Patent US3859412A successfully refreshed from Google Patents.
US3859412A
Expired / Lapsed
US
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Process for production of alkali metal chromates
Assignee: Nippon Chemical Industrial Co Ltd
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Filing: 1974-01-02
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Granted: 1975-01-07
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Expires: 1994-01-02
Abstract
Abstract A process for producing alkali metal chromates which comprises reacting a chrome ore with an alkali metal hydroxide in a molten state and in the presence of 1 to 2.5 moles of an alkali metal salt of a nitrogen oxyacid, the alkali metal hydroxide being present in a ratio of more than 2 moles per mole of Cr2O3 present in the chrome ore, and leaching the resulting alkali metal chromates from the reaction product. Embodiments include adding a nitrogen oxyacid to the leaching residue obtained after leaching the alkali metal chromate to recover the alkali metal content in the residue as an alkali metal salt of the nitrogen oxyacid for reuse in the reaction of the chrome ore with the alkali metal hydroxide and an alkali metal salt of a nitrogen oxyacid, and/or conducting the reaction of the chrome ore with the alkali metal hydroxide and an alkali metal salt of a nitrogen oxyacid in the presence of SiO2 in an amount sufficient to provide an SiO2/Al2O3 molar ratio of 1 to 3 based on the amount of Al2O3 present in the chrome ore.
Inventors
- 👤 Taijiro Okabe
- 👤 Koji Kashiwase
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:09
CPC Classifications
C; C01; C01G; C01G37/00; C01G37/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
PROCESS FOR PRODUCING ALKALI METAL CHROMATES FROM A CHROME ORE WHICH COMPRISES REACTING AT A TEMPERATURE OF 400% TO 700*C A CHROME ORE WITH AN ALKALI METAL HYDROXIDE IN A MOLTEN STATE AND IN THE PRESENCE OF FROM 1 TO 2.5 MOLES OF AN ALKALI METAL SALT OF A NITROGEN OXYACID PER MOLE OF THE CR2O3 PRESENT IN SAID CHROME ORE, SAID ALKALI METAL HYDROXIDE BEING PRESENT IN AN AMOUNT OF MORE THAN 2 MOLES PER MOLE OF THE CR2O3 PRESENT IN SAID CHROME ORE, AND LEACHING THE RESULTING ALKALI METAL CHROMATE FROM THE REACTION PRODUCT WITH WATER OR A DILUTE AQUEOUS SOLUTION OF AN ALKALI METAL CHROMATE, THE ALKALI METAL OF SAID ALKALI METAL CHROMATE IN SAID DILUTE AQUEOUS SOLUTION BEING THE SAME AS THAT OF SAID ALKALI METAL HYDROXIDE.
Claim 2
Dependent Claim
131 words
PROCESS FOR PRODUCING ALKALI METAL CHROMATES FROM A CHROME ORE WHICH COMPRISES REACTING AT A TEMPERATURE OF 400% TO 700*C A CHROME ORE WITH AN ALKALI METAL HYDROXIDE IN A MOLTEN STATE AND IN THE PRESENCE OF FROM 1 TO 2.5 MOLES OF AN ALKALI METAL SALT OF A NITROGEN OXYACID PER MOLE OF THE CR2O3 PRESENT IN SAID CHROME ORE, SAID ALKALI METAL HYDROXIDE BEING PRESENT IN AN AMOUNT OF MORE THAN 2 MOLES PER MOLE OF THE CR2O3 PRESENT IN SAID CHROME ORE, AND LEACHING THE RESULTING ALKALI METAL CHROMATE FROM THE REACTION PRODUCT WITH WATER OR A DILUTE AQUEOUS SOLUTION OF AN ALKALI METAL CHROMATE, THE ALKALI METAL OF SAID ALKALI METAL CHROMATE IN SAID DILUTE AQUEOUS SOLUTION BEING THE SAME AS THAT OF SAID ALKALI METAL HYDROXIDE.
Claim 3
Dependent Claim
29 words
The process according to claim 1, wherein said alkali metal salt of the nitrogen oxyacid is sodium nitrate, potassium nitrate, lithium nitrate, sodium nitrite, potassium nitrite or lithium nitrite.
Claim 4
Dependent Claim
19 words
The process according to claim 1, wherein said alkali metal hydroxide is sodium hydroxide, potassium hydroxide or lithium hydroxide.
Claim 5
Dependent Claim
31 words
The process according to claim 1, wherein said alkali metal hydroxide is used in an amount of from 10 to 25 moles per mole of Cr2O3 contained in said chrome ore.
Claim 6
Dependent Claim
92 words
The process according to claim 1, wherein said process further comprises re-slurrying a residue obtained after leaching of said alkali metal chromate in water, incorporating a nitrogen oxyacid into the resulting slurry and separating the liquid phase from the solid phase of said slurry to recover the alkali metal content in the residue in the form of an aqueous solution of an alkali metal salt of said nitrogen oxyacid for reuse in said reaction of a chrome ore with an alkali metal hydroxide and an alkali metal salt of a nitrogen oxyacid.
Claim 7
Dependent Claim
16 words
The process according to claim 5, wherein said nitrogen oxyacid is nitric acid or nitrous acid.
Claim 8
Dependent Claim
129 words
A process for producing alkali metal chromates from a chrome ore which comprises reacting at a temperature of from 400* to 700*C a chrome ore with an alkali metal hydroxide in a molten state and in the presence of from 1 to 2.5 moles an alkali metal salt of a nitrogen oxyacid per mole of the Cr2O3 and in the presence of SiO2 in a SiO2/Al2O3 molar ratio of 1 to 3 based on the amount of Al2O3 present in said chrome ore, and leaching the resulting alkali metal chromate from the reaction product with water or a dilute aqueous solution of an alkali metal chromate, the alkali metal of said alkali metal chromate in said dilute aqueous solution being the same as that of said alkali metal hydroxide.
Claim 9
Dependent Claim
129 words
A process for producing alkali metal chromates from a chrome ore which comprises reacting at a temperature of from 400* to 700*C a chrome ore with an alkali metal hydroxide in a molten state and in the presence of from 1 to 2.5 moles an alkali metal salt of a nitrogen oxyacid per mole of the Cr2O3 and in the presence of SiO2 in a SiO2/Al2O3 molar ratio of 1 to 3 based on the amount of Al2O3 present in said chrome ore, and leaching the resulting alkali metal chromate from the reaction product with water or a dilute aqueous solution of an alkali metal chromate, the alkali metal of said alkali metal chromate in said dilute aqueous solution being the same as that of said alkali metal hydroxide.
Claim 10
Dependent Claim
28 words
The process according to claim 7, wherein said alkali salt of the nitrogen oxyacid is sodium nitrate, potassium nitrate, lithium nitrate, sodium nitrite, potassium nitrite or lithium nitrite.
Claim 11
Dependent Claim
92 words
The process according to claim 7, wherein the process further comprises re-slurrying a residue obtained after leaching of said alkali metal chromate in water, incorporating a nitrogen oxyacid into the resulting slurry and separating the liquid phase from a solid phase of said slurry to recover the alkali metal content in the residue in the form of an aqueous solution of an alkali metal salt of said nitrogen oxyacid for reuse in the reaction of a chrome ore with an alkali metal hydroxide and an alkali metal salt of a nitrogen oxyacid.
Claim 12
Dependent Claim
16 words
The process according to claim 9, wherein said nitrogen oxyacid is nitric acid or nitrous acid.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |