CA1241523A - Process for the preparation of lithium silicate - Google Patents
Process for the preparation of lithium silicateInfo
- Publication number
- CA1241523A CA1241523A CA000490679A CA490679A CA1241523A CA 1241523 A CA1241523 A CA 1241523A CA 000490679 A CA000490679 A CA 000490679A CA 490679 A CA490679 A CA 490679A CA 1241523 A CA1241523 A CA 1241523A
- Authority
- CA
- Canada
- Prior art keywords
- treatment
- thermal
- precalcination
- process according
- mixture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- 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
- C01B33/20—Silicates
- C01B33/32—Alkali metal silicates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Compositions Of Oxide Ceramics (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Lithium carbonate and silica are intimately mixed;
the thus obtained mixture is submitted to a thermal pre-calcination treatment in moist air at a temperature comprised between 410°C and 440°C so as to form in said mixture at least 25 % by weight of a hexagonal phase composed of lithium, silicon and oxygen,whose crystal parameters are a = 3.06 .ANG.
and c = 4.97 .ANG..
The obtained product is submitted to a high-density sintering treatment either directly or after a calcination treatment at a temperature between 450°C and 600°C.
Lithium carbonate and silica are intimately mixed;
the thus obtained mixture is submitted to a thermal pre-calcination treatment in moist air at a temperature comprised between 410°C and 440°C so as to form in said mixture at least 25 % by weight of a hexagonal phase composed of lithium, silicon and oxygen,whose crystal parameters are a = 3.06 .ANG.
and c = 4.97 .ANG..
The obtained product is submitted to a high-density sintering treatment either directly or after a calcination treatment at a temperature between 450°C and 600°C.
Description
~24~j2~
The present învention relates to a process for the preparation of lithium silicate according to which lithium carbonate and silica are mixed intimately and the mixture obtained is then submitted to a thermal treatment.
The lithium silicate can, e.g., be used as a covering material in fusion reactors with the object of producing tritium.
A usual process for the preparation of lithium silicate consists in mixing lithium carbonate and silica in suitable proportions and in calcining said mixture at a temperature near the melting point of lithium carbonate (718C + 2C). The thus obtained silicate has poor sintering properties and is not suited for the manufacture of dense pellets (more than 85% of the theoretical density) by cold pelletizing and sintering.
An object of the invention is to remedy this drawback and to provide a process for preparing lithium silicate allowing a grade of lithium silicate to be obtained that can be sintered and hence can be used for the manufacture of high-density pellets by cold pelletizing and sintering.
Accordingly, the invention provides a process for the preparation of lithium silicate comprising the steps of: mixing lithium carbonate and silica, and submitting the thus obtained mixture to a thermal precalcination treatment at a temperature between 410C
and 440C for a period of at least 10 hours, so as to form in said mixture at least 25% by weight of a hexagonal phase composed of lithium, silicon and oxygen, whose 30 crystal parameters are a = 3.06 A and c = 4.9~ A, and submitting directly the product obtained by the thermal precalcination to a high-density sintering treatment or to a calGination treatment.
By precalcination a thermal treatment is to be understood at a temperature below 440C.
The above phase not yet described in technical literature and called phase X hereinafter could be isomorphous to lithium aluminate (LiAl02), described by ~24~5;~3 - la -T.I. Barry and collaborators in "The crystallization of glasses based on the Eutectic composition in the System Li20 - A1203 - SiO2, Part II, Lithium Metasilicate-beta Eucryptite"
, :
~Z~1~23 (Journal of Materials Science, 5,1970, 117-126). However, the authors are not sure at all about the composition of the above-mentioned compound and the corresponding descriptive card has been removed from the "Powder Diffraction File"
in 1983.
According to a particular embodiment of the invention the mixture is maintained at a temperature between 410C and 440C for at least 10 hours.
According to an advantageous embodiment of the invention the thermal precalcination treatment is carried out at a temperature comprised between 430C and 435C.
According to an efficient embodiment of the invention the thermal precalcination treatment is carried out in moist air.
Preferably the thermal treatment is carried out in moist air containing at least 10 % of relative humidity.
After the thermal precalcination treatment the product rich in phase X can be pelletized directly and sintered at relatively high density, or it can also be 20 calcined at low temperature (from 450C to 600C) before being pelletized and sintered at high density. Precalcination and calcination are preferably carried out in one single treatment, e.g., by a 91ow rise between 410C and 470C
in 60 hours.
Other particular and advantages of the invention will appear from the description of a process for preparing lithium silicate according to the invention; this description is only given by way of example without limiting the scope of the invention.
For preparing lithium silicate that can be sintered, suitable amounts of lithium carbonate and silica are fixst mixed intimately.
This mixture may be in the form of powder, granules or pellets.
,, _ . . . .
~241523 Then this mixture is submitted to a thermal treatment in moist air for several hours in order to form a hexagonal intermediate phase X composed of lithium, silicon and oxygen, whose crystal parameters are a - 3.06 R and c = 4.97 R.
This phase X i8 ideally formed by a thermal precalcination treatment ox the mixture carried out between 430C and 435C, but it i9 also formed in a sufficient amount between 410C and 430C or between 435C
and 440C on condition that the mixture is kept between these temperatures for at least 10 hours.
It is indeed not necessary to work under the optimal conditions of formation of phase X.
For achieving the expected results it suffices to form at least 25 % by weight of it.
Besides, this phase X is gradually transformed into metasilicate.
Consequently said mixture of lithium carbonate and silica is submitted for several hours to a thermal precalcination treatment at a temperature between 410C
and 440C and preferably between 430C and 435C in moist air.
The treatment is preferably effected in moist air containing at least 10 % of relative humidity. The best results, however, are obtained with air saturated with humidity at room temperature. The precalcination treatment is preferably effected for at least 10 hours, especially if it takes place at temperatures comprised between 410C and 430C or between 435C and 440C.
Evidently, the thermal treatment may take place either at constant temperature, or in successive levels, or in a continuous slow rise.
The thermal treatment modifies the sintering properties of the mixture.
After said thermal precalcination treatment the product rich in phase X is pelletized and sintered at relatively high density, or the product it first calcined at relatively low temperature (from 450C to 600C) for transforming phase X into metasillcate whereafter it is pelletized and sintered at high density Precalcination and calcination are preferably effected in one single treatment, e.g., by a 910w rise between 410C and 460C to 480C within 50 to 70 hours and preferably from 410C to 460C within 60 hours.
The formation of 25 % of phase X i8 essential for obtaining a product having a high specific surface area and thus being very æuited for sintering, even after calcination. The table hereinafter illustrates these results : it lists the values of specific surface area of mixtures of lithium carbonate and silica ground under water, spray-dried and then treated according to the invention or not.
~L~41~;2~
_ _ THERMAL TREATMENT spec.surf.
(BET) in m2 /g According to the invention granules precalcined in moist air .
successively at 410C for 6 h, at 420C for 56 1 h and at 430C for 8 h powders precalcined in air of 60 % of 60 relative humidity at 430C for 15 h pellet precalcined at 421C for 24 h, then 34 calcined at 529C for 24 h granules precalcined at 430C for R h,then 38 calcined at 550C for 12 h powder precalcined at 430C for 30 h,then 15 calcined at 605C for 16.5 h Calcination of a product containinq no phase X
powder precalcined at 380C for 60 h,then 3 calcined at 550C for 24 h powder calcined at 600C for 24 h 3.5 ~4~ 3 It is evident that the process according to the invention i5 suited for obtaining lithium silicates that can be sintered and that are destined for manufacturing high-density sintered parts as well as for making sintered parts however may be the method of shaping and the final form of said parts. Said parts, e.g., are shaped in the form of pellets or granules.
The process according to the invention warrants a high specific surface area (see table above) and favourable sintering properties as well : 90, it i9 possible to make dense parts by sintering at not too high temperatures and during short periods of time. This allows the realization of a fine-grain structure.
The process also allnws to improve the sintering propertie9 of solely precalcined products or of precalcined and calcined products by improving the fineness of the raw materials. This i9 not possible without forming phase X.
According to the above described process one can obtain after the thermal precalcination process a mixture formed of phase X and metasilicate still containing some residual carbonate but being free from disilicate and orthosilicate, even if the general composition of the mixture deviates in one of both senses from the stoichiometric composition corresponding to the meta-silicate. After calcination at low temperature thecomposition of the obtained product is relatively near the nominal composition of the mixture. This is not at all the case by direct calcination at low temperature without the said thermal precalcination process : a mixture is then obtained rich in disilicate that has to be transformed into metasilicate during sintering, which occasions deformation of the pellets and a fall of density.
Some examples illustrate the invention.
~4~i23 Example 1 190 g of lithium carbonate powder and 160 g of silica powder (AEROSIL of Degussa - 300 m /g) are mixed with distilled water so as to form a smooth paste, This paste is ground for 60 min under water in an attritor whose receptacle, balls and arms are made of alumina. The suspension thus obtained is continuously stirred in order to avoid any demixing, then spray-dried.
The resulting fine powder has a specific surface area of 110 sq.m/g.
The powder i9 precalcined in moist air at 430C
for 30 h, then calcined at 605C for 16 h and finally pelletized under 2.5 t/cm2 in a matrix of 6 mm diameter.
After sintering at 950C in the air for 9 h the pellets have a density of 91.4 % T.D. .
The same mixture ground for -2 h instead of 1 h and treated under the same conditions yields sintered pellets of 95 % T.D. (starting from green pellets of 48 % T.D.) and of 98 % T.D. (starting from green pellets of 50 % T.D.) .
Example 2 272 g of lithium carbonate powder is mixed with 228 g of silica (AEROSIL of Degussa) and water, ground for 60 min in an attritor and spray-dried.
The dried powder is precompacted under 1.2 t/cm2 in pellets of 12 mm diameter. The pellets are granulated on a grid of 1 mm; the obtained granules are successively treated at 410C for 6 h, at 420C for 16 h and at 430C
for 8 h in moist air, then pelletized under 2.5 t/cm2.
The pellets attain a density of either 87.6 % T.D. at 950C after 3 h or of 81.1 % T.D. at 950C after 1 h.
Example 3 The precalcined granules of Example 2 are calcined at 525C for 12 h before being pelletized under
The present învention relates to a process for the preparation of lithium silicate according to which lithium carbonate and silica are mixed intimately and the mixture obtained is then submitted to a thermal treatment.
The lithium silicate can, e.g., be used as a covering material in fusion reactors with the object of producing tritium.
A usual process for the preparation of lithium silicate consists in mixing lithium carbonate and silica in suitable proportions and in calcining said mixture at a temperature near the melting point of lithium carbonate (718C + 2C). The thus obtained silicate has poor sintering properties and is not suited for the manufacture of dense pellets (more than 85% of the theoretical density) by cold pelletizing and sintering.
An object of the invention is to remedy this drawback and to provide a process for preparing lithium silicate allowing a grade of lithium silicate to be obtained that can be sintered and hence can be used for the manufacture of high-density pellets by cold pelletizing and sintering.
Accordingly, the invention provides a process for the preparation of lithium silicate comprising the steps of: mixing lithium carbonate and silica, and submitting the thus obtained mixture to a thermal precalcination treatment at a temperature between 410C
and 440C for a period of at least 10 hours, so as to form in said mixture at least 25% by weight of a hexagonal phase composed of lithium, silicon and oxygen, whose 30 crystal parameters are a = 3.06 A and c = 4.9~ A, and submitting directly the product obtained by the thermal precalcination to a high-density sintering treatment or to a calGination treatment.
By precalcination a thermal treatment is to be understood at a temperature below 440C.
The above phase not yet described in technical literature and called phase X hereinafter could be isomorphous to lithium aluminate (LiAl02), described by ~24~5;~3 - la -T.I. Barry and collaborators in "The crystallization of glasses based on the Eutectic composition in the System Li20 - A1203 - SiO2, Part II, Lithium Metasilicate-beta Eucryptite"
, :
~Z~1~23 (Journal of Materials Science, 5,1970, 117-126). However, the authors are not sure at all about the composition of the above-mentioned compound and the corresponding descriptive card has been removed from the "Powder Diffraction File"
in 1983.
According to a particular embodiment of the invention the mixture is maintained at a temperature between 410C and 440C for at least 10 hours.
According to an advantageous embodiment of the invention the thermal precalcination treatment is carried out at a temperature comprised between 430C and 435C.
According to an efficient embodiment of the invention the thermal precalcination treatment is carried out in moist air.
Preferably the thermal treatment is carried out in moist air containing at least 10 % of relative humidity.
After the thermal precalcination treatment the product rich in phase X can be pelletized directly and sintered at relatively high density, or it can also be 20 calcined at low temperature (from 450C to 600C) before being pelletized and sintered at high density. Precalcination and calcination are preferably carried out in one single treatment, e.g., by a 91ow rise between 410C and 470C
in 60 hours.
Other particular and advantages of the invention will appear from the description of a process for preparing lithium silicate according to the invention; this description is only given by way of example without limiting the scope of the invention.
For preparing lithium silicate that can be sintered, suitable amounts of lithium carbonate and silica are fixst mixed intimately.
This mixture may be in the form of powder, granules or pellets.
,, _ . . . .
~241523 Then this mixture is submitted to a thermal treatment in moist air for several hours in order to form a hexagonal intermediate phase X composed of lithium, silicon and oxygen, whose crystal parameters are a - 3.06 R and c = 4.97 R.
This phase X i8 ideally formed by a thermal precalcination treatment ox the mixture carried out between 430C and 435C, but it i9 also formed in a sufficient amount between 410C and 430C or between 435C
and 440C on condition that the mixture is kept between these temperatures for at least 10 hours.
It is indeed not necessary to work under the optimal conditions of formation of phase X.
For achieving the expected results it suffices to form at least 25 % by weight of it.
Besides, this phase X is gradually transformed into metasilicate.
Consequently said mixture of lithium carbonate and silica is submitted for several hours to a thermal precalcination treatment at a temperature between 410C
and 440C and preferably between 430C and 435C in moist air.
The treatment is preferably effected in moist air containing at least 10 % of relative humidity. The best results, however, are obtained with air saturated with humidity at room temperature. The precalcination treatment is preferably effected for at least 10 hours, especially if it takes place at temperatures comprised between 410C and 430C or between 435C and 440C.
Evidently, the thermal treatment may take place either at constant temperature, or in successive levels, or in a continuous slow rise.
The thermal treatment modifies the sintering properties of the mixture.
After said thermal precalcination treatment the product rich in phase X is pelletized and sintered at relatively high density, or the product it first calcined at relatively low temperature (from 450C to 600C) for transforming phase X into metasillcate whereafter it is pelletized and sintered at high density Precalcination and calcination are preferably effected in one single treatment, e.g., by a 910w rise between 410C and 460C to 480C within 50 to 70 hours and preferably from 410C to 460C within 60 hours.
The formation of 25 % of phase X i8 essential for obtaining a product having a high specific surface area and thus being very æuited for sintering, even after calcination. The table hereinafter illustrates these results : it lists the values of specific surface area of mixtures of lithium carbonate and silica ground under water, spray-dried and then treated according to the invention or not.
~L~41~;2~
_ _ THERMAL TREATMENT spec.surf.
(BET) in m2 /g According to the invention granules precalcined in moist air .
successively at 410C for 6 h, at 420C for 56 1 h and at 430C for 8 h powders precalcined in air of 60 % of 60 relative humidity at 430C for 15 h pellet precalcined at 421C for 24 h, then 34 calcined at 529C for 24 h granules precalcined at 430C for R h,then 38 calcined at 550C for 12 h powder precalcined at 430C for 30 h,then 15 calcined at 605C for 16.5 h Calcination of a product containinq no phase X
powder precalcined at 380C for 60 h,then 3 calcined at 550C for 24 h powder calcined at 600C for 24 h 3.5 ~4~ 3 It is evident that the process according to the invention i5 suited for obtaining lithium silicates that can be sintered and that are destined for manufacturing high-density sintered parts as well as for making sintered parts however may be the method of shaping and the final form of said parts. Said parts, e.g., are shaped in the form of pellets or granules.
The process according to the invention warrants a high specific surface area (see table above) and favourable sintering properties as well : 90, it i9 possible to make dense parts by sintering at not too high temperatures and during short periods of time. This allows the realization of a fine-grain structure.
The process also allnws to improve the sintering propertie9 of solely precalcined products or of precalcined and calcined products by improving the fineness of the raw materials. This i9 not possible without forming phase X.
According to the above described process one can obtain after the thermal precalcination process a mixture formed of phase X and metasilicate still containing some residual carbonate but being free from disilicate and orthosilicate, even if the general composition of the mixture deviates in one of both senses from the stoichiometric composition corresponding to the meta-silicate. After calcination at low temperature thecomposition of the obtained product is relatively near the nominal composition of the mixture. This is not at all the case by direct calcination at low temperature without the said thermal precalcination process : a mixture is then obtained rich in disilicate that has to be transformed into metasilicate during sintering, which occasions deformation of the pellets and a fall of density.
Some examples illustrate the invention.
~4~i23 Example 1 190 g of lithium carbonate powder and 160 g of silica powder (AEROSIL of Degussa - 300 m /g) are mixed with distilled water so as to form a smooth paste, This paste is ground for 60 min under water in an attritor whose receptacle, balls and arms are made of alumina. The suspension thus obtained is continuously stirred in order to avoid any demixing, then spray-dried.
The resulting fine powder has a specific surface area of 110 sq.m/g.
The powder i9 precalcined in moist air at 430C
for 30 h, then calcined at 605C for 16 h and finally pelletized under 2.5 t/cm2 in a matrix of 6 mm diameter.
After sintering at 950C in the air for 9 h the pellets have a density of 91.4 % T.D. .
The same mixture ground for -2 h instead of 1 h and treated under the same conditions yields sintered pellets of 95 % T.D. (starting from green pellets of 48 % T.D.) and of 98 % T.D. (starting from green pellets of 50 % T.D.) .
Example 2 272 g of lithium carbonate powder is mixed with 228 g of silica (AEROSIL of Degussa) and water, ground for 60 min in an attritor and spray-dried.
The dried powder is precompacted under 1.2 t/cm2 in pellets of 12 mm diameter. The pellets are granulated on a grid of 1 mm; the obtained granules are successively treated at 410C for 6 h, at 420C for 16 h and at 430C
for 8 h in moist air, then pelletized under 2.5 t/cm2.
The pellets attain a density of either 87.6 % T.D. at 950C after 3 h or of 81.1 % T.D. at 950C after 1 h.
Example 3 The precalcined granules of Example 2 are calcined at 525C for 12 h before being pelletized under
2.5 t/cm . The pellets attain a density of 93 % T.D. at * trademark 925C after 3 h and of 9o % T.D. at 950C after 1 h.
It should be understood that the invention i9 not at all limited to the above described embodiment3 and that many modification can be made without departing from the scope of the present patent application.
It should be understood that the invention i9 not at all limited to the above described embodiment3 and that many modification can be made without departing from the scope of the present patent application.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of lithium silicate comprising the steps of: mixing lithium carbonate and silica, and submitting the thus obtained mixture to a thermal precalcination treatment at a temperature between 410°C and 440°C for a period of at least 10 hours, so as to form in said mixture at least 25%
by weight of a hexagonal phase composed of lithium, silicon and oxygen, whose crystal parameters are a = 3.06 .ANG. and c = 4.97 .ANG., and submitting directly the product obtained by the thermal precalcination to a high-density sintering treatment or to a calcination treatment.
by weight of a hexagonal phase composed of lithium, silicon and oxygen, whose crystal parameters are a = 3.06 .ANG. and c = 4.97 .ANG., and submitting directly the product obtained by the thermal precalcination to a high-density sintering treatment or to a calcination treatment.
2. A process according to claim 1, in which the mixture is submitted to the thermal precalcination treatment at a temperature between 430°C and 435°C.
3. A process according to claim 1, in which the mixture is submitted to the thermal precalcination treatment in moist air.
4. A process according to claim 2, in which the mixture is submitted to a thermal precalcination treatment in moist air.
5. A process according to claim 3 or 4, in which the thermal precalcination treatment is carried out in moist air having a relative humidity of at least 10%.
6. A process according to claim 3 or 4, in which the thermal precalcination treatment is carried out in moist air saturated with humidity at room temperature.
7. A process according to claim 1, in which the calcination treatment is effected at a temperature between 450°C and 600°C.
8. A process according to claim 7, in which the thermal precalcination treatment and the calcination treatment are carried out with a slow temperature rise from about 410°C up to 460°C to 480°C over a period of 50 to 70 hours.
9. A process according to claim 7, in which the thermal precalcination treatment and the calcination treatment are carried out with a slow temperature rise from about 410°C up to 460°C over a period of about 60 hours.
10. A process according to claim 1, 2 or 3, and further comprising submitting said product after the calcination treatment to a high-density sintering treatment.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE2/60505A BE900642A (en) | 1984-09-20 | 1984-09-21 | High specific surface lithium silicate prepn. - useful for blanket pellets in fusion reactors |
| BE2/60505 | 1984-09-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1241523A true CA1241523A (en) | 1988-09-06 |
Family
ID=3865707
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000490679A Expired CA1241523A (en) | 1984-09-21 | 1985-09-13 | Process for the preparation of lithium silicate |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0175423B1 (en) |
| JP (1) | JPS6177621A (en) |
| CA (1) | CA1241523A (en) |
| DE (1) | DE3562008D1 (en) |
| SU (1) | SU1533623A3 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103159222A (en) * | 2011-12-09 | 2013-06-19 | 核工业西南物理研究院 | Method of densification of lithium orthosilicate pellets used in tritium breeding |
| US9757217B2 (en) | 2012-05-11 | 2017-09-12 | Ivoclar Vivadent Ag | Pre-sintered blank for dental purposes |
| US10470854B2 (en) | 2012-05-11 | 2019-11-12 | Ivoclar Vivadent Ag | Pre-sintered blank for dental purposes |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10255124A1 (en) * | 2002-11-26 | 2004-06-03 | Degussa Ag | Fumed oxide powder, process for its preparation and its use in a separator for an electrochemical cell |
| CN101913616B (en) * | 2010-08-13 | 2012-08-22 | 北京科技大学 | Preparation method of lithium silicate material with high purity |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2083545A (en) * | 1935-04-10 | 1937-06-15 | Pennsylvania Salt Mfg Co | Process of making alkali sub-silicates |
| NL7406064A (en) * | 1974-05-06 | 1975-11-10 | Zinkwit Nederland B V | PROCESS FOR THE PREPARATION OF ANHYDROUS ALKALINE TASILICATES. |
-
1985
- 1985-09-13 CA CA000490679A patent/CA1241523A/en not_active Expired
- 1985-09-16 EP EP19850201477 patent/EP0175423B1/en not_active Expired
- 1985-09-16 DE DE8585201477T patent/DE3562008D1/en not_active Expired
- 1985-09-17 JP JP20516385A patent/JPS6177621A/en active Pending
- 1985-09-20 SU SU853957950A patent/SU1533623A3/en active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103159222A (en) * | 2011-12-09 | 2013-06-19 | 核工业西南物理研究院 | Method of densification of lithium orthosilicate pellets used in tritium breeding |
| US9757217B2 (en) | 2012-05-11 | 2017-09-12 | Ivoclar Vivadent Ag | Pre-sintered blank for dental purposes |
| US10206761B2 (en) | 2012-05-11 | 2019-02-19 | Ivoclar Vivadent Ag | Pre-sintered blank for dental purposes |
| US10470854B2 (en) | 2012-05-11 | 2019-11-12 | Ivoclar Vivadent Ag | Pre-sintered blank for dental purposes |
Also Published As
| Publication number | Publication date |
|---|---|
| SU1533623A3 (en) | 1989-12-30 |
| EP0175423A1 (en) | 1986-03-26 |
| DE3562008D1 (en) | 1988-05-05 |
| EP0175423B1 (en) | 1988-03-30 |
| JPS6177621A (en) | 1986-04-21 |
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