GB2102780A - Improvements in or relating to compounds - Google Patents
Improvements in or relating to compounds Download PDFInfo
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- GB2102780A GB2102780A GB08221521A GB8221521A GB2102780A GB 2102780 A GB2102780 A GB 2102780A GB 08221521 A GB08221521 A GB 08221521A GB 8221521 A GB8221521 A GB 8221521A GB 2102780 A GB2102780 A GB 2102780A
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- Prior art keywords
- cerium
- dispersible product
- salt
- prepared
- oxide hydrate
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- 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
- B01J13/0047—Preparation of sols containing a metal oxide
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- 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
- C01F17/224—Oxides or hydroxides of lanthanides
- C01F17/235—Cerium oxides or hydroxides
-
- 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
- C01F17/241—Compounds containing only rare earth metals as the metal element oxide or hydroxide being the only anion containing two or more rare earth metals, e.g. NdPrO3 or LaNdPrO3
-
- 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
- C01F17/253—Halides
- C01F17/271—Chlorides
-
- 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
- C01F17/276—Nitrates
-
- 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
- C01F17/30—Compounds containing rare earth metals and at least one element other than a rare earth metal, oxygen or hydrogen, e.g. La4S3Br6
- C01F17/32—Compounds containing rare earth metals and at least one element other than a rare earth metal, oxygen or hydrogen, e.g. La4S3Br6 oxide or hydroxide being the only anion, e.g. NaCeO2 or MgxCayEuO
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/22—Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Catalysts (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention provides a process for the preparation of a dispersible product containing a cerium compound which comprises heating a cerium (IV) oxide hydrate in the presence of a salt to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dispersible product containing a cerium compound.
Description
SPECIFICATION
Improvements in or relating to compounds
The present invention relates to compounds and more particularly to cerium compounds and cerium compounds in association with other elements.
According to one aspect of the present invention there is provided a process for the preparation of a dispersible product containing a cerium compound which comprises heating a cerium (IV) oxide hydrate in the presence of a salt to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dispersible product containing a cerium compound.
In accordance with one embodiment of the present invention there is provided a process for the preparation of a dispersible product containing a cerium compound which comprises heating a substantially dry cerium (IV) oxide hydrate in the presence of a salt to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dry dispersible product containing a cerium compound.
It is to be understood that the concentration of salt used and the temperature and time of heating is such that the desired degree of deaggregation is effected. The concentration, temperature and time can be determined by experimentation for a particular cerium (IV) oxide hydrate starting material.
By "dispersible product" as used in this Specification it is meant that the dispersible product is dispersible in aqueous media (e.g. water or aqueous acid solutions) to give a colloidal dispersion (i.e. a sol). The dry dispersible product may, of course, still contain "structural" water.
The salt may be, for example, a metal salt such as a metal nitrate, metal chloride or metal perchlorate.
Other salts, for example ammonium nitrate, may also be used in accordance with the present invention.
The salt may be chosen such that a selected chemical element is present in the dispersible product.
Thus, according to another aspect of the invention further provides a process for the preparation of a dispersible product containing a cerium compound in association with a selected element which comprises heating a cerium (IV) oxide hydrate in the presence of a salt of the element to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dispersible product containing a cerium compound in association with the element.
The dispersible product prepared in accordance with the immediately foregoing aspect of the present invention may comprise, for example, a mixture of a cerium compound and a compound of the element, or a mixture of a cerium compound with which ions of the element are associated (e.g. by being sorbed and thereby taken up by the cerium compound).
Byway of example dispersible products containing yttrium or a rare earth element may be prepared by heating cerium (IV) oxide hydrate in the presence of an yttrium salt or rare earth element salt (e.g.
M(NO3)3 where M is yttrium or a rare earth element).
Mixed colloidal dispersions of ceria-M203 have been prepared in accordance with the present invention at concentrations of up to 14woM2O3 where M is as defined above.
The present invention enables mixed colloidal dispersions to be prepared which are difficult or impossible to prepare by other routes such as adding M(NO3)3 salts to ceria sols, or by mixing
M(NO3)3 with Ce(NO3)3 and then processing by aqueous routes to cerium (IV) sols containing added M203.
The mechanism by which a salt effects deaggregation is not fully understood. However, it is believed that the salt gives rise to ionic species which interact with the crystallites (possibly in conjunction with water in the oxide hydrate) to effect the deaggregation.
More than one selected chemical element may be arranged to be present in the disperible product if desired. Thus, optionally, a cerium (IV) oxide hydrate may be heated in the presence of a plurality of salts of selected elements to produce a dispersible product containing a cerium compound in association with the elements.
The present invention may also be used to prepare a dispersible product containing a selected element (e.g. silicon) which does not form a salt convenient for use in accordance with the present invention.
Thus, in accordance with a further aspect the present invention provides a process for the preparation of a dispersible product containing a cerium compound in association with a selected element which comprises heating a cerium (IV) oxide hydrate in the presence of the selected element and a salt of a further element to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate.
The salt of the further element may be, for example, a nitrate or a chloride (e.g. ammonium chloride).
The selected element may be provided in any suitable form such as a heat stable oxide powder(e.g.
silica produced by a vapour phase condensation method such as flame hydrolysis).
Thus, by way of example, cerium (IV) oxide hydrate can be heated in the presence of silica produced by a vapour phase condensation method and a salt of a further element to give a dispersible product.
A mixed colloidal dispersion may also be formed by dispersing a dispersible product prepared in accordance with the present invention in a sol (e.g. a
SiO2 sol) or dispersing the dispersible product in water to form a sol and mixing this with another sol.
Cerium (IV) oxide hydrate for treatment in accordance with the present invention can be obtained commercially or, alternatively, can be prepared by any suitable route. For example, it can be prepared from readily available cerium salts, (e.g. of "reagent grade"). The preparation may be by precipitation from a cerium salt.
Thus, for example, as disclosed in British Patent
Application No.22835/78 (nowBP 1603794) (UKAEA) (to which West German Offenlegungsschrift No.
2857146 corresponds), high purity cerous carbonate can be dissolved in aqueous nitric or hydrochloric acid to give a neutral solution and then oxidised with NH4OH/H2Oto give cerium (IV) oxide hydrate.
By way offurther example cerium (IV) oxide
hydrate for treatment in accordance with the present
invention may be prepared by the conventional
routes disclosed at page 1 lines 40 to 61 of B.P. No.
1342893 (UKAEA).
The degree of hydration ofthe cerium (lV) oxide hydrate starting material may vary over a wide range.
By way of example, dry dispersible products have been prepared in accordance with the present invention from cerium (IV) oxide hydrate starting materials having respectively 8% water and 60% water.
Also by way of example, dispersible products have been prepared from oxide hydrate starting materials having other water contents.
Where, in accordance with the present invention substantially dry cerium (IV) oxide hydrate is heated in the presence of a salt, it is preferred that the temperature of heating of the cerium (IV) oxide hydrate is in the range 200-450"C and it has been found that heating in the range of 300-350 C is particularly useful in producing a dry dispersible product which can be dispersed to give highly concentrated sols (e.g. > 600 9rt (3.5M in Ce (IV)).
A time of 1 to 2 hours has been found to be suitable for heating substantially dry cerium (IV) oxide hydrate in the range of 200"C to 450"C to effect deaggregation in accordance with the present invention.
Preferably the nitrateiCeO2 ratio in the dry dispersible product is in the range 0.05 to 0.25 and a particularly preferred range is 0.8-0.15.
The cerium (IV) oxide hydrate starting material typically can consist of insoluble particles of up to
2000 diameter (i.e. greater than colloidal dimen
sions), the particles comprising aggregates of crystallites.
Colloidal dispersion prepared from dispersible products prepared in accordance with the present invention show, for example, a 10 to 20-fold reduction in this size in that such dispersions include colloidal size particles comprising individual crystallites (~50 A) and small aggregates of crystallites of say 100 A.
Thus, the heating in the presence of a salt in accordance with the present invention achieves deaggregation of the crystallites to enable particles of colloidal dimensions to be obtained.
Deaggregation in accordance with the present invention can involve breaking of bonds between crystallites in an aggregate of crystallites or a weakening of bonds or attractive forces between crystallites in an aggregate of crystallites to a degree that the crystallites can separate when the dispersible product is introduced into an aqueous medium.
A dispersible product prepared in accordance with the present invention may be used in the preparation of a colloidal dispersion (i.e. a sol).
Thus the present invention also provides a process for the preparation of a colloidal dispersion containing a cerium compound which comprises dispersing in an aqueous medium a dispersible product containing a cerium compound prepared in accordance
with the present invention.
The invention further provides a process for the
preparation of a mixed sol containing a cerium com
pound in association with a selected element com
prising dispersing in an aqueous medium a dispers
ible product containing a cerium compound in association with a selected element prepared in
accordance with the invention.
The invention further provides a process for the preparation of a gel which comprises drying a sol which has been prepared by dispersing in an aqueous medium a dispersible product containing a cerium compound prepared in accordance with the present invention.
The invention further provides a process for the preparation of a gel comprising drying a sol which has been prepared by dispersing in an aqueous medium a dispersible product containing a cerium compound in association with a selected element prepared in accordance with the invention.
The aqueous medium in which the dispersible product is dispersed can be water or aqueous acid solutions (e.g. dilute solutions of nitric acid). Gels may be produced by evaporating the sols at room temperature (--23"C) or at elevated temperatures (500C). The gels are glassy and may be redispersed in water.
The invention further provides a process which comprises mixing a dispersible product prepared in accordance with the present invention with water at such a concentration that coagulation occurs to form a slurry and separating the solids of the slurry from liquor of the slurry.
The separated solids may be dispersed in water to form a colloidal dispersion.
It is understood that ionic species can be removed with the liquor such that the ionic concentration in the solids is less than in the dispersible product as initially formed. In this way, if desired, the concentration of ionic species which may interfere with the formation of a colloidal dispersion is reduced and a more concentrated colloidal dispersion may be formed on admixing the separated solids with water.
It will be appreciated that where a dispersible product prepared by heating in accordance with the present invention does not have concentration of ionic species which prevents a desired concentration of sol being formed, there is no necessity for carrying out the further steps of coagulation to form a slurry, separation and dispersion to reduce the concentration of ionic species.
According to another aspect the present invention provides a sol prepared by a process in accordance with the present invention.
According to a further aspect the present invention provides a gel prepared by a process in accordance with the present invention.
According to yet a further aspect the present invention provides a dispersible product prepared by a process in accordance with the invention
British Patent Application No. 22835/78 (UKAEA) (to which West German Offenlegungsschrift 2857146 corresponds) discloses inter alia:
"A process for the preparation of an aqueous dispersion of ceria which comprises forming a slurry of cerium (IV) hydroxide with water and an acid, the acid being capable of causing deaggregation of aggregated crystallites in the cerium (IV) hydroxide, heating the slurry for such a time that the pH reaches a steady value, the quantity of acid in the slurry being such that the said steady value of pH is below 5.4, thereby to produce a conditioned slurry and admixing water with the conditioned slurry to produce an aqueous dispersion of cerium".
British Patent Application No. 22835/78 also discloses (page 6 lines 1 to 3) that certain cerium (IV) hydroxides are not easily susceptible to deaggregation in accordance with the invention disclosed therein and additionally the following passage appears at page 6 line 18 to page 7 line 2:
"Furthermore, to facilitate deaggregation as hereinbefore disclosed we believe that it is preferable that the starting cerium (IV) hydroxide should not have been heated to cause any substantial irreversible loss of water (e.g. heating to > 100 C) prior to treatment in accordance with the present invention. For example we have found that a starting cerium (IV) hydroxide having 25% by weight water can be deaggregated in accordance with the present invention whereas some samples with 10% weight water content were not easily amenable to deaggregation.
Also we believe that the time and temperature and humidity of any prior heat treatment of the starting cerium (IV) hydroxide may affect the susceptibility of the cerium (IV) hydroxide to deaggreation in accordance with the present invention".
Thus, British Patent Application No.22835/78 indicatesthat it is undesirable to heat cerium (IV) hydroxide to an extent which causes any substantial irreversible loss of water if it is desired to effect deaggregation to give a dispersible product.
It is surprising therefore that, in accordance with one embodiment of the present invention, a dispersible product containing a cerium compound which is readily dispersible in aqueous media to give concentrated sols may be prepared by a process which includes heating substantially dry cerium (IV) oxide hydrate to give a dry dispersible product.
British Patent Application No.8112046 discloses inter alia :
"A process for the preparation of a dispersible cerium compound which comprises heating a substantially dry cerium (IV) oxide hydrate in the presence of a deaggregating agent to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dry dispersible cerium compound".
In accordance with Application No. 8112046 pref erablythe deaggregating agent comprises acid species.
As hereinbefore disclosed, cerium (IV) oxide hydrate for treatment in accordance with the present invention can be obtained commercially or, alternatively, can be prepared by any suitable route.
Thus, a salt may, for example, be added to previously prepared cerium (IV) oxide hydrate prior to heating in accordance with the present invention.
By way of further example, cerium (IV) oxide hydrate optionally, may be co-precipitated with a salt, or a precursor therefor, prior to being heated to effect deaggregation. Thus the salt, optionally, may be formed in situ during formation of the cerium (IV) oxide hydrate rather than being added to previously prepared cerium (IV) oxide hydrate.
For example, cerium (IV) oxide hydrate may be precipitated from a cerous salt solution in the presence of a salt of an element to form a mixture of cerium (IV) oxide hydrate and the salt of the element.
Where a mixture contains cerium (IV) oxide hydrate and a precursorforthe saltthe mixture may betreated after formation to form the salt.
Thus, for example, the mixture may contain cerium (IV) oxide hydrate and the hydroxide of another element which may be converted to a salt prior to heating to effect deaggregation (e.g. nitric acid may be used to give a nitrate of the element).
Gels prepared by a process in accordance with the present invention may be heated to form ceramic materials.
The invention will now be further described, by way of example only, as follows:
Example 1
700g of a 99.5% pure cerium IV hydrate (71.4% oxide) was stirred with 0.1341 of a yttrium nitrate solution containing 55.69 of Y203 to give a mixture with the nominal composition of 10 w/o Y203-90 w/o
CeO2. The mixture was dried at 105"C for 3 hours to yield a dry product containing total oxide: 77.6 w/o and NO3, 18.2 w/o with a NO3/Y203 + CeO2 mole ratio = 0.67.A portion of the dry product (1409) was heated in airat320 Cfor4.5 hours using a bed-depth of 2.0 cm and yielded 1 149 of dispersible product containing oxide, 94.0 w/o and NO3, 5.6 w/o with a NO3/Y2O3 + CeO2 mole ratio = 0.17.
Example2
A sol was prepared from the dispersible product prepared in accordance with Example 1. Thus the dispersible product prepared in Example 1 readily dispersed in water to form a 10 w/o Y2O3-CeO2 sol containing 2009U' of Y203 + CeO2 with a pH of 4.7 and conductivity of 5.9 mmhos (22").
Example 3
1079 of a 99.5% pure cerium IV hydrate (93.2 w/o oxide) was mixed with 0.0481 of a yttrium chloride solution containing the equivalent of 11.1 g Y2O3 to give a nominal composition of 10 w/oY2O3 - 90 wlo CeO2. The mixture was dried at 105"C for 18 hours to give 139 of a dry product containing: Y203 + CeO2, 83.6 w/o and Cur,7.1 with a Cr /Y203 + CeO2 mole ratio of 0.42. The dry product was heated in air at 300-320"C for between 0.5 and 1.0 hours to give a dispersible product containing: 94.7 w/o oxide and 6.2% Cr. The dispersible product was dispersed in water to give a dilute sol.
Example 4
Dispersible product prepared in accordance with
Example 3 was dispersed in water at high concentration (1009 1-' ) to cause coagulation to form a slurry.
The slurry was heated to 900C and centrifuged to give a clear superantant liquor containing 0.38M
chloride. The solids of the slurry were readily dis
persed in water to give a sol > 2009 1-' in oxide with
a pH of 3.9 and a conductivity of 8.6 mmhos. The Cm /oxide mole ratio in the sol was 0.13.
Example 5
107g of a 99.9% pure cerium IV hydrate (93.2%
oxide) was mixed with an aqueous solution of
ammonium chloride (75ml) containing 7.79 of NH4CI to give a CL/CeO2 mole ratio of 0.25. The resulting
mixture was dried at 1050C for 18 hours and then
heated in air at 300"C for 0-5 hours (bed depth 2.0 cm) to give a dispersible product containing: oxide 94.0 w/o; and Cm,4.5 w/o with a Cl /CeO2 mole ratio of 0.23. This dispersible product was dispersed in waterto give a sol containing 100 gr1.
Example 6
Dispersible product prepared in accordance with Examples was dispersed in water at high concentration ( > 1009 1 ' ) and heated at 90"C to cause coagulation to give a slurry. The slurry was centrifuged to give a clear supernatant liquor was discarded. The solids of the slurry were readily dispersed in water to a sol having an oxide concentration > 2009 1-' with a pH of 1.7 and a conductivity of 14.0 mmhos (22"C).
Example 7
1079 of a 99.9% pure cerium IV hydrate (93.2 w/o oxide) was mixed with 75ml of an ammonium nitrate solution containing 11.59 of NH4NO3 (NO3/CeO2 mole ratio = 0.23). The resulting mixture was dried at 1 05"C and then heat treated at 300"C for 0.5 hour to give a dispersible product containing: oxide, 93.8 w/o and nitrate, 4.8 w/o with a NOCeO2 mole ratio 0.14.
This dispersible product was dispersed in water to give a dilutesol ( > 1009 1-').
Example 8
Dispersible product prepared in accordance with
Example 7 (i.e. > 1009 1-' ) to cause coagulation to form a slurry. The slurry was centrifuged, the supernatant liquor discarded and the solid dispersed in water to give a sol of high concentration ( > 2009 1-1).
Example 9
50g of 99.5% pure cerium (IV) oxide hydrate were mixed with 21 ml of 2M yttrium perchlorate solution (4.79 g Y203 equivalent- giving - 10 wt % yttrium oxide/total oxide) and the resulting mixture heated in air at 320"C for 30 minutes to give a dispersible product.
Example 10
0.0391 of yttrium nitrate solution containing the equivalent of 251 g.l' Y203 was added to 0.248 1 of a cerous nitrate solution containing the equivalent of 361 g 1' cerium oxide. To the mixture so formed (which contained the equivalent of 9.89 of Y203 and the equivalent of 899 CeO2) 0251 of a europium nitrate solution containing the equivalent of 399.1of Emu202 was added and the whole diluted to 1 litre with water to give a mixed metal nitrate solution.
Whilst stirring a mixture containing 0.037 1 of 100 volume H202 and 0.1151 of 18M NH4OH made to 0.1 I with water was added to the mixed metal nitrate solution. A precipitate formed and this was stirred for
15 minutes after which it was centrifuged. The
residue was washed with two successive 1 I volumes
of water to remove entrained salts.
The resulting washed residue was stirred with 0.04
I of 2.5M HNO2, dried at 1 05"C for 3 hours, and sub- sequently heated at 320"C for 4 hours.
The resulting dispersible product was completely
dispersible in water, contained 91.2 wt % oxide and
had a nitrate: oxide mole ratio of 0.23.
Claims (31)
1. A process for the preparation of a dispersible product containing a cerium compound which comprises heating a cerium (IV) oxide hydrate in the presence of a salt to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dispersible product containing a cerium compound.
2. A process as claimed in claim 1 which comprises heating a substantially dry cerium (IV) oxide hydrate in the presence of a salt two cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dry dispersible product containing a cerium compound.
3. A process as claimed in claim 1 or claim 2 for the preparation of a dispersible product containing a cerium compound in association with a selected element which comprises heating a cerium (IV) oxide hydrate in the presence of a salt of the element to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate and produce a dispersible product containing a cerium compound in association with the element.
4. A process as claimed in any one of the preceding claims wherein the salt is a metal salt or an ammonium salt.
5. A process as claimed in claim 4 wherein the metal salt is a metal nitrate, a metal chloride, or a metal perchlorate.
6. A process as claimed in claim 4 wherein the ammonium salt in ammonium nitrate.
7. A process as claimed in claim 4 or 5 wherein the metal salt is an yttrium salt or a rare earth element salt.
8. A process as claimed in claim 7 wherein the yttrium salt is yttrium nitrate orthe rare earth element salt is a rare earth nitrate.
9. A process as claimed in any one of the preceding claims wherein a cerium (IV) oxide hydrate is heated in the presence of a plurality of salts.
10. A process as claimed in any one of the preceding claims for the preparation of a dispersible product containing a cerium compound in association with a selected element which comprises heating a cerium (IV) oxide hydrate in the presence of the selected element and a salt of a further element to cause deaggregation of aggregated crystallites in the cerium (IV) oxide hydrate.
11. A process as claimed in claim 10 wherein the salt of the further element is a nitrate or a chloride.
12. A process as claimed in claim 10 or 11 wherein the selected element is provided in the form of a heat stable oxide powder.
13. A process as claimed in claim 12 wherein the heat stable oxide powder is silica produced by a vapour phase condensation method.
14. A process as claimed in any one of claims 1 to 13 wherein substantially dry cerium (IV) oxide hydrate is heated in the presence of a salt at a temperature in the range 200"C to 450"C.
15. Aprocess as claimed in claim 14 wherein the temperature is in the range 300"C to 350"C.
16. A dispersible product prepared by a process as claimed in any one of claims 3 to 15 comprising a mixture of a cerium compound and a compound of an element.
17. A dispersible product prepared by a process as claimed in any one of claims 3 to 15 comprising a mixture of a cerium compound with which ions of an element are associated.
18. A dry dispersible product prepared by a process as claimed in any one of claims 2 to 15 having a nitrate/cerium ratio in the range 0.05 to 0.25.
19. A dry dispersible product as claimed in claim 18 wherein the nitrate/cerium ratio is in the range 0.08 to 0.15.
20. A process for the preparation of a colloidal dispersion containing a cerium compound which comprises dispersing in an aqueous medium a dispersible product containing a cerium compound prepared by a process as claimed in any one of claims 1 to 15.
21. A process forthe preparation of a mixed sol containing a cerium compound in association with a selected element comprising dispersing in an aqueous medium a dispersible product containing a cerium compound in association with a selected element prepared by a process as claimed in any one of claims 3 to 15.
22. A process for the preparation of a gel which comprises drying a sol which has been prepared by dispersing in an aqueous medium a dispersible product containing a cerium compound prepared by a process as claimed in any one of claims 1 to 15.
23. A process for the preparation of a gel comprising drying a sol which has been prepared by dispersing in an aqueous medium a dispersible product containing a cerium compound in association with a selected element prepared by a process as claimed in any one of claims 3 to 15.
24. A process for the preparation of a mixed colloidal dispersion comprising dispersing in a sol a dispersible product prepared by a process as claimed in claim 1 or 2.
25. A process for the preparation of a mixed colloidal dispersion comprising dispersing a dispersible product prepared by a process as claimed in claim 1 or 2 in water to form a sol and mixing this sol with another sol.
26. A process for the preparation of a colloidal dispersion which comprises mixing a dispersible product prepared by a process as claimed in any one of claims 1 to 15 with water at such a concentration that coagulation occurs to form a slurry, separating the solids of the slurry from liquor of the slurry and dispersing the separted solids in water to form a colloidal dispersion.
27. A sol or colloidal dispersion prepared by a process as claimed in any one of claims 20,21,24,25 or 26.
28. A gel prepared by a process as claimed in claim 22 or 23.
29. A dispersible product prepared by a process as claimed in any one of claims 1 to 15.
30. A process substantially as hereinbefore described with reference to any one of the Examples.
31. A dispersible product substantially as
hereinbefore described with reference to any one of
Examples 1,3,5,7,9 and 10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08221521A GB2102780B (en) | 1981-08-07 | 1982-07-26 | Improvements in or relating to compounds |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8124245 | 1981-08-07 | ||
| GB08221521A GB2102780B (en) | 1981-08-07 | 1982-07-26 | Improvements in or relating to compounds |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2102780A true GB2102780A (en) | 1983-02-09 |
| GB2102780B GB2102780B (en) | 1985-04-03 |
Family
ID=26280391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08221521A Expired GB2102780B (en) | 1981-08-07 | 1982-07-26 | Improvements in or relating to compounds |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2102780B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2167739A (en) * | 1984-11-30 | 1986-06-04 | Atomic Energy Authority Uk | Preparation of dispersible cerium compounds |
| FR2583736A1 (en) * | 1985-06-20 | 1986-12-26 | Rhone Poulenc Spec Chim | NEW CERIUM IV COMPOUND AND PROCESS FOR PREPARING THE SAME |
| EP0207857A2 (en) * | 1985-07-03 | 1987-01-07 | Rhone-Poulenc Chimie | Composition containing ceric oxide, its preparation and its use |
| EP0208581B1 (en) * | 1985-06-20 | 1990-03-14 | Rhone-Poulenc Chimie | Cerium iv compound and method for its preparation |
| FR2727328A1 (en) * | 1994-11-25 | 1996-05-31 | Rhone Poulenc Chimie | Oxidn. or thermo-hydrolysis of chemical element esp. rare earths by microwave heating |
| EP0744379A1 (en) * | 1995-05-24 | 1996-11-27 | Rhone-Poulenc Chimie | Redispersible yttrium or holmium based sol composition |
| EP0947469A2 (en) * | 1996-07-30 | 1999-10-06 | Nissan Chemical Industries, Limited | Abrasive |
| US7169196B2 (en) | 2001-11-06 | 2007-01-30 | Oxonica Materials Limited | Fuel or fuel additive containing doped cerium oxide nanoparticles |
-
1982
- 1982-07-26 GB GB08221521A patent/GB2102780B/en not_active Expired
Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0186313A2 (en) * | 1984-11-30 | 1986-07-02 | United Kingdom Atomic Energy Authority | Preparation of dispersible cerium compounds |
| GB2167739A (en) * | 1984-11-30 | 1986-06-04 | Atomic Energy Authority Uk | Preparation of dispersible cerium compounds |
| EP0186313A3 (en) * | 1984-11-30 | 1987-04-08 | United Kingdom Atomic Energy Authority | Preparation of dispersible cerium compounds |
| EP0208581B1 (en) * | 1985-06-20 | 1990-03-14 | Rhone-Poulenc Chimie | Cerium iv compound and method for its preparation |
| FR2583736A1 (en) * | 1985-06-20 | 1986-12-26 | Rhone Poulenc Spec Chim | NEW CERIUM IV COMPOUND AND PROCESS FOR PREPARING THE SAME |
| US5344588A (en) * | 1985-06-20 | 1994-09-06 | Rhone-Poulenc Specialites Chimiques | Cerium (IV) compound |
| EP0208580A1 (en) * | 1985-06-20 | 1987-01-14 | Rhone-Poulenc Chimie | Cerium IV compound and method for its preparation |
| EP0396159A2 (en) * | 1985-07-03 | 1990-11-07 | Rhone-Poulenc Chimie | Ceric oxide contaning composition, its preparation and its uses |
| EP0207857A3 (en) * | 1985-07-03 | 1987-09-02 | Rhone-Poulenc Specialites Chimiques | Composition containing ceric oxide, its preparation and its use |
| AU596802B2 (en) * | 1985-07-03 | 1990-05-17 | Rhone-Poulenc Specialites Chimiques | The preparation and use of a ceric oxide based composition |
| FR2584388A1 (en) * | 1985-07-03 | 1987-01-09 | Rhone Poulenc Spec Chim | CERIC OXIDE-BASED COMPOSITION, PREPARATION AND USES THEREOF |
| EP0396159A3 (en) * | 1985-07-03 | 1991-10-23 | Rhone-Poulenc Chimie | Ceric oxide contaning composition, its preparation and its uses |
| EP0207857A2 (en) * | 1985-07-03 | 1987-01-07 | Rhone-Poulenc Chimie | Composition containing ceric oxide, its preparation and its use |
| FR2727328A1 (en) * | 1994-11-25 | 1996-05-31 | Rhone Poulenc Chimie | Oxidn. or thermo-hydrolysis of chemical element esp. rare earths by microwave heating |
| EP0744379A1 (en) * | 1995-05-24 | 1996-11-27 | Rhone-Poulenc Chimie | Redispersible yttrium or holmium based sol composition |
| FR2734560A1 (en) * | 1995-05-24 | 1996-11-29 | Rhone Poulenc Chimie | COMPOUND BASED ON YTTRIUM OR REDISPERSIBLE HOLMIUM IN THE FORM OF A SOIL |
| EP0947469A2 (en) * | 1996-07-30 | 1999-10-06 | Nissan Chemical Industries, Limited | Abrasive |
| EP0947469A3 (en) * | 1996-07-30 | 2000-01-12 | Nissan Chemical Industries, Limited | Abrasive |
| US6372003B1 (en) | 1996-07-30 | 2002-04-16 | Nissan Chemical Industries, Ltd. | Polishing abrasive of crystalline ceric oxide particles having surfaces modified with hydroxyl groups |
| US7169196B2 (en) | 2001-11-06 | 2007-01-30 | Oxonica Materials Limited | Fuel or fuel additive containing doped cerium oxide nanoparticles |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2102780B (en) | 1985-04-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |