CN103723751A - Impurity removal method of alumina for LCD (Liquid Crystal Display) glass base board - Google Patents
Impurity removal method of alumina for LCD (Liquid Crystal Display) glass base board Download PDFInfo
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- CN103723751A CN103723751A CN201310669111.7A CN201310669111A CN103723751A CN 103723751 A CN103723751 A CN 103723751A CN 201310669111 A CN201310669111 A CN 201310669111A CN 103723751 A CN103723751 A CN 103723751A
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- impurity
- aluminum oxide
- glass substrate
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- lcd glass
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Abstract
An impurity removal method of high-purity alumina relates to an impurity removal method of alumina special for an LCD (Liquid Crystal Display) glass base board. The impurity removal method is characterized by sequentially comprising the impurity removal steps as follows: (1), performing electromagnetic deferrization on aluminum hydroxide slurry; (2), performing high-pressure hydrothermal treatment; (3), performing pickling and water washing treatment; (4), performing calcination to obtain alpha-phase alumina; (5), performing the electromagnetic deferrization for iron removal once again. According to the impurity removal method provided by the invention, harmful impurities including Na2O and Fe2O3 in the aluminum hydroxide can be effectively removed, boric acid and fluoride are prevented from corroding a furnace, occupational health noxious gases are not generated, environmental friendliness is realized and fluoride harmful to crop is not generated, and the chemical compositions satisfy the requirement of the alumina for the LCD glass base board on the quality.
Description
Technical field
An impurity-removing method for high-purity alpha-alumina, relates to a kind of for LCD(liquid crystal) impurity-removing method of glass substrate special aluminium oxide.
Background technology
LCD(liquid crystal) glass substrate is the important component part of liquid crystal flat panel display, its thickness is about 0.5mm, belong to aluminium borosilicate glass, due to for liquid-crystal display, therefore performance requriements is harsh: (1) requires alkali metal content low, and maximum alkali metal oxide content general control is below 1000ppm; (2) Fe
3+low Deng colored ion content; (3) good heat resistance (requiring strain point temperature to be greater than 650 ℃); (4) chemically-resistant corruption good (cleaning of strong acid and strong base and etching); (5) surface and subsurface defect few (interior surface zero defect and bubble); (6) physical strength high (requiring Young's modulus>=70GPa).
The about 20%-30% of LCD glass substrate raw material is aluminum oxide, to the requirement of aluminum oxide, is therefore also very harsh, wherein alkalimetal oxide (Na
2o+K
2o) content is no more than 0.02%, Fe
2o
3content is no more than 0.02%, and has good mobility etc.
China just built up first liquid-crystalline glasses production line in 2008, the initial main dependence on import of alumina raw material used.Therefore the production technology of, preparing high-quality alumina stable is important for the development pole of China's liquid-crystalline glasses industry.
At present preparing LCD glass substrate is mainly by high-temperature calcination by the method for high-purity alpha-alumina, add the mineralizers such as boric acid, ammonium chloride, aluminum fluoride and take off sodium, but this technique causes de-sodium not thorough because of the inhomogeneous and processing condition fluctuation of mineralizer, and product fluctuation is larger.
It is raw material that patent (201010030227) adopts commercial alumina or aluminium hydroxide, add the mineralizers such as boric acid, ammonium chloride and barium fluoride and carry out high-temperature calcination, not only contaminate environment and etching apparatus, and because containing poisonous barium fluoride in additive, be harmful to Occupational health.In addition, most of compounds containing sodium of vaporization at high temperature is oxidized aluminium absorption again in process of cooling, cause the sodium oxide content in the finished product higher, need just can obtain the alumina powder jointed of low sodium through processes such as further washings, simultaneously also because mineralizer mixes inequality or temperature inequality in calcination process, cause composition and the crystallization deviation of product large, cause the heterogeneity of index fluctuation, product performance.
Existing Technology is for guaranteeing de-sodium effect, and calcining temperature is higher, and soaking time is partially long, and energy consumption is very high.
Summary of the invention
Object of the present invention is exactly the deficiency existing for above-mentioned prior art, is to provide a kind ofly can effectively remove detrimental impurity Na in aluminium hydroxide
2o, Fe
2o
3, avoid boric acid, fluorochemical to the erosion of stove and poisonous, harmful gas, the impurity-removing method of aluminum oxide for eco-friendly LCD glass substrate.
The object of the invention is to be achieved through the following technical solutions.
An impurity-removing method for aluminum oxide for LCD glass substrate, is characterized in that the step of its removal of impurities process comprises successively:
(1) aluminium hydroxide slurry is carried out to electromagnetism deironing;
(2) carry out high pressure water thermal treatment;
(3) carry out pickling, washing processing;
(4) calcine and obtain α-phase alumina;
(5) again carry out electromagnetism deironing and carry out deironing.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, is characterized in that the aluminium hydroxide slurry of its step (1) is water-based slurry, and in slurry, aluminium hydroxide is solid containing being 200-600g/L.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, is characterized in that in its step (1), aluminium hydroxide slurry is under 25-50 ℃ of condition in temperature, and electric magnetic iron remover by the above intensity of 20000 Gauss carries out deironing.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, is characterized in that it is that aluminium hydroxide slurry is pressed and boiled processing in autoclave that its step (2) is carried out high pressure water thermal treatment, and temperature is 160-230 ℃, and the treatment time is 1-2 hour.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, is characterized in that it is in aluminium hydroxide slurry, to add one or more mineral acids that its step (3) is carried out acid cleaning process, at pH value, is 3-6, and temperature is 65-95 ℃ of condition, pickling 3-7 hour.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, is characterized in that its step (3) carries out water washing process and adopt pure water to wash.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, it is characterized in that it is after pure water is washed that its step (4) is carried out calcination process, the aluminum hydroxide filter cake dress saggar that filtration obtains is calcined in tunnel furnace, calcining temperature is 1280 ℃, time is 5 hours, obtains Alpha-alumina.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, is characterized in that its step (5) is aluminum oxide after calcining and carries out deironing through the electric magnetic iron remover of the above intensity of 20000 Gauss.
The impurity-removing method of aluminum oxide for a kind of LCD glass substrate of the present invention, is the slurry that raw material is made by aluminium hydroxide, through hydrothermal treatment consists, carries out physics and chemistry removal of impurities, reduce aluminium hydroxide, Fe
2o
3deng foreign matter content, after high-temperature calcination, through electromagnetism, physics deironing is carried out in deironing again, meets the alumina impurity content requirement of LCD glass substrate.
The present invention adopts a kind of method of hydrothermal treatment consists, can effectively remove detrimental impurity Na in aluminium hydroxide
2o, Fe
2o
3, in later stage calcining, do not use de-sodium additives, avoided boric acid, the erosion of fluorochemical to stove, do not produce Occupational health poisonous gas, and environmental friendliness, do not produce the fluorochemical harmful to crop.Raw material sources used are extensive, and calcining temperature is below 1350 ℃, the low 200 ℃ of left and right of the calcining temperature of more existing technique, and soaking time is short, and calcinating consumption significantly reduces, and its product foreign matter content is low, every foreign matter content index: SiO
2≤ 0.03%; Fe
2o
3≤ 0.02%; Na
2o+K
2o≤0.02%.
Embodiment
An impurity-removing method for aluminum oxide for LCD glass substrate, removes the mechanical iron in aluminium hydroxide slurry by high-strength electric magnetic iron remover, by autoclave, is pressed and is boiled and add mineral acid to carry out pickling and washing, further removes the Na in raw material
2o and Fe
2o
3, after treated raw material filtering drying, can in tunnel furnace or rotary kiln, at 1350 ℃, be sintered into Alpha-alumina, then pass through electric magnetic iron remover deironing, make its chemical composition meet the specification of quality of aluminum oxide for LCD glass substrate.
An impurity-removing method for aluminum oxide for LCD glass substrate, is prepared into water-based slurry by aluminium hydroxide, and in slurry, aluminium hydroxide is solid containing being 200-600g/L; Raw aluminum hydroxide slurry is pressed in autoclave boil and process and cleanup acid treatment, remove Na
2o and Fe
2o
3, treatment temp is 160-230 ℃, the treatment time is 1-2 hour; Aluminum hydroxide slime adds one or more mineral acids to carry out pickling, thereby removes Na
2o and Fe
2o
3, described mineral acid can be one or more in hydrochloric acid, sulfuric acid, nitric acid, and pH value is 3-6, and treatment temp is 65-95 ℃, and the treatment time is 3-7 hour.
Embodiment 1
10 tons of industrial aluminium hydroxides are joined in the tap water of 20 cubic metres, after stirring under normal temperature, by surge pump, evenly squeeze into electric magnetic iron remover, by the slurry after electric magnetic iron remover deironing, squeeze into again in autoclave, slip is heated to 220 ℃, slurry hydrothermal treatment consists 70 minutes in autoclave, slip is cooled to 80 ℃ to squeeze in normal-pressure reaction kettle afterwards, add hydrochloric acid to stir, controlling pH value is 3 ~ 4, stirs and is cooled to normal temperature after 3 hours, by slurry filtration washing, reach neutral.Filter cake dress saggar is calcined in tunnel furnace, and calcining temperature is 1280 ℃, and 1280 ℃ are incubated 5 hours, after calcining, obtain Alpha-alumina.Alpha-alumina adopts after 20000 Gausses' electric magnetic iron remover deironing, and its Chemical Composition analytical results is: SiO
2content 0.015%; Fe
2o
3content is 0.015%; Na
2o+K
2o content is 0.012%.
Embodiment 2
10 tons of industrial aluminium hydroxides are joined in the tap water of 20 cubic metres, after stirring under normal temperature, by surge pump, evenly squeeze into electric magnetic iron remover, by the slurry after electric magnetic iron remover deironing, squeeze into again in autoclave, slip is heated to 200 ℃, slurry hydrothermal treatment consists 100 minutes in autoclave, slip is cooled to 85 ℃ to squeeze in normal-pressure reaction kettle afterwards, add sulfuric acid to stir, controlling pH value is 4 ~ 5, stirs and is cooled to normal temperature after 3 hours, by slurry filtration washing, reach neutral.Filter cake dress saggar is calcined in tunnel furnace, and calcining temperature is 1300 ℃, and 1300 ℃ are incubated 4 hours, after calcining, obtain Alpha-alumina.Alpha-alumina adopts after 20000 Gauss's electric magnetic iron remover deironing, and its Chemical Composition analytical results is: SiO
2content 0.015%; Fe
2o
3content is 0.017%; Na
2o+K
2o content is 0.015%.
Embodiment 3
10 tons of industrial aluminium hydroxides are joined in the tap water of 20 cubic metres, after stirring under normal temperature, by surge pump, evenly squeeze into electric magnetic iron remover, by the slurry after electric magnetic iron remover deironing, squeeze into again in autoclave, slip is heated to 180 ℃ of slurries hydrothermal treatment consists 70 minutes in autoclave, and slip is cooled to 90 ℃ to squeeze in normal-pressure reaction kettle afterwards, after adding hydrochloric acid to stir, testing its pH value is 5.4, stir and be cooled to normal temperature after 5 hours, by slurry filtration washing, reach neutral.Filter cake dress saggar is calcined in tunnel furnace, and calcining temperature is 1350 ℃, and 1350 ℃ are incubated 3 hours, after calcining, obtain Alpha-alumina.Alpha-alumina adopts after 20000 Gauss's electric magnetic iron remover deironing, and its Chemical Composition analytical results is: SiO
2content 0.015%; Fe
2o
3content is 0.018%; Na
2o+K
2o content is 0.016%.
Claims (9)
1. the impurity-removing method of aluminum oxide for LCD glass substrate, is characterized in that the step of its removal of impurities process comprises successively:
(1) aluminium hydroxide slurry is carried out to electromagnetism deironing;
(2) carry out high pressure water thermal treatment;
(3) carry out pickling, washing processing;
(4) calcine and obtain α-phase alumina;
(5) again carry out electromagnetism deironing and carry out deironing.
2. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 1, is characterized in that the aluminium hydroxide slurry of its step (1) is water-based slurry, and in slurry, aluminium hydroxide is solid containing being 200-600g/L.
3. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 1, is characterized in that in its step (1), aluminium hydroxide slurry is under 25-50 ℃ of condition in temperature, and electric magnetic iron remover by the above intensity of 20000 Gauss carries out deironing.
4. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 1, it is characterized in that it is that aluminium hydroxide slurry is pressed and boiled processing in autoclave that its step (2) is carried out high pressure water thermal treatment, temperature is 160-230 ℃, and the treatment time is 1-2 hour.
5. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 1, it is characterized in that it is in aluminium hydroxide slurry, to add one or more mineral acids that its step (3) is carried out acid cleaning process, at pH value, be 3-6, temperature is under 65-95 ℃ of condition, pickling 3-7 hour.
6. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 1, is characterized in that its step (3) carries out water washing process and adopt pure water to wash.
7. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 1, it is characterized in that it is after pure water is washed that its step (4) is carried out calcination process, the aluminum hydroxide filter cake dress saggar that filtration obtains is calcined in tunnel furnace, calcining temperature is 1280 ℃, time is 5 hours, obtains Alpha-alumina.
8. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 1, is characterized in that its step (5) is aluminum oxide after calcining and carries out deironing through the electric magnetic iron remover of the above intensity of 20000 Gauss.
9. the impurity-removing method of aluminum oxide for a kind of LCD glass substrate according to claim 5, is characterized in that described mineral acid is one or more in hydrochloric acid, sulfuric acid, nitric acid.
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| CN201310669111.7A CN103723751A (en) | 2013-12-11 | 2013-12-11 | Impurity removal method of alumina for LCD (Liquid Crystal Display) glass base board |
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| CN201310669111.7A CN103723751A (en) | 2013-12-11 | 2013-12-11 | Impurity removal method of alumina for LCD (Liquid Crystal Display) glass base board |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104386719A (en) * | 2014-10-31 | 2015-03-04 | 中国铝业股份有限公司 | Method for preparing alpha-aluminum oxide |
| CN107416875A (en) * | 2017-08-16 | 2017-12-01 | 云南冶金集团创能金属燃料电池股份有限公司 | The method for preparing high purity aluminium oxide |
| CN110386615A (en) * | 2019-07-23 | 2019-10-29 | 雅安百图高新材料股份有限公司 | A kind of preparation method and its ball-aluminium oxide of ball-aluminium oxide |
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| CN102020302A (en) * | 2010-12-15 | 2011-04-20 | 中国铝业股份有限公司 | Method for reducing content of sodium in aluminum hydroxide |
| CN102320638A (en) * | 2011-08-04 | 2012-01-18 | 中国铝业股份有限公司 | Preparation method of low-sodium fine grain alumina |
| CN102838151A (en) * | 2012-09-20 | 2012-12-26 | 金刚新材料股份有限公司 | Preparation method of ultralow-sodium non-mineralized alpha alumina powder |
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2013
- 2013-12-11 CN CN201310669111.7A patent/CN103723751A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102020302A (en) * | 2010-12-15 | 2011-04-20 | 中国铝业股份有限公司 | Method for reducing content of sodium in aluminum hydroxide |
| CN102320638A (en) * | 2011-08-04 | 2012-01-18 | 中国铝业股份有限公司 | Preparation method of low-sodium fine grain alumina |
| CN102838151A (en) * | 2012-09-20 | 2012-12-26 | 金刚新材料股份有限公司 | Preparation method of ultralow-sodium non-mineralized alpha alumina powder |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104386719A (en) * | 2014-10-31 | 2015-03-04 | 中国铝业股份有限公司 | Method for preparing alpha-aluminum oxide |
| CN104386719B (en) * | 2014-10-31 | 2016-08-24 | 中国铝业股份有限公司 | A kind of preparation method of Alpha-alumina |
| CN107416875A (en) * | 2017-08-16 | 2017-12-01 | 云南冶金集团创能金属燃料电池股份有限公司 | The method for preparing high purity aluminium oxide |
| CN107416875B (en) * | 2017-08-16 | 2019-09-03 | 云南创能斐源金属燃料电池有限公司 | The method for preparing high purity aluminium oxide |
| CN110386615A (en) * | 2019-07-23 | 2019-10-29 | 雅安百图高新材料股份有限公司 | A kind of preparation method and its ball-aluminium oxide of ball-aluminium oxide |
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Application publication date: 20140416 |