GB1596819A - Method of prolonging durable life of aod furnace refractory linings - Google Patents
Method of prolonging durable life of aod furnace refractory linings Download PDFInfo
- Publication number
- GB1596819A GB1596819A GB14372/78A GB1437278A GB1596819A GB 1596819 A GB1596819 A GB 1596819A GB 14372/78 A GB14372/78 A GB 14372/78A GB 1437278 A GB1437278 A GB 1437278A GB 1596819 A GB1596819 A GB 1596819A
- Authority
- GB
- United Kingdom
- Prior art keywords
- slag
- magnesium oxide
- furnace
- dolomite
- percent
- 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
- 238000000034 method Methods 0.000 title claims description 19
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 59
- 239000000395 magnesium oxide Substances 0.000 claims description 51
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 43
- 239000002893 slag Substances 0.000 claims description 40
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 24
- 239000000126 substance Substances 0.000 claims description 24
- 239000010459 dolomite Substances 0.000 claims description 22
- 229910000514 dolomite Inorganic materials 0.000 claims description 22
- 239000000292 calcium oxide Substances 0.000 claims description 12
- 235000012255 calcium oxide Nutrition 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 12
- 238000009628 steelmaking Methods 0.000 claims description 10
- 239000003795 chemical substances by application Substances 0.000 claims description 9
- 229910000831 Steel Inorganic materials 0.000 claims description 8
- 239000010959 steel Substances 0.000 claims description 8
- 238000004090 dissolution Methods 0.000 claims description 7
- 239000011449 brick Substances 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 5
- 238000007670 refining Methods 0.000 claims description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- 239000011230 binding agent Substances 0.000 claims description 4
- 238000007664 blowing Methods 0.000 claims description 4
- 238000012360 testing method Methods 0.000 claims description 4
- 230000002401 inhibitory effect Effects 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- 229910000676 Si alloy Inorganic materials 0.000 claims description 2
- 239000001569 carbon dioxide Substances 0.000 claims description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 2
- 229910052681 coesite Inorganic materials 0.000 claims description 2
- 229910052906 cristobalite Inorganic materials 0.000 claims description 2
- 229910052839 forsterite Inorganic materials 0.000 claims description 2
- 230000004927 fusion Effects 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 239000011777 magnesium Substances 0.000 claims description 2
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 238000000465 moulding Methods 0.000 claims description 2
- 239000012495 reaction gas Substances 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 229910052682 stishovite Inorganic materials 0.000 claims description 2
- 239000000454 talc Substances 0.000 claims description 2
- 229910052623 talc Inorganic materials 0.000 claims description 2
- 229910052905 tridymite Inorganic materials 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011822 basic refractory Substances 0.000 description 1
- YLUIKWVQCKSMCF-UHFFFAOYSA-N calcium;magnesium;oxygen(2-) Chemical compound [O-2].[O-2].[Mg+2].[Ca+2] YLUIKWVQCKSMCF-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
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
-
- 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
-
- 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)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Description
(54) METHOD OF PROLONGING DURABLE
LIFE OF AOD FURNACE REFRACTORY LININGS
(71) We, QUIGLEY COMPANY, INC. a
Corporation organized and existing under the laws of the State of New York, United States of
America, of 235 East 42nd Street, New York,
State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention is a method for prolonging the durable life of the refractory lining of an
AOD furnace, a type of bottom-blowing converter for steel making, by effectively reducing its loss on fusing.More specifically, the invention relates to a method for increasing the durability of a magnesia refractory lining of an
AOD furnace by adjusting the concentration of magnesium oxide in the slag during the operation of the furnace, thereby reducing the dissolution of the magnesium oxide of the lining into the slag.
Generally, steel-making furnaces are constructed such that an iron container is lined with a refractory lining material, and molten iron is placed in it to produce steel. The lining is replaced when it is markedly lost by the effect of the molten metal and the slag.
Replacement of the lining is performed by stopping the operation for a fairly long period of time, and the cost and labor for the replacement operation are enormous. Moreover, steel cannot be produced during the replacement period, which is a great disadvantage.
The AOD furnace is usually lined with a magnesia-type refractory lining material, which is a basic refractory. The furnace is adapted to strongly remove impurities such as carbon from molten steel by blowing a gas such as oxygen, argon or nitrogen into the molten steel from the bottom of the furnace. In steel making by the AOD furnace, reactions such as decarburization are especially vigorous, and the heat generated by the reaction makes the temperature of the molten steel in the furnace extremely high. This results in the marked fusing loss of the refractory lining of the furnace, particularly its inside wall corresponding to the slag line at the steel bath surface. The furnace whose refractory lining has been markedly lost by fusing must be relined.According to the conventional technique, spray repairing is, for example, performed in order to increase the durability of the lining, and the lining material is replaced after the furnace has been operated through about 80 to 150 cycles.
In general steel-making furnaces, various methods such as spray repairing are used to increase the durability of the lining. As one of such methods, it is known from Japanese
Patent Publication No. 12327/67 (Patent No.
505,698), corresponding to U.S. Patent No.
3,288,592, that the durable life of a magnesiatype lining material in the operation of a furnace lined with it is prolonged by adding a slag-forming agent such as active magnesium oxide or active dolomitic lime to adjust the concentration of magnesium oxide in the slag to 4 to 12 percent by weight and thereby inhibit the dissolution of the magnesium oxide of the lining material into the slag. However, since the AOD furnace is operated at a higher temperature than in ordinary steel-making operations, the inhibiting effect is not so appreciable when the concentration of magnesium oxide in the slag is 12 percent by weight or less.
In ordinary steel-making operations, the flowability of the slag becomes poor and refining is difficult when the concentration of magnesium oxide in the slag exceeds 12 percent by weight. Furthermore, a slag in a converter process has a total iron content of as high as about 17 to 23 percent by weight and a low magnesium oxide content.
The present invention is a method for prolonging the durable life of the refractory lining of an AOD furnace characterized in that in the operation of an AOD furnace lined with a magnesia-type refractory lining, a substance containing magnesium oxide is added to adjust the concentration of magnesium oxide in the slag to 13 to 25 percent by weight to reduce the dissolution of the magnesium oxide of the lining material into the slag.
The drawing is a longitudinal sectional view schematically showing the structure of an AOD furnace.
The magnesium oxide-containing substance used in this invention includes, for example, magnesia (magnesium oxide), magnesium carbonate, dolomite, lightly calcined dolomite obtained by burning dolomite to release carbon dioxide, dolomite clinker, magnesia-dolomite brick scraps, talc and forsterite. Better results are obtained by using these magnesium oxidecontaining substances together with quicklime or other substances as the slag-forming agent, or by molding such a combination together with a binder.
The concentration of magnesium oxide in the slag is adjusted to 13 to 25 percent by weight by adding the magnesium oxide-containing substance. If the concentration is less than 13 percent by weight, the effect of inhibiting the dissolution of magnesium oxide present in the refractory lining into the slag is small, and if it exceeds 25 percent by weight, the flowability of the slag becomes extremely poor and refining becomes difficult.
To illustrate the present invention, an AOD furnace having a capacity of 100 metric tons of molten steel was lined with magnesia-dolomite bricks. The running tests were performed using two kinds of stainless steel, SUS 304 and SUS 430, and the slag-forming agents shown in
Table 1. The indicated amounts of the slagforming agents were standard amounts for a charge. About 2 metric tons of the magnesium oxide-containing substance was fed in the early stage of blowing the reaction gas, with the remainder of the substance and the quicklime, in about 2 metric ton increments, being fed subsequently. Deoxidization was performed using a silicon alloy.
Table 1
Slag-forming Agent
Kg Added
Magnesia
Lightly dolomite
Calcined Brick
Run Quicklime Dolomite Dolomite Scraps 1 8,000 - - - 2 6,500 1,500 - 1,000
3 4,500 - 5,000
4 5,500 - - 3,500
Each run was performed through one lifetime cycle of the furnace, i.e., in the same furnace until the lining was lost by fusion and replaced by a new one.
Table 2
Experimental Results
Number Slag Composition,
of Cycles Average Weight Percent
in the
Run Furnace MgO CaO SiO2 A12O3 1 93 6.12 51.87 33.16 4.19
2 139 10.85 49.31 31.85 4.75
3 295 13.86 46.70 32.27 2.28
4 352 20.14 41.86 30.35 3.17
Experimental results from the testing are shown in Table 2, in which the indicated number of cycles in the furnace is the number of charges which were fed during operation through one lifetime cycle of the furnace.
As shown in Table 2, the number of cycles in the furnace strikingly increased when the concentration of magnesium oxide in the slag reached at least 13 percent by weight.
In Run 1, a magnesium oxide-containing substance was not added. The magnesium oxide in the slag thus resulted from the dissolving of magnesium oxide contained in the refractory lining material of the furnace and the sprayed material. In Run 2, the magnesium oxide concentration of the slag was about 11 percent by weight; the number of cycles in the furnace increased in this case, but the effect was not so appreciable. When the magnesium oxide concentration of the slag exceeded 25 percent by weight, the flowability of the slag was poor and refining was difficult.
As stated hereinabove, the present invention consists in markedly reducing the dissolution of magnesium oxide of a magnesia-type refractory lining material, especially of the slag line portion, into the slag and thereby strikingly increasing the durability of an AOD furnace, by adding a magnesium oxide-containing substance to adjust the concentration of magnesium oxide in the slag to 13 to 25 percent by weight in the operation of an AOD furnace lined with the refractory lining. This greatly contributes to steel making in AOD furnaces.
WHAT WE CLAIM IS:
1. A method for prolonging the durable life of the lining of an AOD furnace lines with a magnesia-type refractory, which comprises adding during the steel-making cycle of said furnace sufficient magnesium oxide-containing substance to adjust the magnesium oxide content of the slag formed during said cycle to from 13 to 25 percent by weight of said slag.
2. A method according to claim 1, wherein said substance is magnesia, dolomite, lightly calcined dolomite or magnesia-dolomite brick scraps.
3. A method according to claim 1 or 2, wherein said substance is added together with quicklime.
4. A method according to claim 3, wherein said substance and said quicklime are molded together with a binder.
5. A method as claimed in claim 1 for prolonging the durable life of the lining of an AOD furnace lined with a magnesia-type refractory, substantially as herein described.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (5)
1 93 6.12 51.87 33.16 4.19
2 139 10.85 49.31 31.85 4.75
3 295 13.86 46.70 32.27 2.28
4 352 20.14 41.86 30.35 3.17
Experimental results from the testing are shown in Table 2, in which the indicated number of cycles in the furnace is the number of charges which were fed during operation through one lifetime cycle of the furnace.
As shown in Table 2, the number of cycles in the furnace strikingly increased when the concentration of magnesium oxide in the slag reached at least 13 percent by weight.
In Run 1, a magnesium oxide-containing substance was not added. The magnesium oxide in the slag thus resulted from the dissolving of magnesium oxide contained in the refractory lining material of the furnace and the sprayed material. In Run 2, the magnesium oxide concentration of the slag was about 11 percent by weight; the number of cycles in the furnace increased in this case, but the effect was not so appreciable. When the magnesium oxide concentration of the slag exceeded 25 percent by weight, the flowability of the slag was poor and refining was difficult.
As stated hereinabove, the present invention consists in markedly reducing the dissolution of magnesium oxide of a magnesia-type refractory lining material, especially of the slag line portion, into the slag and thereby strikingly increasing the durability of an AOD furnace, by adding a magnesium oxide-containing substance to adjust the concentration of magnesium oxide in the slag to 13 to 25 percent by weight in the operation of an AOD furnace lined with the refractory lining. This greatly contributes to steel making in AOD furnaces.
WHAT WE CLAIM IS:
1. A method for prolonging the durable life of the lining of an AOD furnace lines with a magnesia-type refractory, which comprises adding during the steel-making cycle of said furnace sufficient magnesium oxide-containing substance to adjust the magnesium oxide content of the slag formed during said cycle to from 13 to 25 percent by weight of said slag.
2. A method according to claim 1, wherein said substance is magnesia, dolomite, lightly calcined dolomite or magnesia-dolomite brick scraps.
3. A method according to claim 1 or 2, wherein said substance is added together with quicklime.
4. A method according to claim 3, wherein said substance and said quicklime are molded together with a binder.
5. A method as claimed in claim 1 for prolonging the durable life of the lining of an AOD furnace lined with a magnesia-type refractory, substantially as herein described.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7113377A JPS545813A (en) | 1977-06-17 | 1977-06-17 | Method of extending useful life of refractory lining material in aod furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1596819A true GB1596819A (en) | 1981-09-03 |
Family
ID=13451764
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB14372/78A Expired GB1596819A (en) | 1977-06-17 | 1978-04-12 | Method of prolonging durable life of aod furnace refractory linings |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS545813A (en) |
| AU (1) | AU497818B1 (en) |
| BR (1) | BR7802318A (en) |
| DE (1) | DE2816897A1 (en) |
| FR (1) | FR2394609A1 (en) |
| GB (1) | GB1596819A (en) |
| IN (1) | IN148734B (en) |
| IT (1) | IT1102739B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1512163A (en) * | 1976-03-05 | 1978-05-24 | Triplex Safety Glass Co | Toughened glass sheets |
| CA1143947A (en) * | 1979-02-07 | 1983-04-05 | Jerry V. Spruell | Method for increasing vessel lining life for basic oxygen furnaces |
| JPS5839203B2 (en) * | 1979-05-31 | 1983-08-29 | 株式会社神戸製鋼所 | Slag forming agent and its manufacturing method |
| 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 |
| CN113528742A (en) * | 2021-06-22 | 2021-10-22 | 山东莱钢永锋钢铁有限公司 | Maintenance process for converter lining |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1393356A (en) * | 1964-01-16 | 1965-03-26 | Gibsonburg Lime Products Compa | Improved process to reduce deterioration of molten material handling equipment |
| FR1536457A (en) * | 1967-07-07 | 1968-08-16 | Siderurgie Fse Inst Rech | Process for the protection of refractory linings of continuous refining metallurgical vessels |
| FR2227328A1 (en) * | 1973-04-27 | 1974-11-22 | Blanq Cazaux Morales Armando | Iron and steel prodn - with calcium and magnesium oxides addn to lower slag basicity and volume |
-
1977
- 1977-06-17 JP JP7113377A patent/JPS545813A/en active Pending
-
1978
- 1978-04-12 GB GB14372/78A patent/GB1596819A/en not_active Expired
- 1978-04-13 IN IN268/DEL/78A patent/IN148734B/en unknown
- 1978-04-14 BR BR787802318A patent/BR7802318A/en unknown
- 1978-04-14 DE DE19782816897 patent/DE2816897A1/en not_active Withdrawn
- 1978-04-14 IT IT48898/78A patent/IT1102739B/en active
- 1978-04-14 AU AU35117/78A patent/AU497818B1/en not_active Expired
- 1978-04-14 FR FR7811118A patent/FR2394609A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| AU497818B1 (en) | 1979-01-11 |
| FR2394609B1 (en) | 1980-08-01 |
| BR7802318A (en) | 1979-01-16 |
| FR2394609A1 (en) | 1979-01-12 |
| IT7848898A0 (en) | 1978-04-14 |
| IT1102739B (en) | 1985-10-07 |
| DE2816897A1 (en) | 1979-01-04 |
| JPS545813A (en) | 1979-01-17 |
| IN148734B (en) | 1981-05-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930412 |