US4942697A — Rare earth polishing compositions

Claim 1

Independent Claim 114 words

A rare earth polishing composition of reproducible homogeneity produced by a process 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, wherein said calcined precipitate comprises a sulphur content of less than 0.1% by weight.

Claim 2

Dependent Claim 114 words

A rare earth polishing composition of reproducible homogeneity produced by a process 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, wherein said calcined precipitate comprises a sulphur content of less than 0.1% by weight.

Claim 3

Dependent Claim 27 words

The composition defined by claim 1 wherein said solutions are aqueous solutions and further comprising grinding and particle size selecting the polishing composition which results after calcination.

Claim 4

Dependent Claim 39 words

The composition defined by claim 1 wherein said solutions are aqueous solutions and 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.

Claim 5

Dependent Claim 39 words

The composition defined by claim 1 wherein said solutions are aqueous solutions and 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 carbonate.

Claim 6

Dependent Claim 39 words

The composition defined by claim 1 wherein said solutions are aqueous solutions and 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 borate.

Claim 7

Dependent Claim 39 words

The composition defined by claim 1 wherein said solutions are aqueous solutions and 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 silicate.

Claim 8

Dependent Claim 39 words

The composition defined by claim 1 wherein said solutions are aqueous solutions and 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 sulfate.

Claim 9

Dependent Claim 31 words

The composition as defined by claim 1 wherein said calcination is carried out at a temperature between about 600° C. and 1,200° C. for from about 30 minutes to 10 hours.

Claim 10

Dependent Claim 122 words

A rare earth polishing composition of reproducible homogeneity produced by a process 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 and comprising fluoride, 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 to thereby obtain a composition containing fluoride anions and having a sulphur content of less than 0.1% by weight.

Claim 11

Dependent Claim 122 words

A rare earth polishing composition of reproducible homogeneity produced by a process 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 and comprising fluoride, 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 to thereby obtain a composition containing fluoride anions and having a sulphur content of less than 0.1% by weight.

Claim 12

Dependent Claim 122 words

A rare earth polishing composition of reproducible homogeneity produced by a process 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 and comprising phosphate, 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 to thereby obtain a composition containing phosphate anions and having a sulphur content of less than 0.1% by weight.

Claim 13

Dependent Claim 122 words

A rare earth polishing composition of reproducible homogeneity produced by a process 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 and comprising phosphate, 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 to thereby obtain a composition containing phosphate anions and having a sulphur content of less than 0.1% by weight.

Claim 14

Dependent Claim 28 words

The composition defined by claim 9 wherein said obtained composition contains a content of fluoride anions in a range of from about 1 to about 11% by weight.

Claim 15

Dependent Claim 28 words

The composition defined by claim 10 wherein said obtained composition contains a content of phosphate anions in a range of from about 2.7 to about 14% by weight.

Claim 16

Dependent Claim 28 words

In the polishing of glass or like material, the improvement which comprises, utilizing as the polishing composition therefor, the rare earth polishing composition as defined by claim 1.

Claim 17

Dependent Claim 28 words

In the polishing of glass or like material, the improvement which comprises, utilizing as the polishing composition therefor, the rare earth polishing composition as defined by claim 2.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-07-23	1994-01-22	1994-07-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-07-23	1998-01-22	1998-07-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-07-23	2002-01-22	2002-07-24	$7700.00	Window Closed / Lapsed

Rare earth polishing compositions

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