Preparation of unagglomerated metal oxide particles with uniform particle size
First Claim
1. A process for the production of substantially unagglomerated metal oxide particles having a mean diameter of up to about 1 micron and a substantially uniform particle size comprising:
- (a) providing a solution of an oxygen-containing nitrate of a first metal selected from the group consisting of alkaline earth metals, lanthanide metals, transition metals exclusive of vanadium, tungsten, molybdenum, niobium and tantalum, and mixtures of these;
(b) adding to the solution a chelating agent selected from the group consisting of tartaric acid, citric acid, and mixtures of these;
(c) adding to the solution a base selected from the group consisting of ammonium hydroxide, urea, and mixtures of these;
(d) drying the solution by heating for a time and at a temperature sufficient to remove substantially all the solvent from the solution to leave a solid residue; and
(e) calcining the solid residue for a time and at a temperature sufficient to form particles of said metal oxide.
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Accused Products
Abstract
Disclosed is a method for producing substantially unagglomerated submicron metal oxide particles having uniform size distribution. The process is readily adaptable to the production of multicomponent metal oxide particles. The method comprises the steps of (1) providing a solution of a complex of an oxygen-containing metal salt and a chelating agent selected from the group consisting of ethylenediaminetetraacetic acid, hydroxy ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentacetic acid, glycolic acid, lactic acid, citric acid, tartaric acid, succinic acid, alkali salts of the foregoing acids, and mixtures of these; (2) drying the solution by heating the solution under alkaline conditions for a time and at a temperature sufficient to remove substantially all the solvent from the solution and to leave a solid residue; (3) heating the solid residue for time and at a temperature sufficient to convert at least a substantial portion of the residue to substantially unagglomerated particles of the metal oxide having a mean diameter up to about one micron and a uniform particle size.
84 Citations
55 Claims
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1. A process for the production of substantially unagglomerated metal oxide particles having a mean diameter of up to about 1 micron and a substantially uniform particle size comprising:
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(a) providing a solution of an oxygen-containing nitrate of a first metal selected from the group consisting of alkaline earth metals, lanthanide metals, transition metals exclusive of vanadium, tungsten, molybdenum, niobium and tantalum, and mixtures of these; (b) adding to the solution a chelating agent selected from the group consisting of tartaric acid, citric acid, and mixtures of these; (c) adding to the solution a base selected from the group consisting of ammonium hydroxide, urea, and mixtures of these; (d) drying the solution by heating for a time and at a temperature sufficient to remove substantially all the solvent from the solution to leave a solid residue; and (e) calcining the solid residue for a time and at a temperature sufficient to form particles of said metal oxide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A process for the production of substantially unagglomerated metal oxide particles having a mean diameter of up to about 1 micron and a substantially uniform particle size comprising:
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(a) providing an alkaline solution of a salt of a first metal having an ammonium cation and a carbonate anion, said first metal being selected from the group consisting of alkaline earth metals, lanthanide metals, transition metals exclusive of vanadium, tungsten, molybdenum, niobium and tantalum, and mixtures of these; (b) adding a chelating agent to the solution to form a chelated solution, said chelating agent being a sodium salt of an acid selected from the group consisting of EDTA, H-EDTA, NTA, DTPA, lactic acid, glycolic acid, succinic acid, and mixtures of these; (c) drying the chelated solution by heating for a time and at a temperature sufficient to remove substantially all the solvent from the solution to leave a solid residue; and (d) heating the solid residue for a time and at a temperature sufficient to convert at least a substantial portion of the residue to said metal oxide. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A process for the production of substantially unagglomerated metal oxide particles having a mean diameter of up to about 1 micron and a substantially uniform particle size distribution comprising:
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(a) providing a solution of a chelated complex of a salt of a first metal having an ammonium cation and a carbonate anion and a chelating agent, said chelating agent being a rubidium cesium, or sodium salt of an acid selected from the group consisting of EDTA, H-EDTA, NTA, DTPA, glycolic acid, succinic acid, lactic acid, and mixtures of these, said first metal being selected from the group consisting of alkaline earth metals, lanthanide metals, transition metals exclusive of vanadium, tungsten, molybdenum, niobium and tantalum, and mixtures of these; (b) heating the solution under alkaline conditions for a time and at a temperature sufficient to remove substantially all of the solvent from the solution to leave a solid residue; and (c) heating the solid residue for a time and at a temperature sufficient to form particles of said metal oxide. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A process for the production of substantially unagglomerated metal oxide particles having a substantially uniform particle size distribution and a mean diamerter of less than about 1 micron comprising;
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(a) providing a chelated solution selected from the group consisting of; (1) a solution of a chelated complex of an oxygen containing nitrate of a first metal selected from the group consisting of alkaline earth metals, lanthanide metals, transition metals exclusive of vanadium, tungsten, molybdenum, niobium and tantalum, and chelating agent selected from the group consisting of tartaric acid, citric acid, and mixtures of these; and (2) a solution of a chelated complex of an oxygen-containing salt of a first metal selected from the group consisting of alkaline earth metals, lanthanide metals, transition metals exclusive of vanadium, tungsten, molybdenum, niobium and tantalum, and a chelating agent selected from the group consisting of;
EDTA;
H-EDTA;
NTA;
DTPA;
lactic acid;
succinic acid;
sodium, rubidium, or cesium salts of the foreging acids; and
a mixture of these;(b) heating the chelated solution under alkaline conditions, said heating step carried out for a time and at a temperature sufficient to remove substantially all the solvent from the solution to leave a solid residue; and (c) heating the solid residue for a time and at a temperature sufficient to form particles of said metal oxide. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A process of the production of substantially unagglomerated metal oxide particles having a substantial uniform particle size distribution and a mean diameter of less than about 1 micron comprising:
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(a) providing a solution of chelated complex of an oxygen containing salt of a metal selected from the group consisting of alkaline earth metals, lanthanide metals, transition metals exclusive of vanadium, tungsten, molybdenum, niobium and tantalum, and a chelating agent selected from the group consisting of;
EDTA;
H-EDTA;
NTA;
DTPA;
glycolic acid;
lactic acid;
succinic acid;
tartaric acid;
citric acid;
phthalic acid;
alkali salts of the foregoing acids; and
mixtures of these;(b) heating the chelated solution under alkaline conditions, said heating step carried out for a time and at a temperature sufficient to remove substantially all the solvent from the solution to leave a solid residue; and (c) heating the solid residue for a time and at a temperature sufficient to convert at least a substantial portion of the residue to said metal oxide. - View Dependent Claims (51, 52, 53, 54, 55)
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Specification