US4529410A
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Rare earth polishing compositions
Assignee: Rhone Poulenc Industries SA
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Filing: 1980-12-22
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Granted: 1985-07-16
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Expires: 2000-12-22
Abstract
Abstract Rare earth glass-polishing compositions of improved homogeneity and reproducibility are prepared by (a) simultaneously continuously admixing a cerium salt solution, a basic solution and a solution of at least one acid and/or one salt, the anion or anions of which being adopted to form insoluble rare earth compounds, the number of equivalents of base being equal to or greater than the number of equivalents of cerium, and the pH of the reaction medium being greater than about 6; (b) filtering the precipitate which reuslts from the reaction medium; (c) drying said recovered precipitate; and (d) calcining said dried precipitate.
Inventors
- 👤 Jean Khaladji
- 👤 Marcel Peltier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:59
CPC Classifications
C; C09; C09K; C09K3/00; C09K3/14; C09K3/1454
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
102 words
A process for the preparation of a rare earth polishing composition of reproducible homogeneity, comprising (a) simultaneously continuously admixing a cerium salt solution, a basic solution and a solution of at least one acid and/or one salt, the anion or anions of which being adopted to form insoluble rare earth compounds, the number of equivalents of base being equal to or greater than the number of equivalents of cerium, and the pH of the reaction medium being greater than about 6; (b) filtering the precipitate which results from the reaction medium; (c) drying said recovered precipitate; and (d) calcining said dried precipitate.
Claim 2
Dependent Claim
102 words
A process for the preparation of a rare earth polishing composition of reproducible homogeneity, comprising (a) simultaneously continuously admixing a cerium salt solution, a basic solution and a solution of at least one acid and/or one salt, the anion or anions of which being adopted to form insoluble rare earth compounds, the number of equivalents of base being equal to or greater than the number of equivalents of cerium, and the pH of the reaction medium being greater than about 6; (b) filtering the precipitate which results from the reaction medium; (c) drying said recovered precipitate; and (d) calcining said dried precipitate.
Claim 3
Dependent Claim
12 words
The process as defined by claim 1, said solutions being aqueous solutions.
Claim 4
Dependent Claim
21 words
The process as defined by claim 2, wherein the temperature of the reaction medium ranges from about 10° to 95° C.
Claim 5
Dependent Claim
26 words
The process as defined by claim 2, wherein the residence time of the admixture in the reaction medium ranges from about 30 minutes to 2 hours.
Claim 6
Dependent Claim
21 words
The process as defined by claim 2, wherein the cerium salt solution comprises cerous chloride, cerous nitrate and/or ceric nitrate solutions.
Claim 7
Dependent Claim
25 words
The process as defined by claims 2 or 5, wherein the concentration of the cerium salt solution ranges from 0.5 to 2 mols per liter.
Claim 8
Dependent Claim
36 words
The process as defined by claim 2, wherein the cerium is introduced into the reaction medium in the cerous state and is preliminarily oxidized to the ceric state by continuous addition thereto of an oxidizing agent.
Claim 9
Dependent Claim
30 words
The process as defined by claim 7, wherein the oxidizing agent is selected from the group consisting of solutions of perchlorate, chlorate, hypochlorite, persulfate, hydrogen peroxide, air, oxygen and ozone.
Claim 10
Dependent Claim
29 words
The process as defined by claim 7, wherein the amount of oxidizing agent added, relative to the cerous salt, is a stoichiometric excess of from about 10 to 40%.
Claim 11
Dependent Claim
20 words
The process as defined by claim 2, wherein the basic solution comprises ammonia, sodium hydroxide, potassium hydroxide or sodium carbonate.
Claim 12
Dependent Claim
22 words
The process as defined by claims 2 or 1, wherein the normality of the basic solution ranges from 1 to 5 N.
Claim 13
Dependent Claim
25 words
The process as defined by claim 2, there being admixed an excess of base of more than about 5%, relative to the equivalents of cerium.
Claim 14
Dependent Claim
18 words
The process as defined by claim 2, the pH of the reaction medium being no greater than 10.
Claim 15
Dependent Claim
29 words
The process as defined by claim 13, wherein the pH of the reaction medium is controlled to a value which is constant to within ±0.1 of a pH unit.
Claim 16
Dependent Claim
41 words
The process as defined by claim 2, wherein the solution of at least one acid and/or salt, the anion or anions of which being adopted to form insoluble rare earth compounds, comprises oxalate, fluoride, carbonate, borate, silicate, sulfate and/or phosphate anions.
Claim 17
Dependent Claim
23 words
The process as defined by claim 2 or 15, wherein the salt or salts comprising such solution are ammonium, sodium and/or potassium salts.
Claim 18
Dependent Claim
26 words
The process as defined by claims 2 or 15, wherein the concentration of the solution of acid and/or salt is less than 6 mols per liter.
Claim 19
Dependent Claim
28 words
The process as defined by claim 2, further comprising continuously adding an aqueous solution of a salt of at least one trivalent rare earth to the reaction medium.
Claim 20
Dependent Claim
42 words
The process as defined by claim 18, wherein the aqueous solution of a salt of at least one trivalent rare earth comprises a chloride or nitrate of lanthanum, neodymium, praseodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium.
Claim 21
Dependent Claim
32 words
The process as defined by claims 18 or 19, wherein the concentration of the aqueous solution of a salt of a trivalent rare earth is between 0.2 and 1 mol per liter.
Claim 22
Dependent Claim
30 words
The process as defined by claim 2, further comprising aging the reaction medium, prior to filtration, at a temperature between 10° and 95° C., for up to about 2 hours.
Claim 23
Dependent Claim
22 words
The process as defined by claim 2, wherein the filtration is carried out at a temperature between about 10° and 90° C.
Claim 24
Dependent Claim
41 words
The process as defined by claim 2, wherein, after filtration, the filter cake is washed with water or a solution of an ammonium salt, with the water content of said filter cake being about 20 and 80% by weight after washing.
Claim 25
Dependent Claim
30 words
The process as defined by claim 2, wherein the drying is carried out at a temperature between about 100° and 600° C. for from about 30 minutes to 2 hours.
Claim 26
Dependent Claim
30 words
The process as defined by claim 2, wherein the calcination is carried out at a temperature between about 600° and 1,200° C. for from about 30 minutes to 10 hours.
Claim 27
Dependent Claim
21 words
The process as defined by claim 2, further comprising grinding and particle size selecting the polishing composition which results after calcination.
Claim 28
Dependent Claim
21 words
The process as defined by claim 3, wherein the temperature of the reaction medium ranges from about 50° to 70° C.
Claim 29
Dependent Claim
29 words
The process as defined by claim 2, wherein the cerium is introduced into the reaction medium in the cerous state and is preliminarily electrochemically oxidized to the ceric state.
Claim 30
Dependent Claim
19 words
The process as defined by claim 13, the pH of the reaction medium ranging from about 7 to 9.
Claim 31
Dependent Claim
18 words
The process as defined by claim 17, said concentration ranging from about 2 to 4 mols per liter.
Claim 32
Dependent Claim
17 words
The process as defined by claim 21, said aging temperatures ranging from about 50° to 80° C.
Claim 33
Dependent Claim
22 words
The process as defined by claim 22, said filtration being carried out at a temperature ranging from about 35° to 45° C.
Claim 34
Dependent Claim
23 words
The process as defined by claim 23, the water content of the filter cake, after washing, ranging from about 30° to 50° C.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-15 | 1989-01-14 | 1989-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-15 | 1993-01-14 | 1993-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-15 | 1997-01-14 | 1997-07-16 | $7700.00 | Window Closed / Lapsed |