CN1232803A - Mullite synthesizing method - Google Patents
Mullite synthesizing method Download PDFInfo
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- CN1232803A CN1232803A CN 98101568 CN98101568A CN1232803A CN 1232803 A CN1232803 A CN 1232803A CN 98101568 CN98101568 CN 98101568 CN 98101568 A CN98101568 A CN 98101568A CN 1232803 A CN1232803 A CN 1232803A
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Abstract
By using cheap kaolin as main material and adding phase change assistant, partial mullite is produced at 600-900 deg.c and is further acid or alkali extracted to result in mullite with 85% over purity. Compared with available technology, the present invention has the advantages of cheap material, greatly reduced reaction temperature, simple synthesizing process, relatively higher product purity and grain size obviously smaller than that obtained through silica-allumina gel process.
Description
The invention belongs to pottery, technical field of refractory materials, more particularly, be a kind of be the method for raw material mullite synthesizing with kaolin.
Mullite is a kind of crystalline sieve and silica-sesquioxide, and be 3AL typical the composition
2O
3, 2SiO
2, its fusing point is higher, hardness is big, the high temperature creep value is little, resistance to chemical corrosion good (volume such as Ren Guobin, " practical refractory materials ", metallurgical industry press, first version in 1988 P361), is widely used in pottery, metallurgy, semi-conductor, field of petrochemical industry.The method of general mullite synthesizing mainly contains electric smelting method and sintering process.The electric smelting method is that the fusion in electric arc of mixed raw material is formed what propose as the CN85108307A patent application is raw material with aluminum oxide and silica, synthetic high-purity electrofused mullite, mainly be to lead fusion certainly starting the arc difficulty and arc extinguishing problem with commercial alumina, but the problem of electric smelting method maximum is that current consumption is big, the operational condition harshness.The content of sintering process mullite synthesizing report is many, can be divided into following three kinds by raw materials used character:
(1) inorganic silicon-aluminum coagulates than method: will contain aluminium species such as aluminium salt, boehmite, aluminium chlorohydroxide and silicon species such as various silica gel, water glass, white carbon black, by certain chemical constitution (71-73%AL
2O
3, 27-29%SiO
2) make the dried glue of sial, form 1200-1500 ℃ of following roasting then (JP6256356, GB228705, J.Am.Ceram.Soc., 72[3]: 377-382,1989).The shortcoming of this method is that energy consumption is high.
(2) organosilicon alumina gel method: adopt Si
3(OEt)
4Deng organosilicon is the silicon source, with AL
2(OCCHMeEt)
3Deng organoaluminum is the aluminium source, and (AL74-75% Si25-26%) makes the sial colloid, then 1000-1200 ℃ of roasting by certain chemical constitution.The silicon that this method adopted, aluminum feedstock costliness, simultaneously energy consumption also higher (J.Am.Ceram.Soc., 72[3]: 162-163,1988).
(3) mineral facies political reform: when the high temperature more than 1200 ℃, clay minerals such as kaolin, pyrophyllite can partly form mullite (Chem.Mater, 9:677-884,1997).This method advantage is that the kaolin cost of material is cheap, and shortcoming is the energy consumption height.In addition, exist than big-difference, at high temperature can only partly change into mullite, therefore be difficult to make purer mullite, have only 50-60% in the limiting quantity that generates mullite more than 1200 ℃ as kaolin because mineral composition and mullite are formed.
The objective of the invention is to overcome the deficiency of prior art, providing a kind of is raw material with kaolin, and preparation purity reaches the method for the mullite more than 85% under lower temperature.
Realizing purpose main technical schemes of the present invention, is raw material with cheap kaolin, adds the phase transformation auxiliary agent, generates mullite under lower temperature, after acid, alkali extracting reach more than 85% mullite purity.
Preparation method of the present invention comprises following process:
1. kaolin and the phase transformation auxiliary agent of median size less than 15um mixed, 120 ℃ down dry, mill is even, 500-550 ℃, preferably 510-540 ℃ preroasting 1-5 hour, preferably 2-4 hour
With (1) step preroasting the kaolin that contains auxiliary agent at 600-900 ℃, preferably 650-800 ℃ following roasting 0.25-10 hour, preferably 1-8 hour, the kaolin after the roasting contained mullite 5-50%;
3. kaolin and the concentration with roasting is 5-30%, preferably the 6-20% hydrochloric acid soln mixes, at 60-100 ℃, preferably 80-95 ℃ was reacted 0.1-10 hour, preferably 1-8 hour, filter then, washing, filter cake and concentration 3-30% preferably 6-25% sodium hydroxide solution mix, at 60-150 ℃, preferably 80-130 ℃ was reacted 0.1-8 hour down, preferably 1-6 hour, through sedimentation, supernatant liquid inclines, the reusable heat water washing, filter, be drying to obtain finished product, described hydrochloric acid content (in HCL) is the 20-200% of kaolin weight, 50-160% preferably, described NaOH solution amount (in NaOH) is the 30-200% of kaolin weight, 50-160% preferably.
Described phase transformation auxiliary agent comprises the compound of the alum of Vanadium Pentoxide, ammonium meta-vanadate, naphthenic acid alum, and its add-on (in metallic element) is the 0.5-7% of kaolin weight.Use Vanadium Pentoxide to make auxiliary agent and can save step (1), directly mix the back roasting with kaolin; If use the solid ammonium meta-vanadate, the H of available 1-10%, best 2-6%
2O
2Solution dissolves, and makes the solution of aluminiferous 0.1-1.5%, best 0.2-1.0%; If use the naphthenic acid alum, available cyclohexane and naphthenic acid vanadium are mixed with and contain vanadium 0.1-10%, the solution of 1-5% preferably.
Method of the present invention can also use other clay that comprises alabaster, mica, feldspar, polynite to make raw material.
Major advantage of the present invention:
Method of the present invention is compared with the silica-alumina gel method of routine, and raw material is cheap, and temperature of reaction reduces a lot, and the purity of the mullite that makes can reach more than 85%, and crystal grain is significantly less than the crystal grain of the mullite that the silica-alumina gel method makes; Method of the present invention is compared with the mineral facies political reform, the most tangible advantage is that the generation temperature of mullite has been reduced to the temperature province that kaolin changes to metakaolin, aluminum oxide in this zone in the kaolin and silicon oxide all have high reaction activity and high, be easy to be extracted, thereby can make quite pure mullite by bronsted lowry acids and bases bronsted lowry; Though method of the present invention adopts acid, alkali extraction process, but this technology is uncomplicated, therefore generally speaking, method of the present invention is fairly simple, particularly temperature reduces a lot, so just easier operation, the mullite that is made by method of the present invention is a kind of special solid support material, has good DEVELOPMENT PROSPECT.
Further set forth characteristics of the present invention with example below:
Example 1
In 1350 ml waters, add 150 gram hydrogen peroxide (analytical pure), 18.2 gram ammonium meta-vanadates (analytical pure) are dissolved in prepared rare hydrogen peroxide, obtain the vanadium species auxiliary agent.In above-mentioned auxiliary agent, add 180 gram kaolin (3.6 microns of median sizes) stir evenly, dry, grind even, 540 ℃ of roastings after 2 hours 800 ℃ of roastings 1 hour, make roasting kaolin CK
1X-ray diffraction analysis shows CK
1In generated 28% mullite.
Example 2
Other condition just 510 ℃ of pre-calcination temperatures, 4 hours time, 680 ℃ of 8 hours times of maturing temperature, makes roasting kaolin CK with example 1
2By analysis, CK
2In generated 28% mullite.
Example 3
Get CK in the example 1
120 grams, concentration is 150 milliliters of 20% hydrochloric acid solns, mixes, and at 80 ℃ of 6 hours after-filtration of reaction down, makes CK
1-A
1In filter cake, add concentration and be 120 milliliters of 25% sodium hydroxide solutions, 80 ℃ of reactions 6 hours down, through sedimentation, the supernatant liquid that inclines, other adds 300 milliliters of hot water making beating, filtration, drying, makes CK
1-AB
1
Example 4
Get CK in the example 1
120 grams add concentration and are 170 milliliters of 6% hydrochloric acid solns, mix, and at 95 ℃ of 1 hour after-filtration of reaction down, make CK
1-A
2In filter cake, add concentration and be 165 milliliters of 6% sodium hydroxide solutions, 130 ℃ of reactions 1 hour down, through sedimentation, the supernatant liquid that inclines, other adds 300 milliliters of hot water making beating, filtration, drying, makes CK
1-AB
2
Comparative Examples
At 57 ml water glass solution (SiO
2250 gram liters
-1, modulus 3.0) in, adding 100 ml waters, 100 ml concns successively is 15% ammoniacal liquor, 500 milliliters of aqueous solution that contain 170 gram crystal aluminum chlorides, stirs.Ammoniacal liquor with 15% is transferred PH=9.5, and aging, filtration divides three making beating, filters with 4500 milliliters of hot water again, the oven dry filter cake.At 1450 ℃ of following roastings 13 hours, mullite synthesizing DM-1.
The experimental result of example 3,4 and Comparative Examples sees Table 1.As seen from Table 1, adopt the mullite crystal grain of the inventive method preparation to be significantly less than gel method synthetic mullite crystal grain.
Example 5
CK
1With sour consumption with example 3, just the add-on of alkali is 60 milliliters of the aqueous sodium hydroxide solutions of concentration 25%, makes CK
1-AB
3
Example 6
CK
1With sour consumption with example 2, just the add-on of alkali is 30 milliliters of the aqueous sodium hydroxide solutions of concentration 25%, makes CK
1-AB
4
Example 3,5,6 experimental result sees Table 2.
Example 7
CK in the example 3
1Change CK into
2, the add-on of acid is 35 milliliters of the aqueous hydrochloric acids of concentration 20%, and other condition is with example 3, and sour extracting makes CK
2-A
1, the alkali extracting makes CK
2-AB
1
Example 8
Other condition is identical with example 7, be the sour extractive reaction time be 8 hours, sour extracting makes CK
2-A
2, the alkali extracting makes CK
2-AB
2
Example 3,7,8 experimental result sees Table 3.
Example 9
Add 3.4 gram ammonium meta-vanadates in 60 gram kaolin (13.1 microns of median sizes), mill is even, 540 ℃ of following roastings 4 hours, 720 ℃ of following roastings 3 hours, makes roasting kaolin CK then
3X-ray diffraction analysis shows, CK
3In generated 19% mullite.
Example 10
Get CK in the example 9
320 grams, acid, alkali extractive reaction condition is identical with example 3, makes CK respectively
3-A
1, CK
3-AB
1, wherein mullite content is respectively 24%, 86%.
Table 1, example 3,4 and Comparative Examples are relatively
| Project | Example 3, CK 1-AB 1 | Example 4, CK 1-AB 2 | Comparative Examples, CM 1 |
| Main raw material(s) | Kaolin | Kaolin | Silicon, aluminum chemistry reagent |
| The product material phase analysis | Mullite, cristobalite | Mullite, cristobalite | Mullite, a small amount of β-cristobalite and α-Al 2O 3 |
| Mullite content, % | ????90 | ????87 | ????92 |
| Outward appearance | White | White | White |
| Crystal grain *, nanometer | ????23.9 | ????24.2 | ????42.4 |
* X-ray diffraction live width method is measured, and represents with mullite 121 crystal faces.
The experimental result of table 2, example 3,5,6
| Project | Example 3 CK 1-AB 1 | Example 5 CK 1-AB 3 | Example 6 CK 1-AB 4 |
| Material phase analysis | Mullite, a small amount of cristobalite | Mullite, a small amount of cristobalite | Mullite, more cristobalite |
| Outward appearance | White | White | Greyish white |
| Mullite content, % | ????90 | ????85 | ????60 |
The experimental result of table 3, example 3,7,8
| Project | Example 3 CK 1-A 1?CK 1-AB 1 | Example 7 CK 2-A 1?CK 2-AB 1 | Example 8 CK 2-A 2?CK 2-AB 2 |
| The extracting time, hour | ????1 | ????1 | ????8 |
| Mullite content, % | ??30???????90 | ????30????75 | ????32????88 |
Claims (7)
1. the method for a mullite synthesizing is characterized in that preparation process may further comprise the steps:
(1) kaolin and phase transformation auxiliary agent are mixed, 120 ℃ down dry, mill is even, 500-550 ℃ following preroasting 1-5 hour;
(2) (1) was gone on foot the kaolin that contains auxiliary agent of preroasting at 600-900 ℃ of following roasting 0.25-10 hour;
(3) kaolin behind (2) one-step baking is mixed with the hydrochloric acid soln of concentration 5-30%, reacted 0.1-8 hour down at 60-100 ℃, filter, wash, filter cake and concentration are that the sodium hydroxide of 3-30% mixes, reacted 0.1-8 hour down at 60-150 ℃, through sedimentation, supernatant liquid inclines, again through washing, filter, be drying to obtain finished product, the amount of described hydrochloric acid soln (in HCL) is the 20-200% of kaolin weight, and the amount of described sodium hydroxide solution (in NaOH) is the 30-200% of kaolin weight.
2. in accordance with the method for claim 1, it is characterized in that described phase transformation auxiliary agent comprises Vanadium Pentoxide in FLAKES, ammonium meta-vanadate, naphthenic acid vanadium, its add-on (in metallic element) is the 0.5-7% of kaolin weight.
3. according to claim 1,2 described methods when it is characterized in that using described Vanadium Pentoxide in FLAKES as the phase transformation auxiliary agent, can be saved the step (1) of preroasting, directly mix the back roasting with kaolin.
4. in accordance with the method for claim 1, it is characterized in that the described pre-calcination temperature 510-540 of step (1) ℃, time are 2-4 hour.
5. in accordance with the method for claim 1, it is characterized in that the described maturing temperature 650-800 of step (2) ℃, time 1-8 hour.
6. in accordance with the method for claim 1, it is characterized in that the concentration 6-20% of the described hydrochloric acid soln of step (3), its add-on (in HCL) is the 50-160% of kaolin amount, 80-95 ℃ of hydrochloric acid and roasting kaolin temperature of reaction, time 1-8 hour.
7. in accordance with the method for claim 1, the concentration 6-25% that it is characterized in that the described sodium hydroxide solution of step (3), its add-on (in NaOH) is the 50-160% of kaolin weight, and kaolin after the extracting and sodium hydroxide solution temperature of reaction are 80-130 ℃, time 1-6 hour.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98101568A CN1069886C (en) | 1998-04-21 | 1998-04-21 | Mullite synthesizing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98101568A CN1069886C (en) | 1998-04-21 | 1998-04-21 | Mullite synthesizing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1232803A true CN1232803A (en) | 1999-10-27 |
| CN1069886C CN1069886C (en) | 2001-08-22 |
Family
ID=5216781
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN98101568A Expired - Fee Related CN1069886C (en) | 1998-04-21 | 1998-04-21 | Mullite synthesizing method |
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| Country | Link |
|---|---|
| CN (1) | CN1069886C (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1304289C (en) * | 2004-08-13 | 2007-03-14 | 桂林工学院 | Method for preparing mullite multiple phase nanocrystalline using natural kaolin |
| CN101508438B (en) * | 2009-04-01 | 2011-03-16 | 苏州大学 | Method for producing mullite with kleit as raw material |
| CN102584190A (en) * | 2012-04-11 | 2012-07-18 | 广东宝丰陶瓷科技发展股份有限公司 | Method for preparing mullite by using modified kaolin clay |
| CN102674381A (en) * | 2012-05-22 | 2012-09-19 | 中国地质大学（北京） | Method for preparing nano mullite powder from coal-based kaolin |
| CN102875136A (en) * | 2012-11-05 | 2013-01-16 | 上海师范大学 | Recovery method of mullite and recovery preparation of mullite |
| CN103028432A (en) * | 2013-01-11 | 2013-04-10 | 华东理工大学 | Wear-resistant heavy oil catalytic cracking catalyst capable of reducing sulfur content of gasoline and preparation method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0615421B2 (en) * | 1985-09-04 | 1994-03-02 | 株式会社ノリタケカンパニ−リミテド | Method for manufacturing mullite sintered body |
-
1998
- 1998-04-21 CN CN98101568A patent/CN1069886C/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1304289C (en) * | 2004-08-13 | 2007-03-14 | 桂林工学院 | Method for preparing mullite multiple phase nanocrystalline using natural kaolin |
| CN101508438B (en) * | 2009-04-01 | 2011-03-16 | 苏州大学 | Method for producing mullite with kleit as raw material |
| CN102584190A (en) * | 2012-04-11 | 2012-07-18 | 广东宝丰陶瓷科技发展股份有限公司 | Method for preparing mullite by using modified kaolin clay |
| CN102674381A (en) * | 2012-05-22 | 2012-09-19 | 中国地质大学（北京） | Method for preparing nano mullite powder from coal-based kaolin |
| CN102875136A (en) * | 2012-11-05 | 2013-01-16 | 上海师范大学 | Recovery method of mullite and recovery preparation of mullite |
| CN103028432A (en) * | 2013-01-11 | 2013-04-10 | 华东理工大学 | Wear-resistant heavy oil catalytic cracking catalyst capable of reducing sulfur content of gasoline and preparation method thereof |
| CN103028432B (en) * | 2013-01-11 | 2018-04-17 | 华东理工大学 | A kind of wear-resistant catalyst for heavy oil catalytic cracking for reducing content of sulfur in gasoline and preparation method thereof |
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| Publication number | Publication date |
|---|---|
| CN1069886C (en) | 2001-08-22 |
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