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US4370422A
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US
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Process for the production of magnesium oxide from brine or bittern
Assignee: Dalmia Institute of Scientific & Industrial Research
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Filing: 1980-12-16
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Granted: 1983-01-25
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Expires: 2000-12-16
Abstract
Abstract Magnesium oxide, especially suitable for use in basic refractories, is produced from brine or bittern containing magnesium chloride by: (a) adding to the brine or bittern, as a source of MgO and/or CaO, MgO or Mg(OH) 2 or calcined magnesite or calcined dolomite or calcined calcite/limestone in such amount that in the case of MgO, Mg(OH) 2 or calcined magnesite, the molar ratio of MgO:MgCl 2 is in the range of 1:1.5 to 1:15 (i.e. 0.66:1 to 0.066:1) or, in the case of calcined dolomite, the molar ratio of MgO+CaO:MgCl 2 is in the range of 0.66:1 to 0.05:1, or, in the case of calcined calcite/limestone, the molar ratio of CaO:MgCl 2 is in the range of 0.66:1 to 0.1:1; (b) keeping the mixture at a temperature below 90° C. till a solid mass is formed; and (c) drying the said solid mass at a temperature up to 200° C. The said mass may then be calcined at a maximum temperature of 1200° C. and optionally then briquetted with a binder and fired at above 1400° C.
Inventors
- 👤 Jajnya D. Panda
- 👤 Santosh K. Mahapatra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:33
CPC Classifications
C; C01; C01F; C01F5/00; C01F5/14; C01F5/22; C01F5/02; C04; C04B; C04B35/00; C04B35/01; C04B35/03; C04B35/04; C04B35/043
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
164 words
A process for the production of magnesium oxide from brine or bittern containing magnesium chloride in a concentration of at least 25° Be consisting essentially of (a) adding to the brine or bittern, as a source of MgO and/or CaO, MgO or Mg(OH) 2 or calcined magnesite or calcined dolomite or calcined calcite/limestone in such amount that in the case of MgO, Mg(OH) 2 or calcined magnesite, the molar ratio of MgO:MgCl 2 is in the range of 1:1.5 to 1:15 (i.e. 0.66:1 to 0.066:1) or, in the case of calcined dolomite, the molar ratio of MgO+CaO:MgCl 2 is in the range of 0.66:1 to 0.05:1, or, in the case of calcined calcite/limestone, the molar ratio of CaO:MgCl 2 is in the range of 0.66:1 to 0.1:1; (b) keeping the mixture at a temperature below 90° C. till a solidified mass is formed; and (c) drying and calcining the said solid mass at a temperature up to 1200° C. to produce magnesium oxide powder.
Claim 2
Dependent Claim
164 words
A process for the production of magnesium oxide from brine or bittern containing magnesium chloride in a concentration of at least 25° Be consisting essentially of (a) adding to the brine or bittern, as a source of MgO and/or CaO, MgO or Mg(OH) 2 or calcined magnesite or calcined dolomite or calcined calcite/limestone in such amount that in the case of MgO, Mg(OH) 2 or calcined magnesite, the molar ratio of MgO:MgCl 2 is in the range of 1:1.5 to 1:15 (i.e. 0.66:1 to 0.066:1) or, in the case of calcined dolomite, the molar ratio of MgO+CaO:MgCl 2 is in the range of 0.66:1 to 0.05:1, or, in the case of calcined calcite/limestone, the molar ratio of CaO:MgCl 2 is in the range of 0.66:1 to 0.1:1; (b) keeping the mixture at a temperature below 90° C. till a solidified mass is formed; and (c) drying and calcining the said solid mass at a temperature up to 1200° C. to produce magnesium oxide powder.
Claim 3
Dependent Claim
14 words
A process according to claim 1 wherein the magnesium oxide powder obtained is washed.
Claim 4
Dependent Claim
194 words
A process for the production of magnesium oxide from brine or bittern containing magnesium chloride in a concentration of at least 25° Be consisting essentially of (a) adding to the brine or bittern, as a source of MgO and/or CaO, MgO or Mg(OH) 2 or calcined magnesite or calcined dolomite or calcined calcite/limestone in such amount that in the case of MgO, Mg(OH) 2 or calcined magnesite, the molar ratio of MgO:MgCl 2 is in the range of 1:1.5 to 1:15 (i.e. 0.66:1 to 0.066:) or, in the case of calcined dolomite, the molar ratio of MgO+CaO:MgCl 2 is in the range of 0.66:1 to 0.05:1, or, in the case of calcined calcite/limestone, the molar ratio of CaO:MgCl 2 is in the range of 0.66:1 to 0.1:1, (b) keeping the mixture at a temperature below 90° C. till a solidified mass is formed; (c) drying the said solid mass at a temperature up to 200° C.; (d) calcining the said mass at a maximum temperature of 1200° C.; and (e) briquetting the calcined mass into desired shapes with the addition of organic or inorganic binder, and firing the said briquettes at above 1400° C.
Claim 5
Dependent Claim
194 words
A process for the production of magnesium oxide from brine or bittern containing magnesium chloride in a concentration of at least 25° Be consisting essentially of (a) adding to the brine or bittern, as a source of MgO and/or CaO, MgO or Mg(OH) 2 or calcined magnesite or calcined dolomite or calcined calcite/limestone in such amount that in the case of MgO, Mg(OH) 2 or calcined magnesite, the molar ratio of MgO:MgCl 2 is in the range of 1:1.5 to 1:15 (i.e. 0.66:1 to 0.066:) or, in the case of calcined dolomite, the molar ratio of MgO+CaO:MgCl 2 is in the range of 0.66:1 to 0.05:1, or, in the case of calcined calcite/limestone, the molar ratio of CaO:MgCl 2 is in the range of 0.66:1 to 0.1:1, (b) keeping the mixture at a temperature below 90° C. till a solidified mass is formed; (c) drying the said solid mass at a temperature up to 200° C.; (d) calcining the said mass at a maximum temperature of 1200° C.; and (e) briquetting the calcined mass into desired shapes with the addition of organic or inorganic binder, and firing the said briquettes at above 1400° C.
Claim 6
Dependent Claim
16 words
Process according to claim 3, in which the said briquettes are fired at above 1600° C.
Claim 7
Dependent Claim
25 words
A process according to claim 3, in which the said binder is added in amount of up to 3% by weight of the calcined mass.
Claim 8
Dependent Claim
20 words
A process according to claim 5, in which the binder is dextrine, molasses, sulphite lye, sodium chromate or chromic acid.
Claim 9
Dependent Claim
20 words
A process according to claim 3, which comprises the addition of chromite or chrome ore in addition to the binder.
Claim 10
Dependent Claim
25 words
A process according to claim 1 or 3, in which light calcined magnesite is added as a source of MgO to the brine or bittern.
Claim 11
Dependent Claim
31 words
A process according to claim 1 or 3, in which calcined magnesite is added to the brine or bittern in a molar ratio of MgO:MgCl 2 of at least 1:10 (0.1:1).
Claim 12
Dependent Claim
15 words
A process according to claim 9, in which the said molar ratio is 1:4 (0.25:1).
Claim 13
Dependent Claim
72 words
A process according to claim 1 or 3, in which any combination of calcined dolomite, calcined magnesite and calcined calcite/limestone is added to the brine or bittern, and the amount of any one of the components of such combination is such that the minimum molar ratio of: (a) calcined dolomite to MgCl 2 is 0.02:1; (b) calcined calcite to MgCl 2 is 0.05:1; and (c) calcined magnesite to MgCl 2 is 0.03:1.
Claim 14
Dependent Claim
143 words
A process for the production of magnesium oxide from brine or bittern containing magnesium chloride in a concentration of at least 25° Be consisting essentially of: (a) adding to the brine or bittern any combination of calcined dolomite, calcined magnesite, and calcined calcite/limestone in such amount that the minimum molar ratio of calcined dolomite to MgCl 2 is 0.02:1, calcined calcite to MgCl 2 is 0.05:1, and calcined magnesite to MgCl 2 is 0.03:1, the overall molar ratio of MgO to MgCl 2 being 0.066:1 to 0.66:1, of MgO+CaO to MgCl 2 being 0.05:1 to 0.66:1, and of CaO to MgCl 2 being 0.1:1 to 0.66:1; (b) keeping the mixture at a temperature below 90° C. until a solidified mass is formed; and (c) drying and calcining the said solid mass at a temperature up to 1200° C. to produce magnesium oxide powder.
Claim 15
Dependent Claim
143 words
A process for the production of magnesium oxide from brine or bittern containing magnesium chloride in a concentration of at least 25° Be consisting essentially of: (a) adding to the brine or bittern any combination of calcined dolomite, calcined magnesite, and calcined calcite/limestone in such amount that the minimum molar ratio of calcined dolomite to MgCl 2 is 0.02:1, calcined calcite to MgCl 2 is 0.05:1, and calcined magnesite to MgCl 2 is 0.03:1, the overall molar ratio of MgO to MgCl 2 being 0.066:1 to 0.66:1, of MgO+CaO to MgCl 2 being 0.05:1 to 0.66:1, and of CaO to MgCl 2 being 0.1:1 to 0.66:1; (b) keeping the mixture at a temperature below 90° C. until a solidified mass is formed; and (c) drying and calcining the said solid mass at a temperature up to 1200° C. to produce magnesium oxide powder.
Claim 16
Dependent Claim
170 words
A process for the production of basic refractory briquettes based on magnesium oxide consisting essentially of: (a) adding to a brine or bittern containing magnesium chloride in a concentration of at least 25° C. Be any combination of calcined dolomite, calcined magnesite, and calcined calcite/limestone in such amount that the minimum molar ratio of calcined dolomite to MgCl 2 is 0.02:1, calcined calcite to MgCl 2 is 0.05:1, and calcined magnesite to MgCl 2 is 0.03:1, the overall molar ratio of MgO to MgCl 2 being 0.066:1 to 0.66:1, of MgO+CaO to MgCl 2 being 0.05:1 to 0.66:1, and of CaO to MgCl 2 being 0.1:1 to 0.66:1; (b) keeping the mixture at a temperature below 90° C. until a solidified mass is formed; (c) drying the said solid mass at a temperature up to 200° C.; (d) calcining the said mass at a maximum temperature of 1200° C.; and (e) briquetting the calcined mass using an organic or inorganic binder, and firing the said briquettes at above 1400° C.
Claim 17
Dependent Claim
170 words
A process for the production of basic refractory briquettes based on magnesium oxide consisting essentially of: (a) adding to a brine or bittern containing magnesium chloride in a concentration of at least 25° C. Be any combination of calcined dolomite, calcined magnesite, and calcined calcite/limestone in such amount that the minimum molar ratio of calcined dolomite to MgCl 2 is 0.02:1, calcined calcite to MgCl 2 is 0.05:1, and calcined magnesite to MgCl 2 is 0.03:1, the overall molar ratio of MgO to MgCl 2 being 0.066:1 to 0.66:1, of MgO+CaO to MgCl 2 being 0.05:1 to 0.66:1, and of CaO to MgCl 2 being 0.1:1 to 0.66:1; (b) keeping the mixture at a temperature below 90° C. until a solidified mass is formed; (c) drying the said solid mass at a temperature up to 200° C.; (d) calcining the said mass at a maximum temperature of 1200° C.; and (e) briquetting the calcined mass using an organic or inorganic binder, and firing the said briquettes at above 1400° C.
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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) | 1986-01-24 | 1986-07-26 | 1987-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-24 | 1990-07-26 | 1991-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-24 | 1994-07-26 | 1995-01-25 | $7700.00 | Window Closed / Lapsed |