CN104692403A - Preparation method of single-phase mullite sol - Google Patents
Preparation method of single-phase mullite sol Download PDFInfo
- Publication number
- CN104692403A CN104692403A CN201410696774.2A CN201410696774A CN104692403A CN 104692403 A CN104692403 A CN 104692403A CN 201410696774 A CN201410696774 A CN 201410696774A CN 104692403 A CN104692403 A CN 104692403A
- Authority
- CN
- China
- Prior art keywords
- preparation
- sol
- room temperature
- aluminum oxide
- mullite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Silicates, Zeolites, And Molecular Sieves (AREA)
Abstract
The invention discloses a preparation method of single-phase mullite sol. The preparation method comprises the steps of preparing fresh aluminum hydroxide precipitate, preparing aluminum oxide suspension liquid, introducing a silicon source into the aluminum oxide suspension liquid, and carrying out decondensation on mixed suspension liquid, so as to prepare mullite sol. According to the preparation method, the requirement for inhibiting hydrolysis speed of aluminum alkoxide is avoided, process parameters such as pH value and environment humidity are not specially required, the process is simple, and the requirement on synthesis equipment is low; the preparation method is applicable to large-scale industrial production.
Description
Technical field
The present invention relates to a kind of preparation method of single-phase mullite sol, belong to chemical technology field.
Background technology
Mullite (Mullite) is Al
2o
3-SiO
2compound uniquely stable in binary system, stoichiometric equation is 3Al
2o
32SiO
2, natural mullite is very rare, and high performance mullite is by synthetic.Because mullite has outstanding physical and chemical performance, as the high-temperature oxidation resistant of excellence, creep resistance, corrosion-resistant, lower thermal expansivity and thermal conductivity, lower specific inductivity and dielectric loss, higher mechanical strength and toughness etc. are that the mullite ceramic of principal crystalline phase is considered to a kind of ideal High-Temperature Engineering Ceramics with mullite.In recent decades, mullite is subject to paying close attention to more and more widely at high-temperature hot structure, electromagnetism and optical field, has wide future in engineering applications.
Due to can low-temperature growth high purity mullite powder, mullite fiber, mullite material, mullite compact block, mullite coating etc. by " sol-gel " method, research extremely researchist's favor of mullite sol.According to the degree of uniformity of mixing, mullite sol can be divided into single-phase glue and two-phase glue.The degree of uniformity of single-phase glue mixing is high, and belong to the mixing on molecule or atom level, preparation condition is comparatively harsh.The arrangement of Si-O-Al atomic group on atom level in its non-crystalline state is similar to mullite structure, therefore can be converted into mullite by non-crystalline state at about 1000 DEG C presomas.
The preparation method of several single-phase mullite sols is reported both at home and abroad in disclosed document patent, the preparation method of the single-phase glue of a kind of mullite the most common proposes (J.Am.Ceram.Soc.1984,67 (7): 468-471) by Hoffman et al.Be exactly that the ethanolic soln being first dissolved in the aluminum nitrate with crystal water in ethanol, then making itself and tetraethoxy is mixed to get single-phase mullite sol in brief.The core of the method is slowly also carried out step by step by limited crystal water controlled hydrolysis process.Chinese patent CN1810722A discloses a kind of low temperature sintering technology of mullite ceramic, wherein uses the method to prepare the single-phase colloidal sol of mullite.
There is bibliographical information (Joumal of sol-gel science and technology 1997,10:19-30; Journal of sol-gel science and technology 1999,15:191-199), trimethyl carbinol aluminium is adopted to be aluminium source, tetraethoxy is silicon source, Virahol or ethanol make solvent, by control ph, and regulating environmental humidity, control slowly hydrolysis, also can prepare single-phase mullite sol.Chinese patent CN 102602947A reports a kind of alcohol, water of not adopting as the preparation method of the single-phase mullite sol of solvent, invention adopts solvable al inorganic salt, aluminium-alcohol salt together does aluminium source, first soluble aluminum salt is dissolved in organic solvent, after the pH value of acid-conditioning solution, add aluminium-alcohol salt reaction 10-40 minute again, add the hydrolysis of silicon source after 12-36 hour, heat and form mullite sol in 10-60 hour.The core of these class methods is all realize slow hydrolysis by hierarchy of control environment.
In addition, also can control the hydrolysis rate of aluminium salt by adding various sequestrant in system, thus prepare the single-phase colloidal sol of mullite.Such as, the rich seminar of Xiamen University Chen Li with trimethyl carbinol aluminium for aluminium source, the tetraethoxy of partial hydrolysis is silicon source, add methyl aceto acetate as sequestrant, add polyvinylpyrrolidone as fibroblast auxiliary agent, prepared single-phase mullite sol, and prepared gelled fibre (Xiamen University's journal (natural science edition), 2009,48 (4): 610-612).
To sum up, prior art is in the preparation process of single-phase mullite sol, energy consumption is high, preparation cycle is long, processing parameter (as pH value, temperature, ambient moisture) is required strict, need to add extra sequestrant, complex process, repeatability are poor and starting material are expensive alkoxide, unsatisfactory.
Summary of the invention
The object of the invention is to overcome prior art deficiency, provide that a kind of technique is simple, energy consumption is low, preparation cycle is short, low cost, be easy to the preparation method of the single-phase mullite sol of synthesis in enormous quantities.
Technical solution of the present invention: a kind of preparation method of single-phase mullite sol, is realized by following steps:
The first step, prepares fresh aluminum hydroxide precipitation,
The present invention at ambient temperature, take inorganic aluminate as raw material, obtains fresh aluminum hydroxide precipitation by the method adding excessive alkali, does not use expensive aluminium-alcohol salt as raw material, reduces costs.This step can adopt the preparation of following technique that general inorganic aluminate also can be adopted to prepare the method for the precipitation of aluminium hydroxide.
Inorganic aluminate is mixed with the aqueous solution that volumetric molar concentration is 0.2 ~ 2M, under maintenance agitation condition, progressively dripping volumetric molar concentration is wherein the inorganic alkali solution of 0.2 ~ 1.5M, until after having precipitation to generate, at room temperature stir 30min ~ 60min again, subsequent filtration washing obtains solid matter.
The present invention is not particularly limited inorganic aluminate kind, can adopt the one in common Tai-Ace S 150, aluminum chloride, aluminum nitrate.The present invention is not particularly limited mineral alkali kind, can adopt the one in common ammoniacal liquor, sodium hydroxide, potassium hydroxide, Ammonium bicarbonate food grade, take ammoniacal liquor as the best.Inorganic aluminate in the present invention, mineral alkali concentration are unsuitable excessive, if concentration is too large, not high in the efficiency of stirring at room temperature, dispersion, can need heating to a certain degree, at room temperature cannot operate, add cost; And concentration too low time generate precipitation very little.The present invention gives preferred concentration range, take into account ambient operation and precipitation yields.
The method of described extraction solid matter is filter paper vacuum filtration or centrifugation.
Aluminum hydroxide precipitation prepared by this step needs to prepare in 3 hours before subsequent step uses, and now-making-now-using is best.
Second step, prepares aluminum oxide suspension,
The fresh aluminum hydroxide precipitation obtained in the first step is scattered in dehydrated alcohol, at room temperature stirs, obtain aluminum oxide suspension;
In this step, dehydrated alcohol is dispersion agent, as long as aluminum hydroxide precipitation can be made to disperse uniformly, general with reference to consumption be aluminum hydroxide precipitation and dehydrated alcohol quality in 1: 10 ~ 20 scopes, also can select as the case may be.At room temperature stir certain hour, obtain the aluminum oxide suspension of white.
3rd step, introduces silicon source in aluminum oxide suspension,
Keep room temperature agitation condition constant, drip silicon ester according to the ratio of Al/Si mol ratio 3/1 in aluminum oxide suspension, after silicon ester all drips, continue to stir certain hour, churning time is generally not less than 2 hours.
This step silicon ester kind does not have particular requirement, and can be the one in methyl silicate, tetraethoxy, positive silicic acid propyl ester, butyl silicate, the most frequently used be tetraethoxy.
4th step, mix suspending lyolysis is coagulated,
Keep room temperature agitation condition constant, in mixing suspension, the diluted acid that volumetric molar concentration is 1 ~ 2M is dripped according to the ratio of Al/H+ mol ratio 1 ~ 10: 1, can find in dropping process that the white of suspension is taken off very soon, there is nattier blue opalescence in system, continues to stir the mullite sol that certain hour obtains pale yellow transparent.
The diluted acid of approximate quantity, use the large acidolysis of volumetric molar concentration to coagulate, the micelle particle obtained in follow-up colloidal sol is less.The volumetric molar concentration scope that this step requires is by the optimum range value of size controlling in 10-200nm interval, exceeds this scope, likely obtains the mullite sol of lower concentration Large stone or can not get stable sol.
Under equal conditions, the total addition level of diluted acid is larger, and in follow-up colloidal sol, micelle particle is less.This step requires that diluted acid addition scope is by the optimum value of size controlling in 10-200nm interval, exceeds this scope, likely obtains the mullite sol of lower concentration Large stone or can not get stable sol.
The kind of the present invention to diluted acid is not particularly limited, and can adopt the one in conventional hydrochloric acid, nitric acid, sulfuric acid, formic acid, Glacial acetic acid, take nitric acid as the best.Can be corresponding with inorganic aluminate when selection mineral acid, in system, introduce several ion less like this, convenient when the later stage uses, also can use the kind of not homology.
The present invention suppresses the hydrolysis rate of aluminium-alcohol salt to make itself and estersil cohydrolysis by various control device, but the mode of coagulating by adding acidolysis makes aluminum oxide suspension while solution is solidifying and silicon ester cohydrolysis, thus realizes Al
3+and Si
4+high evenness mixing on molecule or atom level.In the solution solidifying stage, the concentration of diluted acid and add-on most important for the mullite sol that can form stable homogeneous.Diluted acid is separate solidifying inducement on the one hand, promotes silicic acid ester hydrolysis again on the one hand, forms stable sol.
The present invention's beneficial effect compared with prior art:
(1) the present invention avoids the demand to suppressing aluminium-alcohol salt hydrolysis rate, and to all not special requirement of the processing parameter such as pH value, ambient moisture, technique is simple, requires low, be suitable for large-scale industrial production to synthesis device;
(2) raw material types that the present invention relates to is few, only need tetraethoxy, ethanol and a kind of inorganic aluminate, a kind of diluted acid, do not need to adjust the proportioning between multiple aluminium source, and avoid the demand to controlling aluminium-alcohol salt hydrolysis rate due to technical process, do not need the pH value of additional acid-alkali accommodation reaction system, do not need additional sequestrant, effectively reduce the impact of starting material factor on single-phase mullite sol forming process, favorable repeatability.The main aluminium source raw material that the present invention relates to is al inorganic salt, cheap, is suitable for industrial application;
(3) the present invention's whole process is all carried out in room temperature, and do not need heating, energy consumption is low, saves production cost, energy-conserving and environment-protective;
(4) preparation cycle of single-phase mullite sol that greatly shortens of the present invention, the whole production cycle is no more than 3 days, far below the existing technology of preparing to be hydrolyzed to core slowly;
(5) the single-phase mullite sol particle diameter prepared of the present invention is little and distribute homogeneous, solid content is about 10%, after rotary evaporation or standing solvent flashing concentrate, solid content can reach 30%, be suitable for low temperature (about 1000 DEG C) and prepare fiber reinforcement mullite matrix material, pyroprocessing (1200-1300 DEG C) needed for reduction two-phase glue mullitization, to the damage of fortifying fibre, improves material property.
Accompanying drawing explanation
Fig. 1 is moulding process schema of the present invention;
Fig. 2 is that mullite sol of the present invention is dried after for xerogel at 80 DEG C, and the XRD figure of the powder obtained after 1050 DEG C of thermal treatments, wherein " * " represents the characteristic peak of mullite.
Embodiment
Below in conjunction with accompanying drawing and specific examples, the present invention is described in detail.
Embodiment 1
Adopt aluminum nitrate and tetraethoxy to be aluminium source and silicon source, dust technology is liquefactent, prepares single-phase mullite sol.
Preparation as shown in Figure 1, is realized by following steps:
1, aluminum nitrate is mixed with the aqueous solution of 1M, progressively drips the ammoniacal liquor of 0.5M wherein, until after having precipitation to generate, more at room temperature stir 30min, filtering and washing obtains solid matter subsequently.
2, the solid matter obtained by suction filtration is scattered in dehydrated alcohol according to the ratio of mass ratio 1: 10, at room temperature stirs the aluminum oxide suspension obtaining white for 6 hours.
3, keep stirring at room temperature constant, in aluminum oxide suspension, drip tetraethoxy according to the ratio of Al/Si mol ratio 3/1, after silicon ester all drips, continue stirring 2 hours.
4, keep stirring at room temperature constant, in suspension, the dust technology of 2M is dripped according to the ratio of Al/H+ mol ratio 4/1, can find in dropping process that the white of suspension is taken off very soon, there is nattier blue opalescence in system, after dust technology all drips, continue stirring and obtain transparent mullite sol in 12 hours.
The median size adopting laser particle analyzer to record this sol particle is 36nm.Sample obtained does not as seen from Figure 2 have dephasign, is pure mullite powder, and peak type is sharp-pointed, proves that crystal property is relatively good.Meanwhile, the thermal treatment temp of 1050 DEG C proves that mullite sol prepared by the present invention is single-phase glue.
Embodiment 2
Adopt aluminum chloride and tetraethoxy to be aluminium source and silicon source, dilute hydrochloric acid is liquefactent, prepares single-phase mullite sol.
Aluminum chloride is mixed with the aqueous solution of 0.5M, progressively drips the potassium hydroxide aqueous solution of 0.2M wherein, until after having precipitation to generate, more at room temperature stir 60min, filtering and washing obtains solid matter subsequently.The solid matter obtained by suction filtration is scattered in dehydrated alcohol according to the ratio of mass ratio 1: 20, at room temperature stirs the aluminum oxide suspension obtaining white for 18 hours.
Keep stirring at room temperature constant, in aluminum oxide suspension, drip tetraethoxy according to the ratio of Al/Si mol ratio 3/1, after silicon ester all drips, continue stirring 2 hours.
Keep stirring at room temperature constant, in suspension, the dilute hydrochloric acid of 1M is dripped according to the ratio of Al/H+ mol ratio 10/1, can find in dropping process that the white of suspension is taken off very soon, there is nattier blue opalescence in system, after dust technology all drips, continue stirring and obtain transparent mullite sol in 12 hours.The median size adopting laser particle analyzer to record this sol particle is 74nm.
Embodiment 3
Adopt Tai-Ace S 150 and tetraethoxy to be aluminium source and silicon source, dilute sulphuric acid is liquefactent, prepares single-phase mullite sol.
Tai-Ace S 150 is mixed with the aqueous solution of 2M, progressively drips the ammoniacal liquor of 1M wherein, until after having precipitation to generate, more at room temperature stir 60min, centrifugation subsequently also washing obtains solid matter.The solid matter obtained by suction filtration is scattered in dehydrated alcohol according to the ratio of mass ratio 1: 10, at room temperature stirs the aluminum oxide suspension obtaining white for 6 hours.
Keep stirring at room temperature constant, in aluminum oxide suspension, drip tetraethoxy according to the ratio of Al/Si mol ratio 3/1, after silicon ester all drips, continue stirring 2 hours.
Keep stirring at room temperature constant, in suspension, the dilute sulphuric acid of 1M is dripped according to the ratio of Al/H+ mol ratio 1/1, can find in dropping process that the white of suspension is taken off very soon, there is nattier blue opalescence in system, after dust technology all drips, continue stirring and obtain transparent mullite sol in 12 hours.The median size adopting laser particle analyzer to record this sol particle is 17nm.
Embodiment 4
Adopt aluminum nitrate and tetraethoxy to be aluminium source and silicon source, dust technology is liquefactent, prepares single-phase mullite sol.
Aluminum nitrate is mixed with the aqueous solution of 1M, progressively drips the ammonium bicarbonate soln of 1.5M wherein, until after having precipitation to generate, more at room temperature stir 60min, filtering and washing obtains solid matter subsequently.The solid matter obtained by suction filtration is scattered in dehydrated alcohol according to the ratio of mass ratio 1: 10, at room temperature stirs the aluminum oxide suspension obtaining white for 18 hours.
Keep stirring at room temperature constant, in aluminum oxide suspension, drip tetraethoxy according to the ratio of Al/Si mol ratio 3/1, after silicon ester all drips, continue stirring 2 hours.
Keep stirring at room temperature constant, in suspension, the dust technology of 1M is dripped according to the ratio of Al/H+ mol ratio 3/1, can find in dropping process that the white of suspension is taken off very soon, there is nattier blue opalescence in system, after dust technology all drips, continue stirring and obtain transparent mullite sol in 24 hours.The median size adopting laser particle analyzer to record this sol particle is 45nm.
Volumetric molar concentration and the add-on of median size and diluted acid have direct relation, from embodiment 1,4, and the diluted acid of approximate quantity, use the large acidolysis of volumetric molar concentration to coagulate, the micelle particle obtained in follow-up colloidal sol is less; From embodiment 2,3,4, the total addition level of diluted acid is larger, and in follow-up colloidal sol, micelle particle is less.
The unspecified part of the present invention is known to the skilled person technology.
Claims (3)
1. a preparation method for single-phase mullite sol, is characterized in that comprising the following steps:
The first step, prepares fresh aluminum hydroxide precipitation;
Second step, prepares aluminum oxide suspension,
The fresh aluminum hydroxide precipitation obtained in the first step is scattered in dehydrated alcohol, at room temperature stirs, obtain aluminum oxide suspension;
3rd step, introduces silicon source at aluminum oxide suspension,
Keep stirring at room temperature constant, in aluminum oxide suspension, drip silicon ester according to the ratio of Al/Si mol ratio 3/1, after silicon ester all drips, continue stirring and obtain mixing suspension;
4th step, mix suspending lyolysis is coagulated,
Keep stirring at room temperature constant, according to Al/H
+the ratio of mol ratio 1 ~ 10: 1 drips diluted acid in mixing suspension, continues stirring and obtains single-phase mullite sol.
2. the preparation method of a kind of single-phase mullite sol according to claim 1, is characterized in that: in described 4th step, the volumetric molar concentration of diluted acid is 1 ~ 2M.
3. the preparation method of a kind of single-phase mullite sol according to claim 1, is characterized in that: the described the first step prepares fresh aluminum hydroxide precipitation, is realized by following steps,
A1.1, preparation volumetric molar concentration are the inorganic aluminate aqueous solution of 0.2 ~ 2M;
Drip the inorganic alkali solution that volumetric molar concentration is 0.2 ~ 1.5M in A1.2, the inorganic aluminate aqueous solution prepared in steps A 1.1, until there is precipitation to generate, more at room temperature stir 30min ~ 60min;
A1.3, obtain fresh aluminum hydroxide precipitation by after throw out filtration washing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410696774.2A CN104692403B (en) | 2014-11-28 | 2014-11-28 | Preparation method of single-phase mullite sol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410696774.2A CN104692403B (en) | 2014-11-28 | 2014-11-28 | Preparation method of single-phase mullite sol |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104692403A true CN104692403A (en) | 2015-06-10 |
| CN104692403B CN104692403B (en) | 2017-05-17 |
Family
ID=53340022
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410696774.2A Active CN104692403B (en) | 2014-11-28 | 2014-11-28 | Preparation method of single-phase mullite sol |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104692403B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110004521A (en) * | 2019-02-28 | 2019-07-12 | 山东大学 | A kind of preparation method of spinnability silicon-aluminum sol |
| CN111715202A (en) * | 2020-06-29 | 2020-09-29 | 沈阳三聚凯特催化剂有限公司 | Porous material and preparation method and application thereof |
| CN114538455A (en) * | 2022-04-09 | 2022-05-27 | 山东大学 | Low crystal transformation temperature, small grain size and NO3Preparation method of mullite sol with adjustable content |
-
2014
- 2014-11-28 CN CN201410696774.2A patent/CN104692403B/en active Active
Non-Patent Citations (1)
| Title |
|---|
| CARLA C. OSAWA ET AL，: ""Mullite Formation from Mixtures of Alumina and Silica Sols: Mechanism and pH Effect"", 《J. BRAZ. CHEM. SOC.》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110004521A (en) * | 2019-02-28 | 2019-07-12 | 山东大学 | A kind of preparation method of spinnability silicon-aluminum sol |
| CN111715202A (en) * | 2020-06-29 | 2020-09-29 | 沈阳三聚凯特催化剂有限公司 | Porous material and preparation method and application thereof |
| CN114538455A (en) * | 2022-04-09 | 2022-05-27 | 山东大学 | Low crystal transformation temperature, small grain size and NO3Preparation method of mullite sol with adjustable content |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104692403B (en) | 2017-05-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110668452B (en) | Preparation of SiO from fly ash2-Al2O3Method of compounding aerogel materials | |
| CN103086692B (en) | Blocky SiO2-Y2O3Preparation method of composite aerogel | |
| CN101391814B (en) | Method for preparing rutile phase hypovanadic oxide powder | |
| CN103408292B (en) | Preparation method for alumina-zirconia ceramic fiber | |
| CN107151029B (en) | A kind of sol-gel self-combustion synthesis preparation process of tetra phase barium titanate powder | |
| CN100462307C (en) | Method for preparation of niobic acid zinc nano material | |
| CN102503387B (en) | Method for preparing high-purity super-fine mullite powder | |
| CN104003699A (en) | Preparation method of yttrium silicate ceramic powder | |
| CN102674898B (en) | Cerium oxide/ aluminium oxide micro-nanostructure ceramic pigment and preparation method thereof | |
| CN104692403A (en) | Preparation method of single-phase mullite sol | |
| CN102390852B (en) | Method for preparing high-purity superfine Alpha-Al2O3 powder from microemulsion | |
| CN101544402B (en) | Nanometer zirconia sol and preparation method thereof | |
| CN103435097B (en) | Preparation method and application of nano zirconia | |
| CN103774208A (en) | Green hydrothermal synthesis method for non-porous high-crystallized magnesium borate nanowhisker | |
| CN114162844B (en) | Precursor composite sol for alumina/mullite biphase fiber and preparation method thereof | |
| CN101891209A (en) | Method for preparing nano powder of spherical silicon dioxide | |
| CN103114352A (en) | Preparation method of sol gel of alumina fiber | |
| CN106315680B (en) | A kind of porous δ-MnO of coralliform2Preparation method | |
| CN104557101A (en) | Preparation method for porous lithium zirconate block | |
| CN101456561B (en) | Method for preparing nano mullite powder | |
| CN1477059A (en) | Preparation method of nano alumina material | |
| CN100467378C (en) | Prepn process of pseudoboehmite for luminescent material | |
| CN104073918A (en) | Method for synthesizing polycrystalline mullite fibers under low temperature condition | |
| CN104973624A (en) | Preparation method of meshy tetragonal phase zirconia nano powder | |
| CN103693689B (en) | Utilize kind of crystallization synthesis of nano t-ZrO between water-oil interface 2the method of particle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |