US4190434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermal processes for the production of magnesium
Assignee: Francais D'electrometallurgie Soc
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Filing: 1978-06-14
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Granted: 1980-02-26
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Expires: 1998-06-14
Abstract
Abstract This invention relates to the thermal production of magnesium, using, as source of magnesium oxide, a residual slag from the manufacture of certain carbon-containing chrome irons and, as reducing agent, a ferro-silico-aluminum for carrying out the MAGNETHERM process. Magnesium is obtained with a high degree of purity and in excellent yields, with the recovery of a residual alloy containing chromium and silicon, and the production capacity of a given furnace is increased by about 16% compared with that obtained when using calcined dolomite.
Inventors
- 👤 Rene Bonfils
- 👤 Andre Mena
- 👤 Christian Payn
- 👤 Louis Septier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:14
CPC Classifications
C; C22; C22B; C22B26/00; C22B26/20; C22B26/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
134 words
A thermal process for the production of magnesium in a closed electric furnace in which magnesium oxide and a metallic reducing agent react in the presence of a molten slag to produce magnesium vapors which are transmitted from the reaction furnace to a condensation zone wherein the vapors are condensed to magnesium, the improvement wherein at least a part of the magnesium oxide is introduced into the furnace in the form of a slag from the manufacture of ferro-chromium and which contains at least 20% by weight magnesium oxide and at least 25% by weight aluminum oxide, and in which the molten slag is formed essentially of lime, silica and alumina present in the molecular ratio of CaO/SiO 2 of at least 1.8 and Al 2 O 3 /SiO 2 of at least 0.26.
Claim 2
Dependent Claim
134 words
A thermal process for the production of magnesium in a closed electric furnace in which magnesium oxide and a metallic reducing agent react in the presence of a molten slag to produce magnesium vapors which are transmitted from the reaction furnace to a condensation zone wherein the vapors are condensed to magnesium, the improvement wherein at least a part of the magnesium oxide is introduced into the furnace in the form of a slag from the manufacture of ferro-chromium and which contains at least 20% by weight magnesium oxide and at least 25% by weight aluminum oxide, and in which the molten slag is formed essentially of lime, silica and alumina present in the molecular ratio of CaO/SiO 2 of at least 1.8 and Al 2 O 3 /SiO 2 of at least 0.26.
Claim 3
Dependent Claim
46 words
A process as claimed in claim 1 in which the lime, silica and alumina are present in the molten slag in the molecular ratio of CaO/SiO 2 within the range of 2.2-2.4 and Al 2 O 3 /SiO 2 are present within the range of 0.3-0.33.
Claim 4
Dependent Claim
25 words
The process as claimed in claim 1 in which the metallic reducing agent is a ferro-silico-aluminum metal containing more than 8% by weight of aluminum.
Claim 5
Dependent Claim
17 words
A process as claimed in claim 3 in which the ferro-silico-aluminum contains 15-25% by weight of aluminum.
Claim 6
Dependent Claim
36 words
A process as claimed in claim 1 which includes the additional step of reclaiming the metallic reducing agent as a residual containing chromium and recycling said residual metal for the production of ferro-chromium or crude chromium.
Claim 7
Dependent Claim
32 words
The process as claimed in claim 1 which includes maintaining the slag at a temperature within the range of 1500-1700° C. during the reaction for reducing the magnesium oxide in the slag.
Claim 8
Dependent Claim
26 words
The method as claimed in claim 1 which includes the step of maintaining the pressure in the closed electric furnace within the range of 27-47 millibars.
References Cited (Backward Citations)
FR1194556A
Cited
US2971833A
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US3658509A
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US3681053A
Cited
US3698888A
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US3994717A
Cited
US4033758A
Cited
US4033759A
Cited
US4066445A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-25 | 1983-08-27 | 1984-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-25 | 1987-08-27 | 1988-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-25 | 1991-08-27 | 1992-02-26 | $7700.00 | Window Closed / Lapsed |