CA3174953A1 - Method for producing inorganic fine powder - Google Patents
Method for producing inorganic fine powder Download PDFInfo
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- CA3174953A1 CA3174953A1 CA3174953A CA3174953A CA3174953A1 CA 3174953 A1 CA3174953 A1 CA 3174953A1 CA 3174953 A CA3174953 A CA 3174953A CA 3174953 A CA3174953 A CA 3174953A CA 3174953 A1 CA3174953 A1 CA 3174953A1
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- powder
- assi
- aci
- carboxyl
- gani
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B1/00—Conditioning for facilitating separation by altering physical properties of the matter to be treated
- B03B1/04—Conditioning for facilitating separation by altering physical properties of the matter to be treated by additives
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
- B07B7/00—Selective separation of solid materials carried by, or dispersed in, gas currents
- B07B7/08—Selective separation of solid materials carried by, or dispersed in, gas currents using centrifugal force
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/16—Metallic particles coated with a non-metal
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Oxygen, Ozone, And Oxides In General (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Powder Metallurgy (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Medicinal Preparation (AREA)
Abstract
This method for producing an inorganic fine powder is a method in which a cumulative 50% particle diameter D50 on a volume basis is within a range of 0.01-5.0 ?m, the method being characterized by comprising: a sorted powder producing step for obtaining a sorted powder which is sorted by dispersing, in a gas phase, a carboxylic acid-adsorbed inorganic raw material powder, in which a carboxylic acid is adsorbed onto an inorganic raw material powder having D50 of 10 ?m or less; and a dry-sorting step for dry-sorting the sorted powder. The present invention can provide a method for producing an inorganic fine powder, with which an inorganic fine powder, having an extremely small number of coarse particles and a cumulative 50% particle diameter D50 on a volume basis within a range of 0.01-5.0 ?m, can be produced with high productivity.
Description
SPEC! Fl CATI ON
METHOD FOR PRODUCI NG I NORGANI C Fl NE POWDER
TECHNICAL FIELD
[ 0001] The present i nvent i on r el at es to a met hod for produci ng an i nor gani c f i ne powder.
BACKGROUND ART
[ 0002]
A conduct i ve met al powder has convent i onal I y been used as a conduct i ve mat er i al for an el ect roni c component . As f or a multi I ayer cerami c capacitor, both a cerami c I ayer and an i nt er nal el ect rode I ayer are r api dl y bei ng made t hi nner.
For t hi s reason, when a met al powder i s used for the i nt er nal el ect rode, the met al powder i s requi red to have a small average part i cl e di ameter and a narrow part i cl e si ze di st ri but i on to form an el ect rode I ayer of uni form t hi ckness, and to be free of coarse part i cl es that coul d contact both of the adj acent i nt er nal el ect rodes across the di el ect ric I ayer and cause a short- ci rcui t of the el ectrodes.
[ 0003]
The cl assi f i cat i on of a powder produced by van i ous product i on methods has been used as a method for produci ng a powder with a desi red particle size distribution.
Examples thereof i ncl ude a met hod of cl assi f yi ng a powder accor di ng to the difference i n part i Cl e Si ze by usi ng the difference i n sedi ment at i on vel oci ty of the part i cl e in the gas or I i qui d phase.
The classification i n the gas phase is called dry classification, whi I e that i n the I i qui d phase i s cal I ed wet cl assi f i cat i on.
Wet cl assi f i cation has super i or cl assi f i cat i on accuracy, but requi res the use of a I i qui d as a di spersi on medi um and dryi ng and crushi ng after cl assi f i cati on. For these reasons, dry cl assi f i cation i s by far I ess costly.
[ 0004]
However, dry classification had a probl em that i t was di ff i cul t to operate for I ong per i ods of time because the powder adhered to van i ous parts i nsi de the cl assi f i er, cl oggi ng the powder suppl y port and the i nsi de of the pi pi ng, etc.
I n addi t i on, the low classification accuracy resul t ed in low yields.
[ 0005] As a met hod aimed at sol vi ng such probl ems, Pat ent Document 1 di scl oses a met hod of dry cl assi f i cat i on of a powder by mixing the powder and an auxi I i ary agent consi st i ng of al cohol s with a boil i ng poi nt of I ower than 200 C or I ower, , such as ethanol , and dry cl assi f yi ng whi I e vaporizing the auxi I i ary agent.
[ 0006] Pat ent Document 2 di scl oses a met hod of dry cl assi f i cation of a powder by mi xi ng the powder and an auxi I i ary agent consi St i ng of an aqueous al cohol sol uti on cont ai ni ng 10 to vol % of al cohol such as ethanol , and dry cl assi f yi ng the powder whi I e vapor i zi ng the auxi I i ary agent.
[ 0007] Pat ent Document 3 discloses a met hod of dry cl assi f i cat i on of a powder by mi xi ng the powder composed of ni ckel and an auxi I i ary agent composed of an organi c sol vent havi ng a fl ash poi nt of 80 C or hi gher, such as di ethyl ene gl ycol , and dry cl assi f yi ng the powder whi I e vapor i zi ng the auxi I i ary agent.
There i s anot her di scl osed met hod of dry cl assi f i cat i on of a powder by mi xi ng the powder consi st i ng of ni ckel and an auxiliary agent consisting of water, and dry cl assi f y i ng the power while vaporizing the auxiliary agent.
[ 0008] Pat ent Document 4 di scl oses a met hod of dry cl assi f i cat i on of a powder by mi xi ng the powder and di ethyl ene gl ycol monomet hyl ether, whi ch is a Ii qui d auxi I i ary agent and then dry cl assi f yi ng the powder.
RELATED ART DOCUMENT
PATENT DOCUMENT
[ 0009] Pat ent Document 1 is WO 2010/047175 Al Patent Document 2 i s WO 2010/ 057206 Al Patent Document 3 i s WO 2010/106716 Al Patent Document 4 is WO 2012/ 124453 Al
METHOD FOR PRODUCI NG I NORGANI C Fl NE POWDER
TECHNICAL FIELD
[ 0001] The present i nvent i on r el at es to a met hod for produci ng an i nor gani c f i ne powder.
BACKGROUND ART
[ 0002]
A conduct i ve met al powder has convent i onal I y been used as a conduct i ve mat er i al for an el ect roni c component . As f or a multi I ayer cerami c capacitor, both a cerami c I ayer and an i nt er nal el ect rode I ayer are r api dl y bei ng made t hi nner.
For t hi s reason, when a met al powder i s used for the i nt er nal el ect rode, the met al powder i s requi red to have a small average part i cl e di ameter and a narrow part i cl e si ze di st ri but i on to form an el ect rode I ayer of uni form t hi ckness, and to be free of coarse part i cl es that coul d contact both of the adj acent i nt er nal el ect rodes across the di el ect ric I ayer and cause a short- ci rcui t of the el ectrodes.
[ 0003]
The cl assi f i cat i on of a powder produced by van i ous product i on methods has been used as a method for produci ng a powder with a desi red particle size distribution.
Examples thereof i ncl ude a met hod of cl assi f yi ng a powder accor di ng to the difference i n part i Cl e Si ze by usi ng the difference i n sedi ment at i on vel oci ty of the part i cl e in the gas or I i qui d phase.
The classification i n the gas phase is called dry classification, whi I e that i n the I i qui d phase i s cal I ed wet cl assi f i cat i on.
Wet cl assi f i cation has super i or cl assi f i cat i on accuracy, but requi res the use of a I i qui d as a di spersi on medi um and dryi ng and crushi ng after cl assi f i cati on. For these reasons, dry cl assi f i cation i s by far I ess costly.
[ 0004]
However, dry classification had a probl em that i t was di ff i cul t to operate for I ong per i ods of time because the powder adhered to van i ous parts i nsi de the cl assi f i er, cl oggi ng the powder suppl y port and the i nsi de of the pi pi ng, etc.
I n addi t i on, the low classification accuracy resul t ed in low yields.
[ 0005] As a met hod aimed at sol vi ng such probl ems, Pat ent Document 1 di scl oses a met hod of dry cl assi f i cat i on of a powder by mixing the powder and an auxi I i ary agent consi st i ng of al cohol s with a boil i ng poi nt of I ower than 200 C or I ower, , such as ethanol , and dry cl assi f yi ng whi I e vaporizing the auxi I i ary agent.
[ 0006] Pat ent Document 2 di scl oses a met hod of dry cl assi f i cation of a powder by mi xi ng the powder and an auxi I i ary agent consi St i ng of an aqueous al cohol sol uti on cont ai ni ng 10 to vol % of al cohol such as ethanol , and dry cl assi f yi ng the powder whi I e vapor i zi ng the auxi I i ary agent.
[ 0007] Pat ent Document 3 discloses a met hod of dry cl assi f i cat i on of a powder by mi xi ng the powder composed of ni ckel and an auxi I i ary agent composed of an organi c sol vent havi ng a fl ash poi nt of 80 C or hi gher, such as di ethyl ene gl ycol , and dry cl assi f yi ng the powder whi I e vapor i zi ng the auxi I i ary agent.
There i s anot her di scl osed met hod of dry cl assi f i cat i on of a powder by mi xi ng the powder consi st i ng of ni ckel and an auxiliary agent consisting of water, and dry cl assi f y i ng the power while vaporizing the auxiliary agent.
[ 0008] Pat ent Document 4 di scl oses a met hod of dry cl assi f i cat i on of a powder by mi xi ng the powder and di ethyl ene gl ycol monomet hyl ether, whi ch is a Ii qui d auxi I i ary agent and then dry cl assi f yi ng the powder.
RELATED ART DOCUMENT
PATENT DOCUMENT
[ 0009] Pat ent Document 1 is WO 2010/047175 Al Patent Document 2 i s WO 2010/ 057206 Al Patent Document 3 i s WO 2010/106716 Al Patent Document 4 is WO 2012/ 124453 Al
2 SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE I NVENTI ON
[ 0010]
However, the inventors of the present invention have found a pr obi em that dry cl assi f i cat i on by adsorbi ng an auxi I i ary agent such as ethanol onto the powder al I ows the cl assi f i er to be operated for a I ong pen i od of ti me, but the obtai ned powder contai ns many coarse part i cl es, so that it is requi red to repeat cl assi f i cat i on many ti mes to reduce the number of coarse part i cl es. Another pr obi em was that, although repeated cl assi f i cat i on may reduce the number of coarse part i cl es, it is t i me- consumi ng and cost I y, resul t i ng i n reduced product i vi ty and a si gni f i cant decrease i n the yi el d of the obtai ned powder.
[ 0011]
Therefore, an obj ect of the present i nventi on is to provi de a method for produci ng an i norgani c f i ne powder havi ng a vol ume- based cumul at i ye 50% part i cl e di ameter D50 rangi ng from 0. 01 pm to 5. 0 pm, contai ni ng an extremely small number of coarse part i cl es with hi gh producti vi ty.
MEANS OF SOLVI NG THE PROBLEMS
[ 0012]
Such an obj ect is achi eyed by the present invention as descri bed in the following items ( 1) to ( 9).
(1) A method for producing an inorganic fine powder havi ng a vol ume- based cumulative 50% particle di ameter D50 rangi ng from O. 01 pm to 5.0 pm, the method compri Si ng:
a step of gener at i ng a powder to be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d- adsorbed i norgani c raw mat er i al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i nor gani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
[ 0013]
(2) A method for producing an inorganic fine powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from O. 01 pm to 5.0 pm, the method compri si ng:
PROBLEMS TO BE SOLVED BY THE I NVENTI ON
[ 0010]
However, the inventors of the present invention have found a pr obi em that dry cl assi f i cat i on by adsorbi ng an auxi I i ary agent such as ethanol onto the powder al I ows the cl assi f i er to be operated for a I ong pen i od of ti me, but the obtai ned powder contai ns many coarse part i cl es, so that it is requi red to repeat cl assi f i cat i on many ti mes to reduce the number of coarse part i cl es. Another pr obi em was that, although repeated cl assi f i cat i on may reduce the number of coarse part i cl es, it is t i me- consumi ng and cost I y, resul t i ng i n reduced product i vi ty and a si gni f i cant decrease i n the yi el d of the obtai ned powder.
[ 0011]
Therefore, an obj ect of the present i nventi on is to provi de a method for produci ng an i norgani c f i ne powder havi ng a vol ume- based cumul at i ye 50% part i cl e di ameter D50 rangi ng from 0. 01 pm to 5. 0 pm, contai ni ng an extremely small number of coarse part i cl es with hi gh producti vi ty.
MEANS OF SOLVI NG THE PROBLEMS
[ 0012]
Such an obj ect is achi eyed by the present invention as descri bed in the following items ( 1) to ( 9).
(1) A method for producing an inorganic fine powder havi ng a vol ume- based cumulative 50% particle di ameter D50 rangi ng from O. 01 pm to 5.0 pm, the method compri Si ng:
a step of gener at i ng a powder to be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d- adsorbed i norgani c raw mat er i al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i nor gani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
[ 0013]
(2) A method for producing an inorganic fine powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from O. 01 pm to 5.0 pm, the method compri si ng:
3 a step of generat i ng a powder to be cl assi f i ed by adsorbing a carboxyl i c aci d onto an i nor gani c raw mat er i al powder havi ng the D50 of 10 m or less to obtain the powder to be classified, under the condi t i on that t he i nor gani c raw mater i al powder bei ng i n a dispersed state in a gas phase at the time of generation has been di spersed i n the gas phase; and a step of subj ect i ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
[ 0014] ( 3) The met hod for producing the inorganic fine powder according to the above i tern ( 2), further comprising:
a step of coil ect i ng the powder to be cl assi f i ed; and a step of di spersi ng the powder to be cl assi f i ed i n a gas phase;
between the step of gener at i ng a powder to be cl assi f i ed and the step of dry cl assi f i cati on.
[ 0015] ( 4) A met hod for producing an inorganic fine powder havi ng a vol ume- based cumul at i ve 50% part i cl e di amet er D50 rangi ng from O. 01 pm to 5.0 um, the method compri Si ng:
a step of gener at i ng a powder to be cl assi f i ed by di spersi ng an i nor gani c raw mat en i al powder havi ng the 050 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ect i ng the powder to be cl assi f i ed to dry cl assi f i cat i on;
wherei n the step of gener at i ng a powder to be cl assi f i ed i s performed i n an atmosphere cont ai ni ng a carboxyl i c aci d in a gaseous state.
[ 0016] ( 5) The met hod for pr oduci ng the i nor gani c f i ne powder according to any one of the above items ( 2) to ( 4) , wherein the carboxyl i c aci d i n an amount of from 30 mol es to 960 mol es i s used per 1 m3 of the i norgani c raw mat en i al powder.
[ 0017] ( 6) The met hod for producing the inorganic fine powder according to any one of the above items (1) to ( 5), wherein a boil i ng poi nt of the carboxyl i c aci d is in the range of from 100 C to 400 C.
[ 0014] ( 3) The met hod for producing the inorganic fine powder according to the above i tern ( 2), further comprising:
a step of coil ect i ng the powder to be cl assi f i ed; and a step of di spersi ng the powder to be cl assi f i ed i n a gas phase;
between the step of gener at i ng a powder to be cl assi f i ed and the step of dry cl assi f i cati on.
[ 0015] ( 4) A met hod for producing an inorganic fine powder havi ng a vol ume- based cumul at i ve 50% part i cl e di amet er D50 rangi ng from O. 01 pm to 5.0 um, the method compri Si ng:
a step of gener at i ng a powder to be cl assi f i ed by di spersi ng an i nor gani c raw mat en i al powder havi ng the 050 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ect i ng the powder to be cl assi f i ed to dry cl assi f i cat i on;
wherei n the step of gener at i ng a powder to be cl assi f i ed i s performed i n an atmosphere cont ai ni ng a carboxyl i c aci d in a gaseous state.
[ 0016] ( 5) The met hod for pr oduci ng the i nor gani c f i ne powder according to any one of the above items ( 2) to ( 4) , wherein the carboxyl i c aci d i n an amount of from 30 mol es to 960 mol es i s used per 1 m3 of the i norgani c raw mat en i al powder.
[ 0017] ( 6) The met hod for producing the inorganic fine powder according to any one of the above items (1) to ( 5), wherein a boil i ng poi nt of the carboxyl i c aci d is in the range of from 100 C to 400 C.
4 [ 0018] (7) The method for produci ng the i nor gani c f i ne powder accordi ng to any one of the above items (1) to (6), wherein the carboxyl i c acid i s at I east one sel ected from acet i c aci d, propi oni c aci d, butyri c aci d, and ol ei c aci d.
[ 0019] (8) The method for produci ng the inorganic fine powder accordi ng to any one of the above items (1) to (7), wherein the step of dry classification i s performed i n the gas phase at a temperature of from 60 C to 300 C.
[ 0020] (9) The method for produci ng the i nor gani c f i ne powder accor di ng to any one of the above items (1) to (8), vvherei n an i nor gani c component of the i nor gani c raw mat en i al powder i s at I east one sel ected from the group consi st i ng of a metal , a metal oxi de, a gl ass, a cerami c, and a semi conductor.
EFFECTS OF THE INVENTION
[ 0021] Accordi ng to the present i nventi on, it is possi bl e to provi de the method for produci ng the i norgani c f i ne powder having the vol ume- based cumul at i ve 50% part i cl e di amet er D50 r angi ng from 0.01 pm to 5.0 pm with the extremely small number of coarse part i cl es with hi gh producti vi ty.
BRIEF DESCRIPTION OF THE DRAWINGS
[ 0022] Fi g. 1 i s a di agr am showi ng a conf i gurati on exampl e of a cl assi f i er used i n the met hod of produci ng an i norgani c fine powder accordi ng to the present i nventi on.
MODE FOR CARRYING OUT THE INVENTION
[ 0023] The following is a detailed description of preferred embodi ments of the present i nventi on.
[ METHOD FOR PRODUCI NG I NORGANI C Fl NE POWDER]
1. Fi rst Embodi ment [ 0024] The method for produci ng an inorganic fine powder accordi ng to the f i rst embodi ment of the present i nventi on i s a method for produci ng an i norgani c f i ne powder with a vol ume-based cumul at i ve 50% part i cl e diameter D50 rangi ng from 0.01 pm to 5.0 pm. The method i ncl udes a step of generati ng a powder to be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d-adsor bed i norgani c raw mat eri al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i norgani c raw mat eri al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
[ 0025]
As a result, it is possi bl e to provide the method for producing the inorganic fine powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, with the extremel y smal I number of coarse part i cl es with high pr oduct i vi ty.
[ 0026]
This excel I ent effect is consi dered to be achi eyed for the f ol I owi ng reasons.
Compared with dry cl assi f i cation i n whi ch an auxi I i ary agent such as ethanol i s adsorbed on a powder, di spersi ng i n the gas phase the carboxyl i c aci d- adsorbed i norgani c raw mat er i al powder i n whi ch the carboxyl i c aci d i s adsorbed on the i norgani c raw mat eri al powder i mpr oyes the di spersi bi I i ty i n the gas phase of the powder to be cl assi f i ed, thereby enhanci ng cl assi f i cat i on accuracy.
For thi s reason, the number of coarse part i cl es i n the produced i nor gani c f i ne powder can be ext remel y reduced. The number of times of cl assi f i cat i ons can al so be reduced and productivity i s i ncreased.
[ 0027]
Adsorption of the carboxyl i c acid on the inorganic raw mat en i al powder i ncreases the f I ui di ty of the powder to be cl assi f i ed to reduce adhesi on of the powder to an i nsi de of the cl assi f i er, thereby i ncreasi ng the yi el d.
I n addi ti on, reduced adhesi on i nsi de the cl assi f i er prevents bl ockage of the powder suppl y port and an i nsi de of the pi pi ng of the cl assi f i er, thereby extendi ng the operati on ti me of the cl assi f i er and i mprovi ng productivity.
[ 0028]
Because this embodi ment uses the carboxyl i c acid-adsorbed i norgani c raw mat eri al powder i n whi ch the carboxyl i c acid i s pre- adsorbed on the i norgani c raw mat eri al powder, a conf i gur at i on of equi pment used to produce the i nor gani c f i ne powder can be advantageously si mpl i f i ed and downsi zed, compared to other embodi ments descri bed i n detai I I at er. .
I n addi t i on, because the carboxyl i c aci d- adsorbed i norgani c raw mat er i al powder with the carboxyl i c acid pre-adsorbed thereon i s used, the powder has a hi gher fl ui di ty, hardl y adheres to an i nsi de of a di spersi ng machi ne, and moves more smoothl y in the di spersi ng machi ne, compared to suppl yi ng an i norgani c raw mat er i al powder with no carboxyl i c aci d adsorbed thereon i nto the di spersi ng machi ne.
[ 0029] I n t hi s speci f i cat i on, unl ess otherwi se speci f i ed, "vol ume- based cumul at i ve 50% part i cl e di ameter ( D50) " refers to a di amet er at vol ume- based cumul at i ve f r act i on 50% of a part i cl e size distribution measured by using a laser particle size anal yzer, for example, a I aser di ff racti on/ scatt eri ng part i cl e Si ze anal yzer LA- 960 (manufactured by HORI BA, Ltd. ).
[ 0030] In this speci f i cat i on, "cl assi f i cat i on"
refers to an operati on of cl assi fyi ng the powder i nto a group of rel at i vel y I arge particles (in other words, coarse powder) and a group of r el at i vel y small part i cl es ( i n other words, f i ne powder) accordi ng to the parti cl e Si ze. Speci f i cal I y, i n t hi s speci f i cat i on, the f i ne powder refers to a group of part i cl es havi ng a vol ume- based cumul at i ve 50% part i Cl e di ameter D50 rangi ng from O. 01 pm and 5.0 pm. The coarse powder refers to a group of part i cl es havi ng a D50 I arger than that of the f i ne powder. The f i ne powder here i s def i ned as i nor gani c f i ne powder produced in the present invention.
[ 0031] The coarse particle refers to a particle that has a suff i ci ent I y I arge di ameter r el at i ve to the D50 of the i nor gani c f i ne powder to be produced.
For exampl e, It can be a part i cl e havi ng a di ameter that i s more than 1. 5 times I arger than the D50 of the inorganic fine powder to be produced, more than 2.0 times I arger than the D50 of the target powder, or more than 2.5 ti mes I arger than the D50 of the target powder.
[ 0032] 2. Second Embodi ment The met hod for produci ng the inorganic f i ne powder accordi ng to the second embodi ment of the present i nventi on i s a met hod for produci ng an i nor gani c f i ne powder havi ng a vol ume-based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, the method i ncl udi ng: a step of gener at i ng a powder to be cl assi f i ed by adsorbing a carboxyl i c aci d onto an i norgani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed, under the condi ti on that the i norgani c raw mat eri al powder bei ng i n a di spersed state in a gas phase at the ti me of generati on has been di spersed i n the gas phase; and a step of subj ect i ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
[ 0033]
As a result, it is possible to provi des the method for produci ng the inorganic fine powder havi ng the vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, cont ai ni ng the extremely small number of part i cl es with high pr oduct i vi ty.
[ 0034]
This excellent effect is consi dered to be achi eyed for the f ol I owi ng reasons.
Compared with dry classification by mi xi ng a powder and an auxi I i ary agent such as ethanol and vapor i zi ng the auxi I i ary agent, i t i s possi bl e to i mprove di spersi bi I i ty of the powder to be classified in the gas phase and to enhance classification accuracy by adsorbi ng the carboxyl i c aci d onto the i norgani c raw mat er i al powder havi ng the D50 of 10 pm or I ess, under the condi ti on that the i norgani c raw mat eri al powder bei ng i n the di spersed state in the gas phase at the ti me of generation has been di spersed i n the gas phase.
Therefore, the number of coarse part i cl es contai ned i n the produced i norgani c f i ne powder can be extremel y reduced.
As a result, the number of times of cl assi f i cat i ons can be reduced and productivity i s i mproved.
[ 0035]
Adsorpti on of the carboxyl i c acid on the inorganic raw mat en i al powder i ncreases the fl ui di ty of the powder to be classified and reduces adhesion thereof to inside the classifier, thereby i ncreasi ng a yi el d.
I n addi t i on, reduced adhesi on i nsi de the cl assi f i er prevents blockage of the powder supply port and i nsi de the pi pi ng of the cl assi f i er, thereby ext endi ng the oper at i on time of the cl assi f i er and i mprovi ng productivity.
[ 0036]
Thi s embodi ment obtai ns the powder to be cl assi f i ed by adsorbi ng the carboxyl i c aci d onto the i norgani c raw material powder havi ng the 050 of 10 pm or I ess, under the condi ti on that the i norgani c raw mat eri al powder bei ng i n the di spersed state i n the gas phase at the ti me of generat i on has been di spersed i n the gas phase.
For t hi s reason, consi der i ng the step of adsorbi ng the carboxyl i c aci d, the number of steps can be reduced compared to the above-described embodi ment, which is advantageous i n the vi ewpoi nt of productivity.
I n addi ti on, a van i at i on i n the amount of carboxyl i c aci d adsorbed on each part of the i norgani c raw mat er i al powder can be more effectively suppressed, and the f i nal i norgani c f i ne powder wi I I have a more i deal part i cl e size di st ri but i on with an extremely smal I number of coarse part i cl es. Furthermore, because the amount of carboxyl i c aci d adsorbed on the powder to be cl assi f i ed can be easi I y controlled by controlling the amount of carboxyl i c acid supplied, the f i nal i norgani c f i ne powder has an extremely smal I
number of coarse part i cl es and a more i deal part i cl e size di stri but i on.
[ 0037] 3. Thi rd Embodi ment The met hod for produci ng the inorganic f i ne powder accordi ng to the t hi rd embodi ment of the present i nventi on i s a method for produci ng an i nor gani c f i ne powder havi ng a vol ume-based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, the method i ncl udi ng: a step of gener at i ng a powder to be cl assi f i ed by di spersi ng an i norgani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ect i ng the powder to be cl assi f i ed to dry cl assi f i cat i on; wherei n the step of generati ng the powder to be cl assi f i ed i s performed i n an atmosphere contai ni ng a carboxyl i c aci d in a gaseous state.
[ 0038]
As a result, it is possible to provide the method for producing the inorganic fine powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, contai ni ng the extremely smal I number of coarse part i cl es with hi gh productivity.
[ 0039]
This excellent effect is consi dered to be achi eyed for the f ol I owi ng reasons.
Compared with dry classification by mi xi ng a powder and an auxi I i ary agent such as ethanol and vapor i zi ng the auxi I i ary agent, i t i s possi bl e to i mprove di spersi bi I i ty of the powder to be classified in the gas phase and to enhance cl assi f i cat i on accuracy by obt ai ni ng the powder to be cl assi f i ed by di spersi ng the i norgani c raw mat er i al powder i n the atmosphere cont ai ni ng the car boxyl i c acid in a gaseous state.
For t hi s reason, the number of coarse part i cl es i n the produced i norgani c f i ne powder can be extremely reduced.
The number of times of classifications can be reduced and product i vi ty is i mproved.
[ 0040]
Adsorpti on of the carboxyl i c acid on the inorganic raw mat en i al powder i ncr eases the fl ui di ty of the powder to be classified and reduces adhesi on thereof to inside the classifier, thereby i ncreasi ng a yi el d.
I n addi t i on, reduced adhesi on i nsi de the cl assi f i er prevents blockage of the powder supply port and i nsi de the pi pi ng of the cl assi f i er, thereby ext endi ng the oper at i on time of the cl assi f i er and i mpr ovi ng productivity.
[ 0041]
Thi s embodi ment obtai ns the powder to be Cl assi f i ed by di spersi ng the i norgani c raw mat er i al powder i n the atmosphere contai ni ng the car boxyl i c aci d in the gaseous state. For t hi s reason, consi der i ng the step of adsorbi ng the car boxyl i c aci d, the number of processes can be reduced compared to the first embodi ment above, whi ch i s advantageous from the vi ewpoi nt of product i vi t y. I n addi t i on, a vari at i on i n the amount of carboxyl i c aci d adsorbed on each part of the i nor gani c raw material powder can be more effectively suppressed, and the final i norgani c f i ne powder wi I I have a more i deal part i cl e size di st r i but i on with an extremely smal I number of coarse part i cl es.
Furthermore, because the amount of carboxyl i c aci d adsorbed on the powder to be cl assi f i ed can be easi I y control I ed by control I i ng the amount of carboxyl i c acid supplied, the final i norgani c f i ne powder has an extremely smal I number of coarse part i cl es and a more i deal part i cl e size di st ri but i on.
[ 0042]
In each of the above embodi ments, the reason why the di spersi bi I i ty of the powder to be cl assi f i ed i s enhanced by obtai ni ng the powder to be classified, whi ch compri ses the i norgani c raw mat eri al powder havi ng a carboxyl i c aci d adsorbed thereon, i s unknown, and the i nvent ors assume as f ol I ows.
The i norgani c raw mat eri al powder general I y has a f uncti onal group such as a hydroxyl group on the surf ace of its constituent part i cl es that can i nteract with carboxyl group.
By adsorbi ng the carboxyl i c aci d on the i norgani c raw mat er i al powder, the functional group such as the hydroxyl group on the surf ace of the constituent part i cl es of the i norgani c raw material powder interact with the carboxyl group (- COOH) of the carboxyl i c acid, thereby a port i on of the carboxyl i c aci d other than the carboxyl group such as a hydrocarbon port i on i s posi ti oned out si de the metal powder part i cl es. As a result, aggr egat i on of the i norgani c raw mat en i al powder by a polar group such as the hydroxyl group i s suppressed, thereby i mprovi ng di spersi bi I i ty.
When the i nor gani c raw mat en i al powder i s, for exampl e, a metal powder, even i n sites where there are no f uncti onal groups that i nteract with the carboxyl group such as the hydroxyl group, the carboxyl i c aci d can adsorb by react i ng with the metal to form metal carboxyl ate, or by f ormi ng coordi nati on bonds with metal atoms on the surf ace of the metal powder, thereby a sui t abl e amount of carboxyl i c aci d can be adsorbed more uni f orml y on the part i cl e surface.
I n addi t i on, due to a sui tabl e amount of carboxyl i c aci d adsorbed uni f orml y on the parti cl e surface, the f ormati on of pol ar group such as the hydroxyl group can be suppressed.
As descri bed above, both physi cal adsorpti on and chemi cal adsorpti on are possi bi e as adsorpti on in the present i nventi on.
[ 0043]
If the above conf i gur at i ons are not sat i sf i ed, it woul d be di ff i cul t to obtai n sat i sf act ory results.
For exampl e, if the carboxyl i c aci d i s not adsorbed on the powder to be cl assi f i ed i n each of the above embodi ments, di spersi bi I i ty of the powder to be classified in the gas phase may not be suf f i ci ent I y i mproved i n the step of dry cl assi f i cat i on.
For t hi s reason, cl assi f i cat i on accuracy may not be suf f i ci ent I y enhanced, and the number of coarse part i cl es i n the produced i norgani c f i ne powder wi I I i ncrease.
The requi red number of times of classifications will increase, resul ti ng i n a reduced product i vi ty.
Because fl ui di ty of the powder to be classified cannot be suf f i ci ent I y i ncr eased, adhesion of the powder to be cl assi f i ed i nsi de the classifier will i ncr ease, and a yi el d will be decreased. I n addi t i on, because i ncreased adhesi on i nsi de the cl assi f i er tends to cl og the powder suppl y port and the i nsi de of the pi pi ng i n the cl assi f i er, the oper at i on ti me of the cl assi f i er will be shortened and the product i vi ty will be reduced.
[ 0044] <CLASSI Fl ER>
FIG. 1 is a di agram showi ng a conf i gurati on exampl e of a cl assi f i er used i n the method for produci ng an i norgani c f i ne powder accordi ng to the present i nventi on.
I n the f ol I owi ng descri pti on, the upper si de i n Fl G. 1 i s ref erred to as "upper" and the I ower si de i n Fl G. 1 i s ref erred to as "1 ower".
[ 0045]
A cl assi f i er 1 i s an ai rf I ow cl assi f i er whi ch perf orms cl assi f i cation using centrifugal force act i ng on the powder. The cl assi f i er 1 i ncl udes a casi ng 3 whi ch forms a cl assi f i cat i on chamber 10.
[ 0046]
At the upstream si de of the classification chamber (Cl assi f i cat i on zone) 10, there i s a di spersi on zone 11 where the i nor gani c raw mat en i al powder i s di spersed pri or to cl assi f i cat i on.
The Cl assi f i cat i on chamber 10 i s the area where the di spersed i nor gani c raw mat eri al powder i s cl assi f i ed.
[ 0047]
The classifier 1 has an introduction port 4 for i ntroduci ng the i nor gani c raw mat en i al powder i nto the di spersi on zone 11, an ai r nozzl e 5 that i nj ects hi gh- pressure ai r (pri mary air) into the dispersion zone 11, a guide vane 6 to introduce secondary ai r to flow i nto the cl assi f i cat i on chamber 10 to form a swi rl i ng ai rf I ow i n the cl assi f i cat i on chamber 10, a f i ne powder di scharge port 7 that has an openi ng at the upper center of the cl assi f i cat i on chamber 10, and a coarse powder di scharge port 8 that has an openi ng al ong the I ower pen i phery of the cl assi f i cat i on chamber 10.
[ 0048]
Next, the method for dispersing and classifying the i norgani c raw mat en i al powder usi ng the cl assi f i er 1 i s expl ai ned.
[ 0049]
The inorganic raw material powder is introduced into the di spersi on zone 11 from the i nt roduct i on port 4.
The i norgani c raw mat eri al powder i s di spersed by a di spersi ng force i mparted by the pri mary ai r i nj ected i nto the di spersi ng zone 11.
Then, the i norgani c raw materi al powder i s i ntroduced i nto the classification chamber 10 in a dispersed state.
[ 0050]
In the classification chamber 10, the secondary air i s fl own t her ei n through the gui de vane 6, whi ch ai rf I ow i s swi rl ed i n the cl assi f i cat i on chamber 10 and is exhausted from the upper center of the cl assi f i cation chamber 10.
An outward centrifugal force exerted by the swi rl i ng ai rf I ow and a centrally-directed airflow separate the inorganic raw material powder i n the sol i d- gas mixture i nto a coarse powder and a f i ne powder.
[ 0051]
The coarse powder moves radi al I y outward i n the cl assi f i cation chamber 10 due to the outward centrifugal force of the swi rl i ng ai rf I ow, and i s col I ect ed from the coarse powder di scharge port 8 on the lower pen i phery of the cl assi f i cat i on chamber 10.
On the other hand, the f i ne powder moves radi ally i nward i n the cl assi f i cat i on chamber 10 due to the central I y-di rected ai rf I ow, and i s col I ect ed from the f i ne powder di scharge port 7 at the upper center of the cl assi f i cat i on chamber 10.
[ 0052] A suction pump ( not shown in the figure) is connected to the f i ne powder discharge port 7.
The f i ne powder i s di scharged and collected together with the ai r ( exhaust ai r) i n the classification chamber 10.
[ 0053] The step of generating a powder to be classified corresponds to the step performed i n the di spersi on zone 11, and the step of dry classification corresponds to the step performed i n the cl assi f i cat i on chamber ( cl assi f i cat i on zone) 10.
That i s, the i nor gani c raw mat en i al powder i n a di spersed state in the di spersi on zone 11, or i n other words, the powder i ntroduced i nt o the cl assi f i cation chamber 10, is the powder to be cl assi f i ed in this speci f i cat i on.
[ 0054] I n the above expl anat i on, the ai rf I ow cl assi f i er that uses the cent ri fugal force from the swi r I i ng ai rf I ow for the cl assi f i cat i on is used as an exampl e, but the cl assi f i cat i on met hod of a Cl assi f i er i s not limited to any part i cul ar method.
For exampl e, a classification met hod for ut i I i zi ng centrifugal force due to rot ati on of a rotor, a cl assi f i cat i on method for usi ng gravity, and a cl assi f i cat i on met hod for usi ng i nert i al force may be used.
[ 0055] I n the present i nvent i on, the step of gener at i ng a powder to be cl assi f i ed and the step of dry cl assi f i cat i on are not I i mi t ed to the case where the same equi pment i s used, and may be perf or med usi ng separate equi pment .
I n other words, the powder to be cl assi f i ed may be obtai ned by di spersi ng the i nor gani c raw mat eri al powder i n a di spersi ng machi ne, and then cl assi f yi ng the powder to be classified in a dry classifier.
[ 0056] <STEP OF GENERATI NG POWDER TO BE CLASSI Fl ED>
I n the step of generat i ng a powder to be cl assi f i ed, the powder to be classified havi ng a carboxyl i c aci d adsorbed thereon i s obtai ned i n the di spersed state in the gas phase.
[ 0057] (I NORGANI C RAW MATER! AL POWDER) The i norgani c raw mat eri al powder is a raw mat eri al for the i nor gani c f i ne powder produced i n the present i nvent i on and has a part i ci e di ameter at a vol ume- based cumulative percentage of 50%, D50, of 10 pm or I ess.
[ 0058]
It is suff i ci ent that a vol ume- based cumul at i ve 50%
part i ci e di ameter 050 of the i norgani c raw material powder i s 10 pm or I ess, but i s pref erabl y greater than 0. 01 pm.
I n part i cul ar, the vol ume- based cumul at i ve 50% part i ci e di ameter D50 of the i norgani c raw mat en i al powder i s preferably greater than 0.03 pm and 2.5 pm or I ess, more preferably greater than 0.05 pm and 1.2 pm or less, and even more preferably greater than 0.10 pm and 0.80 pm or less.
[ 0059]
Examples of inorganic components of the inorganic raw mat en i al powder i ncl ude, though not I i mi ted, van i ous metal s, van i ous metal oxi des, van i ous gl asses, van i ous cerami cs, and van i ous semi conductors.
[ 0060]
Examples of the metals that compose the inorganic raw mat er i al powder i ncl ude, for exampl e, si I ver, gol d, pl at i num, copper, pal I adi um, ni ckel , tungsten, zi nc, t i n, i r on, cobalt, and al I oys contai ni ng one or more sel ected from these metal s.
[ 0061] Exampl es of the met al oxi des t hat compose the i norgani c raw mat eri al powder (metal oxi des other than cerami cs) i ncl ude, for exampl e, ni ckel oxi de, copper oxi de, Si I ver oxi de, and i ron oxi de.
[ 0062]
Examples of the glasses that compose the inorganic raw mater i al powder i ncl ude, for exampl e, bi smut h- based gl ass, tell uri urn-based glass, and silicate glass.
[ 0063]
Exampl es of the cerami cs that compose the i norgani c raw mat er i al powder i ncl ude, for exampl e, oxi de- based cerami c, ni tri de- based cerami c, and bori de- based cerami c, and more speci f i call y, al umi na, Si I i ca, zi rconi a, bar i urn ti tanate, cal ci urn zi rconate, al umi na ni tri de, si I i con ni tri de, and boron ni tri de. The exampl es of cerami cs al so i ncl ude f uncti onal cerami cs such as phosphors.
[ 0064]
Examples of the semi conduct ors that compose the i norgani c raw mat er i al powder i ncl ude, f or exampl e, I nP, GaP, I nAs, GaAs, I nGaP, I nZnP, ZnSe, CdSe, and CdS.
[ 0065] In part i cul ar, the inorganic component of the i norgani c raw mat er i al powder i s pref erabl y at I east one sel ected from the group consi sti ng of metal s, metal oxi des, gl asses, cerami cs, and semi conductors.
[ 0066] These components will make the carboxyl i c acid f uncti on more suitably and further i mprove the di spersi bi I i ty of the i nor gani c raw mat er i al powder.
[ 0067]
When the inorganic component of the inorganic raw mat er i al powder i s a metal , metal oxi de, gl ass, or oxi de- based cerami c, the af or ement i oned effects are more remarkably exhi bi ted. The reason for t hi s has not yet been found, but the i nvent or s assume to be the presence of many hydroxyl groups on the part i cl e surf ace of the i norgani c raw mat eri al powder.
I n part i cul ar, when the i norgani c component of the i norgani c raw material powder i s a metal , there would be many hydroxyl groups on the oxi di zed surf ace of the powder where metal oxi des are formed.
On the other hand, non-oxidized areas can adsorb a sui tabl e amount of carboxyl i c aci d more uni f orml y due to generat i on of metal carboxyl ate by the reaction of the metal with the carboxyl i c aci d, or f ormati on of coordi nati on bonds of the carboxyl group with metal atoms on the powder surface. For these reasons, the i nvent ors assume that the af orementi oned effect i s more remarkabl y exhi bi ted.
Thi s effect i s more remarkably exhi bi ted when the i norgani c component of the i norgani c raw mat er i al powder i s composed of ni ckel .
[ 0068]
A shape of the inorganic raw material powder is not I i mi ted, and exampl es thereof i ncl ude spheri cal , fl aky, granul ar, van i ous other shapes, and a mixture of one or more sel ected t her ef r om.
[ 0069]
I n t hi s speci f i cat i on, the term "spheri cal " refers to a part i cl e shape i n whi ch the rat i o of a I ong di ameter to a short di ameter i s 2 or I ess.
The term "f I aky" refers to a shape i n whi ch the rati o of a I ong di ameter to a short di ameter exceeds 2.
[ 0070]
The method for produci ng the i norgani c raw mat eri al powder i s not I i mi ted, and may be, for exampl e, an el ectrol ysi s method, an at omi zati on method, a mechani cal pul veri zati on method, a wet reducti on method, a spray pyrol ysi s method, a chemi cal vapor deposi ti on method, or a physi cal vapor deposi ti on method.
[ 0071]
The particles of the inorganic raw material powder may compri se a uni form composi ti on or a pl ural i ty of composi ti ons.
[ 0072] (Carboxyl i c acid) The carboxyl i c aci d i s adsorbed on the i nor gani c raw material powder i n the powder to be cl assi f i ed.
The adsorpti on i n the present i nventi on can be either physi cal adsorpti on or chemi cal adsorpti on.
Thi s provi des a sati sf act ory di spersi bi I i ty of the powder to be cl assi f i ed i n the gas phase and facilitates to obtai n the i nor gani c f i ne powder with a desi red part i cl e si ze di st r i but i on i n hi gh yi el d.
The number of coarse part i cl es i n the resul ti ng inorganic fine powder can al so be extremely small .
[ 0073]
The carboxyl i c aci d i s not I i ml ted as I ong as it is a compound havi ng a carboxyl group, and exampl es thereof i ncl ude f ormi c aci d, aceti c aci d, propi oni c aci d, i sobutyri c aci d, but yri c aci d, crotoni c aci d, i soval en i c aci d, val en i c aci d, caproi c aci d, enant hi c aci d, capryl i c aci d, pel argoni c aci d, I act i c aci d, oxal i c aci d, succi ni c aci d, ol ei c aci d, acryl i c aci d, and met hacryl i c aci d, and one or a combi nati on of two or more sel ected therefrom may be used.
[ 0074] Among these, those havi ng a boiling poi nt of from 100 C to 400 C are preferred, those havi ng a boil i ng poi nt of from 105 C to 250 C are more pref erabl e, and those havi ng a boil i ng poi nt of from 110 C to 200 C are even more pref erabl e.
[ 0075] This allows to handle the carboxyl i c acid suitably in a I i qui d state dun i ng the step of generati ng the powder to be cl assi f i ed and to i mprove handl i ng property. When the carboxyl i c aci d i s adsorbed on the powder i n a vapor i zed state, si nteri ng of the i norgani c raw mat eri al powder can be more effectively prevented, al I owi ng a more uni form adsorpti on of the carboxyl i c acid onto the i norgani c raw materi al powder.
[ 0076] I n t hi s speci f i cat i on, unl ess otherwi se speci f i ed, the term "boil i ng poi nt" refers to a boil i ng poi nt under 1 at mos pher e.
[ 0077] The carboxyl i c acid is preferable to be a monocarboxyl i c aci d.
Thi s provi des more sui tabl e di spersi bi I i ty of the powder to be cl assi f i ed, and the effects of the present i nventi on will be more remarkabl y exhi bi t ed.
[ 0078] The carboxyl i c acid is preferably at least one sel ected from aceti c acid, propi oni c aci d, butyri c acid, and ol ei c aci d, and more pref erabl y, acet i c aci d.
[ 0079] These will provi de more sui tabl e di spersi bi I i ty of the powder to be cl assi f i ed, and the effects of the present i nvent i on will be more remarkably exhi bi t ed.
[ 0080] In the first embodi ment above, the powder to be cl assi f i ed i s obtai ned by di spersi ng i n the gas phase the carboxyl i c aci d- adsorbed inorganic raw material powder in which the carboxyl i c aci d i s adsorbed on the i norgani c raw mat eri al powder havi ng the vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 10 pm or I ess.
[ 0081] First, the carboxyl i c acid-adsorbed inorganic raw materi al powder i n whi ch the carboxyl i c aci d i s adsorbed on the inorganic raw material powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 10 prii or I ess i s prepared.
[ 0082] A method for producing the carboxyl i c aci d- adsorbed i nor gani c raw materi al powder i s not I i mi ted, and a preferred exampl e is a method of adsorbi ng a carboxyl i c aci d in a gaseous state onto the i norgani c raw materi al powder.
[ 0083] By adsorbi ng the carboxyl i c acid in the gaseous state onto the i nor gani c raw mat en i al powder, the carboxyl i c aci d can be more uniformly adsorbed on the i norgani c raw materi al powder, so that the effects of the present i nvent i on will be more remarkably exhi bi ted.
[ 0084] The method of adsorbi ng the carboxyl i c acid in the gaseous state onto the i norgani c raw materi al powder i s not I i mi ted, and exampl es thereof i ncl ude pl aci ng the i norgani c raw materi al powder i n an atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state, and bl owi ng gas cont ai ni ng the vapori zed carboxyl i c aci d onto the i norgani c raw materi al powder.
[ 0085] Then, the powder to be classified is obtai ned by di spersi ng the carboxyl i c aci d- adsorbed i norgani c raw materi al powder i n the gas phase.
[ 0086] In the second embodi ment above, the powder to be cl assi f i ed i s obtai ned by adsorbi ng the carboxyl i c aci d onto the inorganic raw material powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 10 pm or I ess under the condi ti on that the i norgani c raw materi al powder bei ng i n the di spersed state in the gas phase at the ti me of generat i on has been di spersed i n the gas phase.
[ 0087] Exampl es of the method of gener at i ng the i nor gani c raw materi al powder bei ng i n the di spersed state in the gas phase at the ti me of generati on i ncl ude gas phase methods such as chemi cal vapor deposi t i on and physi cal vapor deposi t i on, an at omi zat i on method, and a spray pyrol ysi s method.
I n part i cul ar, by gener at i ng the i nor gani c raw mat eri al powder usi ng the gas phase met hod or the spray pyrol ysi s method, a part i cl e size of the i nor gani c raw mat er i al powder can be more easi I y adj ust ed to the part i cl e si ze range according to the present i nventi on.
[ 0088]
The met hod of adsorbing the carboxyl i c acid onto the i nor gani c raw mat eri al powder i s not I i mi t ed, and a met hod of adsor bi ng the carboxyl i c aci d in the gaseous state onto the i nor gani c raw mat eri al powder i s preferred.
Speci f i cal I y, for exampl e, there is a met hod of bi owi ng the vapor i zed car boxyl i c aci d onto the i nor gani c raw mat eri al powder dun i ng a cool i ng process of the i nor gani c raw mat en i al powder bei ng i n the di spersed state in the gas phase at the time of gener at i on and bei ng generated at a predet ermi ned temperature.
[ 0089]
The above methods enable the car boxyl i c acid to adsorb onto the i nor gani c raw mat er i al powder more uniformly.
As a result, the aggregati on of part i cl es can be more effectively suppressed and di spersi bi I ity can be further improved.
Thi s makes the effects of the present i nvent i on to be more remarkably exhi bi t ed.
[ 0090]
I n addi ti on, by adsor bi ng the car boxyl i c aci d onto the i nor gani c raw mat er i al powder under the condi ti on that the i nor gani c raw mat er i al powder bei ng i n the di spersed state i n the gas phase at the ti me of gener at i on has been di spersed i n the gas phase to obtai n the powder to be cl assi f i ed, the number of steps can be reduced, resul ti ng i n further improvement of pr oduct i vi t y.
[ 0091]
in the second embodi ment , it is preferable to further i ncl ude a step of coil ect i ng the powder to be cl assi f i ed and a step of di spersi ng the powder to be cl assi f i ed obt ai ned i n the step of coil ect i ng i n the gas phase between the step of gener at i ng an powder to be cl assi f i ed and the step of dry cl assi f i cat i on.
[ 0092]
As a result, it is possible to facilitate combining more sui tabl e cl assi f i ers to improve a cl assi f i cat i on accuracy i n the subsequent step of dry cl assi f i cat i on, resul ti ng i n an i mproved productivity of i norgani c f i ne powder.
[ 0093]
I n the t hi rd embodi ment of the present i nventi on, the powder to be cl assi f i ed is obt ai ned by di spersi ng the i norgani c raw mat eri al powder havi ng the vol ume- based cumul at i ve 50%
part i cl e di ameter D50 of 10 pm or I ess i n the atmosphere contai ni ng the carboxyl i c aci d in the gaseous state.
[ 0094]
First, the inorganic raw material powder having the vol ume- based cumul at i ve 50% part i cl e di amet er D50 of 10 pm or I ess i s prepared.
The i norgani c raw materi al powder i s then di spersed i n the atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state to obtai n the powder to be cl assi f i ed.
[ 0095]
By dispersing the inorganic raw material powder in the atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state, the carboxyl i c aci d can be adsorbed on the i norgani c raw material powder more uniformly. As a result, the aggregati on of part i cl es can be more effectively suppressed to further i mprove di spersi bi I i ty.
The amount of carboxyl i c aci d adsorbed on the i norgani c raw mat en i al powder i s al so easi er to control .
Thi s enabl es the effects of the present i nvent i on to be more r emarkabl y exhi bi t ed.
I n addi ti on, by di spersi ng the i norgani c raw mat en i al powder i n the atmosphere contai ni ng the carboxyl i c aci d in the gaseous state, the number of steps can be reduced to further i mprove product i vi ty.
[ 0096]
In the second embodi ment and the third embodi ment, the amount of carboxyl i c aci d used i s not I i mi t ed.
Preferably, it is used i n an amount of from 30 mol es to 960 mol es, more pref erabl y from 60 mol es to 480 mol es, and even more pref erabl y from 120 mol es to 240 mol es per 1 m3 of i norgani c raw mat eri al powder.
[ 0097]
I n the above ranges, a sui tabl e amount of carboxyl i c acid can be adsorbed on the i nor gani c raw mat en i al powder more uni f orml y to i mprove the di spersi bi I i ty of the powder to be cl assi f i ed.
I n addi ti on, the amount of carboxyl i c aci d adsorbed on the i norgani c raw material powder wi I I be prevented from being too large, and the properties of the produced inorganic fine powder wi I I be more pref erabl e when the i norgani c f i ne powder i s made i nt o a paste.
[ 0098]
A vol ume of i nor gani c raw mat eri al powder accordi ng to the present i nventi on refers to a vol ume cal cul at ed from the weight and true density of the powder.
[ 0099]
A supply rate of the i norgani c raw mat en i al powder to the cl assi f i er, i . e. , for exampl e, a supply rate of the i norgani c raw mat er i al powder from the i nt roduct i on port 4 to the di spersi on zone 11 i n the cl assi f i er 1 shown i n Fl G. 1, depends on a si ze (capaci ty) of the cl assi fi er.
Prefer abl y, the rate ranges from 1 kg/ hr to 20 kg/ hr, more preferably from 3 kg/ hr to 15 kg/ hr, and even more preferably from 5 kg/ hr to 12 kg/ hr .
[ 0100] In the above ranges, the di spersi bi I i ty of the i norgani c raw mat eri al powder i s superi or, and the producti vi ty of the i nor gani c f i ne powder i s i mproved.
[ 0101]
A suppl y and di spersi ng pressure dun i ng di spersi on, i . e. , for exampl e, a pressure of di spersi ng ai r i nj ect ed from the ai r nozzle 5 i nto the di spersi ng zone 11 in the cl assi f i er 1 shown i n Fl G. 1, i s not limited, and preferably ranges from O. 2 MPa to 1.0 MPa, more preferably from 0.4 MPa to 0.8 MPa, and even more preferably from 0.5 MPa to 0.7 MPa.
[ 0102] In the above ranges, the di spersi bi I i ty of the i norgani c raw mat eri al powder i s superi or, and the producti vi ty of the i nor gani c f i ne powder i s i mproved.
[ 0103] <STEP OF DRY CLASSI Fl CATI ON>
I n the step of dry cl assi f i cat i on, the powder to be classified obtai ned in the step of generating the powder to be cl assi f i ed i s dry cl assi f i ed.
[ 0104]
Because the powder to be cl assi f i ed to whi ch the carboxyl i c aci d i s adsorbed i s sui tabl y di spersed i n the gas phase, the cl assi f i cat i on accuracy i n the step of dry cl assi f i cation i s improved.
Consequent I y, the number of coarse part i cl es in the produced inorganic fine powder can be ext remel y reduced.
I n addi ti on, the i mproved cl assi f i cation accuracy can reduce the number of times of cl assi f i cat i ons to improve pr oduct i vi ty.
[ 0105]
As the f I ui di ty of the powder to be cl assi f i ed i s i ncreased, adhesi on of the powder to be cl assi f i ed to an i nsi de of the cl assi f i er wi I I be reduced, whi ch i mproves the yi el d.
As the adhesi on of the powder to be cl assi f i ed to the i nsi de of the cl assi f i er i s reduced, bl ockage of a powder suppl y port and an i nsi de of the pi pi ng of the cl assi f i er hardl y occur, thereby ext endi ng the oper at i on ti me of the cl assi f i er.
Thus, the product i vi ty is i ncreased.
[ 0106] Thus, the i nor gani c f i ne powder contai ni ng the extremel y smal I number of coarse part i cl es can be produced with a hi gh product i vi ty.
[ 0107]
A gas phase temperature at whi ch the step of dry cl assi f i cation i s performed i s not I i mi ted, and pref erabl y ranges from 60 C to 300 C, more pref erabl y from 100 C to 250 C, and even more pref erabl y from 150 C to 200 C.
[ 0108] in the ranges, probl ems such as deformation of part i cl es by heat and al terat i on of constituent mat er i al s of the part i cl es are prevented more eff ecti vel y. At the same ti me, the cent ri fugal force i s i ncreased due to a hi gher speed of the ai rf I ow.
I n addi ti on, it is possi bl e to prevent water vapor from adher i ng to the part i cl es, thereby further enhanci ng the cl assi f i cation accuracy.
The productivity can al so be further i mproved.
I n addi ti on, the number of coarse part i cl es i n the i norgani c f i ne powder can be part i cul an y reduced.
[ 01091 A sucti on airflow amount during the step of dry cl assi f i cat i on, i . e. , for exampl e, a sucti on ai rf low amount by the sucti on pump connected to the fine part i cl e discharge port 7 i n the cl assi f i er 1 shown i n Fl G. 1, i s not limited, and preferably ranges from 5.0 m3/mi n to 30 m3/mi n, more pref erabl e from 6.0 m3/mi n to 20 m3/mi n, and even more preferably from 7.0 m3/mi n to 9.0 m3/mi n.
I n these ranges, more ef f i ci ent cl assi f i cat i on of the powder to be cl assi f i ed can be achi eyed.
[ 0110]
A sucti on pressure at which dry classification is performed, i . e. , for exampl e, a sucti on pressure by the sucti on pump connected to the f i ne part i cl e di scharge port 7 i n the cl assi f i er 1 shown i n Fl G. 1, i s not I i mi ted, and preferably ranges from -60 kPa to -5 kPa, more preferably from -50 kPa to -10 kPa, and even more preferably from -40 kPa to -15 kPa.
I n these ranges, a more eff i ci ent cl assi f i cat i on of the powder to be cl assi f i ed can be achi eyed.
[ 01111 By the dry cl assi f i cat i on, the powder to be cl assi f i ed i s cl assi f i ed i nt o a fi ne powder and a coarse powder. The powder to be cl assi f i ed is cl assi f i ed i nto, for exampl e, the f i ne powder havi ng the vol ume- based cumul at i ye 50% part i cl e di amet er D50 rangi ng from 0.01 pm to 5. 0 pm, and the coarse powder havi ng the D50 I arger than that of the f i ne powder.
Among them, the fine powder i s col I ected as the i norgani c f i ne powder produced i n the present i nventi on.
[ 0112]
As descri bed above, the inorganic fine powder havi ng the vol ume- based cumulative 50% particle diameter D50 ranging from 0.01 pm to 5.0 pm is produced.
[ 0113]
The inorganic fine powder produced in this way has an extremely small number of coarse part i cl es.
In addi ti on, secondary aggregati on i s prevented due to the adsorpti on of carboxyl i c aci d on the i norgani c f i ne powder.
[ 0114]
Furthermore, the method as descri bed above can reduce the number of times of cl assi f i cat i ons due to the i mpr oved cl assi f i cat i on accuracy.
Further, adhesi on of the powder to be cl assi f i ed to i nsi de the cl assi f i er i s al so reduced, thereby increasing the yield.
in addi ti on, the reduced adhesion inside the cl assi f i er prevents blockage of the powder supply port and the i nsi de of the pi pi ng of the cl assi f i er, thereby extendi ng the oper at i on time of the cl assi f i er and i mpr ovi ng productivity.
[ 0115]
The step of dry cl assi f i cat i on may be perf ormed onl y once or repeat ed multi pie ti mes, whi ch enabl es to further enhance the classification accuracy.
[ 0116]
A yield of inorganic fine powder in the step of dry cl assi f i cat i on i s not I i mi ted, and i s preferably 80% or hi gher, more pref erabl y 85% or hi gher, and even more pref erabl y 88% or hi gher.
Thus, the effects of the pr event i nvent i on are more remarkabl y exhi bi t ed.
[ 0117]
in this speci f i cat i on, the yield of inorganic fine powder i n the step of dry cl assi f i cat i on is cal cul at ed from a wei ght of the powder before cl assi f i cat i on, i . e. , a wei ght of the powder to be cl assi f i ed, and a wei ght of the powder after cl assi f i cat i on, i . e. , a wei ght of the i norgani c f i ne powder, usi ng the foil owi ng f ormul a:
Yi el d (%) = (wei ght of powder after cl assi f i cat i on / wei ght of powder before cl assi f i cat i on) x 100 [ 0118]
The inorganic fine powder produced by the method accordi ng to the present i nventi on as descri bed above have the vol ume- based cumul at i ve 50% part i cl e di ameter 050 rangi ng from 0.01 pm to 5.0 pm.
Pref erabl y, the Dso of the i norgani c f i ne powder ranges from 0.03 pm to 2.0 pm, more preferably from 0.05 pm to 1. 0 pm, and even more pref erabl y from O. 10 pm to 0.60 pm.
[ 0119]
Thus, the inorganic fine powder with an ideal particle si ze di st ri but i on can be obt ai ned.
Convent i onal I y, when the D50 was wi t hi n such a range, a probl em of coarse par t i cl es is li kel y to occur to cause adverse effects.
I n contrast, the present i nventi on can pr event the occurrence of such a probl em more ef f ecti vel y even when the D50 i s wi t hi n the range. That i s, the effects of the present i nventi on are more remarkably exhi bi ted when the D50 of the i nor gani c f i ne powder i s wi t hi n the above range.
[ 0120]
The inorganic fine powder produced by the met hod accor di ng to the present i nventi on as descri bed above preferably has a val ue of (D90 - Dm)/ 050 rangi ng from 0.30 to 0.90, more preferably from 0.35 to 0. 80, and st i I I more preferably from 0.40 to O. 75, wherei n Dio [ pm] i s a part i cl e di amet er at vol ume- based cumul at i ve f racti on 10%, D50 [Mm] i s a part i cl e di ameter at vol ume- based cumul at i ve f ract i on 50%, and D90 [ pm] i s a part i cl e di ameter at vol ume- based cumul at i ve f r act i on 90% of a part i cl e si ze di st ri but i on measured by a I aser part i cl e Si ze anal yzer. .
[ 0121]
The val ue of (D90- Dio)/ D50 i s an index of a uniformity of the part i cl e si ze di st ri but i on.
A small er val ue of ( D90-Dio)/ D50 i ndi cat es a narrower part i cl e si ze di St r i but i on, i . e.
, more uniform particle size.
[ 0122]
In the range, the inorganic fine powder has more uni form part i cl e si ze and i s used sui tabi y for van i ous appl i cat i ons.
[ 0123]
In the method for producing the inorganic fine powder of the present i nventi on, the number of coarse part i cl es, as determi ned by the f ol I owi ng measurements, i s preferred 30 or I ess, more preferably 15 or I ess, and even more preferably 5 or I ess.
[ 0124]
In such cases, van i ous probl ems caused by the presence of coarse particles in the inorganic fine powder can be prevented more effectively.
[ 0125]
The above measurement of the coarse particle count can be performed, for exampl e, as f ol I ows.
Fi rst I y, a di spersi on I i qui d of the i nor gani c f i ne powder i s prepared by mi xi ng 1.0 g of the i nor gani c f i ne powder with 20 ml of ethanol whi ch mi xt ure is then treated with an ul trasoni c cleaner ( e. g. , W-113 manufactured by Honda El ect roni cs Co., Ltd.) for I minute. Subsequently, 30 ill of the dispersion liquid prepared i s sampled and then dropped onto an al umi num sampl e stand, whi ch i s dri ed to remove the di spersi on medi um. Thereby, a sampl e for measurement i s prepared. The sampl e thus prepared i s observed by usi ng a scanni ng el ectron mi croscope (e. g. , SU-1510 manufactured by Hitachi Hi gh- Tech Corporati on) for 50 f i el ds of vi ew at a magni f i cat i on of 10,000 ti mes. The total number of part i cl es havi ng a diameter 1.5 times or greater than the vol ume-based cumul at i ve 50% part i cl e di ameter D50 of the i nor gani c f i ne powder is counted as the coarse particle count.
[ 0126] [APPLI CATI ONS OF I NORGANI C Fl NE POWDER]
The appl i cat i ons of i nor gani c fine powder produced by the method accordi ng to the present i nventi on are not I i mi t ed.
For example, the inorganic fine powder produced using conductive metal powder as i nor gani c raw mat en i al powder can be used as conduct i ve powder.
[ 0127] Exampl es of constituent mater i al s of conduct i ve metal powder i ncl ude silver, gol d, pl at i num, copper, pal I adi um, ni ckel , tungsten, zinc, ti n, i r on, cobalt, and al I oys cont ai ni ng at I east one sel ected therefrom. Two or more of the above mat eri al s may be used i n combi nati on as conductive powder.
[ 0128]
The conductive powder can be suitably used as conduct i ve mat eri al s for el ect roni c components.
The conduct i ve mat er i al s for the el ect r oni c components are used to form conduct i ve parts.
The appl i cat i ons are not I i mi ted, but i s part i cul an I y sui t abl e for f or mi ng i nt er nal conductors ( i nt er nal el ect rodes) or t ermi nal el ect r odes of multi I ayer .. cerami c el ect roni c components such as multi layer ceramic capacitors, multi I ayer cerami c i nduct ors, and mul ti I ayer pi ezo el ect ri c actuators. The conductive powder for such appl i cat i ons requi res part i cul ar I y hi gh rel i ability.
[ 0129]
The conductive powder produced by the met hod according to the present i nventi on has a small average part i cl e Si ze, a narrow part i cl e si ze di st ri but i on, and hardly contains coarse part i cl es.
For t hi s reason, when the conduct i ve powder i s used for an i nner electrode, it is possi bl e to form an el ect rode I ayer of uni form t hi ckness, and suitably prevent the part i cl es of the conduct i ve powder from contact i ng both of the i nner el ect r odes to cause a short ci rcui t. Accor di ngl y, sat i sf act or y effects are achi eyed even for such appl i cat i ons that requi re part i cul ar I y hi gh r el i abi lit y.
Thus, the effects of the present i nvent i on are more remarkably exhi bi ted when the conduct i ve powder produced by the met hod accordi ng to the present i nventi on i s used to form the i nt er nal conduct ors ( i nt er nal el ect r odes) or the t er mi nal el ect rodes of multi layer cerami c el ect roni c components such as multi I ayer cerami c capacitors, multi I ayer cerami c i nduct or s, and multi layer pi ezo el ect ri c actuators.
[ 0130]
The conductive powder may be used to form conductive port i ons of el ect roni c components, for exampl e, as a conductive paste by mi xi ng with gl ass f ri t and an or gani c vehi cl e.
[ 0131]
The sui t abl e embodi ments of the present i nventi on have been descri bed above, but the present i nventi on i s not limited to these.
[ 0132]
For exampl e, the equi pent sui tabl y used i n the met hod for produci ng the i nor gani c f i ne powder of the present i nventi on i s not I i mi ted to those descri bed i n the af or ement i oned embodi ments.
[ 0133]
As for the method for producing the inorganic fine powder of the present i nvent i on, two or more of the af orementi oned methods descri bed i n the f i rst embodi ment through the t hi rd embodi ment may be performed i n combi nat i on.
[ 0134]
More speci f i cal I y, for exampl e, the powder to be cl assi f i ed may be obtai ned by further adsorbi ng a carboxyl i c aci d onto the carboxyl i c aci d- adsorbed i norgani c raw material powder that has a carboxyl i c acid pre-adsorbed thereon and is di spersed i n the gas phase.
I n other words, the method descri bed i n the f i rst embodi ment may be combi ned with the method descri bed i n the t hi rd embodi ment.
[ 0135]
Al t ernat i vel y, for exampl e, after a powder to be cl assi f i ed i s obt ai ned by gener at i ng the i norgani c raw mat er i al powder bei ng i n the di spersed state i n the gas phase at the ti me of gener at i on and havi ng the D50 of 10 pm or I ess, and adsorbi ng the carboxyl i c aci d on the i norgani c raw mat en i al powder whi ch has been di spersed i n the gas phase, the powder to be classified may be col I ected such that an addi ti onal carboxyl i c aci d i s adsorbed onto the call ected powder.
I n thi s case, when the addi ti onal carboxyl i c aci d i s adsorbed, the powder may be either undi spersed or di spersed i n the gas phase.
I n other words, the method descri bed i n the second embodi ment may be combi ned with the method descri bed i n the f i rst embodi ment, or with the method descri bed in the third embodi ment.
[ 0136]
Al so, for exampl e, the method descri bed i n the f i rst embodi ment may be combi ned wi th the method descri bed i n the second embodi ment and the method descri bed i n the t hi rd embodi ment.
[ 0137]
In these cases, the order of the combi nati on of the correspondi ng methods of each embodi ment ( especi all y the order of the methods of adsorbi ng the carboxyl i c aci d) i s not limited to a part i cul ar order.
EXAMPLES
[ 0138]
The present i nvent i on i s descri bed i n more detail with speci f i c exampl es bel ow, but the present i nvent i on i s not I i mi t ed only to the f ol I owi ng exampl es.
I n the f ol I owi ng expl anat i ons, treatments for whi ch no part i cul ar temperature or humi di ty condi ti ons are i ndi cat ed were conducted at room temperature ( 25 C) and a relative humidity of 50%.
In addi ti on, the van i ous measurement condi ti ons, unl ess ot herwi se i ndi cat ed, are those at room temperature (25 C) and a r el at i ve humi di ty of 50%.
The vol ume- based cumul at i ve f ract i on 10% val ue Dio, the vol ume- based cumulative f ract i on 50% val ue D50, and the vol ume- based cumul at i ve f ract i on 90% val ue D90 were measured for the i nor gani c raw mat en i al powder and i nor gani c f i ne powder using a I aser diffraction/scattering particle size anal yzer (manufactured by HORI BA Ltd. ) .
The boil i ng poi nts of the carboxyl i c aci ds used i n each of the f ol I owi ng exampl es are summari zed i n Tabl e 1.
[ 0139] [Tabl e 1]
Table 1 Boiling Carboxylic acid point Et]
Acetic acid (AA) 118.5 Propionic acid (PA) 141 Butyric acid (BA) 164 Isobutyric acid (IBA) Oleic acid (OA) 360 [ 0140] [ 1] PRODUCTI ON OF I NORGANI C Fl NE POWDER
[ 0141] (Example 1) I n t hi s exampl e, an i nor gani c f i ne powder was produced by the met hod accordi ng to the f i rst embodi ment above, i . e. , dispersing a carboxyl i c acid-adsorbed inorganic raw material powder i n a gas phase to obtai n a powder to be classified. The detai I s are descri bed as f ol I ows.
[ 0142] Fi rst, a ni ckel powder with a vol ume- based cumul at i ve 50% part i cl e diameter D50 of 0.31 pm was prepared as the i norgani c raw mat en i al powder.
[ 0143] The ni ckel powder having acetic acid adsorbed thereon was obtai ned by pl aci ng the ni ckel powder i n an atmosphere contai ni ng acet i c aci d as the carboxyl i c aci d.
The aceti c aci d used had a purity cl ose to 100% (speci al grade 99.
7+%, manufactured by FUJ I Fl LM VVako Pure Chemi cal Corporati on).
[ 0144] The obtai ned ni ckel powder was introduced into the dry classifier shown i n FIG. 1 at a rate of 10 kg per hour and was di spersed at a suppl y di spersi on pressure of O. 6 MPa to obtai n the powder to be cl assi f i ed.
[ 0145] Then, the di spersed and acetic acid-adsorbed ni ckel powder (the powder to be cl assi f i ed) was i ntroduced i nto the cl assi f i cation chamber and was subj ected to the dry cl assi f i cation at an i nternal temperature of the Cl assi f i er of 25 C, a sucti on ai rf I ow of 8. 5 m3/mi n, and a sucti on pressure of -35 kPa to obtain the inorganic fine powder.
[ 0146] (Exampl es 2- 5) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that the carboxyl i c aci ds I i sted i n Tabl e 2 were used i nstead of acetic aci d.
[ 0147] (Example 6) I n t hi s example, the i norgani c f i ne powder was produced by the method accordi ng to the second embodi ment above, i . e. , by adsorbi ng the carboxyl i c aci d onto the i norgani c raw material powder bei ng i n the di spersed state i n the gas phase at the ti me of generati on, to obtai n the powder to be cl assi fled.
The detail s are descri bed as f ol I ows.
[ 0148] First, a ni ckel acetate t et r ahydr at e powder was prepared.
The ni ckel acetate t et rahydrat e powder was sprayed and heated at 1,500 C to obtai n a ni ckel powder as the i norgani c raw materi al powder di spersed i n the gas phase.
The gas phase was cool ed to 500 C whi I e the ni ckel powder as the i norgani c raw materi al powder was di spersed i n the gas phase. An aceti c aci d i n a gaseous state was i ntroduced i nto the gas phase to obtai n an acetic aci d- adsor bed ni ckel powder as the powder to be cl assi f i ed. The amount of aceti c acid added (an amount of used) was 120 mol es per 1 m3 of ni ckel raw materi al powder.
[ 0149]
The obtai ned acetic acid-adsorbed ni ckel powder as the powder to be cl assi f i ed was i ntroduced i nto the dry cl assi f i er shown i n FIG. 1 at a rate of 10 kg per hour. The dry cl assi f i cat i on was performed at an internal temperature of the cl assi f i er of 25 C, a sucti on ai rf I ow of 8.5 m3/ mi n, and a sucti on pressure of -35 kPa to obtai n the i norgani c f i ne powder.
[ 0150] (Example 7) I n t hi s example, the i norgani c f i ne powder was produced by the method accordi ng to the t hi rd embodi ment descri bed above, i . e. , by di spersi ng the i norgani c raw mat er i al powder i n the atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state to obtai n the powder to be cl assi f i ed. The detail s are descri bed as follows.
[ 0151] First, a ni ckel powder having a vol ume- based cumul at i ve 50% parti Cl e di ameter D50 of 0.48 m was prepared as the i nor gani c raw materi al powder.
[ 0152]
The ni ckel powder was introduced into the dispersing zone of the dry cl assi f i er shown i n Fl G. 1 at a rate of 10 kg per hour whi I e aceti c aci d gas was i ntroduced i nto the di spersi ng zone i n an amount of 15 mol es per 1 m3 of the ni ckel powder. At a supply di spersi on pressure of 0.6 MPa, the ni ckel powder was di spersed whi I e the acetic aci d i s adsorbed on the ni ckel powder to obtai n a ni ckel powder with the aceti c aci d adsorbed thereon as the powder to be cl assi f i ed.
[ 0153] Then, the powder to be classified was introduced into the cl assi f i cat i on chamber. The dry cl assi f i cat i on was performed at an i nternal temperature of the cl assi f i er of 25 C, a sucti on ai rf I ow of 8.0 m3/ mi n, and a sucti on pressure of - 25 kPa to obtai n the inorganic fine powder.
[ 0154] (Exampl es 8-14) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 7 above, except that the amount of aceti c aci d added was changed as shown i n Tabl e 4.
[ 0155] (Examples 15-18) The inorganic f i ne powder was produced i n the same manner as i n Exampl e 10 above, except that the parti cl e di ameter of the i norgani c raw mat eri al powder was changed as shown i n Tabl e 4, and the condi ti ons of the process of the dry classification were set as shown i n Tabl e 4.
[ 0156] (Example 19) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that a Cu powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 2.45 pm was used as the inorganic raw material powder, and the condi t i ons of the dry cl assi f i cat i on were set as shown i n Table 5.
[ 0157] (Exampl e 20) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that an Ag- Pd al I oy powder (Ag : Pd = 7 : 3 (wei ght rati o)) having a vol ume- based cumul at i ve 50% parti cl e di ameter Dso of 1.30 pm was used as the I norgani c raw materi al powder, and the condi ti ons of the dry cl assi f i cat i on were set as shown i n Tabl e 5.
[ 0158] (Example 21) The inorganic f i ne powder was produced i n the same manner as descri bed in Example 1 above, except that a Ba0- Si 02-based gl ass powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 2.24 [.tm was used as the i nor gani c raw mat eri al powder, and the condi ti ons of the dry cl assi f i cati on were set as shown i n Tabl e 5.
[ 0159] (Example 22) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that a si I i ca powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 of O. 92 pm was used as the i norgani c raw mat eri al powder, and the condi ti ons of the dry cl assi f i cati on were set as shown i n Tabl e
[ 0019] (8) The method for produci ng the inorganic fine powder accordi ng to any one of the above items (1) to (7), wherein the step of dry classification i s performed i n the gas phase at a temperature of from 60 C to 300 C.
[ 0020] (9) The method for produci ng the i nor gani c f i ne powder accor di ng to any one of the above items (1) to (8), vvherei n an i nor gani c component of the i nor gani c raw mat en i al powder i s at I east one sel ected from the group consi st i ng of a metal , a metal oxi de, a gl ass, a cerami c, and a semi conductor.
EFFECTS OF THE INVENTION
[ 0021] Accordi ng to the present i nventi on, it is possi bl e to provi de the method for produci ng the i norgani c f i ne powder having the vol ume- based cumul at i ve 50% part i cl e di amet er D50 r angi ng from 0.01 pm to 5.0 pm with the extremely small number of coarse part i cl es with hi gh producti vi ty.
BRIEF DESCRIPTION OF THE DRAWINGS
[ 0022] Fi g. 1 i s a di agr am showi ng a conf i gurati on exampl e of a cl assi f i er used i n the met hod of produci ng an i norgani c fine powder accordi ng to the present i nventi on.
MODE FOR CARRYING OUT THE INVENTION
[ 0023] The following is a detailed description of preferred embodi ments of the present i nventi on.
[ METHOD FOR PRODUCI NG I NORGANI C Fl NE POWDER]
1. Fi rst Embodi ment [ 0024] The method for produci ng an inorganic fine powder accordi ng to the f i rst embodi ment of the present i nventi on i s a method for produci ng an i norgani c f i ne powder with a vol ume-based cumul at i ve 50% part i cl e diameter D50 rangi ng from 0.01 pm to 5.0 pm. The method i ncl udes a step of generati ng a powder to be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d-adsor bed i norgani c raw mat eri al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i norgani c raw mat eri al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
[ 0025]
As a result, it is possi bl e to provide the method for producing the inorganic fine powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, with the extremel y smal I number of coarse part i cl es with high pr oduct i vi ty.
[ 0026]
This excel I ent effect is consi dered to be achi eyed for the f ol I owi ng reasons.
Compared with dry cl assi f i cation i n whi ch an auxi I i ary agent such as ethanol i s adsorbed on a powder, di spersi ng i n the gas phase the carboxyl i c aci d- adsorbed i norgani c raw mat er i al powder i n whi ch the carboxyl i c aci d i s adsorbed on the i norgani c raw mat eri al powder i mpr oyes the di spersi bi I i ty i n the gas phase of the powder to be cl assi f i ed, thereby enhanci ng cl assi f i cat i on accuracy.
For thi s reason, the number of coarse part i cl es i n the produced i nor gani c f i ne powder can be ext remel y reduced. The number of times of cl assi f i cat i ons can al so be reduced and productivity i s i ncreased.
[ 0027]
Adsorption of the carboxyl i c acid on the inorganic raw mat en i al powder i ncreases the f I ui di ty of the powder to be cl assi f i ed to reduce adhesi on of the powder to an i nsi de of the cl assi f i er, thereby i ncreasi ng the yi el d.
I n addi ti on, reduced adhesi on i nsi de the cl assi f i er prevents bl ockage of the powder suppl y port and an i nsi de of the pi pi ng of the cl assi f i er, thereby extendi ng the operati on ti me of the cl assi f i er and i mprovi ng productivity.
[ 0028]
Because this embodi ment uses the carboxyl i c acid-adsorbed i norgani c raw mat eri al powder i n whi ch the carboxyl i c acid i s pre- adsorbed on the i norgani c raw mat eri al powder, a conf i gur at i on of equi pment used to produce the i nor gani c f i ne powder can be advantageously si mpl i f i ed and downsi zed, compared to other embodi ments descri bed i n detai I I at er. .
I n addi t i on, because the carboxyl i c aci d- adsorbed i norgani c raw mat er i al powder with the carboxyl i c acid pre-adsorbed thereon i s used, the powder has a hi gher fl ui di ty, hardl y adheres to an i nsi de of a di spersi ng machi ne, and moves more smoothl y in the di spersi ng machi ne, compared to suppl yi ng an i norgani c raw mat er i al powder with no carboxyl i c aci d adsorbed thereon i nto the di spersi ng machi ne.
[ 0029] I n t hi s speci f i cat i on, unl ess otherwi se speci f i ed, "vol ume- based cumul at i ve 50% part i cl e di ameter ( D50) " refers to a di amet er at vol ume- based cumul at i ve f r act i on 50% of a part i cl e size distribution measured by using a laser particle size anal yzer, for example, a I aser di ff racti on/ scatt eri ng part i cl e Si ze anal yzer LA- 960 (manufactured by HORI BA, Ltd. ).
[ 0030] In this speci f i cat i on, "cl assi f i cat i on"
refers to an operati on of cl assi fyi ng the powder i nto a group of rel at i vel y I arge particles (in other words, coarse powder) and a group of r el at i vel y small part i cl es ( i n other words, f i ne powder) accordi ng to the parti cl e Si ze. Speci f i cal I y, i n t hi s speci f i cat i on, the f i ne powder refers to a group of part i cl es havi ng a vol ume- based cumul at i ve 50% part i Cl e di ameter D50 rangi ng from O. 01 pm and 5.0 pm. The coarse powder refers to a group of part i cl es havi ng a D50 I arger than that of the f i ne powder. The f i ne powder here i s def i ned as i nor gani c f i ne powder produced in the present invention.
[ 0031] The coarse particle refers to a particle that has a suff i ci ent I y I arge di ameter r el at i ve to the D50 of the i nor gani c f i ne powder to be produced.
For exampl e, It can be a part i cl e havi ng a di ameter that i s more than 1. 5 times I arger than the D50 of the inorganic fine powder to be produced, more than 2.0 times I arger than the D50 of the target powder, or more than 2.5 ti mes I arger than the D50 of the target powder.
[ 0032] 2. Second Embodi ment The met hod for produci ng the inorganic f i ne powder accordi ng to the second embodi ment of the present i nventi on i s a met hod for produci ng an i nor gani c f i ne powder havi ng a vol ume-based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, the method i ncl udi ng: a step of gener at i ng a powder to be cl assi f i ed by adsorbing a carboxyl i c aci d onto an i norgani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed, under the condi ti on that the i norgani c raw mat eri al powder bei ng i n a di spersed state in a gas phase at the ti me of generati on has been di spersed i n the gas phase; and a step of subj ect i ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
[ 0033]
As a result, it is possible to provi des the method for produci ng the inorganic fine powder havi ng the vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, cont ai ni ng the extremely small number of part i cl es with high pr oduct i vi ty.
[ 0034]
This excellent effect is consi dered to be achi eyed for the f ol I owi ng reasons.
Compared with dry classification by mi xi ng a powder and an auxi I i ary agent such as ethanol and vapor i zi ng the auxi I i ary agent, i t i s possi bl e to i mprove di spersi bi I i ty of the powder to be classified in the gas phase and to enhance classification accuracy by adsorbi ng the carboxyl i c aci d onto the i norgani c raw mat er i al powder havi ng the D50 of 10 pm or I ess, under the condi ti on that the i norgani c raw mat eri al powder bei ng i n the di spersed state in the gas phase at the ti me of generation has been di spersed i n the gas phase.
Therefore, the number of coarse part i cl es contai ned i n the produced i norgani c f i ne powder can be extremel y reduced.
As a result, the number of times of cl assi f i cat i ons can be reduced and productivity i s i mproved.
[ 0035]
Adsorpti on of the carboxyl i c acid on the inorganic raw mat en i al powder i ncreases the fl ui di ty of the powder to be classified and reduces adhesion thereof to inside the classifier, thereby i ncreasi ng a yi el d.
I n addi t i on, reduced adhesi on i nsi de the cl assi f i er prevents blockage of the powder supply port and i nsi de the pi pi ng of the cl assi f i er, thereby ext endi ng the oper at i on time of the cl assi f i er and i mprovi ng productivity.
[ 0036]
Thi s embodi ment obtai ns the powder to be cl assi f i ed by adsorbi ng the carboxyl i c aci d onto the i norgani c raw material powder havi ng the 050 of 10 pm or I ess, under the condi ti on that the i norgani c raw mat eri al powder bei ng i n the di spersed state i n the gas phase at the ti me of generat i on has been di spersed i n the gas phase.
For t hi s reason, consi der i ng the step of adsorbi ng the carboxyl i c aci d, the number of steps can be reduced compared to the above-described embodi ment, which is advantageous i n the vi ewpoi nt of productivity.
I n addi ti on, a van i at i on i n the amount of carboxyl i c aci d adsorbed on each part of the i norgani c raw mat er i al powder can be more effectively suppressed, and the f i nal i norgani c f i ne powder wi I I have a more i deal part i cl e size di st ri but i on with an extremely smal I number of coarse part i cl es. Furthermore, because the amount of carboxyl i c aci d adsorbed on the powder to be cl assi f i ed can be easi I y controlled by controlling the amount of carboxyl i c acid supplied, the f i nal i norgani c f i ne powder has an extremely smal I
number of coarse part i cl es and a more i deal part i cl e size di stri but i on.
[ 0037] 3. Thi rd Embodi ment The met hod for produci ng the inorganic f i ne powder accordi ng to the t hi rd embodi ment of the present i nventi on i s a method for produci ng an i nor gani c f i ne powder havi ng a vol ume-based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, the method i ncl udi ng: a step of gener at i ng a powder to be cl assi f i ed by di spersi ng an i norgani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ect i ng the powder to be cl assi f i ed to dry cl assi f i cat i on; wherei n the step of generati ng the powder to be cl assi f i ed i s performed i n an atmosphere contai ni ng a carboxyl i c aci d in a gaseous state.
[ 0038]
As a result, it is possible to provide the method for producing the inorganic fine powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, contai ni ng the extremely smal I number of coarse part i cl es with hi gh productivity.
[ 0039]
This excellent effect is consi dered to be achi eyed for the f ol I owi ng reasons.
Compared with dry classification by mi xi ng a powder and an auxi I i ary agent such as ethanol and vapor i zi ng the auxi I i ary agent, i t i s possi bl e to i mprove di spersi bi I i ty of the powder to be classified in the gas phase and to enhance cl assi f i cat i on accuracy by obt ai ni ng the powder to be cl assi f i ed by di spersi ng the i norgani c raw mat er i al powder i n the atmosphere cont ai ni ng the car boxyl i c acid in a gaseous state.
For t hi s reason, the number of coarse part i cl es i n the produced i norgani c f i ne powder can be extremely reduced.
The number of times of classifications can be reduced and product i vi ty is i mproved.
[ 0040]
Adsorpti on of the carboxyl i c acid on the inorganic raw mat en i al powder i ncr eases the fl ui di ty of the powder to be classified and reduces adhesi on thereof to inside the classifier, thereby i ncreasi ng a yi el d.
I n addi t i on, reduced adhesi on i nsi de the cl assi f i er prevents blockage of the powder supply port and i nsi de the pi pi ng of the cl assi f i er, thereby ext endi ng the oper at i on time of the cl assi f i er and i mpr ovi ng productivity.
[ 0041]
Thi s embodi ment obtai ns the powder to be Cl assi f i ed by di spersi ng the i norgani c raw mat er i al powder i n the atmosphere contai ni ng the car boxyl i c aci d in the gaseous state. For t hi s reason, consi der i ng the step of adsorbi ng the car boxyl i c aci d, the number of processes can be reduced compared to the first embodi ment above, whi ch i s advantageous from the vi ewpoi nt of product i vi t y. I n addi t i on, a vari at i on i n the amount of carboxyl i c aci d adsorbed on each part of the i nor gani c raw material powder can be more effectively suppressed, and the final i norgani c f i ne powder wi I I have a more i deal part i cl e size di st r i but i on with an extremely smal I number of coarse part i cl es.
Furthermore, because the amount of carboxyl i c aci d adsorbed on the powder to be cl assi f i ed can be easi I y control I ed by control I i ng the amount of carboxyl i c acid supplied, the final i norgani c f i ne powder has an extremely smal I number of coarse part i cl es and a more i deal part i cl e size di st ri but i on.
[ 0042]
In each of the above embodi ments, the reason why the di spersi bi I i ty of the powder to be cl assi f i ed i s enhanced by obtai ni ng the powder to be classified, whi ch compri ses the i norgani c raw mat eri al powder havi ng a carboxyl i c aci d adsorbed thereon, i s unknown, and the i nvent ors assume as f ol I ows.
The i norgani c raw mat eri al powder general I y has a f uncti onal group such as a hydroxyl group on the surf ace of its constituent part i cl es that can i nteract with carboxyl group.
By adsorbi ng the carboxyl i c aci d on the i norgani c raw mat er i al powder, the functional group such as the hydroxyl group on the surf ace of the constituent part i cl es of the i norgani c raw material powder interact with the carboxyl group (- COOH) of the carboxyl i c acid, thereby a port i on of the carboxyl i c aci d other than the carboxyl group such as a hydrocarbon port i on i s posi ti oned out si de the metal powder part i cl es. As a result, aggr egat i on of the i norgani c raw mat en i al powder by a polar group such as the hydroxyl group i s suppressed, thereby i mprovi ng di spersi bi I i ty.
When the i nor gani c raw mat en i al powder i s, for exampl e, a metal powder, even i n sites where there are no f uncti onal groups that i nteract with the carboxyl group such as the hydroxyl group, the carboxyl i c aci d can adsorb by react i ng with the metal to form metal carboxyl ate, or by f ormi ng coordi nati on bonds with metal atoms on the surf ace of the metal powder, thereby a sui t abl e amount of carboxyl i c aci d can be adsorbed more uni f orml y on the part i cl e surface.
I n addi t i on, due to a sui tabl e amount of carboxyl i c aci d adsorbed uni f orml y on the parti cl e surface, the f ormati on of pol ar group such as the hydroxyl group can be suppressed.
As descri bed above, both physi cal adsorpti on and chemi cal adsorpti on are possi bi e as adsorpti on in the present i nventi on.
[ 0043]
If the above conf i gur at i ons are not sat i sf i ed, it woul d be di ff i cul t to obtai n sat i sf act ory results.
For exampl e, if the carboxyl i c aci d i s not adsorbed on the powder to be cl assi f i ed i n each of the above embodi ments, di spersi bi I i ty of the powder to be classified in the gas phase may not be suf f i ci ent I y i mproved i n the step of dry cl assi f i cat i on.
For t hi s reason, cl assi f i cat i on accuracy may not be suf f i ci ent I y enhanced, and the number of coarse part i cl es i n the produced i norgani c f i ne powder wi I I i ncrease.
The requi red number of times of classifications will increase, resul ti ng i n a reduced product i vi ty.
Because fl ui di ty of the powder to be classified cannot be suf f i ci ent I y i ncr eased, adhesion of the powder to be cl assi f i ed i nsi de the classifier will i ncr ease, and a yi el d will be decreased. I n addi t i on, because i ncreased adhesi on i nsi de the cl assi f i er tends to cl og the powder suppl y port and the i nsi de of the pi pi ng i n the cl assi f i er, the oper at i on ti me of the cl assi f i er will be shortened and the product i vi ty will be reduced.
[ 0044] <CLASSI Fl ER>
FIG. 1 is a di agram showi ng a conf i gurati on exampl e of a cl assi f i er used i n the method for produci ng an i norgani c f i ne powder accordi ng to the present i nventi on.
I n the f ol I owi ng descri pti on, the upper si de i n Fl G. 1 i s ref erred to as "upper" and the I ower si de i n Fl G. 1 i s ref erred to as "1 ower".
[ 0045]
A cl assi f i er 1 i s an ai rf I ow cl assi f i er whi ch perf orms cl assi f i cation using centrifugal force act i ng on the powder. The cl assi f i er 1 i ncl udes a casi ng 3 whi ch forms a cl assi f i cat i on chamber 10.
[ 0046]
At the upstream si de of the classification chamber (Cl assi f i cat i on zone) 10, there i s a di spersi on zone 11 where the i nor gani c raw mat en i al powder i s di spersed pri or to cl assi f i cat i on.
The Cl assi f i cat i on chamber 10 i s the area where the di spersed i nor gani c raw mat eri al powder i s cl assi f i ed.
[ 0047]
The classifier 1 has an introduction port 4 for i ntroduci ng the i nor gani c raw mat en i al powder i nto the di spersi on zone 11, an ai r nozzl e 5 that i nj ects hi gh- pressure ai r (pri mary air) into the dispersion zone 11, a guide vane 6 to introduce secondary ai r to flow i nto the cl assi f i cat i on chamber 10 to form a swi rl i ng ai rf I ow i n the cl assi f i cat i on chamber 10, a f i ne powder di scharge port 7 that has an openi ng at the upper center of the cl assi f i cat i on chamber 10, and a coarse powder di scharge port 8 that has an openi ng al ong the I ower pen i phery of the cl assi f i cat i on chamber 10.
[ 0048]
Next, the method for dispersing and classifying the i norgani c raw mat en i al powder usi ng the cl assi f i er 1 i s expl ai ned.
[ 0049]
The inorganic raw material powder is introduced into the di spersi on zone 11 from the i nt roduct i on port 4.
The i norgani c raw mat eri al powder i s di spersed by a di spersi ng force i mparted by the pri mary ai r i nj ected i nto the di spersi ng zone 11.
Then, the i norgani c raw materi al powder i s i ntroduced i nto the classification chamber 10 in a dispersed state.
[ 0050]
In the classification chamber 10, the secondary air i s fl own t her ei n through the gui de vane 6, whi ch ai rf I ow i s swi rl ed i n the cl assi f i cat i on chamber 10 and is exhausted from the upper center of the cl assi f i cation chamber 10.
An outward centrifugal force exerted by the swi rl i ng ai rf I ow and a centrally-directed airflow separate the inorganic raw material powder i n the sol i d- gas mixture i nto a coarse powder and a f i ne powder.
[ 0051]
The coarse powder moves radi al I y outward i n the cl assi f i cation chamber 10 due to the outward centrifugal force of the swi rl i ng ai rf I ow, and i s col I ect ed from the coarse powder di scharge port 8 on the lower pen i phery of the cl assi f i cat i on chamber 10.
On the other hand, the f i ne powder moves radi ally i nward i n the cl assi f i cat i on chamber 10 due to the central I y-di rected ai rf I ow, and i s col I ect ed from the f i ne powder di scharge port 7 at the upper center of the cl assi f i cat i on chamber 10.
[ 0052] A suction pump ( not shown in the figure) is connected to the f i ne powder discharge port 7.
The f i ne powder i s di scharged and collected together with the ai r ( exhaust ai r) i n the classification chamber 10.
[ 0053] The step of generating a powder to be classified corresponds to the step performed i n the di spersi on zone 11, and the step of dry classification corresponds to the step performed i n the cl assi f i cat i on chamber ( cl assi f i cat i on zone) 10.
That i s, the i nor gani c raw mat en i al powder i n a di spersed state in the di spersi on zone 11, or i n other words, the powder i ntroduced i nt o the cl assi f i cation chamber 10, is the powder to be cl assi f i ed in this speci f i cat i on.
[ 0054] I n the above expl anat i on, the ai rf I ow cl assi f i er that uses the cent ri fugal force from the swi r I i ng ai rf I ow for the cl assi f i cat i on is used as an exampl e, but the cl assi f i cat i on met hod of a Cl assi f i er i s not limited to any part i cul ar method.
For exampl e, a classification met hod for ut i I i zi ng centrifugal force due to rot ati on of a rotor, a cl assi f i cat i on method for usi ng gravity, and a cl assi f i cat i on met hod for usi ng i nert i al force may be used.
[ 0055] I n the present i nvent i on, the step of gener at i ng a powder to be cl assi f i ed and the step of dry cl assi f i cat i on are not I i mi t ed to the case where the same equi pment i s used, and may be perf or med usi ng separate equi pment .
I n other words, the powder to be cl assi f i ed may be obtai ned by di spersi ng the i nor gani c raw mat eri al powder i n a di spersi ng machi ne, and then cl assi f yi ng the powder to be classified in a dry classifier.
[ 0056] <STEP OF GENERATI NG POWDER TO BE CLASSI Fl ED>
I n the step of generat i ng a powder to be cl assi f i ed, the powder to be classified havi ng a carboxyl i c aci d adsorbed thereon i s obtai ned i n the di spersed state in the gas phase.
[ 0057] (I NORGANI C RAW MATER! AL POWDER) The i norgani c raw mat eri al powder is a raw mat eri al for the i nor gani c f i ne powder produced i n the present i nvent i on and has a part i ci e di ameter at a vol ume- based cumulative percentage of 50%, D50, of 10 pm or I ess.
[ 0058]
It is suff i ci ent that a vol ume- based cumul at i ve 50%
part i ci e di ameter 050 of the i norgani c raw material powder i s 10 pm or I ess, but i s pref erabl y greater than 0. 01 pm.
I n part i cul ar, the vol ume- based cumul at i ve 50% part i ci e di ameter D50 of the i norgani c raw mat en i al powder i s preferably greater than 0.03 pm and 2.5 pm or I ess, more preferably greater than 0.05 pm and 1.2 pm or less, and even more preferably greater than 0.10 pm and 0.80 pm or less.
[ 0059]
Examples of inorganic components of the inorganic raw mat en i al powder i ncl ude, though not I i mi ted, van i ous metal s, van i ous metal oxi des, van i ous gl asses, van i ous cerami cs, and van i ous semi conductors.
[ 0060]
Examples of the metals that compose the inorganic raw mat er i al powder i ncl ude, for exampl e, si I ver, gol d, pl at i num, copper, pal I adi um, ni ckel , tungsten, zi nc, t i n, i r on, cobalt, and al I oys contai ni ng one or more sel ected from these metal s.
[ 0061] Exampl es of the met al oxi des t hat compose the i norgani c raw mat eri al powder (metal oxi des other than cerami cs) i ncl ude, for exampl e, ni ckel oxi de, copper oxi de, Si I ver oxi de, and i ron oxi de.
[ 0062]
Examples of the glasses that compose the inorganic raw mater i al powder i ncl ude, for exampl e, bi smut h- based gl ass, tell uri urn-based glass, and silicate glass.
[ 0063]
Exampl es of the cerami cs that compose the i norgani c raw mat er i al powder i ncl ude, for exampl e, oxi de- based cerami c, ni tri de- based cerami c, and bori de- based cerami c, and more speci f i call y, al umi na, Si I i ca, zi rconi a, bar i urn ti tanate, cal ci urn zi rconate, al umi na ni tri de, si I i con ni tri de, and boron ni tri de. The exampl es of cerami cs al so i ncl ude f uncti onal cerami cs such as phosphors.
[ 0064]
Examples of the semi conduct ors that compose the i norgani c raw mat er i al powder i ncl ude, f or exampl e, I nP, GaP, I nAs, GaAs, I nGaP, I nZnP, ZnSe, CdSe, and CdS.
[ 0065] In part i cul ar, the inorganic component of the i norgani c raw mat er i al powder i s pref erabl y at I east one sel ected from the group consi sti ng of metal s, metal oxi des, gl asses, cerami cs, and semi conductors.
[ 0066] These components will make the carboxyl i c acid f uncti on more suitably and further i mprove the di spersi bi I i ty of the i nor gani c raw mat er i al powder.
[ 0067]
When the inorganic component of the inorganic raw mat er i al powder i s a metal , metal oxi de, gl ass, or oxi de- based cerami c, the af or ement i oned effects are more remarkably exhi bi ted. The reason for t hi s has not yet been found, but the i nvent or s assume to be the presence of many hydroxyl groups on the part i cl e surf ace of the i norgani c raw mat eri al powder.
I n part i cul ar, when the i norgani c component of the i norgani c raw material powder i s a metal , there would be many hydroxyl groups on the oxi di zed surf ace of the powder where metal oxi des are formed.
On the other hand, non-oxidized areas can adsorb a sui tabl e amount of carboxyl i c aci d more uni f orml y due to generat i on of metal carboxyl ate by the reaction of the metal with the carboxyl i c aci d, or f ormati on of coordi nati on bonds of the carboxyl group with metal atoms on the powder surface. For these reasons, the i nvent ors assume that the af orementi oned effect i s more remarkabl y exhi bi ted.
Thi s effect i s more remarkably exhi bi ted when the i norgani c component of the i norgani c raw mat er i al powder i s composed of ni ckel .
[ 0068]
A shape of the inorganic raw material powder is not I i mi ted, and exampl es thereof i ncl ude spheri cal , fl aky, granul ar, van i ous other shapes, and a mixture of one or more sel ected t her ef r om.
[ 0069]
I n t hi s speci f i cat i on, the term "spheri cal " refers to a part i cl e shape i n whi ch the rat i o of a I ong di ameter to a short di ameter i s 2 or I ess.
The term "f I aky" refers to a shape i n whi ch the rati o of a I ong di ameter to a short di ameter exceeds 2.
[ 0070]
The method for produci ng the i norgani c raw mat eri al powder i s not I i mi ted, and may be, for exampl e, an el ectrol ysi s method, an at omi zati on method, a mechani cal pul veri zati on method, a wet reducti on method, a spray pyrol ysi s method, a chemi cal vapor deposi ti on method, or a physi cal vapor deposi ti on method.
[ 0071]
The particles of the inorganic raw material powder may compri se a uni form composi ti on or a pl ural i ty of composi ti ons.
[ 0072] (Carboxyl i c acid) The carboxyl i c aci d i s adsorbed on the i nor gani c raw material powder i n the powder to be cl assi f i ed.
The adsorpti on i n the present i nventi on can be either physi cal adsorpti on or chemi cal adsorpti on.
Thi s provi des a sati sf act ory di spersi bi I i ty of the powder to be cl assi f i ed i n the gas phase and facilitates to obtai n the i nor gani c f i ne powder with a desi red part i cl e si ze di st r i but i on i n hi gh yi el d.
The number of coarse part i cl es i n the resul ti ng inorganic fine powder can al so be extremely small .
[ 0073]
The carboxyl i c aci d i s not I i ml ted as I ong as it is a compound havi ng a carboxyl group, and exampl es thereof i ncl ude f ormi c aci d, aceti c aci d, propi oni c aci d, i sobutyri c aci d, but yri c aci d, crotoni c aci d, i soval en i c aci d, val en i c aci d, caproi c aci d, enant hi c aci d, capryl i c aci d, pel argoni c aci d, I act i c aci d, oxal i c aci d, succi ni c aci d, ol ei c aci d, acryl i c aci d, and met hacryl i c aci d, and one or a combi nati on of two or more sel ected therefrom may be used.
[ 0074] Among these, those havi ng a boiling poi nt of from 100 C to 400 C are preferred, those havi ng a boil i ng poi nt of from 105 C to 250 C are more pref erabl e, and those havi ng a boil i ng poi nt of from 110 C to 200 C are even more pref erabl e.
[ 0075] This allows to handle the carboxyl i c acid suitably in a I i qui d state dun i ng the step of generati ng the powder to be cl assi f i ed and to i mprove handl i ng property. When the carboxyl i c aci d i s adsorbed on the powder i n a vapor i zed state, si nteri ng of the i norgani c raw mat eri al powder can be more effectively prevented, al I owi ng a more uni form adsorpti on of the carboxyl i c acid onto the i norgani c raw materi al powder.
[ 0076] I n t hi s speci f i cat i on, unl ess otherwi se speci f i ed, the term "boil i ng poi nt" refers to a boil i ng poi nt under 1 at mos pher e.
[ 0077] The carboxyl i c acid is preferable to be a monocarboxyl i c aci d.
Thi s provi des more sui tabl e di spersi bi I i ty of the powder to be cl assi f i ed, and the effects of the present i nventi on will be more remarkabl y exhi bi t ed.
[ 0078] The carboxyl i c acid is preferably at least one sel ected from aceti c acid, propi oni c aci d, butyri c acid, and ol ei c aci d, and more pref erabl y, acet i c aci d.
[ 0079] These will provi de more sui tabl e di spersi bi I i ty of the powder to be cl assi f i ed, and the effects of the present i nvent i on will be more remarkably exhi bi t ed.
[ 0080] In the first embodi ment above, the powder to be cl assi f i ed i s obtai ned by di spersi ng i n the gas phase the carboxyl i c aci d- adsorbed inorganic raw material powder in which the carboxyl i c aci d i s adsorbed on the i norgani c raw mat eri al powder havi ng the vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 10 pm or I ess.
[ 0081] First, the carboxyl i c acid-adsorbed inorganic raw materi al powder i n whi ch the carboxyl i c aci d i s adsorbed on the inorganic raw material powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 10 prii or I ess i s prepared.
[ 0082] A method for producing the carboxyl i c aci d- adsorbed i nor gani c raw materi al powder i s not I i mi ted, and a preferred exampl e is a method of adsorbi ng a carboxyl i c aci d in a gaseous state onto the i norgani c raw materi al powder.
[ 0083] By adsorbi ng the carboxyl i c acid in the gaseous state onto the i nor gani c raw mat en i al powder, the carboxyl i c aci d can be more uniformly adsorbed on the i norgani c raw materi al powder, so that the effects of the present i nvent i on will be more remarkably exhi bi ted.
[ 0084] The method of adsorbi ng the carboxyl i c acid in the gaseous state onto the i norgani c raw materi al powder i s not I i mi ted, and exampl es thereof i ncl ude pl aci ng the i norgani c raw materi al powder i n an atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state, and bl owi ng gas cont ai ni ng the vapori zed carboxyl i c aci d onto the i norgani c raw materi al powder.
[ 0085] Then, the powder to be classified is obtai ned by di spersi ng the carboxyl i c aci d- adsorbed i norgani c raw materi al powder i n the gas phase.
[ 0086] In the second embodi ment above, the powder to be cl assi f i ed i s obtai ned by adsorbi ng the carboxyl i c aci d onto the inorganic raw material powder having the vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 10 pm or I ess under the condi ti on that the i norgani c raw materi al powder bei ng i n the di spersed state in the gas phase at the ti me of generat i on has been di spersed i n the gas phase.
[ 0087] Exampl es of the method of gener at i ng the i nor gani c raw materi al powder bei ng i n the di spersed state in the gas phase at the ti me of generati on i ncl ude gas phase methods such as chemi cal vapor deposi t i on and physi cal vapor deposi t i on, an at omi zat i on method, and a spray pyrol ysi s method.
I n part i cul ar, by gener at i ng the i nor gani c raw mat eri al powder usi ng the gas phase met hod or the spray pyrol ysi s method, a part i cl e size of the i nor gani c raw mat er i al powder can be more easi I y adj ust ed to the part i cl e si ze range according to the present i nventi on.
[ 0088]
The met hod of adsorbing the carboxyl i c acid onto the i nor gani c raw mat eri al powder i s not I i mi t ed, and a met hod of adsor bi ng the carboxyl i c aci d in the gaseous state onto the i nor gani c raw mat eri al powder i s preferred.
Speci f i cal I y, for exampl e, there is a met hod of bi owi ng the vapor i zed car boxyl i c aci d onto the i nor gani c raw mat eri al powder dun i ng a cool i ng process of the i nor gani c raw mat en i al powder bei ng i n the di spersed state in the gas phase at the time of gener at i on and bei ng generated at a predet ermi ned temperature.
[ 0089]
The above methods enable the car boxyl i c acid to adsorb onto the i nor gani c raw mat er i al powder more uniformly.
As a result, the aggregati on of part i cl es can be more effectively suppressed and di spersi bi I ity can be further improved.
Thi s makes the effects of the present i nvent i on to be more remarkably exhi bi t ed.
[ 0090]
I n addi ti on, by adsor bi ng the car boxyl i c aci d onto the i nor gani c raw mat er i al powder under the condi ti on that the i nor gani c raw mat er i al powder bei ng i n the di spersed state i n the gas phase at the ti me of gener at i on has been di spersed i n the gas phase to obtai n the powder to be cl assi f i ed, the number of steps can be reduced, resul ti ng i n further improvement of pr oduct i vi t y.
[ 0091]
in the second embodi ment , it is preferable to further i ncl ude a step of coil ect i ng the powder to be cl assi f i ed and a step of di spersi ng the powder to be cl assi f i ed obt ai ned i n the step of coil ect i ng i n the gas phase between the step of gener at i ng an powder to be cl assi f i ed and the step of dry cl assi f i cat i on.
[ 0092]
As a result, it is possible to facilitate combining more sui tabl e cl assi f i ers to improve a cl assi f i cat i on accuracy i n the subsequent step of dry cl assi f i cat i on, resul ti ng i n an i mproved productivity of i norgani c f i ne powder.
[ 0093]
I n the t hi rd embodi ment of the present i nventi on, the powder to be cl assi f i ed is obt ai ned by di spersi ng the i norgani c raw mat eri al powder havi ng the vol ume- based cumul at i ve 50%
part i cl e di ameter D50 of 10 pm or I ess i n the atmosphere contai ni ng the carboxyl i c aci d in the gaseous state.
[ 0094]
First, the inorganic raw material powder having the vol ume- based cumul at i ve 50% part i cl e di amet er D50 of 10 pm or I ess i s prepared.
The i norgani c raw materi al powder i s then di spersed i n the atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state to obtai n the powder to be cl assi f i ed.
[ 0095]
By dispersing the inorganic raw material powder in the atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state, the carboxyl i c aci d can be adsorbed on the i norgani c raw material powder more uniformly. As a result, the aggregati on of part i cl es can be more effectively suppressed to further i mprove di spersi bi I i ty.
The amount of carboxyl i c aci d adsorbed on the i norgani c raw mat en i al powder i s al so easi er to control .
Thi s enabl es the effects of the present i nvent i on to be more r emarkabl y exhi bi t ed.
I n addi ti on, by di spersi ng the i norgani c raw mat en i al powder i n the atmosphere contai ni ng the carboxyl i c aci d in the gaseous state, the number of steps can be reduced to further i mprove product i vi ty.
[ 0096]
In the second embodi ment and the third embodi ment, the amount of carboxyl i c aci d used i s not I i mi t ed.
Preferably, it is used i n an amount of from 30 mol es to 960 mol es, more pref erabl y from 60 mol es to 480 mol es, and even more pref erabl y from 120 mol es to 240 mol es per 1 m3 of i norgani c raw mat eri al powder.
[ 0097]
I n the above ranges, a sui tabl e amount of carboxyl i c acid can be adsorbed on the i nor gani c raw mat en i al powder more uni f orml y to i mprove the di spersi bi I i ty of the powder to be cl assi f i ed.
I n addi ti on, the amount of carboxyl i c aci d adsorbed on the i norgani c raw material powder wi I I be prevented from being too large, and the properties of the produced inorganic fine powder wi I I be more pref erabl e when the i norgani c f i ne powder i s made i nt o a paste.
[ 0098]
A vol ume of i nor gani c raw mat eri al powder accordi ng to the present i nventi on refers to a vol ume cal cul at ed from the weight and true density of the powder.
[ 0099]
A supply rate of the i norgani c raw mat en i al powder to the cl assi f i er, i . e. , for exampl e, a supply rate of the i norgani c raw mat er i al powder from the i nt roduct i on port 4 to the di spersi on zone 11 i n the cl assi f i er 1 shown i n Fl G. 1, depends on a si ze (capaci ty) of the cl assi fi er.
Prefer abl y, the rate ranges from 1 kg/ hr to 20 kg/ hr, more preferably from 3 kg/ hr to 15 kg/ hr, and even more preferably from 5 kg/ hr to 12 kg/ hr .
[ 0100] In the above ranges, the di spersi bi I i ty of the i norgani c raw mat eri al powder i s superi or, and the producti vi ty of the i nor gani c f i ne powder i s i mproved.
[ 0101]
A suppl y and di spersi ng pressure dun i ng di spersi on, i . e. , for exampl e, a pressure of di spersi ng ai r i nj ect ed from the ai r nozzle 5 i nto the di spersi ng zone 11 in the cl assi f i er 1 shown i n Fl G. 1, i s not limited, and preferably ranges from O. 2 MPa to 1.0 MPa, more preferably from 0.4 MPa to 0.8 MPa, and even more preferably from 0.5 MPa to 0.7 MPa.
[ 0102] In the above ranges, the di spersi bi I i ty of the i norgani c raw mat eri al powder i s superi or, and the producti vi ty of the i nor gani c f i ne powder i s i mproved.
[ 0103] <STEP OF DRY CLASSI Fl CATI ON>
I n the step of dry cl assi f i cat i on, the powder to be classified obtai ned in the step of generating the powder to be cl assi f i ed i s dry cl assi f i ed.
[ 0104]
Because the powder to be cl assi f i ed to whi ch the carboxyl i c aci d i s adsorbed i s sui tabl y di spersed i n the gas phase, the cl assi f i cat i on accuracy i n the step of dry cl assi f i cation i s improved.
Consequent I y, the number of coarse part i cl es in the produced inorganic fine powder can be ext remel y reduced.
I n addi ti on, the i mproved cl assi f i cation accuracy can reduce the number of times of cl assi f i cat i ons to improve pr oduct i vi ty.
[ 0105]
As the f I ui di ty of the powder to be cl assi f i ed i s i ncreased, adhesi on of the powder to be cl assi f i ed to an i nsi de of the cl assi f i er wi I I be reduced, whi ch i mproves the yi el d.
As the adhesi on of the powder to be cl assi f i ed to the i nsi de of the cl assi f i er i s reduced, bl ockage of a powder suppl y port and an i nsi de of the pi pi ng of the cl assi f i er hardl y occur, thereby ext endi ng the oper at i on ti me of the cl assi f i er.
Thus, the product i vi ty is i ncreased.
[ 0106] Thus, the i nor gani c f i ne powder contai ni ng the extremel y smal I number of coarse part i cl es can be produced with a hi gh product i vi ty.
[ 0107]
A gas phase temperature at whi ch the step of dry cl assi f i cation i s performed i s not I i mi ted, and pref erabl y ranges from 60 C to 300 C, more pref erabl y from 100 C to 250 C, and even more pref erabl y from 150 C to 200 C.
[ 0108] in the ranges, probl ems such as deformation of part i cl es by heat and al terat i on of constituent mat er i al s of the part i cl es are prevented more eff ecti vel y. At the same ti me, the cent ri fugal force i s i ncreased due to a hi gher speed of the ai rf I ow.
I n addi ti on, it is possi bl e to prevent water vapor from adher i ng to the part i cl es, thereby further enhanci ng the cl assi f i cation accuracy.
The productivity can al so be further i mproved.
I n addi ti on, the number of coarse part i cl es i n the i norgani c f i ne powder can be part i cul an y reduced.
[ 01091 A sucti on airflow amount during the step of dry cl assi f i cat i on, i . e. , for exampl e, a sucti on ai rf low amount by the sucti on pump connected to the fine part i cl e discharge port 7 i n the cl assi f i er 1 shown i n Fl G. 1, i s not limited, and preferably ranges from 5.0 m3/mi n to 30 m3/mi n, more pref erabl e from 6.0 m3/mi n to 20 m3/mi n, and even more preferably from 7.0 m3/mi n to 9.0 m3/mi n.
I n these ranges, more ef f i ci ent cl assi f i cat i on of the powder to be cl assi f i ed can be achi eyed.
[ 0110]
A sucti on pressure at which dry classification is performed, i . e. , for exampl e, a sucti on pressure by the sucti on pump connected to the f i ne part i cl e di scharge port 7 i n the cl assi f i er 1 shown i n Fl G. 1, i s not I i mi ted, and preferably ranges from -60 kPa to -5 kPa, more preferably from -50 kPa to -10 kPa, and even more preferably from -40 kPa to -15 kPa.
I n these ranges, a more eff i ci ent cl assi f i cat i on of the powder to be cl assi f i ed can be achi eyed.
[ 01111 By the dry cl assi f i cat i on, the powder to be cl assi f i ed i s cl assi f i ed i nt o a fi ne powder and a coarse powder. The powder to be cl assi f i ed is cl assi f i ed i nto, for exampl e, the f i ne powder havi ng the vol ume- based cumul at i ye 50% part i cl e di amet er D50 rangi ng from 0.01 pm to 5. 0 pm, and the coarse powder havi ng the D50 I arger than that of the f i ne powder.
Among them, the fine powder i s col I ected as the i norgani c f i ne powder produced i n the present i nventi on.
[ 0112]
As descri bed above, the inorganic fine powder havi ng the vol ume- based cumulative 50% particle diameter D50 ranging from 0.01 pm to 5.0 pm is produced.
[ 0113]
The inorganic fine powder produced in this way has an extremely small number of coarse part i cl es.
In addi ti on, secondary aggregati on i s prevented due to the adsorpti on of carboxyl i c aci d on the i norgani c f i ne powder.
[ 0114]
Furthermore, the method as descri bed above can reduce the number of times of cl assi f i cat i ons due to the i mpr oved cl assi f i cat i on accuracy.
Further, adhesi on of the powder to be cl assi f i ed to i nsi de the cl assi f i er i s al so reduced, thereby increasing the yield.
in addi ti on, the reduced adhesion inside the cl assi f i er prevents blockage of the powder supply port and the i nsi de of the pi pi ng of the cl assi f i er, thereby extendi ng the oper at i on time of the cl assi f i er and i mpr ovi ng productivity.
[ 0115]
The step of dry cl assi f i cat i on may be perf ormed onl y once or repeat ed multi pie ti mes, whi ch enabl es to further enhance the classification accuracy.
[ 0116]
A yield of inorganic fine powder in the step of dry cl assi f i cat i on i s not I i mi ted, and i s preferably 80% or hi gher, more pref erabl y 85% or hi gher, and even more pref erabl y 88% or hi gher.
Thus, the effects of the pr event i nvent i on are more remarkabl y exhi bi t ed.
[ 0117]
in this speci f i cat i on, the yield of inorganic fine powder i n the step of dry cl assi f i cat i on is cal cul at ed from a wei ght of the powder before cl assi f i cat i on, i . e. , a wei ght of the powder to be cl assi f i ed, and a wei ght of the powder after cl assi f i cat i on, i . e. , a wei ght of the i norgani c f i ne powder, usi ng the foil owi ng f ormul a:
Yi el d (%) = (wei ght of powder after cl assi f i cat i on / wei ght of powder before cl assi f i cat i on) x 100 [ 0118]
The inorganic fine powder produced by the method accordi ng to the present i nventi on as descri bed above have the vol ume- based cumul at i ve 50% part i cl e di ameter 050 rangi ng from 0.01 pm to 5.0 pm.
Pref erabl y, the Dso of the i norgani c f i ne powder ranges from 0.03 pm to 2.0 pm, more preferably from 0.05 pm to 1. 0 pm, and even more pref erabl y from O. 10 pm to 0.60 pm.
[ 0119]
Thus, the inorganic fine powder with an ideal particle si ze di st ri but i on can be obt ai ned.
Convent i onal I y, when the D50 was wi t hi n such a range, a probl em of coarse par t i cl es is li kel y to occur to cause adverse effects.
I n contrast, the present i nventi on can pr event the occurrence of such a probl em more ef f ecti vel y even when the D50 i s wi t hi n the range. That i s, the effects of the present i nventi on are more remarkably exhi bi ted when the D50 of the i nor gani c f i ne powder i s wi t hi n the above range.
[ 0120]
The inorganic fine powder produced by the met hod accor di ng to the present i nventi on as descri bed above preferably has a val ue of (D90 - Dm)/ 050 rangi ng from 0.30 to 0.90, more preferably from 0.35 to 0. 80, and st i I I more preferably from 0.40 to O. 75, wherei n Dio [ pm] i s a part i cl e di amet er at vol ume- based cumul at i ve f racti on 10%, D50 [Mm] i s a part i cl e di ameter at vol ume- based cumul at i ve f ract i on 50%, and D90 [ pm] i s a part i cl e di ameter at vol ume- based cumul at i ve f r act i on 90% of a part i cl e si ze di st ri but i on measured by a I aser part i cl e Si ze anal yzer. .
[ 0121]
The val ue of (D90- Dio)/ D50 i s an index of a uniformity of the part i cl e si ze di st ri but i on.
A small er val ue of ( D90-Dio)/ D50 i ndi cat es a narrower part i cl e si ze di St r i but i on, i . e.
, more uniform particle size.
[ 0122]
In the range, the inorganic fine powder has more uni form part i cl e si ze and i s used sui tabi y for van i ous appl i cat i ons.
[ 0123]
In the method for producing the inorganic fine powder of the present i nventi on, the number of coarse part i cl es, as determi ned by the f ol I owi ng measurements, i s preferred 30 or I ess, more preferably 15 or I ess, and even more preferably 5 or I ess.
[ 0124]
In such cases, van i ous probl ems caused by the presence of coarse particles in the inorganic fine powder can be prevented more effectively.
[ 0125]
The above measurement of the coarse particle count can be performed, for exampl e, as f ol I ows.
Fi rst I y, a di spersi on I i qui d of the i nor gani c f i ne powder i s prepared by mi xi ng 1.0 g of the i nor gani c f i ne powder with 20 ml of ethanol whi ch mi xt ure is then treated with an ul trasoni c cleaner ( e. g. , W-113 manufactured by Honda El ect roni cs Co., Ltd.) for I minute. Subsequently, 30 ill of the dispersion liquid prepared i s sampled and then dropped onto an al umi num sampl e stand, whi ch i s dri ed to remove the di spersi on medi um. Thereby, a sampl e for measurement i s prepared. The sampl e thus prepared i s observed by usi ng a scanni ng el ectron mi croscope (e. g. , SU-1510 manufactured by Hitachi Hi gh- Tech Corporati on) for 50 f i el ds of vi ew at a magni f i cat i on of 10,000 ti mes. The total number of part i cl es havi ng a diameter 1.5 times or greater than the vol ume-based cumul at i ve 50% part i cl e di ameter D50 of the i nor gani c f i ne powder is counted as the coarse particle count.
[ 0126] [APPLI CATI ONS OF I NORGANI C Fl NE POWDER]
The appl i cat i ons of i nor gani c fine powder produced by the method accordi ng to the present i nventi on are not I i mi t ed.
For example, the inorganic fine powder produced using conductive metal powder as i nor gani c raw mat en i al powder can be used as conduct i ve powder.
[ 0127] Exampl es of constituent mater i al s of conduct i ve metal powder i ncl ude silver, gol d, pl at i num, copper, pal I adi um, ni ckel , tungsten, zinc, ti n, i r on, cobalt, and al I oys cont ai ni ng at I east one sel ected therefrom. Two or more of the above mat eri al s may be used i n combi nati on as conductive powder.
[ 0128]
The conductive powder can be suitably used as conduct i ve mat eri al s for el ect roni c components.
The conduct i ve mat er i al s for the el ect r oni c components are used to form conduct i ve parts.
The appl i cat i ons are not I i mi ted, but i s part i cul an I y sui t abl e for f or mi ng i nt er nal conductors ( i nt er nal el ect rodes) or t ermi nal el ect r odes of multi I ayer .. cerami c el ect roni c components such as multi layer ceramic capacitors, multi I ayer cerami c i nduct ors, and mul ti I ayer pi ezo el ect ri c actuators. The conductive powder for such appl i cat i ons requi res part i cul ar I y hi gh rel i ability.
[ 0129]
The conductive powder produced by the met hod according to the present i nventi on has a small average part i cl e Si ze, a narrow part i cl e si ze di st ri but i on, and hardly contains coarse part i cl es.
For t hi s reason, when the conduct i ve powder i s used for an i nner electrode, it is possi bl e to form an el ect rode I ayer of uni form t hi ckness, and suitably prevent the part i cl es of the conduct i ve powder from contact i ng both of the i nner el ect r odes to cause a short ci rcui t. Accor di ngl y, sat i sf act or y effects are achi eyed even for such appl i cat i ons that requi re part i cul ar I y hi gh r el i abi lit y.
Thus, the effects of the present i nvent i on are more remarkably exhi bi ted when the conduct i ve powder produced by the met hod accordi ng to the present i nventi on i s used to form the i nt er nal conduct ors ( i nt er nal el ect r odes) or the t er mi nal el ect rodes of multi layer cerami c el ect roni c components such as multi I ayer cerami c capacitors, multi I ayer cerami c i nduct or s, and multi layer pi ezo el ect ri c actuators.
[ 0130]
The conductive powder may be used to form conductive port i ons of el ect roni c components, for exampl e, as a conductive paste by mi xi ng with gl ass f ri t and an or gani c vehi cl e.
[ 0131]
The sui t abl e embodi ments of the present i nventi on have been descri bed above, but the present i nventi on i s not limited to these.
[ 0132]
For exampl e, the equi pent sui tabl y used i n the met hod for produci ng the i nor gani c f i ne powder of the present i nventi on i s not I i mi ted to those descri bed i n the af or ement i oned embodi ments.
[ 0133]
As for the method for producing the inorganic fine powder of the present i nvent i on, two or more of the af orementi oned methods descri bed i n the f i rst embodi ment through the t hi rd embodi ment may be performed i n combi nat i on.
[ 0134]
More speci f i cal I y, for exampl e, the powder to be cl assi f i ed may be obtai ned by further adsorbi ng a carboxyl i c aci d onto the carboxyl i c aci d- adsorbed i norgani c raw material powder that has a carboxyl i c acid pre-adsorbed thereon and is di spersed i n the gas phase.
I n other words, the method descri bed i n the f i rst embodi ment may be combi ned with the method descri bed i n the t hi rd embodi ment.
[ 0135]
Al t ernat i vel y, for exampl e, after a powder to be cl assi f i ed i s obt ai ned by gener at i ng the i norgani c raw mat er i al powder bei ng i n the di spersed state i n the gas phase at the ti me of gener at i on and havi ng the D50 of 10 pm or I ess, and adsorbi ng the carboxyl i c aci d on the i norgani c raw mat en i al powder whi ch has been di spersed i n the gas phase, the powder to be classified may be col I ected such that an addi ti onal carboxyl i c aci d i s adsorbed onto the call ected powder.
I n thi s case, when the addi ti onal carboxyl i c aci d i s adsorbed, the powder may be either undi spersed or di spersed i n the gas phase.
I n other words, the method descri bed i n the second embodi ment may be combi ned with the method descri bed i n the f i rst embodi ment, or with the method descri bed in the third embodi ment.
[ 0136]
Al so, for exampl e, the method descri bed i n the f i rst embodi ment may be combi ned wi th the method descri bed i n the second embodi ment and the method descri bed i n the t hi rd embodi ment.
[ 0137]
In these cases, the order of the combi nati on of the correspondi ng methods of each embodi ment ( especi all y the order of the methods of adsorbi ng the carboxyl i c aci d) i s not limited to a part i cul ar order.
EXAMPLES
[ 0138]
The present i nvent i on i s descri bed i n more detail with speci f i c exampl es bel ow, but the present i nvent i on i s not I i mi t ed only to the f ol I owi ng exampl es.
I n the f ol I owi ng expl anat i ons, treatments for whi ch no part i cul ar temperature or humi di ty condi ti ons are i ndi cat ed were conducted at room temperature ( 25 C) and a relative humidity of 50%.
In addi ti on, the van i ous measurement condi ti ons, unl ess ot herwi se i ndi cat ed, are those at room temperature (25 C) and a r el at i ve humi di ty of 50%.
The vol ume- based cumul at i ve f ract i on 10% val ue Dio, the vol ume- based cumulative f ract i on 50% val ue D50, and the vol ume- based cumul at i ve f ract i on 90% val ue D90 were measured for the i nor gani c raw mat en i al powder and i nor gani c f i ne powder using a I aser diffraction/scattering particle size anal yzer (manufactured by HORI BA Ltd. ) .
The boil i ng poi nts of the carboxyl i c aci ds used i n each of the f ol I owi ng exampl es are summari zed i n Tabl e 1.
[ 0139] [Tabl e 1]
Table 1 Boiling Carboxylic acid point Et]
Acetic acid (AA) 118.5 Propionic acid (PA) 141 Butyric acid (BA) 164 Isobutyric acid (IBA) Oleic acid (OA) 360 [ 0140] [ 1] PRODUCTI ON OF I NORGANI C Fl NE POWDER
[ 0141] (Example 1) I n t hi s exampl e, an i nor gani c f i ne powder was produced by the met hod accordi ng to the f i rst embodi ment above, i . e. , dispersing a carboxyl i c acid-adsorbed inorganic raw material powder i n a gas phase to obtai n a powder to be classified. The detai I s are descri bed as f ol I ows.
[ 0142] Fi rst, a ni ckel powder with a vol ume- based cumul at i ve 50% part i cl e diameter D50 of 0.31 pm was prepared as the i norgani c raw mat en i al powder.
[ 0143] The ni ckel powder having acetic acid adsorbed thereon was obtai ned by pl aci ng the ni ckel powder i n an atmosphere contai ni ng acet i c aci d as the carboxyl i c aci d.
The aceti c aci d used had a purity cl ose to 100% (speci al grade 99.
7+%, manufactured by FUJ I Fl LM VVako Pure Chemi cal Corporati on).
[ 0144] The obtai ned ni ckel powder was introduced into the dry classifier shown i n FIG. 1 at a rate of 10 kg per hour and was di spersed at a suppl y di spersi on pressure of O. 6 MPa to obtai n the powder to be cl assi f i ed.
[ 0145] Then, the di spersed and acetic acid-adsorbed ni ckel powder (the powder to be cl assi f i ed) was i ntroduced i nto the cl assi f i cation chamber and was subj ected to the dry cl assi f i cation at an i nternal temperature of the Cl assi f i er of 25 C, a sucti on ai rf I ow of 8. 5 m3/mi n, and a sucti on pressure of -35 kPa to obtain the inorganic fine powder.
[ 0146] (Exampl es 2- 5) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that the carboxyl i c aci ds I i sted i n Tabl e 2 were used i nstead of acetic aci d.
[ 0147] (Example 6) I n t hi s example, the i norgani c f i ne powder was produced by the method accordi ng to the second embodi ment above, i . e. , by adsorbi ng the carboxyl i c aci d onto the i norgani c raw material powder bei ng i n the di spersed state i n the gas phase at the ti me of generati on, to obtai n the powder to be cl assi fled.
The detail s are descri bed as f ol I ows.
[ 0148] First, a ni ckel acetate t et r ahydr at e powder was prepared.
The ni ckel acetate t et rahydrat e powder was sprayed and heated at 1,500 C to obtai n a ni ckel powder as the i norgani c raw materi al powder di spersed i n the gas phase.
The gas phase was cool ed to 500 C whi I e the ni ckel powder as the i norgani c raw materi al powder was di spersed i n the gas phase. An aceti c aci d i n a gaseous state was i ntroduced i nto the gas phase to obtai n an acetic aci d- adsor bed ni ckel powder as the powder to be cl assi f i ed. The amount of aceti c acid added (an amount of used) was 120 mol es per 1 m3 of ni ckel raw materi al powder.
[ 0149]
The obtai ned acetic acid-adsorbed ni ckel powder as the powder to be cl assi f i ed was i ntroduced i nto the dry cl assi f i er shown i n FIG. 1 at a rate of 10 kg per hour. The dry cl assi f i cat i on was performed at an internal temperature of the cl assi f i er of 25 C, a sucti on ai rf I ow of 8.5 m3/ mi n, and a sucti on pressure of -35 kPa to obtai n the i norgani c f i ne powder.
[ 0150] (Example 7) I n t hi s example, the i norgani c f i ne powder was produced by the method accordi ng to the t hi rd embodi ment descri bed above, i . e. , by di spersi ng the i norgani c raw mat er i al powder i n the atmosphere contai ni ng the carboxyl i c aci d i n the gaseous state to obtai n the powder to be cl assi f i ed. The detail s are descri bed as follows.
[ 0151] First, a ni ckel powder having a vol ume- based cumul at i ve 50% parti Cl e di ameter D50 of 0.48 m was prepared as the i nor gani c raw materi al powder.
[ 0152]
The ni ckel powder was introduced into the dispersing zone of the dry cl assi f i er shown i n Fl G. 1 at a rate of 10 kg per hour whi I e aceti c aci d gas was i ntroduced i nto the di spersi ng zone i n an amount of 15 mol es per 1 m3 of the ni ckel powder. At a supply di spersi on pressure of 0.6 MPa, the ni ckel powder was di spersed whi I e the acetic aci d i s adsorbed on the ni ckel powder to obtai n a ni ckel powder with the aceti c aci d adsorbed thereon as the powder to be cl assi f i ed.
[ 0153] Then, the powder to be classified was introduced into the cl assi f i cat i on chamber. The dry cl assi f i cat i on was performed at an i nternal temperature of the cl assi f i er of 25 C, a sucti on ai rf I ow of 8.0 m3/ mi n, and a sucti on pressure of - 25 kPa to obtai n the inorganic fine powder.
[ 0154] (Exampl es 8-14) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 7 above, except that the amount of aceti c aci d added was changed as shown i n Tabl e 4.
[ 0155] (Examples 15-18) The inorganic f i ne powder was produced i n the same manner as i n Exampl e 10 above, except that the parti cl e di ameter of the i norgani c raw mat eri al powder was changed as shown i n Tabl e 4, and the condi ti ons of the process of the dry classification were set as shown i n Tabl e 4.
[ 0156] (Example 19) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that a Cu powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 2.45 pm was used as the inorganic raw material powder, and the condi t i ons of the dry cl assi f i cat i on were set as shown i n Table 5.
[ 0157] (Exampl e 20) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that an Ag- Pd al I oy powder (Ag : Pd = 7 : 3 (wei ght rati o)) having a vol ume- based cumul at i ve 50% parti cl e di ameter Dso of 1.30 pm was used as the I norgani c raw materi al powder, and the condi ti ons of the dry cl assi f i cat i on were set as shown i n Tabl e 5.
[ 0158] (Example 21) The inorganic f i ne powder was produced i n the same manner as descri bed in Example 1 above, except that a Ba0- Si 02-based gl ass powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 of 2.24 [.tm was used as the i nor gani c raw mat eri al powder, and the condi ti ons of the dry cl assi f i cati on were set as shown i n Tabl e 5.
[ 0159] (Example 22) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that a si I i ca powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 of O. 92 pm was used as the i norgani c raw mat eri al powder, and the condi ti ons of the dry cl assi f i cati on were set as shown i n Tabl e
5.
[ 0160] (Comparative Example 1) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that the carboxyl i c aci d was not used.
[ 0161] (Comparative Exampl es 2, 3) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that the compounds I i sted i n Tabl e 2 were used i nstead of the carboxyl i c aci d.
[ 0162] (Comparative Example 4) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 7 above, except that the carboxyl i c aci d was not used.
[ 0163] (Comparative Example 5) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 10 above, except that the compounds I i sted i n Tabl e 4 were used i nstead of the carboxyl i c aci d.
[ 0164] (Comparative Example 6) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 15 above, except that the carboxyl i c acid was not used.
[ 0165] (Comparative Example 7) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 19 above, except that the carboxyl i c acid was not used.
[ 0166] (Comparative Example 8) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 20 above, except that the carboxyl i c acid was not used.
[ 0167] (Comparative Example 9) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 21 above, except that the carboxyl i c acid was not used.
[ 0168] (Comparative Example 10) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 22 above, except that the carboxyl i c acid was not used.
[ 0169] [ 2] EVALUATI ON
[ 2-1] Yield For each of the above Exampl es and Comparative Exampl es, a wei ght of the powder before cl assi f i cat i on, i . e. , the wei ght of the powder to be Cl assi f i ed, and a wei ght of the powder after cl assi f i cat i on, i . e. , the wei ght of the i nor gani c f i ne powder were measured, and the yi el d was cal cul at ed usi ng the f ol I owl ng f ormul a:
Yi el d (%) = (wei ght of powder after cl assi f i cat i on / wei ght of powder before cl assi f i cat i on) x 100 [ 0170] An addi ti onal dry classification was performed for the i norgani c f i ne powder of each of the above Examples and Comparative Examples i n the same manner as descr i bed above, i . e. , the dry cl assi f i cati on was performed twi ce i n total , and a yi el d was al so cal cul at ed.
[ 0171] [ 2- 2] EVALUATI ON OF PARTI CLE SI ZE DI STRI BUTI ON
For each of the above Exampl es and Comparati ve Exampl es, part i cl e si ze di st ri but i ons were measured for the i norgani c raw mat er i al powder and for the obtai ned i norgani c f i ne powder by usi ng the I aser di ff racti on/ scatt eri ng part i cl e Si ze anal yzer LA- 960 (manufactured by HORI BA, Ltd. ) .
Based on the results, a val ue at t he vol ume- based cumul at i ve f r act i on 10% (Dio) [ pm], a val ue at the vol ume- based cumul at i ve f racti on 50% (D50) [rim], and a val ue at the vol ume- based cumul at i ve f racti on 90% (D90) [Pm]
of the part i cl e si ze di St r i but i on were det ermi ned respect i vel y.
[ 0172]
Then, (D90 - Dio) / D50 was cal cul at ed based on the val ues of Dio [ pm] , D50 [ Pm] , and D90 [rim] determi ned as descri bed above.
[ 0173] [ 2- 3] EVALUATI ON OF COARSE PARTI CLE COUNT
For each of the above Exampl es and Comparative Exampl es, a di spersi on I i qui d was prepared by mi xi ng 1 g of the powder after two ti mes of the Cl assi f i cat i on with 20 ml of ethanol , which mixture was treated with an ul t rasoni c cl eaner ( W- 113 manufactured by Honda El ectroni cs Co., Ltd. ) for 1 mi nut e.
A
sample for measurement was prepared by sampling 30 il of the prepared di spersi on I i qui d, droppi ng the sampl ed di spersi on I i qui d onto an al umi num sampl e stand, and dryi ng to remove the di spersi on medi um.
The sampl e obtai ned was observed with the scanning electron microscope ( SU-1510 manufactured by Hitachi Hi gh- Tech Corporati on) for 50 f i el ds of vi ew at a magni f i cation of 10, 000 ti mes.
The total number of coarse part i cl es, whi ch were def i ned as those with a part i cl e di ameter 2.0 times or greater than the D50 of the target i norgani c f i ne powder determi ned i n [ 2- 2] above, was counted.
[ 0174]
These resul ts are summari zed i n Tabl es 2 through 5, al ong with the condi ti ons for produci ng the i nor gani c f i ne powder.
I n the tabl es, "AA" stands for aceti c aci d, "PA" stands for propi oni c aci d, "BA" stands for butyri c aci d, "I BA" stands for i sobutyri c aci d, "OA" stands for ol ei c aci d, "Et OH" stands for ethanol , and "I PA" stands for i sopropanol .
The uni t for sucti on airflow is [ m3/ mi n], and the unit for suction pressure is [ kPa] .
I n Tabl es 3 and 4, the uni t for the numeri cal val ue of the amount of the carboxyl i c acid added is [mol e/1m3 Ni ] .
The number of part i cl es that had a part i cl e di ameter of 3. 0 ti mes or greater than the vol ume- based cumul at i ve 50% part i cl e diameter D50 was counted for each inorganic fine powder obtai ned i n each of the above Exampl es, accordi ng to the met hod descri bed i n [ 2- 3] above.
No such part i cl es were cont ai ned i n the i norgani c f i ne powder obtai ned in any of the Exampl es.
[ 0175] [Tabl e 2]
C?
2, o La , A
Lo w U' r.., o r.., Y
, P
Table 2 &
Inorganic raw material powder Carboxylic acid Conditions for dry classification Inorganic fine powder Step Number of ification Operating Class cisarse Particle diameter [Tar] conditions of Yield [4] Particle diameter [am]
temperature particles Compound Method of classifier Msn-Camposition {tau-Dio)(Dha [pus]
Caine addition 0.0/1/.1 Classifi Classifi Classifi D D" r-C]
Suction Suction ", , cation cation cation D,a D", P,, airflow pressure once twice tIC_CE.
Example 1 Ni 0.21 0.31 0.48 0.87 AA PlaCed In 25 8.5 -05 86.6 E2.1 23 0.19 0.28 0.41 0.78 atamsphere Example 2 Ni 0.21 0.31 0.48 0.87 PA Placed in 25 8.5 -35 85.6 81.0 26 0.10 0.28 0.42 0.82 atmosphere Example 3 N Placed ini 0.21 0.31 0.48 0.87 BA
25 8.5 -35 05.4 80.7 28 0.18 0.27 0.42 0-09 atmosphere Nxampie 4 Ni 0.21 0.31 0.48 0.87 LELA Placed in 25 8.5 -38 86.2 80.E 35 0.18 0.27 0.42 0.8S
atmosphere E Placed inxample 5 Ni 0.21 0.01 0.40 0.07 OA 25 3.5 -35 35.1 00.4 31 0.10 0.27 0.42 0.05 atmosphere Co-mparativre Ni 0.21 0.31 0.48 0.07 - - 25 0.5 -35 71.6 52.5 E2 0.10 0.27 0.42 0.00 Example I
Comparative-Ni 0.21 0.31 0.48 0.87 8e06 Placed in 25 8.5 -35 76.8 64.7 55 0.10 0.30 0.45 0.87 icample 2 atmosphere Comparative Placed in Ni 0.21 0.01 0.48 0.87 IPA 25 8.5 -35 78.5 65.4 56 0.14 0.30 0.45 0.87 axampie 3 atmosphere OD
OD
[ 0176] [Tabl e 3]
ET:
ftHA' T
A
!
d p;
a w 3 !1 "
u:
A A
= , "
2 .5 N
÷;
'1,f2 uCO, A .d Lri P4 9 8=r' u mu.
H
.61 r.
r n /
C) >
U., , LO
On Ul NJ
NJ
, 9 Table 4 CD inorganic raw material powder Carboxylic acid Ccndi,lans for dry clasaffication step, incrganic fine pdwdar (:) Number of Par -a diar.erer [lam] Adsorp,Lom Classificatipn Operating 55n517ions coarse .....1 Yield W
Particle d amster [pad componfrion õa. Comppund MeMpd uf Amount-,emPsra,.rP te.Weraturs (0. D'''-. name addifico ad..-cSed of classifier partic-es . ......1 {1,..-0,),De, EPc.]
Du: 0, 5g, _ [,--] [1.D
Suction Succion Ciansifica CLasaificas Clasafficar 1 D,, , airflow _, pressure Tion once ion Twice ion twice , Supplied in Ex.7 N 0.33 0.40 D.72 0.31 AA dispersion 13 100 25 6.0 -25 22.6 44.2 15 0.35 0.13 0.60 2.56 LORE 1 . , . - - - - - ..
,.- - ,. 1 Supplied fr.
611.0 Nf 0.33 0.44 D.7: 0.31 AA dispersion 33 100 :5 6.0 -25 60.7 66.0 11 0.34 0.16 0.53 DAB
P.\
..ne H
.
, . , , , Supplied in .
EU
61.5 Nf 0.33 0.48 2.72 0.01 AA dispersion ED
160 25 6.0 -25 25.3 60.2 10 0.3.6 0.40 0.50 0.46 CD-7.011E
, 4 . .
Supplied ta 11.10 NI 0.33 0.40 D.7: 0.51 AA dispersion 120 100 25 0.0 -25 03.2 00.4 3 0. 0.36 0.14 56 0.45 m 501525251 _a .
E0.11 1./ 0.33 0.48 D.72 E.,51 AA disuersion 240 I,J
25 8.0 -25 29...L.' 60.1 9 0.36 0.46 0.59 D.45 lk.J
, Supolied in E0.12 0.33 0.48 1.51 AA dispersion 400 11.0 25 5.0 -25 S2.0 .91.2 ID 0.38 0.4E 0.59 0.48 Supplied in Ex.13 Ni 0.33 0.48 D.72 3.51 AA dispersion 9.10 25 6.0 -25 51.5 60.9 11 0.30 0.46 0.58 0.48 . . .
. . , Supplied in .
E1.14 Ni 0.35 0.40 D.72 3.51 06 dispersion 1020 100 05 8.0 -25 85.6 71.1 13 0.36 0.16 0.58 0.40 is,ne . . , .
.
Supplied ia ' Ex.15 0.88 1.15 0.55 AT.
dis,ersion 1.76. 1.-, 25 ,.5 =5.0 52.5 7 C.,:
.7...38 1.04 D.5.9 ZORE
. .
.
.
Supplied fn Ex1E56 0.21 0., 71.46. AA dispersion 120 105 25 5.5 -35 Of.e 53.3 20 G.41 D.79 .
Supplied tr.
-P. 11.17 N o0(35 0.25 D.46. 0.17 Al d0015001100 120 . 100 60 8.5 -35 e1.1 86.1 15 0.15 0.28 0.40 0.75 C:# , , , . . Supplied Or.
E0.10 Ni 0.21 1 2,16 3.57 AA dispersion 120 100 110 6.5 -35 55.1 50.2 0.15 0.28 0.39 , Ni 0.33 0.48 D.7: D.2.1 :5 6.0 . .2 -25 76 59.5 17 0.35 C, Ex.4 .44 0.61 . 0.59 . . .
:cm 011001150 25 Na 0.33 0.48 2.72 3.01 ZPL dispersion 127 1G0 55 6.0 -25 78.5 61.5 54 0.35 0.14 0.61 0.59 Ex.5 , :OrE
O.., 0.88 L.15 D.S3 25 C.6 61.8 4G.,. 12 C..,8 1.66 D.E3 Ex.6 refers to Example.
'Coln Ex" refers Sc Comparative Example.
[ 0178] [Tabl e 5]
,..-1-- 6161 0 l:Il . 11.
. 'IPA C16 co i.
e_ , r-I DJ 0-6 6,16 , 0 = , ,,, Ill =:16 6E6 1-1 61-6 Lo a !, .:, n ....; =
Lt!
'2, E 8' 'n. '''' '' H
. C; h '.. .3.; Ln ..3 =H; c; c; c;
t 8 rEl CO , 0 CC 0 lal VI 11 ": .
0 , co - .
Cr! 0 , m C; n C! I
.-1 17.1 'rr.1 , Pr' , õ LL.= 01 fi, 8' LE1 V4, .07 -; H
rt57; ''il EI .41 84 ' H ;r3 rl IC u., ..x. ...3 Co E
14 111 1-= 1' 6-1 1- '6 "6 C 0 ,63 1,-, 6, 1 1 Ln CI DJ In 'L Ei r.1 i ,LI
r, 2 .7, g er3 .:11 co cr; h ro .33 0 DI .4 .n CCC L:11 Lo r13 'En ''j 40 ''l H o H H en 1-.; E trl L.
5, g ,pj '-d ;1 L.V=1 0. 0. . ,,, , 0 %
-.
Ill .:, 116 . =
=- .3 Lj .-.
:1 0 Li . _ . .
[ 0160] (Comparative Example 1) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that the carboxyl i c aci d was not used.
[ 0161] (Comparative Exampl es 2, 3) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 1 above, except that the compounds I i sted i n Tabl e 2 were used i nstead of the carboxyl i c aci d.
[ 0162] (Comparative Example 4) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 7 above, except that the carboxyl i c aci d was not used.
[ 0163] (Comparative Example 5) The inorganic f i ne powder was produced i n the same manner as descri bed i n Exampl e 10 above, except that the compounds I i sted i n Tabl e 4 were used i nstead of the carboxyl i c aci d.
[ 0164] (Comparative Example 6) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 15 above, except that the carboxyl i c acid was not used.
[ 0165] (Comparative Example 7) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 19 above, except that the carboxyl i c acid was not used.
[ 0166] (Comparative Example 8) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 20 above, except that the carboxyl i c acid was not used.
[ 0167] (Comparative Example 9) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 21 above, except that the carboxyl i c acid was not used.
[ 0168] (Comparative Example 10) The inorganic f i ne powder was produced i n the same manner as descr i bed in Example 22 above, except that the carboxyl i c acid was not used.
[ 0169] [ 2] EVALUATI ON
[ 2-1] Yield For each of the above Exampl es and Comparative Exampl es, a wei ght of the powder before cl assi f i cat i on, i . e. , the wei ght of the powder to be Cl assi f i ed, and a wei ght of the powder after cl assi f i cat i on, i . e. , the wei ght of the i nor gani c f i ne powder were measured, and the yi el d was cal cul at ed usi ng the f ol I owl ng f ormul a:
Yi el d (%) = (wei ght of powder after cl assi f i cat i on / wei ght of powder before cl assi f i cat i on) x 100 [ 0170] An addi ti onal dry classification was performed for the i norgani c f i ne powder of each of the above Examples and Comparative Examples i n the same manner as descr i bed above, i . e. , the dry cl assi f i cati on was performed twi ce i n total , and a yi el d was al so cal cul at ed.
[ 0171] [ 2- 2] EVALUATI ON OF PARTI CLE SI ZE DI STRI BUTI ON
For each of the above Exampl es and Comparati ve Exampl es, part i cl e si ze di st ri but i ons were measured for the i norgani c raw mat er i al powder and for the obtai ned i norgani c f i ne powder by usi ng the I aser di ff racti on/ scatt eri ng part i cl e Si ze anal yzer LA- 960 (manufactured by HORI BA, Ltd. ) .
Based on the results, a val ue at t he vol ume- based cumul at i ve f r act i on 10% (Dio) [ pm], a val ue at the vol ume- based cumul at i ve f racti on 50% (D50) [rim], and a val ue at the vol ume- based cumul at i ve f racti on 90% (D90) [Pm]
of the part i cl e si ze di St r i but i on were det ermi ned respect i vel y.
[ 0172]
Then, (D90 - Dio) / D50 was cal cul at ed based on the val ues of Dio [ pm] , D50 [ Pm] , and D90 [rim] determi ned as descri bed above.
[ 0173] [ 2- 3] EVALUATI ON OF COARSE PARTI CLE COUNT
For each of the above Exampl es and Comparative Exampl es, a di spersi on I i qui d was prepared by mi xi ng 1 g of the powder after two ti mes of the Cl assi f i cat i on with 20 ml of ethanol , which mixture was treated with an ul t rasoni c cl eaner ( W- 113 manufactured by Honda El ectroni cs Co., Ltd. ) for 1 mi nut e.
A
sample for measurement was prepared by sampling 30 il of the prepared di spersi on I i qui d, droppi ng the sampl ed di spersi on I i qui d onto an al umi num sampl e stand, and dryi ng to remove the di spersi on medi um.
The sampl e obtai ned was observed with the scanning electron microscope ( SU-1510 manufactured by Hitachi Hi gh- Tech Corporati on) for 50 f i el ds of vi ew at a magni f i cation of 10, 000 ti mes.
The total number of coarse part i cl es, whi ch were def i ned as those with a part i cl e di ameter 2.0 times or greater than the D50 of the target i norgani c f i ne powder determi ned i n [ 2- 2] above, was counted.
[ 0174]
These resul ts are summari zed i n Tabl es 2 through 5, al ong with the condi ti ons for produci ng the i nor gani c f i ne powder.
I n the tabl es, "AA" stands for aceti c aci d, "PA" stands for propi oni c aci d, "BA" stands for butyri c aci d, "I BA" stands for i sobutyri c aci d, "OA" stands for ol ei c aci d, "Et OH" stands for ethanol , and "I PA" stands for i sopropanol .
The uni t for sucti on airflow is [ m3/ mi n], and the unit for suction pressure is [ kPa] .
I n Tabl es 3 and 4, the uni t for the numeri cal val ue of the amount of the carboxyl i c acid added is [mol e/1m3 Ni ] .
The number of part i cl es that had a part i cl e di ameter of 3. 0 ti mes or greater than the vol ume- based cumul at i ve 50% part i cl e diameter D50 was counted for each inorganic fine powder obtai ned i n each of the above Exampl es, accordi ng to the met hod descri bed i n [ 2- 3] above.
No such part i cl es were cont ai ned i n the i norgani c f i ne powder obtai ned in any of the Exampl es.
[ 0175] [Tabl e 2]
C?
2, o La , A
Lo w U' r.., o r.., Y
, P
Table 2 &
Inorganic raw material powder Carboxylic acid Conditions for dry classification Inorganic fine powder Step Number of ification Operating Class cisarse Particle diameter [Tar] conditions of Yield [4] Particle diameter [am]
temperature particles Compound Method of classifier Msn-Camposition {tau-Dio)(Dha [pus]
Caine addition 0.0/1/.1 Classifi Classifi Classifi D D" r-C]
Suction Suction ", , cation cation cation D,a D", P,, airflow pressure once twice tIC_CE.
Example 1 Ni 0.21 0.31 0.48 0.87 AA PlaCed In 25 8.5 -05 86.6 E2.1 23 0.19 0.28 0.41 0.78 atamsphere Example 2 Ni 0.21 0.31 0.48 0.87 PA Placed in 25 8.5 -35 85.6 81.0 26 0.10 0.28 0.42 0.82 atmosphere Example 3 N Placed ini 0.21 0.31 0.48 0.87 BA
25 8.5 -35 05.4 80.7 28 0.18 0.27 0.42 0-09 atmosphere Nxampie 4 Ni 0.21 0.31 0.48 0.87 LELA Placed in 25 8.5 -38 86.2 80.E 35 0.18 0.27 0.42 0.8S
atmosphere E Placed inxample 5 Ni 0.21 0.01 0.40 0.07 OA 25 3.5 -35 35.1 00.4 31 0.10 0.27 0.42 0.05 atmosphere Co-mparativre Ni 0.21 0.31 0.48 0.07 - - 25 0.5 -35 71.6 52.5 E2 0.10 0.27 0.42 0.00 Example I
Comparative-Ni 0.21 0.31 0.48 0.87 8e06 Placed in 25 8.5 -35 76.8 64.7 55 0.10 0.30 0.45 0.87 icample 2 atmosphere Comparative Placed in Ni 0.21 0.01 0.48 0.87 IPA 25 8.5 -35 78.5 65.4 56 0.14 0.30 0.45 0.87 axampie 3 atmosphere OD
OD
[ 0176] [Tabl e 3]
ET:
ftHA' T
A
!
d p;
a w 3 !1 "
u:
A A
= , "
2 .5 N
÷;
'1,f2 uCO, A .d Lri P4 9 8=r' u mu.
H
.61 r.
r n /
C) >
U., , LO
On Ul NJ
NJ
, 9 Table 4 CD inorganic raw material powder Carboxylic acid Ccndi,lans for dry clasaffication step, incrganic fine pdwdar (:) Number of Par -a diar.erer [lam] Adsorp,Lom Classificatipn Operating 55n517ions coarse .....1 Yield W
Particle d amster [pad componfrion õa. Comppund MeMpd uf Amount-,emPsra,.rP te.Weraturs (0. D'''-. name addifico ad..-cSed of classifier partic-es . ......1 {1,..-0,),De, EPc.]
Du: 0, 5g, _ [,--] [1.D
Suction Succion Ciansifica CLasaificas Clasafficar 1 D,, , airflow _, pressure Tion once ion Twice ion twice , Supplied in Ex.7 N 0.33 0.40 D.72 0.31 AA dispersion 13 100 25 6.0 -25 22.6 44.2 15 0.35 0.13 0.60 2.56 LORE 1 . , . - - - - - ..
,.- - ,. 1 Supplied fr.
611.0 Nf 0.33 0.44 D.7: 0.31 AA dispersion 33 100 :5 6.0 -25 60.7 66.0 11 0.34 0.16 0.53 DAB
P.\
..ne H
.
, . , , , Supplied in .
EU
61.5 Nf 0.33 0.48 2.72 0.01 AA dispersion ED
160 25 6.0 -25 25.3 60.2 10 0.3.6 0.40 0.50 0.46 CD-7.011E
, 4 . .
Supplied ta 11.10 NI 0.33 0.40 D.7: 0.51 AA dispersion 120 100 25 0.0 -25 03.2 00.4 3 0. 0.36 0.14 56 0.45 m 501525251 _a .
E0.11 1./ 0.33 0.48 D.72 E.,51 AA disuersion 240 I,J
25 8.0 -25 29...L.' 60.1 9 0.36 0.46 0.59 D.45 lk.J
, Supolied in E0.12 0.33 0.48 1.51 AA dispersion 400 11.0 25 5.0 -25 S2.0 .91.2 ID 0.38 0.4E 0.59 0.48 Supplied in Ex.13 Ni 0.33 0.48 D.72 3.51 AA dispersion 9.10 25 6.0 -25 51.5 60.9 11 0.30 0.46 0.58 0.48 . . .
. . , Supplied in .
E1.14 Ni 0.35 0.40 D.72 3.51 06 dispersion 1020 100 05 8.0 -25 85.6 71.1 13 0.36 0.16 0.58 0.40 is,ne . . , .
.
Supplied ia ' Ex.15 0.88 1.15 0.55 AT.
dis,ersion 1.76. 1.-, 25 ,.5 =5.0 52.5 7 C.,:
.7...38 1.04 D.5.9 ZORE
. .
.
.
Supplied fn Ex1E56 0.21 0., 71.46. AA dispersion 120 105 25 5.5 -35 Of.e 53.3 20 G.41 D.79 .
Supplied tr.
-P. 11.17 N o0(35 0.25 D.46. 0.17 Al d0015001100 120 . 100 60 8.5 -35 e1.1 86.1 15 0.15 0.28 0.40 0.75 C:# , , , . . Supplied Or.
E0.10 Ni 0.21 1 2,16 3.57 AA dispersion 120 100 110 6.5 -35 55.1 50.2 0.15 0.28 0.39 , Ni 0.33 0.48 D.7: D.2.1 :5 6.0 . .2 -25 76 59.5 17 0.35 C, Ex.4 .44 0.61 . 0.59 . . .
:cm 011001150 25 Na 0.33 0.48 2.72 3.01 ZPL dispersion 127 1G0 55 6.0 -25 78.5 61.5 54 0.35 0.14 0.61 0.59 Ex.5 , :OrE
O.., 0.88 L.15 D.S3 25 C.6 61.8 4G.,. 12 C..,8 1.66 D.E3 Ex.6 refers to Example.
'Coln Ex" refers Sc Comparative Example.
[ 0178] [Tabl e 5]
,..-1-- 6161 0 l:Il . 11.
. 'IPA C16 co i.
e_ , r-I DJ 0-6 6,16 , 0 = , ,,, Ill =:16 6E6 1-1 61-6 Lo a !, .:, n ....; =
Lt!
'2, E 8' 'n. '''' '' H
. C; h '.. .3.; Ln ..3 =H; c; c; c;
t 8 rEl CO , 0 CC 0 lal VI 11 ": .
0 , co - .
Cr! 0 , m C; n C! I
.-1 17.1 'rr.1 , Pr' , õ LL.= 01 fi, 8' LE1 V4, .07 -; H
rt57; ''il EI .41 84 ' H ;r3 rl IC u., ..x. ...3 Co E
14 111 1-= 1' 6-1 1- '6 "6 C 0 ,63 1,-, 6, 1 1 Ln CI DJ In 'L Ei r.1 i ,LI
r, 2 .7, g er3 .:11 co cr; h ro .33 0 DI .4 .n CCC L:11 Lo r13 'En ''j 40 ''l H o H H en 1-.; E trl L.
5, g ,pj '-d ;1 L.V=1 0. 0. . ,,, , 0 %
-.
Ill .:, 116 . =
=- .3 Lj .-.
:1 0 Li . _ . .
6,l 4,1 q 1
7 , r7d ri.2 U
C; CC ,7. 7, ',-2, F1 .2., ',:,1 1 1 rt :1 11 LI
, c 7,, 1,-, g 'r'21 r'12, 0 0 0 0 1 i i rfti en en ;3; r -en co a;
e i' Ql=
5. - . -a CO,,., - - - _, -= -1 ¨ CO Cl CO ,i .1. ,;:l L.; .1,' AI
VI', SI c, ..... d. ._., c..
,-I
L'1 CO 6, H
co Lo u. CO 1-1 F'.' 1.1 Cl CC!
El I
6g 11, 6:6 I 11 6.1, 60 I .1 I-1 1 11=l 66-1 0 . 1 6 .1 El 1 L, 0 rd ,.-.4 in R, 2 L 'FJ /71 2 Li) ',19 1 r",j In 0 F ; ¨, c, " cl g' '' ' = , . ,L.'. 2 d.I ill II
q' a .,, . ..
,i, 1. kJ 14 44 ,1_, 1:1 , Pill d ,3 24 [ 0179]
As is evi dent from Tables 2 through 5, each of the above Exampl es sui tabl y produced the met al f i ne powder havi ng the D50 i n the range of from 0.01 pm to 5. 0 pm and an extremely small number of coarse part i cl es with a hi gh yi el d.
I NDUSTRI AL APPLI CABI LI TY
[ 0180]
The met hod for produci ng the inorganic fine powder accordi ng to the present i nventi on i s a met hod for produci ng an i nor gani c f i ne powder havi ng a vol ume- based cumul at i ve 50%
part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, the met hod i ncl udi ng: a step of generati ng a powder to be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d- adsor bed i norgani c raw mat eri al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i nor gani c raw mat en i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry classification.
Further, the method for produci ng the i nor gani c f i ne powder accordi ng to the present i nventi on i s a met hod for produci ng an i norgani c f i ne powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from O. 01 pm to 5.0 pm, the method i ncl udi ng: a step of generati ng a powder to be Cl assi f i ed by adsorbi ng a carboxyl i c acid onto an i norgani c raw material powder havi ng the D50 of 10 pm or I ess to obtain the powder to be cl assi f i ed, under the condi ti on that the i nor gani c raw mat en i al powder bei ng i n a di spersed state in a gas phase at the ti me of generati on has been di spersed i n the gas phase; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi fi cat i on.
Furthermore, the method for produci ng the i norgani c f i ne powder accordi ng to the present i nventi on i s a method for produci ng an i nor gani c f i ne powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0. 01 pm to 5.0 pm, the method i ncl udi ng: a step of generati ng a powder to be cl assi f i ed by di spersi ng an i nor gani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obt ai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on; wherei n the step of generati ng the powder to be cl assi f i ed i s performed i n an atmosphere contai ni ng a carboxyl i c aci d in a gaseous state.
These met hods provide methods for producing the i norgani c f i ne powder havi ng the vol ume- based cumul at i ve 50% part i cl e di ameter D50 within the range of 0.01 ktm to 5.0 m, contai ni ng an extremely smal I number of coarse part i cl es with high producti vi ty.
For t hi s reason, the methods for produci ng the i norgani c f i ne powder accordi ng to the present i nventi on have i ndustri al appl i cabi I i ty.
EXPLANATION OF REFERENCE NUMERALS
[ 0181] 1: CLASSI Fl ER
3: CASI NG
4: I NTRODUCTI ON PORT
5: Al R NOZZLE
6: GUI DE VANE
7: Fl NE POWDER DI SCHARGE PORT
C; CC ,7. 7, ',-2, F1 .2., ',:,1 1 1 rt :1 11 LI
, c 7,, 1,-, g 'r'21 r'12, 0 0 0 0 1 i i rfti en en ;3; r -en co a;
e i' Ql=
5. - . -a CO,,., - - - _, -= -1 ¨ CO Cl CO ,i .1. ,;:l L.; .1,' AI
VI', SI c, ..... d. ._., c..
,-I
L'1 CO 6, H
co Lo u. CO 1-1 F'.' 1.1 Cl CC!
El I
6g 11, 6:6 I 11 6.1, 60 I .1 I-1 1 11=l 66-1 0 . 1 6 .1 El 1 L, 0 rd ,.-.4 in R, 2 L 'FJ /71 2 Li) ',19 1 r",j In 0 F ; ¨, c, " cl g' '' ' = , . ,L.'. 2 d.I ill II
q' a .,, . ..
,i, 1. kJ 14 44 ,1_, 1:1 , Pill d ,3 24 [ 0179]
As is evi dent from Tables 2 through 5, each of the above Exampl es sui tabl y produced the met al f i ne powder havi ng the D50 i n the range of from 0.01 pm to 5. 0 pm and an extremely small number of coarse part i cl es with a hi gh yi el d.
I NDUSTRI AL APPLI CABI LI TY
[ 0180]
The met hod for produci ng the inorganic fine powder accordi ng to the present i nventi on i s a met hod for produci ng an i nor gani c f i ne powder havi ng a vol ume- based cumul at i ve 50%
part i cl e di ameter D50 rangi ng from 0.01 pm to 5.0 pm, the met hod i ncl udi ng: a step of generati ng a powder to be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d- adsor bed i norgani c raw mat eri al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i nor gani c raw mat en i al powder havi ng the D50 of 10 pm or I ess to obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry classification.
Further, the method for produci ng the i nor gani c f i ne powder accordi ng to the present i nventi on i s a met hod for produci ng an i norgani c f i ne powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from O. 01 pm to 5.0 pm, the method i ncl udi ng: a step of generati ng a powder to be Cl assi f i ed by adsorbi ng a carboxyl i c acid onto an i norgani c raw material powder havi ng the D50 of 10 pm or I ess to obtain the powder to be cl assi f i ed, under the condi ti on that the i nor gani c raw mat en i al powder bei ng i n a di spersed state in a gas phase at the ti me of generati on has been di spersed i n the gas phase; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi fi cat i on.
Furthermore, the method for produci ng the i norgani c f i ne powder accordi ng to the present i nventi on i s a method for produci ng an i nor gani c f i ne powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter D50 rangi ng from 0. 01 pm to 5.0 pm, the method i ncl udi ng: a step of generati ng a powder to be cl assi f i ed by di spersi ng an i nor gani c raw mat er i al powder havi ng the D50 of 10 pm or I ess to obt ai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on; wherei n the step of generati ng the powder to be cl assi f i ed i s performed i n an atmosphere contai ni ng a carboxyl i c aci d in a gaseous state.
These met hods provide methods for producing the i norgani c f i ne powder havi ng the vol ume- based cumul at i ve 50% part i cl e di ameter D50 within the range of 0.01 ktm to 5.0 m, contai ni ng an extremely smal I number of coarse part i cl es with high producti vi ty.
For t hi s reason, the methods for produci ng the i norgani c f i ne powder accordi ng to the present i nventi on have i ndustri al appl i cabi I i ty.
EXPLANATION OF REFERENCE NUMERALS
[ 0181] 1: CLASSI Fl ER
3: CASI NG
4: I NTRODUCTI ON PORT
5: Al R NOZZLE
6: GUI DE VANE
7: Fl NE POWDER DI SCHARGE PORT
8: COARSE POWDER DI SCHARGE PORT
10: CLASSI Fl CATI ON CHAMBER (CLASSI Fl CATI ON ZONE) 11: DI SPERSI ON ZONE
10: CLASSI Fl CATI ON CHAMBER (CLASSI Fl CATI ON ZONE) 11: DI SPERSI ON ZONE
Claims (9)
1. A method f or produci ng an i nor gani c f i ne powder havi ng a vol ume- based cumul at i ve 50% part i cl e di ameter 050 rangi ng f rom O. 01 pm to 5. 0 pm, the method compri si ng:
a st ep of gener at i ng a powder t o be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d- adsorbed i norgani c raw mat eri al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i norgani c raw mat er i al powder havi ng t he D50 of 10 pm or I ess t o obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
a st ep of gener at i ng a powder t o be cl assi f i ed by di spersi ng i n a gas phase a carboxyl i c aci d- adsorbed i norgani c raw mat eri al powder i n whi ch a carboxyl i c aci d i s adsorbed on an i norgani c raw mat er i al powder havi ng t he D50 of 10 pm or I ess t o obtai n the powder to be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
2. A method f or produci ng an i nor gani c f i ne powder havi ng a vol ume- based cumul at i ve 50% part i cl e di amet er D50 rangi ng f rom O. 01 pm to 5. 0 pm, the method compri si ng:
a step of generat i ng a powder to be cl assi f i ed by adsorbi ng a carboxyl i c aci d onto an i nor gani c raw mat eri al powder havi ng the D50 of 10 pm or l ess to obtai n the powder to be cl assi f i ed, under t he condi t i on t hat t he i nor gani c r aw mat er i al powder bei ng i n a di spersed state in a gas phase at the ti me of generati on has been di spersed i n the gas phase; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
a step of generat i ng a powder to be cl assi f i ed by adsorbi ng a carboxyl i c aci d onto an i nor gani c raw mat eri al powder havi ng the D50 of 10 pm or l ess to obtai n the powder to be cl assi f i ed, under t he condi t i on t hat t he i nor gani c r aw mat er i al powder bei ng i n a di spersed state in a gas phase at the ti me of generati on has been di spersed i n the gas phase; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on.
3. The met hod f or produci ng t he i nor gani c f i ne powder accordi ng t o cl ai m 2, f urt her compri si ng:
a step of col l ecti ng the powder to be cl assi f i ed; and a step of di spersi ng the powder to be cl assi f i ed i n a gas phase;
between the step of generati ng a powder to be cl assi f i ed and the step of dry cl assi f i cat i on.
a step of col l ecti ng the powder to be cl assi f i ed; and a step of di spersi ng the powder to be cl assi f i ed i n a gas phase;
between the step of generati ng a powder to be cl assi f i ed and the step of dry cl assi f i cat i on.
4. A method f or produci ng an i nor gani c f i ne powder havi ng a vol ume- based cumul at i ve 50% part i cl e di amet er D50 rangi ng f rom O. 01 pm to 5. 0 pm, the method compri si ng:
a st ep of generati ng a powder t o be cl assi f i ed by di spersi ng an i norgani c raw mat eri al powder havi ng the D50 of 10 pm or l ess to obtai n the powder t o be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on;
wherei n the step of generati ng a powder to be cl assi f i ed i s perf ormed i n an atmosphere contai ni ng a carboxyl i c aci d in a gaseous st at e.
a st ep of generati ng a powder t o be cl assi f i ed by di spersi ng an i norgani c raw mat eri al powder havi ng the D50 of 10 pm or l ess to obtai n the powder t o be cl assi f i ed; and a step of subj ecti ng the powder to be cl assi f i ed to dry cl assi f i cat i on;
wherei n the step of generati ng a powder to be cl assi f i ed i s perf ormed i n an atmosphere contai ni ng a carboxyl i c aci d in a gaseous st at e.
5. The met hod f or produci ng t he i nor gani c f i ne powder accordi ng to any one of cl ai ms 2 to 4, wherei n the carboxyl i c aci d i n an amount of f r om 30 mol es to 960 mol es i s used per 1 m3 of t he i nor gani c raw mat er i al powder.
6. The met hod f or produci ng t he i nor gani c f i ne powder accordi ng to any one of cl ai ms 1 to 5, wherei n a boi l i ng poi nt of the carboxyl i c aci d is in the range of f rom 100 C to 400 C.
7. The met hod f or produci ng t he i nor gani c f i ne powder accordi ng to any one of cl ai ms 1 to 6, wherei n the carboxyl i c aci d i s at l east one sel ected f rom aceti c aci d, propi oni c aci d, but yr i c aci d, and ol ei c aci d.
8. The met hod f or produci ng t he i nor gani c f i ne powder accordi ng t o any one of cl ai ms 1 to 7, wherei n the step of dry cl assi f i cat i on i s perf ormed i n the gas phase at a t emperature of f rom 60 C to 300 C.
9. The met hod f or produci ng t he i nor gani c f i ne powder accordi ng to any one of cl ai ms 1 to 8, wherei n an i norgani c component of the i norgani c raw mat eri al powder i s at I east one sel ected f rom t he group consi sti ng of a metal , a met al oxi de, a gl ass, a cerami c, and a semi conductor.
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|---|---|---|---|
| JP2020-072562 | 2020-04-14 | ||
| JP2020072562 | 2020-04-14 | ||
| PCT/JP2021/015250 WO2021210557A1 (en) | 2020-04-14 | 2021-04-13 | Method for producing inorganic fine powder |
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|---|---|
| CA3174953A1 true CA3174953A1 (en) | 2021-10-21 |
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| CA3174962A Pending CA3174962A1 (en) | 2020-04-14 | 2021-04-13 | Carboxylic acid-containing nickel powder and carboxylic acid-containing nickel powder production method |
| CA3174953A Pending CA3174953A1 (en) | 2020-04-14 | 2021-04-13 | Method for producing inorganic fine powder |
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| JP2002025550A (en) * | 2000-07-05 | 2002-01-25 | Sanyo Electric Co Ltd | Manufacturing method of hydrogen storage alloy powder, hydrogen storage alloy powder, hydrogen storage alloy electrode and alkaline storage battery |
| JP4233334B2 (en) * | 2003-01-23 | 2009-03-04 | 三井金属鉱業株式会社 | Copper paste and printed wiring board using the copper paste |
| JP4530617B2 (en) * | 2003-01-23 | 2010-08-25 | 三井金属鉱業株式会社 | Method for producing copper powder for copper paste and copper powder for copper paste obtained by the production method |
| CN102196868B (en) * | 2008-10-24 | 2014-04-23 | 株式会社日清制粉集团本社 | Method for classifying powder |
| EP2596945B1 (en) | 2008-11-17 | 2014-07-02 | Ranpak Corp. | Compact dunnage conversion machine |
| JP5323174B2 (en) * | 2009-03-18 | 2013-10-23 | 日清エンジニアリング株式会社 | Powder classification method |
| JP5297344B2 (en) * | 2009-11-04 | 2013-09-25 | 京都エレックス株式会社 | Heat curable conductive paste composition |
| PT2330162E (en) * | 2009-12-07 | 2013-08-22 | Omya Development Ag | Method for classifying mineral material in the presence of additives containing glycerol, products obtained and uses thereof |
| CN102892533B (en) * | 2010-03-17 | 2014-12-10 | 新日铁住金化学株式会社 | Process for production of nickel nanoparticles |
| CN103442814B (en) | 2011-03-16 | 2017-06-09 | 株式会社日清制粉集团本社 | The stage division of powder |
| KR101885391B1 (en) * | 2011-06-08 | 2018-08-03 | 스미토모 긴조쿠 고잔 가부시키가이샤 | Silver powder and method for producing same |
| CN102357655B (en) * | 2011-06-20 | 2014-05-14 | 宁波广博纳米新材料股份有限公司 | Superfine powder cooling method |
| JP5848552B2 (en) * | 2011-08-29 | 2016-01-27 | 日立金属株式会社 | Method for producing copper fine particle dispersion, method for producing copper fine particle, copper fine particle dispersion and copper fine particle |
| KR20130136639A (en) * | 2012-06-05 | 2013-12-13 | 삼성전기주식회사 | Nickel nano particle, manufacturing method thereof and multi-layered ceramic capacitor using the same |
| JP6042747B2 (en) * | 2013-02-26 | 2016-12-14 | 新日鉄住金化学株式会社 | Nickel fine particles, method of using the same, and method of producing nickel fine particles |
| TWI593763B (en) * | 2015-06-12 | 2017-08-01 | 日油股份有限公司 | Surface-coated copper filler, method for producing the same, and electrically conductive composition |
| JPWO2017056741A1 (en) * | 2015-09-29 | 2018-07-19 | 東邦チタニウム株式会社 | Nickel powder and nickel paste |
| JP6897278B2 (en) * | 2016-04-25 | 2021-06-30 | 住友金属鉱山株式会社 | Nickel paste and nickel paste manufacturing method |
| CN110461503B (en) * | 2017-03-10 | 2022-01-14 | 东邦钛株式会社 | Nickel powder and nickel paste |
| WO2019146411A1 (en) * | 2018-01-26 | 2019-08-01 | 日清エンジニアリング株式会社 | Fine particle production method and fine particles |
| KR102509366B1 (en) * | 2018-01-26 | 2023-03-10 | 닛신 엔지니어링 가부시키가이샤 | Manufacturing method of fine silver particles |
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| CN115397583A (en) | 2022-11-25 |
| WO2021210557A1 (en) | 2021-10-21 |
| CN115427171A (en) | 2022-12-02 |
| TW202146114A (en) | 2021-12-16 |
| TW202146133A (en) | 2021-12-16 |
| WO2021210558A1 (en) | 2021-10-21 |
| JPWO2021210557A1 (en) | 2021-10-21 |
| CA3174962A1 (en) | 2021-10-21 |
| JPWO2021210558A1 (en) | 2021-10-21 |
| KR20230008044A (en) | 2023-01-13 |
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