CN100522817C - Process for producing low-soda alumina, apparatus therefor, and alumina - Google Patents
Process for producing low-soda alumina, apparatus therefor, and alumina Download PDFInfo
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- CN100522817C CN100522817C CNB2005800196552A CN200580019655A CN100522817C CN 100522817 C CN100522817 C CN 100522817C CN B2005800196552 A CNB2005800196552 A CN B2005800196552A CN 200580019655 A CN200580019655 A CN 200580019655A CN 100522817 C CN100522817 C CN 100522817C
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Abstract
A process for producing a low-soda alumina comprising calcining aluminum hydroxide in a calciner in the presence of a soda-removal agent, wherein the alumina dust produced in the calciner is sorted by particle size and collected in a dust collector and at least a portion of the collected alumina dust is subjected to a soda-removal process and is then returned to the calciner. An apparatus for producing a low-soda alumina, comprising a calciner for calcining aluminum hydroxide in the presence of a soda-removal agent, by which alumina dust is produced; a unit connected to the calciner for collecting, by particle size, the alumina dust; a unit for removing soda from a slurry containing at least a portion of the collected alumina dust; and a circuit for returning the soda-removed alumina dust back into the calciner.
Description
The cross reference of related application
The application is the application of submitting to according to 35 U.S.C the 111st (a) part, according to 35U.S.C the 119th (e) (1) part, requires to enjoy the provisional application No.60/640 that submits in 2005.01.03 according to 35U.S.C the 111st (b), the right of 255 the applying date.
Invention field
The method that the present invention relates to low-soda alumina and be used to produce low-soda alumina.Particularly, the present invention relates to a kind of method of producing low-soda alumina, its can reduce effectively soda alumina sodiun carbomate inventory and can the continuous production low-soda alumina.The present invention relates to a kind of device that is used to produce low-soda alumina in addition, and the low-soda alumina that makes by this method and apparatus.
Background of invention
Aluminum oxide has high chemical stability, high mechanical strength and good physicals, therefore is used for multiple mechanical part and electronic component.Employed aluminum oxide great majority are to make by the aluminium hydroxide that calcining adopts Bayer process (Bayer process) to obtain in the industrial application.But the aluminium hydroxide that adopts Bayer process to obtain contains the soda component inevitably, usually content based on the aluminum oxide that has transformed with Na
2O counts about 0.15～0.80 quality %.When such aluminum oxide during, comprise soda component and inadvisable, because the soda component can cause insulation defect and other problem as the ceramic raw material of the electrical insulator of IC plate or sparking plug etc.The particularly important is, when aluminum oxide is intended to be used for the parts of semiconductor production, the content of soda component is minimized, even because the sodium of trace also can influence the performance of semiconductor film unfriendly.
Therefore, taked various technology to remove soda component in the aluminum oxide.In a kind of such technology, will based on the mineralizer of fluorochemical and silica containing particle join as in raw-material aluminium hydroxide or the alumina particle (referring to, Japan has examined patent gazette No.Sho 63-35573).Another technology comprise with the fine particle of aluminum oxide and fluorochemical with the silicon-dioxide based compound as the soda remover join in the aluminium hydroxide (referring to, Japanese Patent open source literature NO.Hei 10-167725 and No.Hei 11-49515).In another technology, fluoride-based mineralizer and alpha-alumina powder are joined in the aluminium hydroxide (referring to, Japanese Patent open source literature No.Hei 7-41318) with the chloride-based compound as the soda remover.But each of the technology of these employings includes uses silicon-dioxide based compound such as quartz sand as the soda remover, to such an extent as to the aluminum oxide that obtains tends to be subjected to the pollution of silicon-dioxide, causes the sintering character of degenerating.
In another technology, make aluminium hydroxide in the presence of mineralizer, carry out twin-stage calcination processing (referring to, Japanese Patent open source literature No.Hei 6-329412).Though the aluminum oxide that obtains in this method does not exist by the risk of silicate fouling, the twin-stage calcination processing has increased cost.A kind of technology has been proposed before the applicant, wherein be collected in the discarded aluminum oxide dust that in the aluminium hydroxide calcining furnace, generates during the processing of removing soda, and make the collected aluminum oxide dust of a part remove the processing of soda and loop back in the calcining furnace (referring to, the brochure of WO2002/034692).But the aluminum oxide of collecting in this method is chosen, so this technology still requires further improvement to realize removing effectively the soda component.
Low-soda alumina is used for the field of electronic ceramic materials as IC plate and IC encapsulation.There is demand for low-cost low-soda alumina always.In recent years, stronger demand is the Na with low-soda alumina
2O content further reduces from existing 0.10 weight % level.
Visualize the present invention based on the demand.That is to say, the purpose of this invention is to provide a kind of low-cost low-soda alumina, production method of alumina effectively and its device are provided with stability.
Summary of the invention
The present invention relates to a kind of soda remover that is included in and have the method for the production low-soda alumina of calcinations of aluminum hydroxide down, it has successfully obtained the aluminum oxide of expectation by following method: collect the dust that generates in the calcining furnace by dust collection, and use specific device to choose this dust according to the particle diameter of dust; The processing that makes the dust of selection remove soda; Send back in the calcining furnace with the dust after will handling.In addition, the inventor finds, can further its sodiun carbomate inventory be reduced to 0.01 quality % or lower thus with the acidic aqueous solution washing by the low-soda alumina that preceding method obtains, and this scope is applicable to semiconductor production etc.
(1) a kind of method of producing low-soda alumina, it comprises step:
In calcining furnace, in the presence of the soda remover, the Calcined polishing aluminum oxide source material makes incinerating alumina source material dust thus;
Collect dust;
According to particle diameter selection dust;
The processing that the dust that at least a portion is chosen is removed soda; With
Turn back in the calcining furnace having carried out removing the dust that soda handles like this.
(2) method of the production low-soda alumina described in (1) is wherein collected and is chosen the step of dust and carries out in dust collection.
(3) method of the production low-soda alumina described in (2), wherein dust collection is at least two grades according to particle diameter with the dust selection.
(4) method of the production low-soda alumina described in (2), wherein dust collection comprises at least two dust collections, and according to particle diameter the dust selection is at least two grades.
(5) as the method for the production low-soda alumina of (2)～(4) described in each, the processing that wherein makes at least a portion remove soda than the dust of small particle size part, and subsequently it is turned back in the calcining furnace.
(6) as the method for the production low-soda alumina of (2)～(4) described in each, wherein at least a portion is discharged from this system than the dust of small particle size part.
(7) as the method for the production low-soda alumina of (2)～(4) described in each, wherein making first part at least remove the processing of soda and subsequently it be turned back in the calcining furnace and with second section than the dust of small particle size part discharges from this system than the dust of small particle size part.
(8) as the method for the production low-soda alumina of (2)～(4) described in each, wherein the dust with at least a portion greater particle size part turns back in the calcining furnace, and the processing that makes remaining greater particle size partly remove soda simultaneously also turns back to it in calcining furnace subsequently.
(9) method of the production low-soda alumina described in (5), wherein the dust with at least a portion greater particle size part turns back in the calcining furnace, and the processing that makes remaining greater particle size partly remove soda simultaneously also turns back to it in calcining furnace subsequently.
(10) method of the production low-soda alumina described in (6), wherein the dust with at least a portion greater particle size part turns back in the calcining furnace, and the processing that makes remaining greater particle size partly remove soda simultaneously also turns back to it in calcining furnace subsequently.
(11) as the method for the production low-soda alumina of (1)～(4) described in each, wherein make dust remove the processing of soda with slurry form.
(12) as the method for the production low-soda alumina of (1)～(4) described in each, wherein the low-soda alumina that obtains in this method further washs with acidic aqueous solution.
(13) method of the production low-soda alumina described in (5), wherein the low-soda alumina that obtains in this method further washs with acidic aqueous solution.
(14) method of the production low-soda alumina described in (6), wherein the low-soda alumina that obtains in this method further washs with acidic aqueous solution.
(15) method of the production low-soda alumina described in (8), wherein the low-soda alumina that obtains in this method further washs with acidic aqueous solution.
(16) method of the production low-soda alumina described in (12) wherein before washing with acidic aqueous solution, is used based on the chemical equivalent meter and is equal to or greater than the Na that exists in the low-soda alumina
2This low-soda alumina is washed in the acid of O.
(17) method of the production low-soda alumina described in (12), wherein wash this low-soda alumina with acidic aqueous solution under the condition that contains 200～600g low-soda alumina in every liter of acidic aqueous solution making, under 50 ℃ or higher temperature, stirred 15 minutes or the longer time simultaneously, and with the low-soda alumina washing that obtains, filter, dry and if necessary screening.
(18) method of the production low-soda alumina described in (16), wherein wash this low-soda alumina with acidic aqueous solution under the condition that contains 200～600g low-soda alumina in every liter of acidic aqueous solution making, under 50 ℃ or higher temperature, stirred 15 minutes or the longer time simultaneously, and with the low-soda alumina washing that obtains, filter, dry and if necessary screening.
(19) method of the production low-soda alumina described in (12), wherein after with acid elution, the Na that exists in this low-soda alumina
2The O foreign matter content is 0.01 quality % or lower.
(20) by as the low-soda alumina that obtains of the method for (1)～(4) described in each, wherein the median size of the alpha-crystal that exists in this low-soda alumina is 0.5～10 μ m.
(21) by as the low-soda alumina that obtains of the method for (1)～(4) described in each, the wherein Na of this low-soda alumina
2O content is 0.04 quality % or lower.
(22) by as the low-soda alumina that obtains of the method for (1)～(4) described in each, the impurity Na that wherein contains
2O, K
2O, SiO
2And Fe
2O
3Total amount be 0.01 quality %～0.10 quality %.
(23) a kind of device that is used to produce low-soda alumina, it comprises:
The calcining furnace that is used for Calcined polishing aluminum oxide source material in the presence of the soda remover makes aluminum oxide dust by this calcining furnace;
What be connected with calcining furnace is used for unit according to particle diameter collecting aluminum oxide powder dirt;
Be used for removing the unit of soda from the slurry that contains the collected dust of at least a portion; With
The aluminum oxide dust that is used for removing soda turns back to the circuit of calcining furnace.
(24) device that is used to produce low-soda alumina described in (23), it comprises that further the dust that is used for collecting turns back to the branch road of calcining furnace.
(25) device that is used to produce low-soda alumina described in (23), the unit that wherein is used for according to particle diameter collection dust is the dust collection with selection function.
(26) device that is used to produce low-soda alumina described in (23) wherein is used for comprising two or more dust collections according to the unit of particle diameter collection dust.
(27) by as the low-soda alumina that obtains of the method for (1)～(4) described in each.
(28) by as the low-soda alumina that makes of the device of (23)～(26) described in each.
(29) pottery that makes by the low-soda alumina that uses described in (20).
(30) pottery that makes by the low-soda alumina that uses described in (21).
(31) pottery that makes by the low-soda alumina that uses described in (22).
(aluminum oxide) dust of being collected by dust collection is thin more, and the soda concentration in (aluminum oxide) dust is just high more.In the present invention, collected (aluminum oxide) dust is chosen according to particle diameter, to from this system, discharge, after removing soda, turn back to amount in the calcining furnace and that directly turn back to (aluminum oxide) dust granules in the calcining furnace and be controlled, remove the soda in the aluminum oxide thus effectively.For example, when requiring to have the aluminum oxide of low especially sodiun carbomate inventory or when not needing thin aluminum oxide, discharge from system with the larger proportion fine grain size that a part is collected (aluminum oxide) dust, and, coarse grain footpath (aluminum oxide) dust directly can be turned back in the calcining furnace when be not when requiring to remove soda much more so.
Description of drawings
Fig. 1 produces the schematic block diagram of the method for low-soda alumina for showing according to the present invention.
The skeleton diagram that Fig. 2 arranges for the another kind of the dust collection of demonstration Fig. 1.
The best mode that carries out an invention
The conventional production method of low-soda alumina depends on calcinations of aluminum hydroxide in the presence of the soda remover, and this method has generated the aluminum oxide dust particle.The present invention is based on the following fact: thin more aluminum oxide dust particle contains high-load more soda component.Particularly, the invention is characterized in the aluminum oxide dust particle collected, and control: some are discharged, make some remove the processing of soda and it is turned back in the calcining furnace simultaneously from system according to their purpose according to particle diameter selection.Thus, the present invention can collect low-soda alumina effectively.Herein, the dust that generates during the Calcined polishing aluminum oxide source material (as aluminium hydroxide) mainly contains alumina particle, but this dust can contain the particle of alumina source material in addition.Thisly in this specification sheets and claims, abbreviate " dust " or " aluminum oxide dust " as at the dust that generates during the Calcined polishing aluminum oxide source material.
Describe the present invention in detail now with reference to accompanying drawing.
Fig. 1 is for showing that the present invention produces the skeleton diagram of the method for low-soda alumina.Fig. 2 is for showing the skeleton diagram of Fig. 1 part that comprises dust collection.
With reference to Fig. 1, in calcining furnace 2, add the alumina source material by pipeline 1, as the aluminium hydroxide that obtains by Bayer process.In calcining furnace 2, add the soda remover by pipeline 3.Calcining furnace can be a rotary kiln.Usually in about 1000～1400 ℃ of following calcinations of aluminum hydroxide.The waste gas of discharging from incinerating alumina source material is by pipeline 4 and be incorporated in the dust collection 5, collects the dust in the waste gas here.
Among Fig. 1, dust collection 5 is divided into two portions according to particle diameter with the particle in the dust: macrobead and small-particle.Dust collection has (aluminum oxide dust) particle is divided into two-part function, and can be equipped with separator such as centrifugal sorter or tiny segregator.
Among Fig. 2, be used for being connected with each other according to two dust collection districts of particle diameter selection particulate 5 and 5 '.For example, first dust collection 5 can be collected big relatively particle, and second dust collection 5 ' can be collected relatively little particle.By connecting three dust collections, can be three parts with the particle selection according to particle diameter.Among Fig. 2, the dust in a part of dust collection 5 and 5 ' can be discharged from this system by pipeline 7, and the dust in another part dust collection 5 and 5 ' can turn back in the calcining furnace by pipeline 6.
Among the present invention, the sequence of steps of collecting and choosing dust is also unrestricted, and they can carry out simultaneously.
This dust collection can be conventional arbitrarily dust collection: it can be the gravity dust collection, as settling pocket; The inertia dust collection is as louver type baffle; The ELECTROSTATIC DUST collector; Centrifugal dust collection is as multiclone and multi-cyclone; The Chalk-dust filtering collector is as deep bed filter; Or washer, as scrubber.
Can use two or more dust collections, make the inertia dust collection collect coarse particles, centrifugal dust collection is collected medium grain, and washer or electric dust collector collection fine particle.
By using these dust collections, can be with the particle diameter of desirable mode controlled oxidation aluminium powder dirt, and can handle this aluminum oxide dust to obtain low-soda alumina effectively, and particularly, can be with the Na in the obtainable low-soda alumina
2O content preferably controls to 0.04 quality % or lower, more preferably 0.03 quality % or lower, and can be with the Na in the obtainable low-soda alumina
2O, K
2O, SiO
2And Fe
2O
3The total content of impurity controls to 0.01 quality %～0.10 quality %, more preferably 0.06 quality % or lower.
Collected aluminum oxide dust can be divided into two portions according to particle diameter: for example, and thin part and thick part.At this moment, be about 25～40 μ m in median size preferably, more preferably median size is that about 25～30 μ m separate these parts.Alternatively, can aluminum oxide dust be divided into three parts according to particle diameter: thin, medium and thick part.At this moment, the median size of medium part for example is about 20～50 μ m, more preferably 25～30 μ m.
In the methods of the invention, the aluminum oxide dust that at least a portion is collected is incorporated in the slurry dissolving device 11, removes the soda component of aluminum oxide dust at this.Subsequently, the aluminum oxide of handling is like this turned back in the calcining furnace.
For purposes of the present invention, preferably, preferentially make some or all thin parts remove the processing of soda and it is turned back in the calcining furnace.Also preferably some or all thin parts are discharged from this system by pipeline 7.Because thin part contains the soda component of higher concentration, so can be: preferentially make thin part remove the processing of soda and it is turned back in the calcining furnace as getting off to reduce effectively the soda component of aluminum oxide; Perhaps preferentially thin part is discharged from this system.Like this, when hope drops to low especially level with the soda component of aluminum oxide, make more thin part remove the processing of soda and it is turned back in the calcining furnace, perhaps from this system, discharge.By pipeline 8 the pending soda of removing is handled and turned back to (aluminum oxide) dust of calcining furnace and is incorporated in the slurry dissolving device 11.Thick part can directly all send back in the calcining furnace 2 by pipeline 6, and perhaps the thick part of a part can be delivered in the slurry dissolving device 11 by pipeline 10, and remainder turns back in the calcining furnace 2 simultaneously.The thick part of a part can be discharged from this system.When hope drops to lower level with the soda component of aluminum oxide, more thick part will be turned back in the slurry dissolving device 11.When according to particle diameter collected aluminum oxide being divided into three parts, medium part can discharge from this system, deliver to slurry dissolving device or turn back in the calcining furnace, and this depends on the sodiun carbomate inventory of the aluminum oxide of expection.Therefrom having removed the waste gas of aluminum oxide dust discharges from dust collection by pipeline 9.When (aluminum oxide) when dust turns back to calcining furnace, preferably mineralizer is joined in this aluminum oxide dust.
In slurry dissolving device, handle to remove after the soda component, aluminum oxide dust is delivered in washing and the filtration unit 12 by pipeline 14, in this filtration with wash aluminum oxide dust.(aluminum oxide) dust that will wash by pipeline 15 is delivered in the calcining furnace subsequently.
By pipeline 16 low-soda alumina that obtains in the aforesaid way is taken out from calcining furnace.
Each pipeline has the cock (valve) of closing or opening in required mode.For example, regulate the valve on the pipeline 6 and 10, calcining furnace 2 and the ratio of delivering to the aluminum oxide powder dust quantity of slurry dissolving device 11 are delivered in control thus.Also can control the valve of pipeline 7 on the fulcrum of pipeline 8, control Dust Capacity of from system, discharging and the Dust Capacity of delivering to slurry dissolving device thus.Suitably determine the consumption of additive (comprising soda remover and mineralizer).When preferably mineralizer being looped back calcining furnace with the collected dust of a part, it directly can be joined in the calcining furnace.In the present invention, the mode that is used to regulate the dust feed rate is not limited in aforementioned valve, and can be other suitable way arbitrarily.
In the present invention, the soda component that exists in selection/collection and the aluminum oxide dust that have first size one of in by a plurality of dust collections or the concentration of mineralizer are different from the soda component that exists or the concentration of mineralizer in by another the selection/collection in a plurality of dust collections and aluminum oxide dust that have second size.Thinner part tends to contain the soda component or the mineralizer of greater concn.Like this, be intended to collect in different size a plurality of dust collections partly of dust granules, the collector of collecting thin part preferentially will collected dust discharge to being used for pipeline of discharging from this system or the pipeline that is used for joining slurry dissolving device, other dust collection of collecting the thicker part branch simultaneously preferentially is discharged into the pipeline that is used for turning back to calcining furnace.In this way, by handling the aluminium powder dirt of relatively small amount, can reduce the sodiun carbomate inventory of aluminum oxide dust effectively.
As previously mentioned, according to the present invention, the starting material by supplying with this method continuously also return collected aluminium powder dirt, can be easily and produce low-soda alumina continuously.
The preferred aluminum oxide source material that is used for the inventive method is the aluminium hydroxide that obtains by Bayer process.Though can comprise the particle of arbitrary shape as the alumina source material of original material, economically the gibbsite type aluminium hydroxide that preferably obtains by Bayer process.
Alumina source material in the inventive method contains based on alumina amount counts 0.04 quality % or higher soda component Na
2During O, the addition of soda remover is preferably 1～15 times with respect to theoretical consumption (chemical equivalent) meter of alumina source material middle soda content.Having added the alumina source material of specified amount soda remover calcines subsequently.Be used for soda remover of the present invention and can be any agent that when heating, also to remove the soda component thus with the reaction of soda component.Example comprises based on muriatic soda remover, example hydrochloric acid, ammonium chloride, magnesium chloride and other chlorine-containing compound.These reagent can use separately or use with the mixture of two or more reagent.In the present invention, preferably the soda remover is joined in the logistics of alumina source material with convection type.In this way, make the alumina source material be exposed to the soda remover of gasification, with this reagent react.
In the dust in the waste gas that calcining furnace generates, will be with respect to the Na of aluminum oxide meter
2O content simmer down to 0.3～1.5 quality %, but can remove the sodiun carbomate inventory of 50～80 quality % by changing slurry, washing and filtration.In washing and filtration step, preferably be controlled at slurry pH between 7～11, the more preferably numerical value between 7～9.If pH drops on outside this scope, the efficient of removing soda may reduce, and may have problems aspect the device of this method.By being to change slurry step and washing/filtration step 7～11 times at pH, can remove concentrated component such as fluorine as mineralizer.
Dust by dust collection 5 selection/collections is divided into part (a), is made into slurry and washing/filtration, forms filter cake thus; And part (b), it is returned (recycled) in the calcining furnace with collected state.Amount by control section (a) is with respect to the ratio of the amount meter of part (b), promptly change into the total amount that is less than or equal to collected dust by the amount of (a) partly, even also can change the particle diameter of alpha-crystal when calcining temperature is identical with other calcination condition.Wash/amount of the part (a) of filtration step by increase, can reduce the soda component; Same mineralizer component also can.
In addition, by a part of dust and highly enriched soda component or mineralizer component are discharged from this system, for example by the pipeline 7 shown in Fig. 1, even under identical calcination condition, also the sodiun carbomate inventory of gained low-soda alumina can be further reduced, and the deviation of alpha-crystal particle diameter can be reduced.Guaranteed stable calcination process like this.From this system, discharge the sodiun carbomate inventory that spissated soda component can further reduce aluminum oxide, from this system, discharge the mineralizer component simultaneously and make mineralization minimize the influence of calcination process.
Preferably, control Dust Capacity that collect and that be recycled to calcining furnace, thereby the amount of ratio, the Dust Capacity of discharging from system or the mineralizer such as the fluorine-based compound of the dust by control slurry step and washing/filtration step makes the content of fluorine-based compound (in the aluminum oxide) drop in scope 200～1800ppm (in F).If the mineralizer consumption is low excessively, the aluminum oxide alpha-crystal particle that is obtained so may be big inadequately.If the mineralizer consumption is too high, the crystal that is obtained may become tabular crystal so.
Can be selected from least a in aluminum fluoride, hydrogen fluoride, Neutral ammonium fluoride, Sodium Fluoride, magnesium fluoride and the Calcium Fluoride (Fluorspan) as the fluorine cpd of mineralizer.The preferred median size of alpha-crystal of the low-soda alumina product that is obtained is 0.5～10 μ m, more preferably 0.5～2 μ m.Can obtain the alpha-crystal of particle diameter within this scope by suitably selecting fluorine-based compound content, calcining temperature and calcination time.
When the sodiun carbomate inventory in the low-soda alumina that obtains in the further reduction of the expectation aforesaid method, preferably wash the low-soda alumina that is obtained with acidic aqueous solution.The acidic aqueous solution that is used for carrying out washing treatment for example is hydrochloric acid, nitric acid, sulfuric acid or citric acid.Carrying out washing treatment can be carried out as getting off: make the slurry that concentration is 200～600g/l, and stir this slurry 15 minutes or longer time, subsequent filtration and washing under 50 ℃ or higher temperature.Though the pH of acidic aqueous solution can be an acid number arbitrarily, preferable range is 0～5.In this way, removed sodium and reduced its content from alumina surface.Sodiun carbomate inventory in this low-soda alumina is with Na
2The O meter can drop to 0.01 quality % or lower.After this is handled, dry aluminum oxide or screening when needed.
The low-soda alumina that makes by the inventive method is the material that is applicable to ceramic product, and this ceramic product can be used for the parts of electron device such as IC plate and IC circuit, sparking plug and semiconductor production.
Embodiment
The present invention is described in more detail now with reference to embodiment, and these embodiment do not limit the present invention in any way.The method for quantitative measuring that adopts among each embodiment is as follows:
(1) compositional analysis
Na
2O: by the ICP emission spectroscopy measurements.
(2) pH measures
30g powder in the 70ml pure water was heated in hot water 2 hours, and cool off subsequently.Measure the pH of chilled solution.
(3) size distribution is measured
Measure by Microtrac HRA X-100 (Nikkiso manufacturing).
(4) alpha-crystal grain diameter measurement
Measure by Microtrac HRA X-100.
That to obtain by Bayer process and contain 0.20 quality % soda component Na
2The aluminium hydroxide of O (with respect to aluminum oxide) joins in the calcining furnace.This material contains the water of the 10 quality % that have an appointment.The hydrochloric acid of 35 quality % is incorporated in the aluminium hydroxide with convection type.The hydrochloric acid addition is about the theoretical consumption of the soda component of its aluminium hydroxide, and (theoretical consumption: 2mol HCl is to 1mol Na
2O) 7 times.In rotary kiln, under 1100 ℃, calcine.The dust collection that use is made up of centrifugal dust collection and electric dust collector is collected the dust that generates during the calcinations of aluminum hydroxide, and according to particle diameter it is divided into two portions.Greater particle size partly accounts for the 60 quality % of (aluminum oxide) dust always, and its median size is about 60 μ m.Partly account for the 40 quality % of (aluminum oxide) dust always than small particle size, and its median size is about 20 μ m.The smaller portions of 80 quality % are made the slurry of pH8.5, filtration/washing, and subsequently it is turned back in the calcining furnace calcining once more under 1100 ℃ here.There is not (aluminum oxide) dust from this system, to discharge.The coarse particles of 100 quality % and the fine particle of 20 quality % are directly turned back in the calcining furnace.
The low-soda alumina that is obtained contains the Na of 0.030 quality %
2The K of O, 0.004 quality %
2The Fe of O, 0.016 quality %
2O
3SiO with 0.010 quality %
2The mean diameter of alpha-crystal is 1.1 μ m.
As in Example 1, that will obtain by Bayer process and contain 0.20 quality % soda component Na
2The aluminium hydroxide of O (with respect to aluminum oxide) joins in the calcining furnace.This material contains the water of the 10 quality % that have an appointment.The hydrochloric acid of 35 quality % is incorporated in the aluminium hydroxide with convection type.The hydrochloric acid addition is about 7 times of theoretical consumption of the soda component of its aluminium hydroxide.Identical mode is calcined among the employing embodiment 1.The dust collection that use is made up of centrifugal dust collection that is connected with each other and electric dust collector, collect the dust that generates during the calcinations of aluminum hydroxide, and according to particle diameter it is divided into two portions: median size is that the aluminum oxide dust particulate fraction of about 60 μ m accounts for the 60 quality % of (aluminum oxide) dust always; Median size is that the aluminum oxide dust particulate fraction of about 20 μ m accounts for the 40 quality % of (aluminum oxide) dust always.
The thick part of about 50 quality % is made the slurry of pH8.5, filtration/washing, and subsequently it is turned back in the calcining furnace.The coarse particles of 50 quality % is directly turned back in the calcining furnace (not adding mineralizer), the fine particle of 25 quality % is discharged from this system, and the fine particle of 75 quality % is directly turned back in the calcining furnace.With aluminum oxide calcining once more under 1100 ℃, obtain low-soda alumina thus subsequently.
The low-soda alumina that is obtained contains the Na of 0.009 quality %
2The K of O, 0.004 quality %
2The Fe of O, 0.019 quality %
2O
3SiO with 0.010 quality %
2The mean diameter of alpha-crystal is 1.2 μ m.
By being joined in the 250ml water, the 2g vitriol oil makes aqueous sulfuric acid.Add the Alpha-alumina that obtains among the 100g embodiment 1 in the prepared aqueous sulfuric acid to form slurry (slurry concentration=400g/l).Slurry was stirred 1 hour down at 80 ℃, with the water washing of three times (volume) amount, and subsequently 200 ℃ of dryings 12 hours down.
The aluminum oxide that is obtained contains the Na of 0.005 quality %
2The K of O, 0.002 quality %
2The Fe of O, 0.015 quality %
2O
3SiO with 0.007 quality %
2
Embodiment 4
By being joined in the 250ml water, the 2g vitriol oil makes aqueous sulfuric acid.Add the Alpha-alumina that obtains among the 100g embodiment 2 in the prepared aqueous sulfuric acid to form slurry (slurry concentration=400g/l).Slurry was stirred 1 hour down at 80 ℃, with the water washing of three times (volume) amount, and subsequently 200 ℃ of dryings 12 hours down.
The aluminum oxide that is obtained contains the Na of 0.004 quality %
2The K of O, 0.002 quality %
2The Fe of O, 0.017 quality %
2O
3SiO with 0.006 quality %
2
The comparative example 1
Calcine in mode identical among the embodiment 1.The dust that generates during the calcinations of aluminum hydroxide is collected by dust collection as whole dust.The collected whole dust of about 30 quality % are made the slurry of pH8.5, filtration/washing, and subsequently it is turned back in the calcining furnace; Simultaneously the collected whole dust of about 70 quality % are directly turned back in the calcining furnace calcining once more under 1100 ℃ here.
The low-soda alumina that is obtained contains the Na of 0.054 quality %
2The K of O, 0.004 quality %
2The Fe of O, 0.017 quality %
2O
3SiO with 0.009 quality %
2
The comparative example 2
By being joined in the 250ml water, the 2g vitriol oil makes aqueous sulfuric acid.Add the Alpha-alumina that obtains among the 100g comparative example 1 in the prepared aqueous sulfuric acid to form slurry (slurry concentration=400g/l).Slurry was stirred 1 hour down at 80 ℃, with the water washing of three times (volume) amount, and subsequently 200 ℃ of dryings 12 hours down.
The aluminum oxide that is obtained contains the Na of 0.012 quality %
2The K of O, 0.003 quality %
2The Fe of O, 0.015 quality %
2O
3SiO with 0.006 quality %
2
Industrial applicibility
The present invention can produce cheap low-soda alumina effectively, continuously. Low Soviet Union of the present invention Breaking aluminium oxide can be stablize productive rate production, and has the sintering character of excellence, can not cause two The problem of silica contamination. The low-soda alumina that makes by the inventive method is applicable to various application, Comprise the ceramic material for IC plate, IC circuit, spark plug and semiconductor production parts, and Has high industrial value.
Claims (24)
1, a kind of method of producing low-soda alumina, it may further comprise the steps:
In calcining furnace in the presence of the soda remover Calcined polishing aluminum oxide source material, make incinerating alumina source material dust thus;
Collect dust;
According to particle diameter selection dust;
The processing that the dust that at least a portion is chosen is removed soda; With
Turn back in the calcining furnace having carried out removing the dust that soda handles like this.
2, the method for the production low-soda alumina of claim 1 is wherein collected and is chosen the step of dust and carries out in dust collection.
3, the method for the production low-soda alumina of claim 2, wherein dust collection is at least two grades according to particle diameter with the dust selection.
4, the method for the production low-soda alumina of claim 2, wherein dust collection comprises at least two dust collections, and according to particle diameter the dust selection is at least two grades.
5, the method for each production low-soda alumina in the claim 2～4, the processing that wherein makes at least a portion remove soda than the dust of small particle size part, and subsequently it is turned back in the calcining furnace.
6, the method for each production low-soda alumina in the claim 2～4 is wherein discharged than the dust of small particle size part at least a portion from this system.
7, the method for each production low-soda alumina in the claim 2～4, wherein making first part at least remove the processing of soda and subsequently it be turned back in the calcining furnace and with second section than the dust of small particle size part discharges from this system than the dust of small particle size part.
8, the method for each production low-soda alumina in the claim 2～4, wherein the dust with at least a portion greater particle size part turns back in the calcining furnace, and the processing that makes remaining greater particle size partly remove soda simultaneously also turns back to it in calcining furnace subsequently.
9, the method for the production low-soda alumina of claim 5, wherein the dust with at least a portion greater particle size part turns back in the calcining furnace, and the processing that makes remaining greater particle size partly remove soda simultaneously also turns back to it in calcining furnace subsequently.
10, the method for the production low-soda alumina of claim 6, wherein the dust with at least a portion greater particle size part turns back in the calcining furnace, and the processing that makes remaining greater particle size partly remove soda simultaneously also turns back to it in calcining furnace subsequently.
11, the method for each production low-soda alumina in the claim 1～4 wherein makes dust remove the processing of soda with slurry form.
12, produce the method for low-soda alumina, wherein the low-soda alumina that obtains in each the method in claim 1～4 further washs with acidic aqueous solution.
13, produce the method for low-soda alumina, wherein the low-soda alumina that obtains in the method for claim 5 further washs with acidic aqueous solution.
14, produce the method for low-soda alumina, wherein the low-soda alumina that obtains in the method for claim 6 further washs with acidic aqueous solution.
15, produce the method for low-soda alumina, wherein the low-soda alumina that obtains in the method for claim 8 further washs with acidic aqueous solution.
16, the method for the production low-soda alumina of claim 12 wherein before washing with acidic aqueous solution, is used based on the chemical equivalent meter and is equal to or greater than the Na that exists in the low-soda alumina
2This low-soda alumina is washed in the acid of O.
17, the method for the production low-soda alumina of claim 12, wherein wash this low-soda alumina with acidic aqueous solution under the condition that contains 200～600g low-soda alumina in every liter of acidic aqueous solution making, under 50 ℃ or higher temperature, stirred 15 minutes or the longer time simultaneously, and with the low-soda alumina washing that obtains, filter, dry and screening where necessary.
18, the method for the production low-soda alumina of claim 16, wherein wash this low-soda alumina with acidic aqueous solution under the condition that contains 200～600g low-soda alumina in every liter of acidic aqueous solution making, under 50 ℃ or higher temperature, stirred 15 minutes or the longer time simultaneously, and with the low-soda alumina washing that obtains, filter, dry and screening where necessary.
19, the method for the production low-soda alumina of claim 12, wherein after with acid elution, the Na that exists in this low-soda alumina
2The O foreign matter content is 0.01 quality % or lower.
20, the low-soda alumina that obtains by each method in the claim 1～4, the impurity Na that wherein contains
2O, K
2O, SiO
2And Fe
2O
3Total amount be 0.01 quality %～0.10 quality %.
21, a kind of device that is used to produce low-soda alumina, it comprises:
The calcining furnace that is used for Calcined polishing aluminum oxide source material in the presence of the soda remover makes aluminum oxide dust by this calcining furnace;
What be connected with calcining furnace is used for unit according to particle diameter collecting aluminum oxide powder dirt;
Be used for removing the unit of soda from the slurry that contains the collected dust of at least a portion; With
The aluminum oxide dust that is used for removing soda turns back to the circuit of calcining furnace.
22, the device that is used to produce low-soda alumina of claim 21, it comprises that further the dust that is used for collecting turns back to the branch road of calcining furnace.
23, the device that is used to produce low-soda alumina of claim 21, the unit that wherein is used for according to particle diameter collection dust is to have the functional dust collection of selection.
24, the device that is used to produce low-soda alumina of claim 21 wherein is used for comprising two or more dust collections according to the unit of particle diameter collection dust.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004177878 | 2004-06-16 | ||
| JP177878/2004 | 2004-06-16 | ||
| JP368274/2004 | 2004-12-20 | ||
| US60/640,255 | 2005-01-03 |
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| CN1968893A CN1968893A (en) | 2007-05-23 |
| CN100522817C true CN100522817C (en) | 2009-08-05 |
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| JP5846233B2 (en) * | 2014-03-04 | 2016-01-20 | 日本軽金属株式会社 | Low soda α-alumina powder having excellent viscosity characteristics and method for producing the same |
| CN104477958B (en) * | 2014-11-24 | 2016-05-25 | 山东鲲鹏新材料科技股份有限公司 | The method of the de-sodium of a kind of commercial alumina ion-exchange |
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