CA1143947A - Method for increasing vessel lining life for basic oxygen furnaces - Google Patents
Method for increasing vessel lining life for basic oxygen furnacesInfo
- Publication number
- CA1143947A CA1143947A CA000342245A CA342245A CA1143947A CA 1143947 A CA1143947 A CA 1143947A CA 000342245 A CA000342245 A CA 000342245A CA 342245 A CA342245 A CA 342245A CA 1143947 A CA1143947 A CA 1143947A
- Authority
- CA
- Canada
- Prior art keywords
- melt
- inert gas
- slag
- amount
- vessel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/36—Processes yielding slags of special composition
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/44—Refractory linings
- C21C5/441—Equipment used for making or repairing linings
- C21C5/443—Hot fettling; Flame gunning
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/36—Processes yielding slags of special composition
- C21C2005/366—Foam slags
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Abstract
D-12,293 METHOD FOR INCREASING VESSEL LINING LIFE FOR BASIC
OXYGEN FURNACES
ABSTRACT
A method for increasing the life of the refractory lining of a basic-refractory-lined vessel for the production of steel by blowing oxygen into a ferrous melt from above the surface of the melt, comprising:
(a) introducing into the vessel slag forming ingredients, including dolomitic lime, such that the amount of dolomitic lime exceeds the amount normally used, and (b) introducing inert gas into the melt in such manner as to cause intensive interaction between the slag and the melt.
The preferred inert gas is argon.
OXYGEN FURNACES
ABSTRACT
A method for increasing the life of the refractory lining of a basic-refractory-lined vessel for the production of steel by blowing oxygen into a ferrous melt from above the surface of the melt, comprising:
(a) introducing into the vessel slag forming ingredients, including dolomitic lime, such that the amount of dolomitic lime exceeds the amount normally used, and (b) introducing inert gas into the melt in such manner as to cause intensive interaction between the slag and the melt.
The preferred inert gas is argon.
Description
D-12,293 ~ ~ ~ 3~
BACKGROUND
This invention relates, in general, to a process for refining steel, and more specifically, to an improve-ment in the basic oxygen process wherein molten steel con-tained in a vessel is refined by top blowing oxygen into the melt, i.e. :Erom above the melt surface.
One problem frequently encountered in making basic-oxygen steel is the limited life of the vessel's refractory lining. It is periodically necessary therefore to reline the vessel, incurring loss of production an~ relining expense Prior methods of improving lining life have been ~o add dolomitic lime to the slag, see for example Kristiansen et al, 'tThe Effects of Operating Variables On Sulfur Performance in a BOF Shop," 1976 Open Hearth Pro-ceedin~ ISS-AIME, pp. 28-41~ However, too much dolomitic l~me renders the slag too viscous for efficient sulfur re-moval.
OBJECTS
Accordingly, it is an object of this invention to increase the life of refractory linings for basic oxygen vessels.
It is another object of this invention to increase the life of refractory linîngs for basic oxygen vessels without interfering with the ability to make steel having a low sulfur content.
BACKGROUND
This invention relates, in general, to a process for refining steel, and more specifically, to an improve-ment in the basic oxygen process wherein molten steel con-tained in a vessel is refined by top blowing oxygen into the melt, i.e. :Erom above the melt surface.
One problem frequently encountered in making basic-oxygen steel is the limited life of the vessel's refractory lining. It is periodically necessary therefore to reline the vessel, incurring loss of production an~ relining expense Prior methods of improving lining life have been ~o add dolomitic lime to the slag, see for example Kristiansen et al, 'tThe Effects of Operating Variables On Sulfur Performance in a BOF Shop," 1976 Open Hearth Pro-ceedin~ ISS-AIME, pp. 28-41~ However, too much dolomitic l~me renders the slag too viscous for efficient sulfur re-moval.
OBJECTS
Accordingly, it is an object of this invention to increase the life of refractory linings for basic oxygen vessels.
It is another object of this invention to increase the life of refractory linîngs for basic oxygen vessels without interfering with the ability to make steel having a low sulfur content.
2.
D-12,293 ~ ~3~7 S~MMARY OF THE INVENTION
The above and other objects, which will readily be apparent to those skilled in the art, are achieved by the present invention, which comprises:
a method for increasing the life of the refractory lining of a basic-refractory-lined vessel for the production o steel by blowing oxygen into a ferrous melt from above the surface of the melt, comprising:
(a) introducing into the vessel~ slag forming ingredients, including dolomitic lime, such that the amount of dolomitic lime exceeds the amount normally used, and (b) introducing inert gas into the melt in such manner as to cause intensive interaction between the slag and the melt.
The term "inert gas" as used throughout the present specification and claims is intended to mean a gas other than oxygen having as many as possible of the following character-istics: low reactivity, low specific heat, absence o~ ob jectionable contaminents, and high density. The preferred~
~O inert gas is argon. However, if nitrogen contamination of the melt is not a problem, nitrogen or air may be used.
Other possible inert gases for use in practicing the inven-tion include helium, neon, krypton, xenon, carbon dioxide, steam, a~nmonia, and mixtures thereof. However, argon, which may be either commercially pure or crude argon is by far the most preferable inert gas.
The preferred method of introducing inert gas is D-12,293 ~3~34t~
through the oxygen lance admixed with oxygen.
DETAILED DESCRIPTION OF T~E INVENTION
The iron charged to a basic oxygen furnace typically contains carbon, silicon, sulfur, and other impurities. The main purpose of the oxygen is to remove carbon and silicon from the melt. The silicon is oxidized to silicon dioxide which floats on the surface of the melt. The carbon is oxidized to carbon monoxide gas which escapes from the mouth of the vessel. Slag forming ingredients, typically including high-calcium lime, are added to the melt to form a basic slag.
The high-calcium lime, normally containing at least 90 percent by weight of CaO, also removes sulEur by reacting with it to form calcium sul~ide. Dolomitic lime, i.e. lime containing ~ -at least 30% by weight magnesium o~ide, is known to improve the life of a vessel's lining, but in addition, it increases the viscosity of the slag, thereby reducing the amount of interaction between the lime in the slag and the melt. The reduced interaction makes it difficult for the lime to remove sulfur from the melt. Since the conventional solution to the problem of obtaining long vessel lining life makes it difficult to make steel having a sufficiently low sulfur content, the amount of dolomitic lime charged to the vessel for conventional oxygen blowing must be limited.
The normal amount of dolomitic lime used for con-ventional processes varies from zero to about 40% of the total slag-forming ingredients. Typical slag-forming ingredients include high-calcium lime, dolomitic lime, lime stone, and D-12,293 ~3~3~7 flurospar. In accordance with the present invention, dolomitic lime is introduced to the slag in an amount exceeding that normally used. That is, each basic oxygen refining system will have a normal amount of dolomitic lime added to the vessel for each grade of steel produced. To practice the present invention the amount of dolomitic lime introduced must ~ -exceed the normal amount. Of course, the slag forming com-pounds should be introduced in an amount sufficient to reduce the sulfur content of the melt to a desired level, based upon the s~oichiometric and thermodynamic aspects of the reaction of sulfur with the compounds.
The use of increased amounts of dolomitie lime over that normally used is essential to increasing the life of the vessel's refractory lining. Preferably, if high-calcium li~e is used to remove sulfur, the amount of dolomitic lime will be at least equal to that of the lime introdueed, as shown ln the examples to follow. The sulfur content of the steel can be reduced to meet the speci~ication, even i~ the amount of h . ~
dolomitic lime is equal to 2 or 3 times the amount of lime introduced ~ xtra agitation or mixing is required in the vessel because of the increased slag viscosity caused by the larger amount of dolomitic lime. The extra agitation is provided by introducing inert gas into the vessel in sueh manner as to cause intensive interaction between the slag and the melt.
The present invention may be practiced in conjunc-tion with the method of Thokar et al for using argon in the D-12,293 BOF or make low nitrogen and low oxygen steel as disclosed~
in U.S. application Serial No. 880,562, filed February 23, 1978, now U.S. Patent No. 4,149,878.
The inert gas must be introduced in such manner as to cause intensive interaction between the slag and the melt.
Preferably, the inert gas is introduced through the oxygen ~ `
lance by metering it into the oxygen line. Alternatively, the inert gas may be introduced through a separate lance , directed to impinge oxygen-free fluid against the surface of the melt. However, there is no reason for incurring the extra expense of adding a second lance to a basic oxygen vessel~
Since the sulfur content of the melt, at the end of the oxygen blow is one of the most difficult variables to ~;
control in the basic oxygen process, occasionally, even when the present invention is practiced the sulfur content of the melt at ~he end of a blow will be higher than desired. How-ever, the sulfur content of the melt may be lowered in accor-, , dance with the present invention by adding at least onesulfur-removing compound, such as high-calcium lime, to the slag in the vessel and reblowing the melt with inert gas alone in such a manner as to cause intensive interaction between the slag and the melt until the sulfur content is reduced to the desired level.
.;:
If the slag already contains sufficient sulfur-removing compounds, then merely reblowing the melt with inert gas alone in the above described manner may be used to lower the sulfur content to the desired level.
~ ~ .
.
6.
D-12,293 ~ ~ ~ 3 EX~YPLES
The following examples will serve to illustrate the advantage o practicing the invention. A series of heats was performed in a BOF (~asic Oxygen Furance) system having the following characteristics:
nominal vessel volume: 5,000 cubic feet tap weight of heat: 235 tons inert gas used: argon The normal dolomitic lime charge for this vessel was 16,000 lbs. The normal slag-forming ingredients were comprised of 16,000 lbs. of dolomitic lime and 24,000 lbs.
of high-calcium lime, and 2,000 lbs. of flurospar.
The dolomitic lime charge was increased to 35,000 lbs. and the high-calcium lime charge was reduced to 10,000 lbs. and argon was injected into the vessel in accordance with the method of add:ition disclosed in Thokar et al mentioned previously. The argon was injected at a constant rate of 3,500 standard cubic feet per minute during the latter portion of the oxygen blow. As a result of practicing the invention, the life of the lining of this vessel was extended from a previous life of about 780 heats to about 1100 heats.
In spite of the very large amounts of dolomitic lime added as slag forming ingredients, no difficulty was encountered making steel having sulfur content as low as desired. Further-more, during this test, flurospar, which is known to aid sulfur removal, was not used. In spite of the omission of the normal amount of flurospar, the process was still able to D-12,293 ~ ~ ~3~ ~7 produce steel meeting low-sulfur specifications. Hence, another advantage of the invention is a saving in the amount of flurospar charged to the vessel. The typical maximum sulfur content allowed by the specifications for steel made by this ' ~-vessel was 0.025% sulfur.
It can be seen that the practice of the invention yields significant results. The life of the vessel lining :
was increased to more than 40% beyond that which had been previously obtained for this vessel.
D-12,293 ~ ~3~7 S~MMARY OF THE INVENTION
The above and other objects, which will readily be apparent to those skilled in the art, are achieved by the present invention, which comprises:
a method for increasing the life of the refractory lining of a basic-refractory-lined vessel for the production o steel by blowing oxygen into a ferrous melt from above the surface of the melt, comprising:
(a) introducing into the vessel~ slag forming ingredients, including dolomitic lime, such that the amount of dolomitic lime exceeds the amount normally used, and (b) introducing inert gas into the melt in such manner as to cause intensive interaction between the slag and the melt.
The term "inert gas" as used throughout the present specification and claims is intended to mean a gas other than oxygen having as many as possible of the following character-istics: low reactivity, low specific heat, absence o~ ob jectionable contaminents, and high density. The preferred~
~O inert gas is argon. However, if nitrogen contamination of the melt is not a problem, nitrogen or air may be used.
Other possible inert gases for use in practicing the inven-tion include helium, neon, krypton, xenon, carbon dioxide, steam, a~nmonia, and mixtures thereof. However, argon, which may be either commercially pure or crude argon is by far the most preferable inert gas.
The preferred method of introducing inert gas is D-12,293 ~3~34t~
through the oxygen lance admixed with oxygen.
DETAILED DESCRIPTION OF T~E INVENTION
The iron charged to a basic oxygen furnace typically contains carbon, silicon, sulfur, and other impurities. The main purpose of the oxygen is to remove carbon and silicon from the melt. The silicon is oxidized to silicon dioxide which floats on the surface of the melt. The carbon is oxidized to carbon monoxide gas which escapes from the mouth of the vessel. Slag forming ingredients, typically including high-calcium lime, are added to the melt to form a basic slag.
The high-calcium lime, normally containing at least 90 percent by weight of CaO, also removes sulEur by reacting with it to form calcium sul~ide. Dolomitic lime, i.e. lime containing ~ -at least 30% by weight magnesium o~ide, is known to improve the life of a vessel's lining, but in addition, it increases the viscosity of the slag, thereby reducing the amount of interaction between the lime in the slag and the melt. The reduced interaction makes it difficult for the lime to remove sulfur from the melt. Since the conventional solution to the problem of obtaining long vessel lining life makes it difficult to make steel having a sufficiently low sulfur content, the amount of dolomitic lime charged to the vessel for conventional oxygen blowing must be limited.
The normal amount of dolomitic lime used for con-ventional processes varies from zero to about 40% of the total slag-forming ingredients. Typical slag-forming ingredients include high-calcium lime, dolomitic lime, lime stone, and D-12,293 ~3~3~7 flurospar. In accordance with the present invention, dolomitic lime is introduced to the slag in an amount exceeding that normally used. That is, each basic oxygen refining system will have a normal amount of dolomitic lime added to the vessel for each grade of steel produced. To practice the present invention the amount of dolomitic lime introduced must ~ -exceed the normal amount. Of course, the slag forming com-pounds should be introduced in an amount sufficient to reduce the sulfur content of the melt to a desired level, based upon the s~oichiometric and thermodynamic aspects of the reaction of sulfur with the compounds.
The use of increased amounts of dolomitie lime over that normally used is essential to increasing the life of the vessel's refractory lining. Preferably, if high-calcium li~e is used to remove sulfur, the amount of dolomitic lime will be at least equal to that of the lime introdueed, as shown ln the examples to follow. The sulfur content of the steel can be reduced to meet the speci~ication, even i~ the amount of h . ~
dolomitic lime is equal to 2 or 3 times the amount of lime introduced ~ xtra agitation or mixing is required in the vessel because of the increased slag viscosity caused by the larger amount of dolomitic lime. The extra agitation is provided by introducing inert gas into the vessel in sueh manner as to cause intensive interaction between the slag and the melt.
The present invention may be practiced in conjunc-tion with the method of Thokar et al for using argon in the D-12,293 BOF or make low nitrogen and low oxygen steel as disclosed~
in U.S. application Serial No. 880,562, filed February 23, 1978, now U.S. Patent No. 4,149,878.
The inert gas must be introduced in such manner as to cause intensive interaction between the slag and the melt.
Preferably, the inert gas is introduced through the oxygen ~ `
lance by metering it into the oxygen line. Alternatively, the inert gas may be introduced through a separate lance , directed to impinge oxygen-free fluid against the surface of the melt. However, there is no reason for incurring the extra expense of adding a second lance to a basic oxygen vessel~
Since the sulfur content of the melt, at the end of the oxygen blow is one of the most difficult variables to ~;
control in the basic oxygen process, occasionally, even when the present invention is practiced the sulfur content of the melt at ~he end of a blow will be higher than desired. How-ever, the sulfur content of the melt may be lowered in accor-, , dance with the present invention by adding at least onesulfur-removing compound, such as high-calcium lime, to the slag in the vessel and reblowing the melt with inert gas alone in such a manner as to cause intensive interaction between the slag and the melt until the sulfur content is reduced to the desired level.
.;:
If the slag already contains sufficient sulfur-removing compounds, then merely reblowing the melt with inert gas alone in the above described manner may be used to lower the sulfur content to the desired level.
~ ~ .
.
6.
D-12,293 ~ ~ ~ 3 EX~YPLES
The following examples will serve to illustrate the advantage o practicing the invention. A series of heats was performed in a BOF (~asic Oxygen Furance) system having the following characteristics:
nominal vessel volume: 5,000 cubic feet tap weight of heat: 235 tons inert gas used: argon The normal dolomitic lime charge for this vessel was 16,000 lbs. The normal slag-forming ingredients were comprised of 16,000 lbs. of dolomitic lime and 24,000 lbs.
of high-calcium lime, and 2,000 lbs. of flurospar.
The dolomitic lime charge was increased to 35,000 lbs. and the high-calcium lime charge was reduced to 10,000 lbs. and argon was injected into the vessel in accordance with the method of add:ition disclosed in Thokar et al mentioned previously. The argon was injected at a constant rate of 3,500 standard cubic feet per minute during the latter portion of the oxygen blow. As a result of practicing the invention, the life of the lining of this vessel was extended from a previous life of about 780 heats to about 1100 heats.
In spite of the very large amounts of dolomitic lime added as slag forming ingredients, no difficulty was encountered making steel having sulfur content as low as desired. Further-more, during this test, flurospar, which is known to aid sulfur removal, was not used. In spite of the omission of the normal amount of flurospar, the process was still able to D-12,293 ~ ~ ~3~ ~7 produce steel meeting low-sulfur specifications. Hence, another advantage of the invention is a saving in the amount of flurospar charged to the vessel. The typical maximum sulfur content allowed by the specifications for steel made by this ' ~-vessel was 0.025% sulfur.
It can be seen that the practice of the invention yields significant results. The life of the vessel lining :
was increased to more than 40% beyond that which had been previously obtained for this vessel.
Claims (10)
1. A method for increasing the life of the refractory lining of a basic-refractory-lined vessel for the production of steel by blowing oxygen into a ferrous melt from above the surface of the melt, comprising:
(a) introducing into the vessel, slag forming ingredients, including dolomitic lime, such that the amount of dolomitic lime exceeds the amount normally used, and (b) introducing inert gas into the melt in such manner as to cause intensive interaction between the slag and the melt.
(a) introducing into the vessel, slag forming ingredients, including dolomitic lime, such that the amount of dolomitic lime exceeds the amount normally used, and (b) introducing inert gas into the melt in such manner as to cause intensive interaction between the slag and the melt.
2. The method of claim 1 wherein the inert gas is introduced through the oxygen lance.
3. The method of claim 1 wherein the inert gas is introduced through a separate lance directed to impinge the inert gas against the surface of the melt.
4. The method of claim l wherein the sulfur content of the melt is higher than desired at the end of the oxygen blow, further comprising the step of:
(c) reblowing the melt with inert gas alone in such manner as to cause intensive interaction between the slag and the melt until the sulfur content is reduced to the desired level.
(c) reblowing the melt with inert gas alone in such manner as to cause intensive interaction between the slag and the melt until the sulfur content is reduced to the desired level.
5. The method of claim 4 wherein at least one 9.
D-12,293 sulfur-removing compound is added to the slag in the vessel prior to the reblowing step.
D-12,293 sulfur-removing compound is added to the slag in the vessel prior to the reblowing step.
6. The process of claims 1 or 4, wherein the inert gas is argon.
7. The method of claim 1, wherein high calcium lime is introduced as a slag forming ingredient in step (b) and the amount of dolomitic lime introduced in step (b) is at least equal to that of the high-calcium lime introduced.
8. The method of claim 4 wherein high calcium lime is introduced as a slag forming ingredient in step (b) and the amount of dolomitic lime introduced in step (b) is at least equal to that of the high-calcium lime introduced.
9. The method of claims 7 or 8 wherein the amount of dolomitic lime introduced in step (b) is at least two times the amount of high-calcium lime introduced.
10. The method of claims 7 or 8 wherein the inert gas is argon.
10.
10.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US1031579A | 1979-02-07 | 1979-02-07 | |
| US010,315 | 1979-02-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1143947A true CA1143947A (en) | 1983-04-05 |
Family
ID=21745183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000342245A Expired CA1143947A (en) | 1979-02-07 | 1979-12-19 | Method for increasing vessel lining life for basic oxygen furnaces |
Country Status (14)
| Country | Link |
|---|---|
| EP (1) | EP0015396B1 (en) |
| JP (1) | JPS5952201B2 (en) |
| AU (1) | AU5526080A (en) |
| BR (1) | BR8000733A (en) |
| CA (1) | CA1143947A (en) |
| DE (1) | DE3070636D1 (en) |
| ES (1) | ES488303A0 (en) |
| FI (1) | FI800335A (en) |
| IN (1) | IN153626B (en) |
| MX (1) | MX154163A (en) |
| NO (1) | NO800301L (en) |
| PH (1) | PH15430A (en) |
| RO (1) | RO79757A (en) |
| ZA (1) | ZA80213B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2525633A1 (en) * | 1982-04-22 | 1983-10-28 | Siderurgie Fse Inst Rech | METHOD FOR IMPROVING THE LIFETIME OF PERMEABLE REFRACTORY ELEMENTS LODGED IN THE BOTTOM OF METALLURGIC REFINING CONTAINERS, IN PARTICULAR OXYGEN-BLOW-CONTAINING OXYGEN STEEL CONVERTERS |
| AT385771B (en) * | 1986-06-16 | 1988-05-10 | Voest Alpine Ag | METHOD FOR COVERING THE FIREPROOF LINING OF A METALLURGICAL MELTING FURNACE WITH A HEAT-RESISTANT MATERIAL |
| DE3936715A1 (en) * | 1989-11-03 | 1991-05-08 | Kortec Ag | METHOD FOR INPUTING FLOWABLE ADDITIVES INTO A METALLURGICAL VESSEL AND VESSEL FOR THIS METHOD |
| CN1035017C (en) * | 1994-04-21 | 1997-05-28 | 鞍山钢铁公司 | Slag fomation agent for adding magnesium in magnesium balls for smelting steel |
| GB2553342A (en) * | 2016-09-02 | 2018-03-07 | Materials Proc Institute | Producing steel |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3288592A (en) * | 1963-01-16 | 1966-11-29 | Pfizer & Co C | Process for reducing deterioration in equipment handling molten materials |
| FR1346148A (en) * | 1963-01-31 | 1963-12-13 | Centre Nat Rech Metall | Process for the protection of the interior lining of metallurgical furnaces |
| FR1536457A (en) * | 1967-07-07 | 1968-08-16 | Siderurgie Fse Inst Rech | Process for the protection of refractory linings of continuous refining metallurgical vessels |
| US3726665A (en) * | 1969-10-15 | 1973-04-10 | C & W Corson H Inc | Slagging in basic steel-making process |
| US3915696A (en) * | 1970-01-08 | 1975-10-28 | Ferdinand Fink | Sintered preformed slag for the steel industry |
| BR7302595D0 (en) * | 1972-05-09 | 1974-06-27 | Blanq Cazaux Morales A | PROCESSING PROCESSES FOR IRON MANUFACTURING AND PROCESSING PROCESSES FOR IRON MANUFACTURE AND STEELS |
| FR2322202A1 (en) * | 1975-08-29 | 1977-03-25 | Siderurgie Fse Inst Rech | Steel refining by oxygen lancing and bottom blowing - for improved quality steel of various grades |
| ZA775918B (en) * | 1977-01-11 | 1978-05-30 | Nat Steel Corp | The use of orgon to prepare low-carbon,low-nitrogen steels in the basic oxygen process |
| JPS545813A (en) * | 1977-06-17 | 1979-01-17 | Fuaizaa Kuiguree Kk | Method of extending useful life of refractory lining material in aod furnace |
-
1979
- 1979-12-19 CA CA000342245A patent/CA1143947A/en not_active Expired
-
1980
- 1980-01-14 ZA ZA00800213A patent/ZA80213B/en unknown
- 1980-01-21 IN IN40/DEL/80A patent/IN153626B/en unknown
- 1980-02-04 JP JP55011600A patent/JPS5952201B2/en not_active Expired
- 1980-02-04 FI FI800335A patent/FI800335A/en not_active Application Discontinuation
- 1980-02-05 PH PH23600A patent/PH15430A/en unknown
- 1980-02-05 NO NO800301A patent/NO800301L/en unknown
- 1980-02-06 ES ES488303A patent/ES488303A0/en active Granted
- 1980-02-06 BR BR8000733A patent/BR8000733A/en unknown
- 1980-02-06 EP EP80100604A patent/EP0015396B1/en not_active Expired
- 1980-02-06 MX MX181089A patent/MX154163A/en unknown
- 1980-02-06 DE DE8080100604T patent/DE3070636D1/en not_active Expired
- 1980-02-06 AU AU55260/80A patent/AU5526080A/en not_active Abandoned
- 1980-02-06 RO RO80100107A patent/RO79757A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| PH15430A (en) | 1983-01-18 |
| JPS55107714A (en) | 1980-08-19 |
| BR8000733A (en) | 1980-10-21 |
| ZA80213B (en) | 1980-12-31 |
| ES8100349A1 (en) | 1980-11-01 |
| MX154163A (en) | 1987-05-28 |
| FI800335A (en) | 1980-08-08 |
| EP0015396B1 (en) | 1985-05-15 |
| ES488303A0 (en) | 1980-11-01 |
| EP0015396A1 (en) | 1980-09-17 |
| NO800301L (en) | 1980-08-08 |
| IN153626B (en) | 1984-07-28 |
| RO79757A (en) | 1983-02-01 |
| JPS5952201B2 (en) | 1984-12-18 |
| AU5526080A (en) | 1980-08-14 |
| DE3070636D1 (en) | 1985-06-20 |
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