCl ₂ -Y(NO ₃ ) ₃ ethanol solution to form a white precipitate of ZrO(OH) ₂ containing Y(OH) ₃ , and the reaction temperature is room temperature.

4) dropwise until the solution pH is 6.8, the reaction ends, _and ZrO(OH) containing Y(OH) _{Precipitation} is complete,

5) filter the reaction solution to separate the precipitate from the mother liquor,

6) the precipitate is washed with ethanol until there is no chloride ion,

7) Place the washed precipitate in an oven and dry it at 115°C for 2 hours,

8) Put the dried precipitate in a muffle furnace and bake at 700° C. for 2 hours to obtain dispersed nano-zirconia powder doped with Y ₂ O ₃ .

The productive rate of the present embodiment is 91.1%, and the average particle diameter of the product measured by Fig. 3 is 19nm.

Example 3

The method for preparing MgO-doped nano zirconia by direct liquid phase precipitation method comprises the following steps::

1) Prepare a metal salt ethanol solution, weigh a certain amount of ZrOCl ₂ 8H ₂ O and a certain amount of Mg(NO ₃ ) ₂ 6H ₂ O, so that the molar percentage of MgO in the final product is 9%, and the volume percentage is 12% % water to dissolve it, and then dilute _with ethanol to prepare the ZrOCl ethanol solution containing Mg(NO ₃ ) ₂ concentration of 0.45mol/L,

2) Dilute the strong ammonia water with ethanol to prepare a 2mol/L ammonia ethanol solution,

3) Under full stirring, the ammonia water ethanol solution is dropped into the ZrOCl ₂ -Mg(NO ₃ ) ₃ ethanol solution to form a white precipitate of ZrO(OH) ₂ containing Mg(OH) ₂ , the reaction temperature is room temperature,

₄ ) when dropping to solution pH is 6.8, reaction finishes, and contains Mg(OH) ZrO(OH) _{Precipitation} is complete,

5) filter the reaction solution to separate the precipitate from the mother liquor,

6) the precipitate is washed with ethanol until there is no chloride ion,

7) Place the washed precipitate in an oven and dry it at 115°C for 2 hours,

8) Put the dried precipitate in a muffle furnace and bake at 800° C. for 2 hours to obtain dispersed MgO-doped nano-zirconia powder.

The productive rate of the present embodiment is 87.2%, and the average particle diameter of product recorded by Fig. 4 is 29nm.

Example 4

The method for preparing nano magnesium oxide by direct liquid phase precipitation method comprises the following steps:

1) Prepare a magnesium salt ethanol solution, weigh a certain amount of MgCl ₂ 6H ₂ O, dissolve it with 6% water by volume, then dilute it with ethanol, and prepare a MgCl ₂ ethanol solution with a concentration of 0.2mol/L ,

2) Dilute the concentrated ammonia water with ethanol to prepare a 0.4mol/L ammonia ethanol solution,

3) under sufficient stirring, drip ammonia water ethanol solution in the prepared magnesium salt ethanol solution, generate magnesium hydroxide white precipitate, and reaction temperature is room temperature,

4) when dropping to solution pH is 9.6, reaction finishes, and magnesium hydroxide precipitation is complete,

5) the reaction solution is filtered to separate the magnesium hydroxide precipitation from the mother liquor,

6) washing the separated magnesium hydroxide precipitate with ethanol to no chloride ion,

7) Place the washed magnesium hydroxide precipitate in an oven and dry it at 115°C for 2 hours,

8) The dried magnesium hydroxide precipitate is placed in a muffle furnace and roasted at 800° C. for 2 hours to obtain dispersed nano magnesium oxide powder.

The yield rate of this embodiment is 79.2%. Analysis of Fig. 5 and Fig. 6 shows that the average particle diameter of the product is 48nm, and it is a cubic crystal form.

Example 5

The method for preparing nano-titanium oxide by direct liquid phase precipitation method comprises the following steps:

1) prepare titanium salt ethanol solution, take a certain amount of TiCl _Liquid , directly dilute with ethanol, be mixed with the TiCl ethanol solution that concentration is _0.5mol /L,

2) Dilute the strong ammonia water with ethanol to prepare a 2mol/L ammonia ethanol solution,

3) under full stirring, drip ammonia water ethanol solution into the prepared titanium salt ethanol solution to generate white titanium hydroxide precipitate, the reaction temperature is room temperature,

4) The pH value at the end point of the mixed reaction is controlled at 7.2, the reaction ends, and the precipitation of titanium hydroxide is complete.

5) the reaction solution is filtered to separate the titanium hydroxide precipitate from the mother liquor,

6) washing the separated titanium hydroxide precipitate with ethanol until there is no chloride ion,

7) Put the washed titanium hydroxide precipitate in a drying box and dry it at 110°C for 2 hours,

8) Put the dried titanium hydroxide precipitate in a muffle furnace and bake at 600° C. for 2 hours to obtain dispersed nano-titanium oxide powder.

The yield rate of this embodiment is 91.5%. Analysis of Fig. 7 and Fig. 8 shows that the average particle size of the product is 28nm, and it is a mixed crystal form of anatase and rutile (mainly anatase).

Example 6

The method for preparing nano-tin oxide by direct liquid phase precipitation method may further comprise the steps:

1) Prepare tin salt ethanol solution, weigh a certain amount of SnCl ₄ 5H ₂ O, dissolve it with 8% water by volume, then dilute it with ethanol, and prepare a SnCl ₄ ethanol solution with a concentration of 0.5mol/L ,

2) Dilute the strong ammonia water with ethanol to prepare a 2mol/L ammonia ethanol solution,

3) under sufficient agitation, in the ethanolic solution of prepared _SnCl , drip ammonia water ethanol solution, generate tin hydroxide precipitation, and reaction temperature is room temperature,

4) the pH value of the reaction end point of the mixed solution is controlled at 6.8, the reaction ends, and the precipitation of tin hydroxide is complete,

5) the reaction solution is filtered to separate the tin hydroxide precipitation from the mother liquor,

6) washing the isolated tin hydroxide precipitate with ethanol to no chloride ion,

7) Place the washed tin hydroxide precipitate in an oven and dry it at 110°C for 2 hours,

8) Put the dried tin hydroxide precipitate in a muffle furnace and bake at 600° C. for 2 hours to obtain dispersed nano tin oxide powder.

The yield rate of this embodiment is 92.5%. Analysis of Fig. 9 and Fig. 10 shows that the average particle size of the product is 11nm, and it is tetragonal crystal form.

Example 7

The method for preparing nano-alumina by direct liquid phase precipitation method comprises the following steps:

1) Prepare aluminum salt ethanol solution, weigh a certain amount of AlCl ₃ 6H ₂ O, dissolve it with 15% water by volume, then dilute it with ethanol, and prepare ethanol with a concentration of 0.5mol/L AlCl ₃ solution,

2) Dilute the strong ammonia water with ethanol to prepare a 1.5mol/L ammonia ethanol solution,

3) under sufficient stirring, in the ethanolic solution of prepared _AlCl3 , drop ammoniacal ethanol solution, generate aluminum hydroxide precipitation, reaction temperature is room temperature,

4) the pH value of the control reaction end point is 7.0, the reaction ends, and the precipitation of aluminum hydroxide is complete,

5) the reaction solution is filtered to separate the aluminum hydroxide precipitation from the mother liquor,

6) washing the separated aluminum hydroxide precipitate with ethanol to no chloride ion,

7) Place the washed aluminum hydroxide precipitate in an oven and dry it at 110°C for 2 hours,

8) Put the dried aluminum hydroxide precipitate in a muffle furnace and bake at 800° C. for 2 hours to obtain loose nano-alumina powder.

The yield rate of this example is 95.2%. Analysis of Figure 11 and Figure 12 shows that the average particle size of the product is 5nm, which is γ-Al ₂ O ₃ .

In the above-mentioned preparation processes, ethanol can be recovered by distilling the filtrate including the mother liquor, and ammonium chloride by-product can be obtained at the same time, which basically realizes zero discharge, which can be called a green chemical synthesis method.

Claims (14)

1, the direct liquid-phase precipitation method of a kind of usefulness prepares the method for nano-metal-oxide, it is characterized in that comprising the following steps:

1) selecting metal-salt for use is that the metal chloride that can be dissolved in the alcoholic acid metal chloride, have the metal chloride of crystal water or have a crystal water adds the metal nitrate that has crystal water,

2) preparing metal salt ethanolic soln dissolves metal-salt for≤25% water with volume percent, uses alcohol dilution then, and being mixed with concentration range is the metal-salt ethanolic soln of 0.05mol/L～1mol/L,

3) preparation ammoniacal liquor ethanolic soln, with the strong aqua alcohol dilution, being mixed with concentration range is the ammoniacal liquor ethanolic soln of 0.05mol/L～4mol/L,

4) ethanolic soln that makes the metal-salt ethanolic soln for preparing and ammoniacal liquor thorough mixing under agitation carries out precipitin reaction, and temperature of reaction can be controlled in 5 ℃ to the 70 ℃ scopes,

5) the pH value of control precipitin reaction terminal point makes precipitate metal hydroxides complete in 5～11 scope,

6) with reacting liquid filtering, precipitate metal hydroxides is separated with mother liquor,

7) with ethanol with the washing of isolated precipitate metal hydroxides to there not being chlorion,

8) metal hydroxides after will washing is 30 ℃～120 ℃ oven dry 1～6 hour down,

9) metal hydroxides after will drying can obtain loose nanometer metal oxide powder 500 ℃～1000 ℃ following roastings 1～4 hour.

2, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described metal-salt is selected from the period of element Table II _A～V _AFamily, III _B～VII _BAt least 1 metal ion species in family and the group of the lanthanides.

3, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is for containing the period of element Table II _A～V _AFamily, III _B～VII _BThe oxide compound of at least a kind of metallic element in family and the group of the lanthanides.

4, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, and the concentration range that it is characterized in that described metal-salt ethanolic soln is 0.2mol/L～0.5mol/L.

5, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, and the temperature that it is characterized in that described precipitin reaction is a room temperature.

6, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described ethanol adopts dehydrated alcohol, 95% ethanol or circulation to reclaim ethanol.

7, the direct liquid-phase precipitation method of usefulness according to claim 6 prepares the method for nano-metal-oxide, it is characterized in that described recovery ethanol for the filtrate to producing in the whole process of preparation, comprises mother liquor, distills the ethanol that obtains.

8, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is a nano zircite, and the preparation method may further comprise the steps:

1) preparation zirconates ethanolic soln takes by weighing a certain amount of ZrOCl ₂8H ₂It is in 12% the water, to add ethanol again and be made into the ZrOCl that concentration is 0.5mol/L that O is dissolved in volume percent ₂Ethanolic soln,

2) with the strong aqua alcohol dilution, being mixed with concentration is the ammoniacal liquor ethanolic soln of 2mol/L,

3) under fully stirring, the ammoniacal liquor ethanolic soln is splashed into ZrOCl ₂In the ethanolic soln, generate white ZrO (OH) ₂Precipitation, temperature of reaction is a room temperature,

4) dropping to pH value of solution is 6～8 o'clock, and reaction finishes, ZrO (OH) ₂Precipitation is complete,

5), make ZrO (OH) with reacting liquid filtering ₂Precipitation is separated with mother liquor,

6) with ethanol with ZrO (OH) ₂Washing of precipitate is not to there being chlorion,

7) ZrO (OH) after will washing ₂Precipitation places baking oven, dried 2 hours down at 115 ℃,

8) ZrO (OH) after will drying ₂Precipitation places retort furnace, 600 ℃～800 ℃ following roastings 1～2 hour, promptly obtains the dispersing nanometer Zirconium powder of white.

9, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is doping Y ₂O ₃Nano zircite, the preparation method may further comprise the steps:

1) preparing metal salt ethanolic soln takes by weighing a certain amount of ZrOCl ₂8H ₂O and a certain amount of Y (NO ₃) ₃6H ₂O makes the Y of the finished product ₂O ₃Molar percentage is 3～10%, and they are dissolved in volume percent is in 10% the water, adds ethanol again and is mixed with and contains Y (NO ₃) ₃Concentration be the ZrOCl of 0.48mol/L ₂Ethanolic soln,

2) with the strong aqua alcohol dilution, being mixed with concentration is the ammoniacal liquor ethanolic soln of 2mol/L,

3) under fully stirring, the ammoniacal liquor ethanolic soln is splashed into Y (NO ₃) ₃-ZrOCl ₂In the ethanolic soln, generation contains Y (OH) ₃ZrO (OH) ₂White precipitate, temperature of reaction are room temperature,

4) dropping to pH value of solution is 6～8 o'clock, and reaction finishes, and contains Y (OH) ₃ZrO (OH) ₂Precipitation is complete,

5) with reacting liquid filtering, throw out is separated with mother liquor,

6) with ethanol with throw out washing to there not being chlorion,

7) throw out after will washing places baking oven 115 ℃ of oven dry 2 hours down,

8) throw out after will drying places retort furnace 600 ℃～900 ℃ following roastings 1～2 hour, promptly obtains dispersive doping Y ₂O ₃Nano metal oxide zirconium powder body.

10, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is the nano zircite of doped with Mg O, and the preparation method may further comprise the steps:

1) preparing metal salt ethanolic soln takes by weighing a certain amount of ZrOCl ₂8H ₂O and a certain amount of Mg (NO ₃) ₂6H ₂O, the MgO molar percentage that makes the finished product is 3～10%, is that 12% water dissolves it with volume percent, is mixed with alcohol dilution then to contain Mg (NO ₃) ₂Concentration be the ZrOCl of 0.45mol/L ₂Ethanolic soln,

2) with the strong aqua alcohol dilution, being mixed with concentration is the ammoniacal liquor ethanolic soln of 2mol/L,

3) under fully stirring, the ammoniacal liquor ethanolic soln is splashed into Mg (NO ₃) ₂-ZrOCl ₂In the ethanolic soln, generation contains Mg (OH) ₂ZrO (OH) ₂White precipitate, temperature of reaction are room temperature,

4) dropping to pH value of solution is 6.5～9 o'clock, and reaction finishes, and contains Mg (OH) ₂ZrO (OH) ₂Precipitation is complete,

5) with reacting liquid filtering, throw out is separated with mother liquor,

6) with ethanol with throw out washing to there not being chlorion,

7) throw out after will washing places baking oven 115 ℃ of oven dry 2 hours down,

8) throw out after will drying places retort furnace 800 ℃ of following roastings 1～2 hour, promptly obtains the nano metal oxide zirconium powder body of dispersive doped with Mg O.

11, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is a nano magnesia, and the preparation method may further comprise the steps:

1) preparation magnesium salts ethanolic soln takes by weighing a certain amount of MgCl ₂6H ₂O is that 6% water dissolves it with volume percent, uses alcohol dilution then, is mixed with the MgCl that concentration is 0.2mol/L ₂Ethanolic soln,

2) with the strong aqua alcohol dilution, being mixed with concentration is the ammoniacal liquor ethanolic soln of 0.4mol/L,

3) under fully stirring, splash into the ammoniacal liquor ethanolic soln in the magnesium salts ethanolic soln for preparing, generate the magnesium hydroxide white precipitate, temperature of reaction is a room temperature,

4) dropping to pH value of solution is 9.5～11 o'clock, and reaction finishes, and magnesium hydrate precipitate is complete,

5) with reacting liquid filtering, magnesium hydrate precipitate is separated with mother liquor,

6) with ethanol with the washing of isolated magnesium hydrate precipitate to there not being chlorion,

7) magnesium hydrate precipitate after will washing places baking oven 115 ℃ of oven dry 2 hours down,

8) magnesium hydrate precipitate after will drying places retort furnace 600～900 ℃ of following roastings 1～3 hour, promptly obtains dispersive nano magnesia powder.

12, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is a nano-titanium oxide, and the preparation method may further comprise the steps:

1) preparation titanium salt ethanolic soln takes by weighing a certain amount of TiCl ₄Liquid is directly used alcohol dilution, is mixed with the TiCl that concentration is 0.5mol/L ₄Ethanolic soln,

2) with the strong aqua alcohol dilution, being mixed with concentration is the ammoniacal liquor ethanolic soln of 2mol/L,

3) under fully stirring, splash into the ammoniacal liquor ethanolic soln in the titanium salt ethanolic soln for preparing, generate white titanium hydroxide precipitation, temperature of reaction is a room temperature,

4) the pH value with the hybrid reaction terminal point is controlled at 6～8, and reaction finishes, and the titanium hydroxide precipitation is complete,

5) with reacting liquid filtering, the titanium hydroxide precipitation is separated with mother liquor,

6) with ethanol with isolated titanium hydroxide washing of precipitate to there not being chlorion,

7) precipitation of the titanium hydroxide after will washing places in the drying baker 110 ℃ of oven dry 2 hours down,

8) precipitation of the titanium hydroxide after will drying places retort furnace 500 ℃～700 ℃ following roastings 1～2 hour, promptly obtains dispersive nano-titanium oxide powder.

13, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is a nano tin dioxide, and the preparation method may further comprise the steps:

1) preparation pink salt ethanolic soln takes by weighing a certain amount of SnCl ₄5H ₂O is that 8% water dissolves it with volume percent, uses alcohol dilution then, is mixed with the SnCl that concentration is 0.5mol/L ₄Ethanolic soln,

2) with the strong aqua alcohol dilution, being mixed with concentration is the ammoniacal liquor ethanolic soln of 2mol/L,

3) under fully stirring, to the SnCl for preparing ₄Ethanolic soln in splash into the ammoniacal liquor ethanolic soln, generate the stannic hydroxide precipitation, temperature of reaction is a room temperature,

4) the pH value with the mixed solution reaction end is controlled at 6～8, and reaction finishes, and the stannic hydroxide precipitation is complete,

5) with reacting liquid filtering, the stannic hydroxide precipitation is separated with mother liquor,

6) with ethanol with isolated stannic hydroxide washing of precipitate to there not being chlorion,

7) precipitation of the stannic hydroxide after will washing places in the baking oven 110 ℃ of oven dry 2 hours down,

8) precipitation of the stannic hydroxide after will drying places retort furnace 500 ℃～700 ℃ following roastings 1～3 hour, promptly obtains dispersive nano tin dioxide powder.

14, the direct liquid-phase precipitation method of usefulness according to claim 1 prepares the method for nano-metal-oxide, it is characterized in that described nano-metal-oxide is a nano aluminium oxide, and the preparation method may further comprise the steps:

1) preparation aluminium salt ethanolic soln takes by weighing a certain amount of AlCl ₃6H ₂O is that 15% water dissolves it with volume percent, uses alcohol dilution then, is mixed with the AlCl that concentration is 0.5mol/L ₃Ethanolic soln,

2) with the strong aqua alcohol dilution, being mixed with concentration is the ammoniacal liquor ethanolic soln of 1.5mol/L,

3) under fully stirring, to the AlCl for preparing ₃Ethanolic soln in splash into the ammoniacal liquor ethanolic soln, generate aluminum hydroxide precipitation, temperature of reaction is a room temperature,

4) the pH value of control reaction end is 6～8, and reaction finishes, and aluminum hydroxide precipitation is complete,

5) with reacting liquid filtering, aluminum hydroxide precipitation is separated with mother liquor,

6) with ethanol with the washing of isolated aluminum hydroxide precipitation to there not being chlorion,

7) aluminum hydroxide precipitation after will washing places in the baking oven 110 ℃ of oven dry 2 hours down,

8) aluminum hydroxide precipitation after will drying places retort furnace 700 ℃～1000 ℃ following roastings 2 hours, promptly obtains loose nano alumina powder jointed.

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