GB1568862A - Production of colloidal dispersions - Google Patents
Production of colloidal dispersions Download PDFInfo
- Publication number
- GB1568862A GB1568862A GB39626/77A GB3962677A GB1568862A GB 1568862 A GB1568862 A GB 1568862A GB 39626/77 A GB39626/77 A GB 39626/77A GB 3962677 A GB3962677 A GB 3962677A GB 1568862 A GB1568862 A GB 1568862A
- Authority
- GB
- United Kingdom
- Prior art keywords
- compound
- colloidal dispersion
- gel
- colloidal
- sol
- 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.)
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Classifications
-
- 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
- C04B35/10—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 aluminium oxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
- B01J13/0004—Preparation of sols
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F17/00—Compounds of rare earth metals
- C01F17/20—Compounds containing only rare earth metals as the metal element
- C01F17/206—Compounds containing only rare earth metals as the metal element oxide or hydroxide being the only anion
- C01F17/218—Yttrium oxides or hydroxides
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Colloid Chemistry (AREA)
- Compositions Of Oxide Ceramics (AREA)
Description
(54) IMPROVEMENTS IN OR RELATING TO PRODUCTION OF COLLOIDAL
DISPERSIONS
(71) We, UNITED KINGDOM ATOMIC ENERGY AUTHORITY, London a
British Authority, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
The present invention relates to the production of colloidal dispersions.
According to one aspect of the present invention there is provided a colloidal dispersion comprising, dispersed in a liquid medium (i) a compound of a Group IIA element, or a compound of a Group IIIA element, and (ii) colloidal particles of an inorganic substance, the inorganic substance having been made by a vapour phase condensation method (as hereinafter defined), wherein the compound is soluble in the liquid medium and the colloidal particles are dispersed in the liquid medium in the form of a sol thereof.
According to another aspect of the present invention there is provided a process for the production of a colloidal dispersion which comprises providing, in a liquid medium, colloidal particles of an inorganic substance dispersed therein to constitute a sol and a compound of a
Group IIA element, or a compound of a Group IIIA element dissolved therein, the inorganic substance having been made by a vapour phase condensation method (as hereinafter defined).
The compound of the Group IIIA element may be, for example, a compound of lanthanide (rare earth) element of a compound of yttrium.
In this Specification the term "lanthanide" includes lanthanum and the lanthanide elements.
We believe, but are by no means certain, that the colloidal particles of the inorganic substance "take up" ions (e.g. anions) from the compound in solution (i.e. act as an ion "getter") thereby to enable the Group IIa, Group IIIA (e.g. lanthanide) element to be incorporated in a colloidal form so the colloidal dispersion comprises a mixed sol. It is to be understood that the term "dispersed" as used in this Specification in relation to the compound of the Group IIA or Group IIIA element may embrace true solution.
In carrying out the method of the present invention to produce the colloidal dispersion, a sol of the inorganic substance and a solution of the compound in the liquid medium can be mixed together.
Alternatively, the colloidal particles of the inorganic substance can be added to a solution of the compound in the liquid medium. In a further alternative the compound can be added to a sol comprising colloidal particles of the inorganic substance dispersed in the liquid medium.
In the production of certain chemical products, such as catalysts and catalytic materials (e.g. as described in our co-pending U.K. Application of even date, Serial No. 1568861 43435/75) a useful starting material can be a colloidal dispersion containing a refractory oxide and a grain growth inhibitor to inhibit grain growth in refractory oxide formed from the dispersion.
Generally the colloidal dispersion does not contain a grain growth inhibitor as such, but a precursor therefor (e.g a substance capable of producing a grain growth inhibitor on heating).
Thus, the term " grain growth inhibitor" as used in this specification embraces both a grain growth inhibitor and a precursor therefor.
Colloidal dispersions suitable for use as starting materials as hereinbefore mentioned can be prepared by mixing sols of refractory oxide and of grain growth inhibitor. However, it can be difficult and/or expensive to obtain both oxide and grain growth inhibitor in the form of sols which are suitable for mixing together to give a stable mixed colloidal dispersion.
The present invention provides a process which may be used to avoid the necessity of obtaining both oxide and grain growth inhibitor separately in the required sol form prior to mixing together.
Thus, in a preferred embodiment of the invention the colloidal particles of inorganic substance comprise colloidal particles of a refractory oxide and the compound is a grain growth inhibitor, so that the colloidal dispersion contains refractory oxide and grain growth inhibitor for the oxide.
The grain growth inhibitor may be a Group IIA or a Group IIIA element (e.g. a lanthanide (rare earth) element or yttrium).
In the process of the present Invention the compound is preferably a salt (e.g. a nitrate) and the solvent is preferably water.
Examples of refractory oxides which can be used in accordance with the preferred embodiment of the invention are lanthanide (rare earth) oxides (e.g. ceria), zirconia, magnesia, beryllia, thoria, silica. alumina, titania, tungsten oxide and combinations thereof. In the preparation of starting materials suitable for the production of catalysts or of carriers for catalytic materials we prefer that the refractory oxide is an oxide of an element whose atomic number does not exceed 40.
Although some elements (e.g. lanthanides) may be used in accordance with the present invention either as the refractory oxide or as the grain growth inhibitor, in a given combination, the refractory oxide and grain growth inhibitor should be different.
In one preferred example of the invention the colloidal particles comprise alumina and the compound is yttrium nitrate and we belive. but are by no means certain, that in this case the colloidal alumina particles in the colloidal dispersion 'take-up" nitrate ions (i.e. act as a nitrate "getter") thereby to enable the yttrium present to be incorporated into a colloidal form so that the colloidal dispersion comprises a mixed sol.
Colloidal dispersions containing alumina and yttrium have been prepared in accordance with the present invention by dispersing a fine small particle size, high surface area form of alumina produced by flame hydrolysis of a halide in water to form a sol as described in our co-pending U.K. Application No. Serial No. 1567003 43463/75 of even date) and subsequently adding yttrium nitrate in aqueous solution.
Flame hydrolysis is a specific example of a vapour phase condensation method for preparing substances in a fine. small particle size. high surface area form suitable for dispersing in a liquid medium to form a sol. Accordingly it is to be understood that substance produced by other vapour phase condensation methods can be used in accordance with the present invention.
Bv 'vapour phase condensation method" we mean a method which makes use of a vapour phase intermediate. Examples of vapour phase condensation methods are hydrolysis of salt solutions or alkalides, electron beam evaporation and condensation, metal oxidation (e.g. of
Mg) to gi -e a smoke which is then condensed, and RF plasma heating.
Colloidal dispersions of alumina containing up to 5 WtZ yttria (equivalent) have been prepared in accordance with the invention. Higher concentration of ytttria can be incorporated if required.
Gels containing alumina and vttria have been prepared by drying the colloidal dispersions.
Thus, according to a further aspect of the present invention there is provided a process for the production of a mixed gel which comprises providing in a liquid medium colloidal particles of an inorganic substance dispersed therein to constitute a sol (said inorganic substance having been made by a vapour phase condensation method (as hereinbefore defined)) and a compound of a Group IIA element. or a compound of a Group IIIA element dissolved therein. thereby to give a colloidal dispersion, and drying said colloidal dispersion to form a gel.
The compound of the Group IIIA element may be, for example, a compound of a lanthanide (rare earth) element or a compound of yttrium.
Drying may be effected by one or more of a number of methods (e.g. spray drying or tray drying).
According to yet a further aspect of the present invention there is provided a process for the production of a porous ceramic material comprising providing in a liquid medium colloidal particles of an inorganic substance dispersed therein to constitute a sol (said inorganic substance having been made bv a vapour phase condensation method (as hereinbefore defined)) and a compound of a Group IIA element. or a compound of a Group IIIA element dissolved therein, therebv to yive a colloidal dispersion, drying said colloidal dispersion to form a gel and heating said gel to form a porous ceramic material.
The compound of the Group IIIA e meat may be, for example, a compound of a lanthanide (rare earth) element of a compound of yttrium.
Gel particles or particles of porous ceramic material can be produced in accordance with
the present invention, for example by forming the colloidal dispersion into droplets prior to
drying thereby to give substantially spherical particles.
It will be appreciated that in some cases the colloidal particles will not necessarily be a
refractory oxide as such, but can be a precursor therefor.
According to yet a further aspect, the invention provides a colloidal dispersion prepared by
a process in accordance with the present invention.
The invention also provides a mixed gel or porous material prepared by a process in
accordance with the present invention.
The invention further provides a gel obtainable by drying a colloidal dispersion in accor
dance with the present invention. Also the invention provides a porous ceramic material obtainable by drying a colloidal dispersion in accordance with the present invention to form a gel and subsequently heating the gel.
The invention will now be particularly described, by way of example, as follows:
EXAMPLE 1
Finely powdered alumina (a commercially available alumina powder produced by flame hydrolysis) having a small particle size (about 0.01 ,um) and high surface area (N 100 m2/g) was dispersed in water to give a sol containing 160 gil aluminium oxide (Al203). Yttrium nitrate was dissolved in water to form a solution containing 170 gil yttria (Y203) equivalent.
The above sol and the above solution were mixed in proportions to give a colloidal dispersion (which may be referred to as a mixed sol") having the composition:
Al203:91,5g/l; Y203 equivalent :0.46g/l; NO3:0.75git; mol ratio NO3/Al+Y:0.006 (i.e.
0.5 wt% Y203/Al203). The colloidal dispersion ("mixed sol") was observed to be stable.
EXAMPLE 2
The procedure of Example 1 was repeated but the proportions were adjusted to prepare a colloidal dispersion having 0.1 wt% Y203/Al203.
EXAMPLE 3
The procedure of Example l was repeated but the proportions were adjusted to prepare a colloidal dispersion having 1 wt% Y203/Al203.
EXAMPLE 4
The procedure of Example 1 was repeated but the porportions were adjusted to prepare a colloidal dispersion having 5 wt% Y203/Al203.
EXAMPLE 5
Samples of alumina gels containing 0.2% w/w Y203 were prepared from sols similar to those prepared in Examples 1 to 4 and their surface and porous properties measured.
The properties were also measured after calcining for 2 hours in air at various temperatures.
The results are summarised in the following table:
Specific surface Total pore Calcination area value
3 1
Temp (0C) (SBET/m2g 1) Vpldm Kg ) 1100 72 0.56
1150 10
1200 410 EXAMPLE 6
This example relates to the preparation of a 0.2 wt% yttrium oxide - aluminium oxide gel.
300 g of alumina powder produced by flame by hydrolysis were added to 1.2 1 of 0.03M
nitric acid and stirred for 2 hours. When the alumina powder had been dispersed 2.4 ml of a
yttrium nitrate solution containing the equivalent of 250 g/l of Y203 were added.
The colloidal dispersion thereby formed was evaporated at 25 C over a period of 5 days to
yield a gel containing 93.7 wt% oxide.
EXAMPLE 7
The gel produced in Example 6 was calcined at 700"C to give a porous ceramic material.
After this calcination photomicrography showed that 3 mm fragments of oxide had shrunk by
less than 2% from the original gel.
WHAT WE CLAIM IS:
1. A colloidal dispersion comprising, dispersed in a liquid medium. (i) a compound of a
Group IIA element, or a compound of a Group IIIA element and (ii) colloidal particles of an
inorganic substance, the inorganic substance having been made by a vapour phase condensa
tion method (as hercinbefore defined), wherein the compound is soluble in the liquid
medium and the colloidal particles are dispersed in the liquid medium in the form of a sol
thereof.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (24)
1. A colloidal dispersion comprising, dispersed in a liquid medium. (i) a compound of a
Group IIA element, or a compound of a Group IIIA element and (ii) colloidal particles of an
inorganic substance, the inorganic substance having been made by a vapour phase condensa
tion method (as hercinbefore defined), wherein the compound is soluble in the liquid
medium and the colloidal particles are dispersed in the liquid medium in the form of a sol
thereof.
2. A colloidal dispersion as claimed in claim 1 wherein the compound of the Group IIIA
element is a compound of a lanthanide (rare earth) element or a compound of yttrium.
3. A colloidal dispersion as claimed in claim 1 or claim 2 wherein the colloidal particles are of a refractory oxide, or a precursor therefor, and the compound is a grain growth inhibitor for the oxide.
4. A colloidal dispersion as claimed in claim 3 wherein the refractory oxide, or the precursor therefor, is an oxide of an element, whose atomic number does not exceed 4U, or a precursor for an oxide of an element whose atomic number does not exceed 40.
5. A colloidal dispersion comprising. dispersed in water, a water soluble salt of yttrium in solution in the water and colloidal particles of alumina dispersed in the water, said colloidal particles of alumina having been made by a vapour phase condensation method (as hereinbefore defined).
6. A process for the production of a colloidal dispersion which comprises providing, in a liquid medium, colloidal particles of an inorganic substance dispersed therein to constitute a sol and a compound of a Group IIA element, or a compound of a Group IIIA element, dissolved therein, the inorganic substance having been made by a vapour phase condensation method (as hereinbefore defined).
7. A process as claimed in claim 6 wherein the compound of the Group IIIA is a compound of a lanthanide (rare earth) element or a compound or yttrium.
8. A process as claimed in clairn 6 or claim 7 wherein a sol of the inorganic substance and a solution of the compound are mixed together.
9. A process as claimed in claim 8 wherein the sol of the inorganic substance is formed by dispersing in water a fine, small particle size. high surface area form of an oxide which has been produced by a vapour phase condensation process (as hereinbefore defined).
10. A process as claimed in claim 9 wherein the sol of the inorganic substance is formed by dispersing in water a fine, small particle size, high surface area form of an oxide which has been produced by flame hydrolysis of a halide.
11. A process for the production of a mixed gel which comprises providing in a liquid medium colloidal particles of an inorganic substance dispersed therein to constitute a sol (said inorganic substance having been made by a vapour phase condensation method (as hereinbefore defined)) and a compound of a Group IIA element. or a compound of a Group IIIA element. dissolved therein, thereby to give a colloidal dispersion, and drying said colloidal dispersion to form a gel.
12. A process as claimed in claim 11 wherein the compound of the Group IIIA element is a compound of a lanthanide (rare earth) element or a compound of yttrium.
13. A process as claimed in claim 11 or claim 12 wherein the colloidal dispersion is dried by spray drying.
14. A process for the production of a porous ceramic material comprising providing in a liquid medium colloidal particles of an inorganic substance dispersed therein to constitute a sol (said inorganic substance having been made by a vapour phase condensation method (as hereinbefore defined)) and a compound of a Group IIA element, or a compound of a Group
IIIA clement, dissolved therein, thereby to give a colloidal dispersion, drying said colloidal dispersion to form a gel and heating said gel to form a porous ceramic material.
15. A process as claimed in claim 14 wherein the compound of the Group IIIA element is a compound of a lanthanide (rare earth) element or a compound of yttrium.
16. A mixed gel whenever prepared by a process as claimed in any one of claims 11 to 13.
17. A gel obtainable by drying a colloidal dispersion as claimed in any one of claims 1 to 5 inclusively.
18. A porous ceramic material whenever prepared by a process as claimed in claim 14 or claim 15.
19. A porous ceramic material obtainable by drying a colloidal dispersion as claimed in any one of claims 1 to 5 to form a gel and subsequently heating the gel.
0. A gel as claimed in claim 16 when in the form of particles.
21. A porous ceramic material as claimed in claim 18 when in the form of particles.
22. A colloidal dispersion substantially as hereinbefore described with reference to any one of Examples 1 to 5.
23. A gel substantially as hereinbefore described with reference to Example 6.
24. A porous ceramic material substantially as hereinbefore described with reference to
Example 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB39626/77A GB1568862A (en) | 1976-10-12 | 1976-10-12 | Production of colloidal dispersions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB39626/77A GB1568862A (en) | 1976-10-12 | 1976-10-12 | Production of colloidal dispersions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1568862A true GB1568862A (en) | 1980-06-11 |
Family
ID=10410591
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB39626/77A Expired GB1568862A (en) | 1976-10-12 | 1976-10-12 | Production of colloidal dispersions |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1568862A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0078098A2 (en) * | 1981-08-07 | 1983-05-04 | United Kingdom Atomic Energy Authority | Cerium compounds |
| US4787439A (en) * | 1985-06-06 | 1988-11-29 | Remet Corporation | Casting of reactive metals into ceramic molds |
| FR2697832A1 (en) * | 1992-11-12 | 1994-05-13 | Rhone Poulenc Chimie | Lanthanum stabilized alumina and process for its preparation |
-
1976
- 1976-10-12 GB GB39626/77A patent/GB1568862A/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0078098A2 (en) * | 1981-08-07 | 1983-05-04 | United Kingdom Atomic Energy Authority | Cerium compounds |
| EP0078098A3 (en) * | 1981-08-07 | 1983-07-27 | United Kingdom Atomic Energy Authority | Cerium compounds |
| US4787439A (en) * | 1985-06-06 | 1988-11-29 | Remet Corporation | Casting of reactive metals into ceramic molds |
| FR2697832A1 (en) * | 1992-11-12 | 1994-05-13 | Rhone Poulenc Chimie | Lanthanum stabilized alumina and process for its preparation |
| EP0597738A1 (en) * | 1992-11-12 | 1994-05-18 | Rhone-Poulenc Chimie | By lanthan stabilized alumina and its procedure for preparation |
| US5718879A (en) * | 1992-11-12 | 1998-02-17 | Rhone-Poulenc Chimie | Lanthanum-stabilized alumina particulates |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| 746 | Register noted 'licences of right' (sect. 46/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |