CN1583567A - Preparation of nano aluminum oxide without hard coacervation - Google Patents

Abstract

A process for preparing nano-alumina without hard conglomerations includes such steps as proportionally and respectively dissolving aluminium nitrate and ammonium carbonate in secondary distilled water to obtain their solutions, adding polyethanediol to them to obtain their composite solutions, mixing them together, stirring, centrifugal dewatering, drying, azeotropic distilling, and high-temp calcining.

Description

A kind of preparation method of nano aluminium oxide of hard aggregation-free

Technical field

The present invention relates to the preparation of nano aluminium oxide, belong to field of fine chemical, the preparation method who more specifically relates to a kind of nano aluminium oxide of hard aggregation-free uses this method can prepare basic hard aggregation-free nano alumina powder jointed of median size partial controllable in the 10-70nm scope.

Background technology

Nano aluminium oxide (Al ₂O ₃) refer to that particle size is less than the alumina product of 100 nanometers, because its particle is little, specific area is big, thereby higher chemism is arranged, and is widely used in synthetic cut stone, reagent and catalyst and carrier, luminescent material, electronic ceramic substrate and aerospace field.Nano aluminium oxide exceeds several times to ceramic and rubber toughened, enhancing than common aluminium oxide.The densifications, fineness, cold and hot fatigue etc. that particularly improve pottery are used for the main accessory of YGA laser instrument and ic substrate etc.At present, the industrial preparation alumina powder mainly adopts methods such as Bel's method and the thermolysis of aluminium ammonium alum, and this method requires to carry out under 1300-1500 ℃ hot conditions, needs special heating installation, has increased synthetic difficulty.And traditional wet chemical method is difficult to effectively control the size and shape of particle, particularly importantly, under aluminium oxide makes the transition needed high temperature, usually is difficult to stop the alligatoring of particle and the formation of hard agglomeration.Therefore, traditional wet chemical method is difficult to truly nano alumina powder jointed of preparation.In case and hard agglomeration forms, will affect the compression and sintering performance of powder, thereby greatly affect the thus reproducibility and reliability of the ceramic material property of preparation, make it to form sharp-pointed contradiction with the requirement of new and high technology.And, adopt supercritical drying, Freeze Drying Technique in the post-processing stages of wet chemical method, though can solve the hard aggregation problem of nanoparticle preferably, there are problems such as equipment complexity, production process be discontinuous in these class methods.Be that raw material adopts sol-gel method to prepare the particle better performances of nano aluminium oxide but cost is too high with the alkoxide of aluminium, only be suitable for prepared in laboratory and use.

Summary of the invention

Problem to be solved by this invention provides gentle, easy, the lower-cost nano alumina powder jointed preparation method of a kind of processing condition, and particle diameter is partial controllable in the 10-70nm scope, does not have the hard aggregation phenomenon.

Technical scheme provided by the invention is a kind of preparation method of nano aluminium oxide of lower-cost hard aggregation-free, comprises the following steps:

(1) takes by weighing 750.26g aluminum nitrate [Al (NO ₃) ₃9H ₂O] and 480g ammonium carbonate [(NH ₄) ₂CO ₃], be dissolved in respectively in the redistilled water, be made into the stock solution that 1L concentration is respectively 2mol/L and 5mol/L, with microporous barrier (0.25 μ m) elimination impurity;

(2) get the above-mentioned aluminum nitrate [Al (NO of 50mL ₃) ₃9H ₂O] stock solution, add polyethylene glycol (PEG) 400, be mixed with and contain the Al (NO that 2-10wt%PEG400 concentration is 0.1-0.4mol/L ₃) ₃Solution (A); It is the ammonium carbonate [(NH of 0.3-1.2mol/L that the same method preparation contains 2-10wt% polyethylene glycol (PEG) 1540 concentration ₄) ₂CO ₃] solution, regulate its pH to 9-11 (B) with ammoniacal liquor;

(3) under the magnetic agitation of 1200-1500r/min, in above-mentioned (B) solution with 40-60 drip/speed of min adds isopyknic (A) solution, after titration is finished, continues to stir 1-2h, ageing 1-2 days; Centrifugation is washed 3-5 time, absolute ethanol washing 2-3 time with secondary water washing, and 60-80 ℃ of dry 10-15h obtains dry powder;

(4) dry powder that obtains is joined in the propyl carbinol, to the complete submergence sample of propyl carbinol, after the ultrasonic dispersing, backflow 1-2h, distillation removes 93-95 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 115-120 ℃ of propyl carbinol boiling point, stop distillation, after continuing backflow 1-2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder;

(5) 700-800 ℃ of calcining obtains γ-Al ₂O ₃Nano-powder, 1100-1200 ℃ of calcining obtains α-Al ₂O ₃Nano-powder, heat treatment time are 1-2h;

It is better to obtain monodispersity by above-mentioned steps, the local adjustable γ of particle diameter in the 10-70nm scope of hard aggregation-free-or α-Al ₂O ₃Nanometer powder.

Outstanding feature of the present invention:

1. the concentration by conditioned reaction thing and additive realizes nano alumina powder jointed particle diameter and distribution partial controllable thereof.

2. utilize azeotropic distillation technology, remove moisture effectively, basically eliminate the hard aggregation phenomenon of nanoparticle, the preparation have good particle performance nanometer alumina powder, the compacting and sintering character good.

3. by preparation technology's optimization, can obtain purity and be 99.99% high purity aluminium oxide nano-powder.

Technological process easy, reduce γ-and α-Al significantly ₂O ₃Temperature and time transition transition, thereby cut down the consumption of energy greatly.

5. characteristics such as starting material sources is wide, working condition is gentle, easy, energy consumption and cost are low are fit to suitability for industrialized production.

Description of drawings

Fig. 1 is the TEM photos of the present invention's calcining products obtained therefrom under 750 ℃, magnification 90000;

Fig. 2 is the TEM photos of the present invention's calcining products obtained therefrom under 1150 ℃, magnification 180000;

Fig. 3 is the TEM photos of the present invention's calcining products obtained therefrom under 750 ℃, magnification 30000;

Fig. 4 is the TEM photos of the present invention's calcining products obtained therefrom under 1150 ℃, magnification 97000.

Embodiment

Preparation flow of the present invention is as follows:

1. aluminum nitrate, volatile salt and propyl carbinol are the commercially available prod, for control purity, can directly buy ammonia and carbonic acid gas prepares volatile salt and ammoniacal liquor simultaneously.

2. under the magnetic agitation of 1400r/min, in above-mentioned (B) solution with 40-60 drip/speed of min adds isopyknic (A) solution, after titration is finished, continues to stir 1h, ageing 36h; Centrifugation is washed 4 times, absolute ethanol washing 3 times with secondary water washing, and 80 ℃ of dry 10h remove surface water, obtains dry powder.

3. the dry powder that obtains is joined in the propyl carbinol, to the complete submergence sample of propyl carbinol, after the ultrasonic dispersing, backflow 2h, distillation removes the azeotrope of 93 ℃ n-butanol-water, slough remnants, absorption and surface-bonded water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stop distillation, continue backflow 2h after, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder;

4. 750 ℃ of calcinings obtain γ-Al ₂O ₃Nano-powder, 1150 ℃ of calcinings obtain α-Al ₂O ₃Nano-powder.Heat treatment time is 1h; As: will contain 8wt%PEG400 concentration is the Al (NO of 0.2mol/L ₃) ₃Solution take 40-60 drip/minute speed add the isopyknic 8wt%PEG1540 of containing concentration as the (NH of 0.6mol/L ₄) ₂CO ₃In the solution (pH is 9.5), can prepare particle size range by such scheme is the nano alumina powder jointed of 8-14nm, and Fig. 1 and Fig. 2 are respectively it and obtain γ-and α-Al after 750 ℃ and 1150 ℃ of calcinings ₂O ₃The TEM photo.And will contain the Al (NO that 6wt%PEG400 concentration is 0.4mol/L ₃) ₃Solution take 40-60 drip/minute speed add the concentration of isopyknic 6wt%PEG1540 of containing as (the NH of 1.2mol/L ₄) ₂CO ₃In the solution (pH is 10), can prepare the nanometer alumina powder that particle size range is 35-60nm by such scheme, Fig. 3 and 4 is respectively its γ that obtains afterwards 750 ℃ and 1150 ℃ of calcinings-and α-Al ₂O ₃The TEM photo.

5. 750 ℃ of calcinings obtain γ-Al ₂O ₃The main diffraction maximum of X-ray powder diffraction pattern of nano-powder is: 46.0 ° (100), and 67.1 ° (90), 37.0 ° (60), 49.0 ° (58), 39.7 ° (53) are γ-Al ₂O ₃Characteristic peak, and do not find the characteristic diffraction peak of any other type body.1150 ℃ of calcinings obtain α-Al ₂O ₃The main diffraction maximum of X-ray powder diffraction pattern of nano-powder is: 44.0 ° (100), and 59.1 ° (95), 26.1 ° (83), 35.5 ° (75), 67.0 ° (78) are α-Al ₂O ₃Characteristic peak, and do not find the characteristic diffraction peak of any other type body, crystalline phase purity is higher.

The concentration that will contain 8wt%PEG 400 under the magnetic agitation of embodiment 1:1400r/min is the Al (NO of 0.2mol/L ₃) ₃Solution take 40-60 drip/speed of min adds the concentration of isopyknic 8wt%PEG of containing 1540 as the (NH of 0.6mol/L ₄) ₂CO ₃In the solution (pH is 9.5), after titration is finished, continue to stir 1h, ageing 36h; Centrifugation, with intermediate water washing 4 times, absolute ethanol washing 3 times, 60-80 ℃ of dry 10h removes surface water, obtains dry powder.The dry powder that obtains is joined in the propyl carbinol, after the ultrasonic dispersing, backflow 2h, distillation removes 93 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stops distillation, after continuing backflow 2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.750 ℃ of products that calcining obtains, its particle morphology is seen Fig. 1, and size of particles and shape homogeneity are better, and monodispersity is good, and hard aggregation-free phenomenon, particle size range are 8-14nm, median size is 10nm.Fig. 2 is that it is at 1150 ℃ of lower α-Al of acquisition ₂O ₃The TEM photo of nano powder, particle diameter slightly increases, and particle size and shape homogeneity are better, and monodispersity is good, basic hard aggregation-free phenomenon, particle size range is 8-20nm, average grain diameter is 13nm.

To contain the Al (NO that 6wt%PEG 400 concentration are 0.3mol/L under the magnetic agitation of embodiment 2:1400r/min ₃) ₃Solution take 40-60 drip/speed of min adds the isopyknic 6wt%PEG of containing 1540 concentration as the (NH of 0.9mol/L ₄) ₂CO ₃In the solution (pH is 9.8), after titration is finished, continue to stir 1h, ageing 36h; Centrifugation, with intermediate water washing 4 times, absolute ethanol washing 3 times, 60-80 ℃ of dry 10h removes surface water, obtains dry powder.The dry powder that obtains is joined in the propyl carbinol, after the ultrasonic dispersing, backflow 2h, distillation removes 93 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stops distillation, after continuing backflow 2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.The size of particles and the shape homogeneity of the product of 750 ℃ of calcining acquisitions are better, and monodispersity is good, and hard aggregation-free phenomenon, particle size range are 25-35nm, and median size is 30nm.At 1150 ℃ of lower α-Al that obtain ₂O ₃Nano powder particle diameter slightly increase, particle size and shape homogeneity are better, monodispersity is good, basic hard aggregation-free phenomenon, particle size range is 25-40nm, average grain diameter is 35nm.

To contain the Al (NO that 10wt%PEG 400 concentration are 0.4mol/L under the magnetic agitation of embodiment 3:1400r/min ₃) ₃Solution take 40-60 drip/speed of min adds equal-volume and contains 10wt%PEG1540 concentration as the (NH of 1.2mol/L ₄) ₂CO ₃In the solution (pH is 10), after titration is finished, continue to stir 1h, ageing 36h; Centrifugation, with intermediate water washing 4 times, absolute ethanol washing 3 times, 60-80 ℃ of dry 10h removes surface water, obtains dry powder.The dry powder that obtains is joined in the propyl carbinol, after the ultrasonic dispersing, backflow 2h, distillation removes 93 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stops distillation, after continuing backflow 2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.750 ℃ of products that calcining obtains, its particle morphology is seen Fig. 3, and size of particles and shape homogeneity are better, and monodispersity is good, and hard aggregation-free phenomenon, particle size range are 35-60nm, median size is 50nm.Fig. 4 is that it is at 1150 ℃ of lower α-Al of acquisition ₂O ₃The TEM photo of nano powder, particle diameter slightly increases, and particle size and shape homogeneity are better, and monodispersity is good, basic hard aggregation-free phenomenon, particle size range is 35-65nm, average grain diameter is 55nm.

Claims (1)

1, a kind of preparation method of nano aluminium oxide of hard aggregation-free is characterized in that:

(1) takes by weighing 750.26g aluminum nitrate and 480g volatile salt, be dissolved in the redistilled water, be made into the stock solution that 1L concentration is respectively 2mol/L and 5mol/L, with microporous membrane elimination impurity;

(2) get the above-mentioned aluminum nitrate stock solution of 50mL, add poly(oxyethylene glycol) 400, be mixed with and contain the aluminum nitrate solution (A) that 2-10wt% poly(oxyethylene glycol) 400 concentration is 0.1-0.4mol/L; Containing 2-10wt% Macrogol 1540 concentration with the quadrat method preparation is the sal volatile of 0.3-1.2mol/L, regulates its pH to 9-11 (B) with ammoniacal liquor;

(3) under the magnetic agitation of 1200-1500r/min, in above-mentioned (B) solution with 40-60 drip/speed of min adds isopyknic (A) solution, after titration is finished, continues to stir 1-2h, ageing 1-2 days; Centrifugation is washed 3-5 time, absolute ethanol washing 2-3 time with secondary water washing, and 60-80 ℃ of dry 10-15h obtains dry powder;

(4) dry powder that obtains is joined in the propyl carbinol, to the complete submergence sample of propyl carbinol, after the ultrasonic dispersing, backflow 1-2h, distillation removes 93-95 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 115-120 ℃ of propyl carbinol boiling point, stop distillation, after continuing backflow 1-2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder;

(5) 700-800 ℃ of calcining obtains γ-Al ₂O ₃Nano-powder, 1100-1200 ℃ of calcining obtains α-Al ₂O ₃Nano-powder, heat treatment time are 1-2h.

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