US4069015A
Expired / Lapsed
US
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Method of inhibiting rusting of sponge iron
Assignee: ZURICH BRANCH OF MIDREX INTERNATIONAL BV A NETHERLANDS Corp
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Filing: 1975-09-19
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Granted: 1978-01-17
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Expires: 1995-09-19
Abstract
Abstract A method for inhibiting rusting of sponge iron or any form of directly reduced iron when contacted by air, water, or other oxidant, by treating the sponge iron with a water soluble alkali metal silicate solution. The resulting product, a sodium silicate treated, rust-resistant metallized iron pellet, is also disclosed.
Inventors
- 👤 William A. Ahrendt
- 👤 David C. Meissner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:47
CPC Classifications
C; C23; C23F; C23F15/00; C21; C21B; C21B13/00; C21B13/0086; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/134
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
26 words
A method of inhibiting oxidation of sponge iron consisting of contacting said sponge iron with a solution consisting of an aqueous solution of alkali metal silicate.
Claim 2
Independent Claim
26 words
A method of inhibiting oxidation of sponge iron consisting of contacting said sponge iron with a solution consisting of an aqueous solution of alkali metal silicate.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein said alkali metal is sodium.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein the aqueous solution contains at least 0.3 weight percent sodium silicate.
Claim 5
Dependent Claim
17 words
The method of claim 2 wherein the aqueous solution contains at least 0.7 weight percent sodium silicate.
Claim 6
Dependent Claim
17 words
The method of claim 4 wherein the aqueous solution contains at least 1.5 weight percent sodium silicate.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein said aqueous solution contacts said sponge iron as a quenching spray.
Claim 8
Dependent Claim
16 words
A method according to claim 1 wherein said sponge iron is immersed in said aqueous solution.
Claim 9
Dependent Claim
17 words
A method according to claim 1 wherein said sponge iron falls into said aqueous solution by gravity.
Claim 10
Independent Claim
48 words
A method of preventing the generation of hydrogen when water contacts directly reduced metallized iron pellets consisting of treating said pellets with a water soluble alkali metal silicate by immersing said pellets in an aqueous solution of said alkali metal silicate, then removing the pellets from the solution.
Claim 11
Independent Claim
48 words
A method of preventing the generation of hydrogen when water contacts directly reduced metallized iron pellets consisting of treating said pellets with a water soluble alkali metal silicate by immersing said pellets in an aqueous solution of said alkali metal silicate, then removing the pellets from the solution.
Claim 12
Dependent Claim
12 words
A method according to claim 9 wherein said alkali metal is sodium.
Claim 13
Dependent Claim
11 words
A method according to claim 10 further comprising drying the pellets.
Claim 14
Dependent Claim
19 words
A method according to claim 11 wherein said treated pellets are dried by passing them through a heated furnace.
Claim 15
Independent Claim
39 words
A method for preventing oxidation of sponge iron in air consisting of contacting sponge iron with a liquid sodium silicate, then drying said sponge iron under oxidizing conditions at a temperature substantially below the auto-ignition temperature of sponge iron.
Claim 16
Independent Claim
39 words
A method for preventing oxidation of sponge iron in air consisting of contacting sponge iron with a liquid sodium silicate, then drying said sponge iron under oxidizing conditions at a temperature substantially below the auto-ignition temperature of sponge iron.
Claim 17
Dependent Claim
20 words
A method according to claim 13 wherein said drying step is carried out at a temperature below about 400° F.
Claim 18
Dependent Claim
20 words
A method according to claim 13 wherein said drying step is carried out at a temperature below about 350° F.
Claim 19
Dependent Claim
20 words
A method according to claim 13 wherein said drying step is carried out at a temperature below about 250° F.
Claim 20
Dependent Claim
16 words
A method according to claim 13 wherein said sponge iron is dried by convection of air.
Claim 21
Independent Claim
24 words
A method of manufacturing improved sponge iron consisting of the step of contacting sponge iron with a liquid consisting of an alkali metal silicate.
Claim 22
Independent Claim
24 words
A method of manufacturing improved sponge iron consisting of the step of contacting sponge iron with a liquid consisting of an alkali metal silicate.
Claim 23
Dependent Claim
15 words
A method according to claim 18 wherein said liquid is a solution comprising sodium silicate.
Claim 24
Dependent Claim
11 words
A method according to claim 19 wherein said solution is aqueous.
Claim 25
Independent Claim
44 words
A method of making improved sponge iron comprising the steps: a. reducing particulate iron ore; and b. contacting the reduced iron of step (a) with a liquid consisting solely of a water soluble alkali metal silicate capable of inhibiting oxidation of said reduced iron.
Claim 26
Independent Claim
44 words
A method of making improved sponge iron comprising the steps: a. reducing particulate iron ore; and b. contacting the reduced iron of step (a) with a liquid consisting solely of a water soluble alkali metal silicate capable of inhibiting oxidation of said reduced iron.
Claim 27
Dependent Claim
17 words
A method according to claim 21 wherein said liquid is a solution comprising said alkali metal silicate.
Claim 28
Dependent Claim
12 words
A method according to claim 22 wherein said alkali metal is sodium.
Claim 29
Dependent Claim
11 words
A method according to claim 23 wherein said solution is aqueous.
Claim 30
Dependent Claim
15 words
A method according to claim 21 further comprising drying the reduced iron of step (b).
Claim 31
Independent Claim
34 words
A method of making a rust-resistant metallized iron pellet consisting of treating a directly reduced iron pellet by contacting said pellet with a solution consisting of an aqueous solution of an alkali metal silicate.
Claim 32
Independent Claim
34 words
A method of making a rust-resistant metallized iron pellet consisting of treating a directly reduced iron pellet by contacting said pellet with a solution consisting of an aqueous solution of an alkali metal silicate.
Claim 33
Dependent Claim
12 words
A method according to claim 26 wherein said alkali metal is sodium.
Claim 34
Dependent Claim
39 words
A metallized iron pellet suitable for long-term open storage in which the iron present is at least 80% in the metallic state, the remainder being present as iron oxide, said pellet being made by the method of claim 26.
Claim 35
Dependent Claim
20 words
A product according to claim 28 in which at least 90% of the iron present is in the metallic state.
Claim 36
Dependent Claim
12 words
An improved sponge iron consisting essentially of sponge iron and sodium silicate.
Claim 37
Dependent Claim
12 words
An improved sponge iron consisting essentially of sponge iron and sodium silicate.
Claim 38
Dependent Claim
21 words
Improved sponge iron according to claim 30 resulting from the contacting of sponge iron with a liquid consisting of sodium silicate.
Claim 39
Dependent Claim
17 words
Improved sponge iron according to claim 31 wherein said liquid is a solution consisting of sodium silicate.
Claim 40
Dependent Claim
12 words
Improved sponge iron according to claim 32 wherein said solution is aqueous.
Claim 41
Dependent Claim
15 words
A method according to claim 2 further comprising drying said sponge iron under oxidizing conditions.
Claim 42
Dependent Claim
15 words
A method according to claim 20 further comprising drying said sponge iron under oxidizing conditions.
Claim 43
Dependent Claim
16 words
A method according to claim 25 wherein the drying step is carried out under oxidizing conditions.
Claim 44
Dependent Claim
15 words
A method according to claim 27 further comprising drying said sponge iron under oxidizing conditions.
Claim 45
Dependent Claim
20 words
Improved sponge iron according to claim 31 further resulting from the drying of said contacted sponge iron under oxidizing conditions.
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) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |