CN117025867A - Method for improving service life of pouring repair type blast furnace - Google Patents
Method for improving service life of pouring repair type blast furnace Download PDFInfo
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- CN117025867A CN117025867A CN202310866408.6A CN202310866408A CN117025867A CN 117025867 A CN117025867 A CN 117025867A CN 202310866408 A CN202310866408 A CN 202310866408A CN 117025867 A CN117025867 A CN 117025867A
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- slag
- castable
- blast furnace
- hearth
- temperature
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- 230000008439 repair process Effects 0.000 title claims abstract description 23
- 238000000034 method Methods 0.000 title claims abstract description 15
- 239000002893 slag Substances 0.000 claims abstract description 61
- 238000002844 melting Methods 0.000 claims abstract description 18
- 238000005266 casting Methods 0.000 claims abstract description 16
- 230000008018 melting Effects 0.000 claims abstract description 16
- 239000011241 protective layer Substances 0.000 claims abstract description 12
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000011449 brick Substances 0.000 claims abstract description 8
- 239000011229 interlayer Substances 0.000 claims abstract description 7
- 238000011835 investigation Methods 0.000 claims abstract description 7
- 239000011701 zinc Substances 0.000 claims description 41
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 18
- 229910052725 zinc Inorganic materials 0.000 claims description 10
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 9
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 9
- 239000000571 coke Substances 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 238000007711 solidification Methods 0.000 claims description 8
- 230000008023 solidification Effects 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 230000000694 effects Effects 0.000 claims description 7
- 239000010410 layer Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 230000008021 deposition Effects 0.000 claims description 6
- 238000013461 design Methods 0.000 claims description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 5
- 229910052596 spinel Inorganic materials 0.000 claims description 4
- 239000011029 spinel Substances 0.000 claims description 4
- 239000003513 alkali Substances 0.000 claims description 3
- 229910052783 alkali metal Inorganic materials 0.000 claims description 3
- 150000001340 alkali metals Chemical class 0.000 claims description 3
- 229910000323 aluminium silicate Inorganic materials 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 239000000498 cooling water Substances 0.000 claims description 3
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 3
- 238000009826 distribution Methods 0.000 claims description 3
- 230000009969 flowable effect Effects 0.000 claims description 3
- 239000000446 fuel Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- BITYAPCSNKJESK-UHFFFAOYSA-N potassiosodium Chemical compound [Na].[K] BITYAPCSNKJESK-UHFFFAOYSA-N 0.000 claims description 3
- 239000011734 sodium Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 2
- 239000011819 refractory material Substances 0.000 claims description 2
- 238000004458 analytical method Methods 0.000 abstract description 3
- 238000004886 process control Methods 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 229910052814 silicon oxide Inorganic materials 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 3
- 230000003628 erosive effect Effects 0.000 description 3
- 238000003723 Smelting Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000005255 carburizing Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B7/00—Blast furnaces
- C21B7/04—Blast furnaces with special refractories
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Abstract
The invention discloses a method for improving the service life of a casting repair type blast furnace, which comprises the following steps: (1) Forming a stable slag-rich protective layer on the hearth refractory hot surface; (2) The temperature of an interlayer thermocouple between the recycled carbon brick and the castable is controlled to be lower than the melting point of Zn. According to the damage investigation result of the pouring repair type blast furnace, the invention combines theoretical analysis to provide multidirectional process control measures, thereby providing a certain technical support for the in-service repair type blast furnace.
Description
Technical Field
The invention relates to the field of long service life of a hearth of an iron-making blast furnace, in particular to a method for improving the service life of a casting repair type blast furnace.
Background
With the progress of the iron-making technology level, the industrial structure is gradually perfected, the blast furnace is changed to a large-scale direction, and under the background, the long service life of the blast furnace is already an extremely important proposition in modern iron-making. In recent years, as the utilization coefficient and smelting strength of the blast furnace in China are increased stepwise, the erosion of the hearth is serious, the maintenance pressure of the hearth is increased, most of the blast furnaces cannot reach the design life, even the condition that the temperature of the side wall of the hearth exceeds the upper control limit in a period of time away from the design life occurs in some newly produced blast furnaces, and great potential safety hazards are caused to production. If the blast furnace is directly shut down for overhaul, the investment is large, the time consumption is long, and the current market demand is not met. Therefore, the integral casting repair technology of the blast furnace hearth is a new technology for quickly reconstructing a ceramic cup and a safe heat transfer structure of the blast furnace hearth, and the integral seamless ceramic cup which is high-temperature resistant, slag erosion resistant and insoluble in molten iron is cast on the hot surface of the old hearth carbon brick to meet the normal smelting requirement of the blast furnace.
Because the technology has remarkable advantages, the number of blast furnaces repaired by the technology is increased year by year, and most casting repair types of active production are regulated and controlled from which angles to prolong the service life of the hearth, so that the improvement of the safety production life is an important point of attention of technicians. Based on the method, according to the damage investigation result of the pouring repair type blast furnace and by combining theoretical analysis, multidirectional process control measures are provided, so that a certain technical support is provided for the in-service repair type blast furnace.
Disclosure of Invention
The invention aims to provide a method for improving the service life of a casting repair type blast furnace, which can prolong the service life of the casting repair type blast furnace and provide a certain technical guarantee for safe production.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a method for improving the service life of a casting repair type blast furnace, which comprises the following steps:
(1) Forming a stable slag-rich protective layer on the hearth refractory hot surface;
(2) The temperature of an interlayer thermocouple between the recycled carbon brick and the castable is controlled to be lower than the melting point of Zn.
Further, the method specifically comprises the following steps:
(1) Casting repair typeIn the initial stage of the service of the blast furnace, the heat conductivity of the castable is poor, and the temperature of a hot surface is difficult to reach 1350 ℃ of a slag phase solidification point, so that the actual protection cannot be formed in the stage, and the period is 0.5-1 year; as the castable is corroded, the thickness is gradually reduced, when the temperature of the hot surface of the refractory reaches 1350 ℃ of the solidification point of slag phase, the slag phase can adhere to the surface of the castable under certain conditions to prevent the flowable slag iron from further corroding the castable; as a result of breakage investigation, it was found that Al as a slag phase component in the slag-rich protective layer on the hearth side wall was provided by castable, while Ca and Mg mainly originated from slag phases in the hearth, and that when the blast furnace hearth hot face was provided with conditions for forming the slag-rich protective layer, the slag CaO and SiO should be paid attention to the operation 2 、Al 2 O 3 On the premise of stable furnace conditions, the binary alkalinity of the furnace slag is adjusted according to the upper limit, al 2 O 3 The content is properly adjusted downwards, the control interval is selected to be 1.16-1.20 of binary basicity of slag, and the slag Al 2 O 3 The content of the aluminum alloy is 12.4 to 12.8 percent, so that the slag is brought into the side wall of the hearth through the coke and then reacts with the high-aluminum castable to dissolve the Al in the castable 2 O 3 Separating out magnesia-alumina spinel high-melting point phase; the cooling system of the colleague controls the cooling water quantity and water speed of the blast furnace hearth strictly according to the design capacity, and the heat flow intensity of the hearth is not more than 12000kcal/m 2 H, controlling, namely if the heat flow intensity continuously exceeds the upper limit, properly increasing the water flow rate and the water speed to reduce the temperature of a hot surface of the castable, and ensuring that the slag-rich layer is stably combined with the castable while forming the slag-rich layer;
(2) Under the normal production condition of a blast furnace, alkali metal and Zn-containing substances carried in furnace charge are reduced into alkali steam and Zn steam, and enter the interior of the castable through cracks on the surface of the castable, when the temperature of a hot surface reaches over 900 ℃, zinc and potassium sodium steam are oxidized and react with oxides in the castable to generate liquid aluminosilicate, so that the internal volume of the refractory is expanded, and the microstructure of the castable is damaged; since the melting point of Na is 883 ℃, the melting point of K is 758 ℃, and the melting point of Zn is 419 ℃, the temperature interval of Zn solidification is closer to the cold surface, and the deposition of Zn can cause the change of the castable structure and the heat conducting property of the region, thereby affecting the property of the refractory material closer to the cold surface; in order to protect the integral performance of the refractory from being damaged by deposition of Zn prematurely, the temperature of an interlayer thermocouple between the recycled carbon brick and the castable is controlled to be lower than the melting point temperature of Zn, so that Zn enrichment at an interface is avoided, and the binding capacity of the material is further influenced; meanwhile, source control of harmful elements of raw fuel entering the furnace is enhanced, load content of zinc entering the furnace is reduced, and circulating enrichment amount of Zn in the blast furnace is reduced. The discharge of Zn in the blast furnace mainly takes the gas flow out, so the blast furnace should take the stable edge gas flow of the development center as the guide in the selection of the distribution system, the control of the activity degree of the hearth of the blast furnace is focused, the temperature stability rate of the blast furnace is improved, the fluctuation frequency of the blast furnace is reduced, and the effect of zinc discharge is achieved.
Compared with the prior art, the invention has the beneficial technical effects that:
according to the damage investigation result of the pouring repair type blast furnace, the invention combines theoretical analysis to provide multidirectional process control measures, thereby providing a certain technical support for the in-service repair type blast furnace.
Drawings
The invention is further described with reference to the following description of the drawings.
Fig. 1 is a diagram showing a mechanism of forming a slag-rich protective layer.
Detailed Description
A method for improving the service life of a pouring repair type blast furnace comprises the following steps:
1. forming a stable slag-rich protective layer on the hearth refractory hot surface;
2. and controlling the temperature of an interlayer thermocouple between the old carbon brick and the castable.
The method specifically comprises the following steps:
at present, the main composition phase of the castable used in the blast furnace hearth casting repair technology is Al 2 O 3 With SiC, accounting for 85 percent of the active ingredient, because SiC is easy to oxidize, a certain amount of SiO is also arranged in the casting material 2 The main composition of the castable is Al 2 O 3 Large particles, siC, C and other phases exist among the large particles to play a role of connection, and in order to strengthen the performance of the castable, the castable is also added withA certain amount of TiO 2 。
According to the damage investigation result of the ladle steel pouring repair type blast furnace, the slag in the area above the central line of the iron notch approaches the final slag component of the blast furnace, and the closer to the lower part of the hearth, the Al 2 O 3 The content gradually increases, while the alkalinity shows a tendency to gradually decrease. Through the judgment of slag components, the slag has good flowing property, can smoothly reach the side wall of the hearth, and provides a material source for the slag-rich protective layer. And only molten iron and coke are present at the position below the iron notch, carbon in the molten iron is unsaturated, the molten iron and the coke further undergo carburizing reaction, one part of residual coke ash floats upwards to form slag, and the other part of residual coke ash is enriched on the side wall of the hearth. Due to the Al contained in the casting material 2 O 3 SiO (silicon oxide) 2 And the high-melting-point phases such as CaS, magnesia-alumina spinel and the like with the coke ash, the slag permeated and wrapped in the coke pores and the like are generated in a certain amount in the slag phase, and finally a slag-rich layer is formed. The specific forming process is shown in fig. 1.
In the initial stage of service of the casting repair type blast furnace, the heat conductivity of the casting material is poor, and the temperature of a hot surface is difficult to reach 1350 ℃ of a slag phase solidification point, so that real protection cannot be formed at the stage, and the period is about 0.5-1 year. As the castable is eroded, the thickness is gradually reduced, and when the temperature of the hot surface of the refractory reaches 1350 ℃ of the solidification point of the slag phase, the slag phase can adhere to the surface of the castable under certain conditions to prevent the flowable slag iron from further eroding the castable. As a result of breakage investigation, it was found that Al as a slag phase component in the slag-rich protective layer on the hearth side wall is provided by castable, and Ca and Mg mainly originate from slag phases in the hearth, so that when the blast furnace hearth hot face is provided with conditions for forming the slag-rich protective layer, the slag CaO and SiO should be paid attention to in operation 2 、Al 2 O 3 On the premise of stable furnace conditions, the binary alkalinity of the furnace slag is adjusted according to the upper limit, al 2 O 3 The content is properly adjusted downwards, the control interval is selected to be 1.16-1.20 of binary basicity of slag, and the slag Al 2 O 3 Al content in slag is 12.4-12.8% 2 O 3 The content is recommended to be controlled according to 12.4-12.8 percent, so that the slag is carried into the side wall of the hearth through coke and then is mixed with high aluminumDissolving Al in the castable 2 O 3 And precipitating phases with high melting point such as magnesia-alumina spinel. In terms of cooling system, the cooling water quantity and water speed of the blast furnace hearth are strictly controlled according to the design capacity, and the heat flow intensity of the hearth is not more than 12000kcal/m 2 H, controlling, namely, if the heat flow intensity continuously exceeds the upper limit, properly increasing the water flow rate and the water speed to reduce the temperature of a hot surface of the castable, and ensuring that the slag-rich layer is formed and simultaneously the slag-rich layer and the castable are stably combined.
On the other hand, under the normal production condition of the blast furnace, alkali metal and Zn-containing substances carried in the furnace burden are reduced into alkali steam and Zn steam, and enter the interior of the castable through cracks on the surface of the castable, when the hot surface temperature reaches over 900 ℃, zinc and potassium sodium steam are oxidized and react with oxides in the castable to generate liquid aluminosilicate, so that the volume of the interior of the refractory is expanded, and the microstructure of the castable is damaged. Since Na has a melting point of 883 ℃, K has a melting point of 758 ℃, and Zn has a melting point of 419 ℃, the temperature interval in which Zn solidifies is closer to the cold face, and deposition of Zn causes changes in the castable structure and the heat conductivity of the region, thereby affecting the refractory properties closer to the cold face. In order to protect the integral performance of the refractory from being damaged by deposition of Zn prematurely, the temperature of an interlayer thermocouple between the recycled carbon brick and the castable should be controlled to be lower than the melting point 419 ℃ of Zn, which is beneficial to avoiding the enrichment of Zn at an interface to influence the binding capacity of the material. Meanwhile, source control of harmful elements of raw fuel entering the furnace is enhanced, load content of zinc entering the furnace is reduced, and circulating enrichment amount of Zn in the blast furnace is reduced. The discharge of Zn in the blast furnace mainly takes the gas flow out, so the blast furnace should take the stable edge gas flow of the development center as the guide in the selection of the distribution system, the control of the activity degree of the hearth of the blast furnace is focused, the temperature stability rate of the blast furnace is improved, the fluctuation frequency of the blast furnace is reduced, and the effect of zinc discharge is achieved.
The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.
Claims (2)
1. A method for improving the service life of a casting repair type blast furnace is characterized by comprising the following steps of: comprising the following steps:
(1) Forming a stable slag-rich protective layer on the hearth refractory hot surface;
(2) The temperature of an interlayer thermocouple between the recycled carbon brick and the castable is controlled to be lower than the melting point of Zn.
2. The method for improving the service life of a pouring repair type blast furnace according to claim 1, wherein the method comprises the following steps: the method specifically comprises the following steps:
(1) In the initial service period of the casting repair type blast furnace, the heat conductivity of the casting material is poor, and the temperature of a hot surface is difficult to reach 1350 ℃ of a slag phase solidification point, so that real protection cannot be formed at the stage, and the period is 0.5-1 year; as the castable is corroded, the thickness is gradually reduced, when the temperature of the hot surface of the refractory reaches 1350 ℃ of the solidification point of slag phase, the slag phase can adhere to the surface of the castable under certain conditions to prevent the flowable slag iron from further corroding the castable; as a result of breakage investigation, it was found that Al as a slag phase component in the slag-rich protective layer on the hearth side wall was provided by castable, while Ca and Mg mainly originated from slag phases in the hearth, and that when the blast furnace hearth hot face was provided with conditions for forming the slag-rich protective layer, the slag CaO and SiO should be paid attention to the operation 2 、Al 2 O 3 On the premise of stable furnace conditions, the binary alkalinity of the furnace slag is adjusted according to the upper limit, al 2 O 3 The content is properly adjusted downwards, the control interval is selected to be 1.16-1.20 of binary basicity of slag, and the slag Al 2 O 3 The content is 12.4 to 12.8 percent, so that the slag is brought into the side wall of the hearth through the coke and then reacts with the high-alumina castable to dissolve Al in the castable 2 O 3 Separating out magnesia-alumina spinel high-melting point phase; the cooling system of the colleague controls the cooling water quantity and water speed of the blast furnace hearth strictly according to the design capacity, and the heat flow intensity of the hearth is not more than 12000kcal/m 2 H control, if the heat flow intensity continuously exceeds the upper limit, properly increasing the water flow and waterThe temperature of the hot surface of the castable is reduced, so that the slag-rich layer is ensured to be stably combined with the castable while the slag-rich layer is formed;
(2) Under the normal production condition of a blast furnace, alkali metal and Zn-containing substances carried in furnace charge are reduced into alkali steam and Zn steam, and enter the interior of the castable through cracks on the surface of the castable, when the temperature of a hot surface reaches over 900 ℃, zinc and potassium sodium steam are oxidized and react with oxides in the castable to generate liquid aluminosilicate, so that the internal volume of the refractory is expanded, and the microstructure of the castable is damaged; since the melting point of Na is 883 ℃, the melting point of K is 758 ℃, and the melting point of Zn is 419 ℃, the temperature interval of Zn solidification is closer to the cold surface, and the deposition of Zn can cause the change of the castable structure and the heat conducting property of the region, thereby affecting the property of the refractory material closer to the cold surface; in order to protect the integral performance of the refractory from being damaged by deposition of Zn prematurely, the temperature of an interlayer thermocouple between the recycled carbon brick and the castable is controlled to be lower than the melting point temperature of Zn, so that Zn enrichment at an interface is avoided, and the binding capacity of the material is further influenced; meanwhile, the source control of harmful elements of raw fuel entering the furnace is enhanced, the load content of zinc entering the furnace is reduced, and the circulating enrichment amount of Zn in the blast furnace is reduced; the discharge of Zn in the blast furnace mainly takes the gas flow out, so the blast furnace should take the stable edge gas flow of the development center as the guide in the selection of the distribution system, the control of the activity degree of the hearth of the blast furnace is focused, the temperature stability rate of the blast furnace is improved, the fluctuation frequency of the blast furnace is reduced, and the effect of zinc discharge is achieved.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310866408.6A CN117025867A (en) | 2023-07-14 | 2023-07-14 | Method for improving service life of pouring repair type blast furnace |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310866408.6A CN117025867A (en) | 2023-07-14 | 2023-07-14 | Method for improving service life of pouring repair type blast furnace |
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| CN202310866408.6A Pending CN117025867A (en) | 2023-07-14 | 2023-07-14 | Method for improving service life of pouring repair type blast furnace |
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| Country | Link |
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