CN111826499B - Blast furnace molten iron decarburization treatment method based on converter LT fly ash - Google Patents
Blast furnace molten iron decarburization treatment method based on converter LT fly ash Download PDFInfo
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- CN111826499B CN111826499B CN202010622593.0A CN202010622593A CN111826499B CN 111826499 B CN111826499 B CN 111826499B CN 202010622593 A CN202010622593 A CN 202010622593A CN 111826499 B CN111826499 B CN 111826499B
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- 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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
Abstract
The invention relates to a blast furnace molten iron decarburization treatment method based on converter LT fly ash, which comprises the following steps: the converter LT dedusting ash is used as a decarbonizer to be mixed with molten iron from a blast furnace, and carbon in the molten iron is oxidized to achieve the aim of decarbonization, so that carbon-containing dust generated by temperature drop of the molten iron is reduced. The converter LT fly ash is added into the blast furnace tapping to serve as a decarbonizer, so that the carbon content in the molten iron is reduced, and the problem of graphite dust pollution in the molten iron inversion link of a steel plant is radically solved. The decarbonizer is converter LT fly ash of a steel mill, has obvious decarbonization effect on blast furnace molten iron, can reduce the carbon precipitation amount of molten iron, relieves the graphite dust pollution problem of the steel mill, fully utilizes waste resources, recycles iron in the converter LT fly ash, and improves the utilization value of the converter LT fly ash.
Description
Technical Field
The invention belongs to the technical field of molten iron pretreatment in a steelmaking process, and particularly relates to a blast furnace molten iron decarburization treatment method based on converter LT fly ash.
Background
The energy consumption and the environmental load of the iron and steel enterprises are closely related to the process flow required by production. On the basis that the current steel production process basically tends to be mature and stable, the continuous improvement of the interface technology among equipment is an effective measure for optimizing production indexes. Among them, the "interface" between the blast furnace and the converter (mixer) is particularly important, and is generally called as "iron-steel interface". The 'iron-steel interface' comprises molten iron from a blast furnace, and various links such as molten iron transportation, pretreatment and the like. In this process, the temperature of the molten iron may be sharply decreased due to heat dissipation loss. According to the data provided by Bao Steel institute, the temperature drop of molten iron at the 'iron-steel interface' can reach more than 150 ℃.
On-site observation shows that a large amount of high-temperature smoke dust is generated in the molten iron transportation process, particularly in the molten iron inversion link. Through detection and analysis, the main components of the smoke dust are carbon and iron, such as the carbon and iron content of the smoke dust of the martial steel, saddle steel and climbing steel is over 70 percent; the carbon and iron content in the smoke dust of the first steel, Kun steel and Tai steel is over 80 percent. This is because carbon in the molten iron is supersaturated and precipitated while the temperature of the molten iron is lowered, and a large amount of flake graphite is even visible in the precipitated dust. In addition, the high-temperature molten iron reacts with oxygen in the air to generate iron oxide dust particles. It has been found that the saturated solubility of carbon decreases by 0.24% on average for every 100 ℃ drop in the temperature of molten iron, i.e., about 2.4kg of carbon is precipitated from 1 ton of molten iron. For a "steel-iron interface" of thousands of tons of molten iron per day, tens of tons of carbon-containing dust will be produced.
The formation of the smoke not only wastes carbon and iron resources and affects the atmospheric quality, but also causes great damage to equipment and human bodies. Particularly, the graphite dust is flaky and is easy to slip when falling on the rail surface of a running vehicle or a train. Under the influence of carbon supersaturated precipitation, part of carbon and iron form Fe3C is released, and when the graphite dust is Fe with magnetism3When the form C appears, the influence on electrical equipment with a magnetic field on a production site is great, and the heat dissipation and insulation performance and the service life of the electrical equipment are seriously influenced. In addition, the graphite dust is smooth and easy to adhere, and causes symptoms of skin itch, red swelling and the like when contacting human skin.
Currently, there are several methods for solving this problem. Firstly, each large steel plant adopts an air draft dust removal method to purify air. Secondly, the heat loss of the molten iron in the torpedo tank car is reduced by improving the external heat insulation structure of the torpedo tank car, so that the temperature drop of the molten iron in the transportation process is reduced. Thirdly, a part of steel plants adopt a capping mode at a molten iron port at the top of the torpedo tank car, so that the heat loss of molten iron is reduced. The first dust removing method is limited by process operation, and the main problems are that the dust removing smoke hood conflicts with the operation of other equipment, the equipment is difficult to arrange, the maintenance and operation cost is high, the smoke and dust complementary effect is poor, and the treatment of symptoms and root causes is not good. The latter two methods have achieved certain results, but still cannot avoid the generation of a large amount of graphite dust. Because, the carbon-saturated molten iron produced by the blast furnace inevitably undergoes carbon precipitation during the temperature reduction.
Therefore, there is a need to solve the problem of reducing graphite dust contamination by reducing the carbon content in the molten iron based on the prior art. For this reason, Tsinghun et al developed a molten iron carbon reduction laboratory study based on Kun iron and steel water samples, using iron concentrate powders such as Yunnan beach ore, Brazil powder, premixed powder, sintered return ore, etc. as decarburizing agents. The field test selects Kunzi No. 6 blast furnace, and uses Yunnan Tibet mineral powder which has low cost and is easy to organize and supply as a decarbonizer. The mineral powder is loaded into a 25kg woven bag, and when molten iron is discharged from a blast furnace, the mineral powder is manually added into an iron runner behind a small dam in front of the blast furnace. Although the technology has remarkable effect on carbon reduction of molten iron, the following problems still exist: (1) the iron ore concentrate powder is used as a decarbonizer, so the cost is higher; (2) after the Yunnan beach mineral powder at room temperature is directly added into the molten iron, the temperature of the molten iron is reduced by about 20 ℃, the heat loss is larger, and the generation of carbon-containing dust is aggravated. (3) When the iron ore concentrate powder is used on site, the ore powder is added into an iron runner when the Yunnan beach ore powder packaged by a woven bag is directly added into molten iron discharged from a blast furnace manually, so that molten iron splashing and material loss are easily caused, and potential safety hazards exist.
Disclosure of Invention
Technical problem to be solved
In order to solve the problems in the prior art, the invention provides a method for decarbonizing the blast furnace molten iron based on the converter LT fly ash, which adopts the converter LT fly ash with lower cost as a decarbonizer to be applied to the blast furnace molten iron, so that the cost of the molten iron decarbonization treatment can be reduced, and the iron element in the converter LT fly ash can be efficiently recycled, so that the resources can be fully utilized.
(II) technical scheme
In order to achieve the purpose, the invention adopts the main technical scheme that:
a blast furnace molten iron decarburization treatment method based on converter LT fly ash is characterized in that converter LT fly ash is used as a decarburization agent to be mixed with molten iron from a blast furnace, carbon in the molten iron is oxidized to achieve decarburization effect, and carbon-containing dust generated by temperature drop of the molten iron is reduced.
In a preferred embodiment of the present invention, the LT precipitator dust consists of: comprises 0.060 to 0.075 percent of S and SiO by mass percent2 1.50％-2.90％、Al2O3 0.02％-0.05％、CaO 6.00％-9.10％、MgO 3.5％-5.0％、MnO 0.40％-0.55％、P2O50.15 to 0.25 percent of iron, 27.0 to 32.0 percent of FeO, 56.00 to 63.40 percent of Tfe total iron, 1.00 to 2.00 percent of C and Fe2O350.0% -55.00% and the rest is 1.00% -3.00% of the undetected part.
In a preferred embodiment of the invention, the usage amount of the converter LT dedusting ash is 2-5% of the mass of the molten iron.
In a preferred embodiment of the invention, the converter LT fly ash is mixed with the molten iron from the blast furnace in a powder or block form; the size of the block is 0.3-5 cm.
The shape of the block is not limited, and can be regular cylindrical, rectangular, ellipsoidal or irregular solid after spherical. The purpose of pre-preparing the powdery converter LT fly ash into blocks is to increase the particle size of the converter LT fly ash when the converter LT fly ash is added into molten iron and prevent the loss and safety problems caused by high-temperature splashing. Of course, the powdery converter LT fly ash can also be directly mixed with the molten iron from the blast furnace, but if the adding mode is improper, splashing can be easily generated, certain loss is caused, the safety is poor, and the block-shaped converter LT fly ash can reduce the splashing. If the size of the block is too small, the splash-proof effect cannot be achieved, and the workload of the block-making pressing block is too large; if the block size is too large, the decarburization reaction speed is too slow, the reaction time is prolonged, the carbon reduction effect is poor, and converter LT fly ash remains after the reaction.
In a preferred embodiment of the invention, converter LT fly ash is further mixed with iron concentrate powder to form a decarbonizer which is mixed with molten iron from a blast furnace; the iron ore concentrate powder contains 50-67 wt% of total iron TFe.
Preferably, the mixing mass ratio of the converter LT fly ash to the iron ore concentrate powder is 50-100: 1-50; for example, the ratio may be in the range of 100:1, 50:50, 50: 1: mixing the components in a mass ratio of 100:50 to prepare the decarbonizer for use.
In a preferred embodiment of the present invention, the processing method comprises: when the mixture of the converter LT dedusting ash or the mixture of the converter LT dedusting ash and the iron concentrate powder is adopted to perform mixed decarburization on the molten iron discharged from the blast furnace, the temperature of the molten iron is 1330-1500 ℃, and the optimal temperature is 1400-1500 ℃. In the research, it is found that if the temperature of molten iron is lower than 1400 ℃, the decarburization reaction speed is slow, the required reaction time is prolonged, and thus, part of the dust removed by the LT of the converter may remain and the reaction is incomplete.
In a preferred embodiment of the present invention, the processing method includes: after molten iron is poured into a converter or a ladle of a steel plant from a torpedo ladle car, filling the mixture of the block converter LT fly ash or the converter LT fly ash and the iron concentrate powder into the bottom of the torpedo ladle car, and preheating the decarbonizing agent by using the waste heat of the torpedo ladle car in the process that the torpedo ladle car returns to the steel plant from the steel plant, so that the heat loss of the molten iron caused by the direct mixing of the decarbonizing agent and the molten iron of a blast furnace is reduced.
The method comprises the following steps of filling a mixture of bulk converter LT (LT) fly ash or converter LT fly ash and iron ore concentrate powder into an evacuated torpedo ladle car for preheating, wherein on one hand, a decarbonizer is pre-filled at the bottom of the torpedo ladle car, so that when molten iron in a blast furnace is poured into the torpedo ladle car, the decarbonizer is positioned at the bottom of the molten iron and is fully mixed and reacted with the molten iron under the impact action of the molten iron, the decarbonization effect is improved, and special stirring is not needed; on the other hand, the preheated decarbonizer can reduce the heat loss to the molten iron.
In a preferred embodiment of the present invention, the processing method includes: before the molten iron from the blast furnace, powdered converter LT dedusting ash or a mixture of the converter LT dedusting ash and iron concentrate powder is paved in an iron runner connecting a molten iron outlet of the blast furnace and a torpedo tank car, so that the molten iron flows through the powdered decarbonizing agent and reacts with each other to realize decarbonization.
A small amount of powdery converter LT fly ash or a mixture of the converter LT fly ash and iron concentrate powder is paved in the molten iron ditch, so that a large amount of splashing can not occur, the effect of partial decarburization is realized on the flowing blast furnace molten iron, and the workload of briquetting all decarbonizing agents is reduced.
In a preferred embodiment of the present invention, the processing method includes:
s1, briquetting: fully mixing converter LT fly ash or a mixture of the converter LT fly ash and iron ore concentrate powder with a binder and water for pulping, pressing into blocks, and drying to obtain a block decarbonizer;
s2, filling the blocky decarbonizing agent to the bottom of the emptied torpedo ladle car, and preheating the decarbonizing agent by using the waste heat of the torpedo ladle car;
s3, before the molten iron from the blast furnace, paving powdery decarbonizing agent into the molten iron ditch connecting the molten iron outlet of the blast furnace and the torpedo car, so that the molten iron from the blast furnace reacts with the decarbonizing agent to realize decarbonization in the process of flowing through the molten iron ditch and entering the torpedo car; and after the molten iron is poured backwards to the torpedo ladle car, the molten iron is contacted with a blocky decarbonizer which is filled at the bottom of the torpedo ladle car in advance and reacts, so that decarbonization is further realized.
Preferably, in step S1, the binder is an inorganic binder to prevent the organic binder from introducing carbon into the molten iron. Preferably, the inorganic binder is bentonite. Further preferably, the addition amount of the binder is 5-8% of the mass of the converter LT fly ash or the mixture of the converter LT fly ash and the iron ore concentrate powder.
Preferably, in step S1, the drying temperature is 110-120 ℃ and the time is 3-5 hours.
Preferably, the decarbonizing agents used twice in the steps S2 and S3 account for 2-5% of the molten iron capacity of the single torpedo ladle car; the excessive consumption of the decarbonizer can not only cause the excessive heat loss of molten iron, the too fast temperature drop and the carbon precipitation, but also cause the incomplete reaction of the decarbonizer within a limited time.
Converter LT fly ash:
the converter LT fly ash comes from the dry method (LT method) purification and recovery technology of converter gas. The LT process system was jointly developed by lurgi, germany, and tson steelworks in the last 60 s. The method mainly comprises flue gas cooling, purification and recovery and dust briquetting 3, wherein the temperature of flue gas generated in the converter steelmaking process is reduced to 800-1000 ℃ from about 1450 ℃ through a cooling flue, and then the flue gas enters a flue gas purification system. The flue gas purification system comprises an evaporative cooler and a cylindrical electric dust remover, the temperature of the flue gas is reduced to 180-200 ℃ after passing through the evaporative cooler, meanwhile, the resistivity of the flue gas is reduced through quenching and tempering, and coarse dust is collected. The flue gas enters a cylindrical electric dust remover after the primary treatment for further purification, so that the dust content mass concentration of the flue gas is reduced to 10mg/m3Thus, the best dust removal efficiency is achieved. The coarse dust collected by the evaporative cooler and the dust collected by the cylindrical electric precipitator constitute converter LT fly ash. The powder can be conveyed to a briquetting station through a conveyor, the powder is heated to 500-600 ℃ in a rotary kiln, and the powder is pressed and formed in a hot briquetting mode.
(III) advantageous effects
The invention has the beneficial effects that:
the converter LT fly ash is added into the blast furnace tapping to serve as a decarbonizer, so that the carbon content in the molten iron is reduced, and the problem of graphite dust pollution in the molten iron inversion link of a steel plant is radically solved. The decarbonizer is converter LT fly ash of a steel mill, has obvious decarbonization effect on blast furnace molten iron, reduces the carbon precipitation amount of the molten iron, relieves the graphite dust pollution problem of the steel mill, fully utilizes waste resources, recycles iron in the converter LT fly ash, and improves the utilization value of the converter LT fly ash.
The invention also makes innovation on the application mode of the decarbonizer, comprising the following steps: (1) the powdery decarbonizing agent is paved in an iron runner between a blast furnace and a torpedo tank car in advance, the flowing molten iron is subjected to pre-decarbonization, and the molten iron flows through the iron runner in sequence in a flowing state, fully contacts with the decarbonizing agent and reacts for decarbonization, so that the stirring operation is omitted; (2) the method comprises the steps of placing the blocky decarbonizing agent into a torpedo ladle car emptied of molten iron, preheating the decarbonizing agent by using waste heat of the torpedo ladle car in the process that the torpedo ladle car returns to an iron making plant from the steel making plant, raising the temperature from normal temperature to 800-1000 ℃, reducing heat loss caused by contact between the blocky decarbonizing agent and high-temperature molten iron (about 1480 ℃), and relieving carbon precipitation.
The method for decarbonizing the blast furnace molten iron has simple and easy operation, has less investment and low cost compared with the dust removal equipment for removing the graphite dust, solves the problem of the graphite dust from the source and has ideal decarbonization effect.
Detailed Description
For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail below with reference to specific embodiments.
The current molten iron transportation process of an iron-steel interface comprises the following steps: molten iron from a blast furnace of an iron and steel plant is filled into a torpedo car, and then the molten iron is transported into a mixer furnace or a converter ladle of the iron and steel plant through the torpedo car. The temperature of the molten iron from the blast furnace is about 1500 ℃, the temperature is reduced to about 1320 ℃ when the molten iron is poured into a mixer or a converter ladle, and the temperature is reduced to over 100 ℃ in the period, so that the solubility of carbon in the molten iron is greatly reduced due to the temperature reduction, a large amount of carbon powder is separated out, and the molten iron becomes one of the main pollution sources of a steel mill.
In order to solve the problems, the main technical means adopted by the invention comprise: and adding a decarbonizer into molten iron discharged from the blast furnace to perform decarbonization treatment, so as to reduce the generation of carbon dust from the source. When the decarbonizer is selected, converter LT fly ash is selected, or the converter LT fly ash is matched with iron concentrate powder for use. Fe of LT fly ash of converter2O3The content of the carbon dioxide reaches more than 50 percent, has stronger oxidizability at high temperature, and can oxidize C contained in the molten iron into CO or CO2The iron element in the dust removed by the converter LT is efficiently recovered. In the time and mode of adding the decarbonizing agent, the invention selects powdery decarbonizing agent and massive decarbonizing agent. The application method mainly comprises two improvements: first, the powdery decarbonizer is preferably a layer of powdery decarbonizer which is laid in a molten iron runner (a molten iron flow channel connecting a blast furnace and a torpedo car) before tapping molten iron from the blast furnace, and the decarbonizer oxidizes carbon in the molten iron to realize partial pre-decarbonization when the molten iron flows through the powdery decarbonizer. Secondly, the torpedo car pours the transported molten iron back to the converter ladle or the iron mixing furnace, the torpedo car is in an emptying state, at the moment, the blocky decarbonizer which plays a main decarbonization role is filled into the tank body of the torpedo car, the decarbonizer is heated by using the waste heat of the torpedo car, when the torpedo car returns to the iron smelting plant to carry the molten iron again, the decarbonizer in the torpedo car is heated to about 800-. Since the decarbonizing agent is preheated to a high temperature, excessive heat loss does not occur even if the decarbonizing agent is mixed with molten iron discharged from the blast furnace.
In order to further explain the technical features and effects of the present invention, the following description is given with reference to specific examples.
Example 1
In this example, converter LT fly ash was used as a decarburization agent and mixed with blast furnace molten iron to effect decarburization. In this example, the composition of the converter LT fly ash sample is:
| composition (I) | Mass percentage of | Composition (I) | Mass percentage of |
| S | 0.069 | Tfe full iron | 59.49 |
| SiO2 | 1.63 | C | 1.53 |
| Al2O3 | 0.36 | Mfe magnetic iron | -- |
| CaO | 8.12 | Fe2O3 | 52.23 |
| MgO | 4.19 | ZnO | Micro-scale |
| MnO | 0.426 | Na2O | Micro-scale |
| P2O5 | 0.199 | K2O | Micro-scale |
| FeO | 29.48 | Remaining undetected portions | 1.77 |
The particle size of the converter LT fly ash is 10-50 microns, a certain amount of the converter LT fly ash, bentonite and water are fully and uniformly mixed, slurried and pressed into blocks, and the blocks are dried at the temperature of 110-120 ℃ for 3-5 hours to obtain the cylindrical blocky decarbonizer, wherein the diameter is 1cm, and the height is 1.5 cm. Wherein the bentonite accounts for 5 percent of the mass of the LT fly ash of the converter.
Initial values of carbon were determined from samples taken from a steel mill, with slight differences in composition in each iron block sample (weighing approximately 500 g). In order to make the detection result more accurate, each sample is detected for 3 times, the average value of three times is taken, and the carbon content in the iron block sample is repeatedly detected in each experiment. The average contents of Si and Mn in the iron block sample are respectively 0.28 percent and 0.20 percent
In this example, the influence of different amounts of decarburizing agents on the decarburization effect of molten iron was studied, specifically, 3%, 4%, and 5% (based on the mass of molten iron) of the bulk decarburization agent of converter LT dedusting ash (converted into the mass of converter LT dedusting ash) was added to molten iron, and the temperature of molten iron was kept at 1450 ℃. The results are reported in table 1.
TABLE 1
As is clear from Table 1, the amount of carbon reduction in molten iron gradually increased with the increase in the amount of fly ash in converter LT, and the decarburization effect was remarkable. Compared with the prior art that the decarburizing agent adopts 3 percent of Yunnan beach ore to realize about 0.30 percent of carbon reduction amount under the same experiment temperature, the decarburizing agent used by the invention has higher decarburization efficiency.
Example 2
In this example, converter LT fly ash was used as a decarburization agent and mixed with blast furnace molten iron to effect decarburization, and the composition, specification and briquetting steps of converter LT fly ash were the same as those of example 1. For the measurement, three tests were carried out for each sample and the average was taken.
This example investigated the effect of converter LT fly ash as a decarboniser on the decarbonisation of molten iron at different temperatures. Specifically, the temperature of molten iron for decarburization reaction is maintained at 1420 ℃, 1450 ℃ and 1480 ℃, and in each temperature experiment, the use amount of converter LT dedusting ash is 4% of the mass of the molten iron. The results of the experiment are reported in Table 2.
TABLE 2
As can be seen from the above table, when the amount of the converter LT fly ash is constant, the relationship between the carbon reduction effect and the temperature of the molten iron during the decarburization reaction is not large, that is, the temperature has almost no influence on the decarburization effect, and the carbon reduction amount greatly depends on the amount of the converter LT fly ash decarburization agent. Therefore, considering the complete reaction and cost saving, the converter LT dedusting ash can meet the decarburization requirement of the blast furnace on molten iron after tapping when being used as a decarburization agent with the use amount of 3-4%; when the decarbonizer is used in 4 percent, the carbon reduction rate reaches 0.42 percent.
Example 3
In this example, converter LT fly ash was mixed with iron ore concentrate powder (Brazilian iron ore concentrate powder) at a mass ratio of 80:20 as a decarbonizing agent, and the composition, specification and briquetting steps of the converter LT fly ash were the same as those of example 1. The composition of iron ore concentrate powder is as follows:
in this example, the influence of different amounts of decarburizing agents on the decarburization effect of molten iron was studied, specifically, 3% and 4% (by mass of the converter LT fly ash + the iron concentrate powder and by mass of the molten iron) of block-shaped decarburizing agents (made of the converter LT fly ash + the iron concentrate powder and 5% of bentonite briquettes) were added to the molten iron, and the temperature of the molten iron was kept at 1450 ℃. The results are reported in table 3.
TABLE 3
As is clear from the above table, the mixture of the converter LT fly ash and the iron ore concentrate powder is used as the decarbonizing agent, and the same ideal carbon reduction effect can be obtained. In the embodiment, the decarbonization of the iron ore concentrate powder and the production of the molten iron are directly utilized, and the special pelletizing treatment of the iron ore concentrate powder is not needed (normally, the special pelletizing is needed before the iron ore concentrate powder is added into a blast furnace).
In the above examples 1-3, it was verified in the laboratory that the decarburization agent comprising the fly ash from the converter LT as a decarburization agent or the mixture of the fly ash from the converter LT as a base material and the iron ore concentrate powder could achieve the desired carbon reduction effect when mixed with the blast furnace molten iron.
When the decarbonizer is used on site in a steel plant, the invention also comprises at least one of the following improvements in the adding mode and adding time of the decarbonizer:
firstly, after molten iron is poured into a converter or a ladle of a steel plant from a torpedo car, filling the mixture of the block converter LT fly ash or the converter LT fly ash and iron concentrate powder to the bottom of the torpedo car, and preheating a decarbonizing agent by using the waste heat of the torpedo car in the process of returning the torpedo car from the steel plant to the steel plant, so that the heat loss of the molten iron caused by directly mixing the decarbonizing agent with blast furnace molten iron is reduced, and special stirring operation can be omitted.
Secondly, before the molten iron from the blast furnace, paving powdery converter LT dedusting ash or a mixture of the converter LT dedusting ash and iron concentrate powder in an iron runner connecting a molten iron outlet of the blast furnace and a torpedo tank car, and enabling the molten iron to flow through a powdery decarbonizer and react with each other to realize decarbonization. The powdery decarbonizer can quickly react with molten iron in the molten iron ditch without splashing.
It should be understood that the above description of specific embodiments of the present invention is only for the purpose of illustrating the technical lines and features of the present invention, and is intended to enable those skilled in the art to understand the contents of the present invention and to implement the present invention, but the present invention is not limited to the above specific embodiments. It is intended that all such changes and modifications as fall within the scope of the appended claims be embraced therein.
Claims (8)
1. A blast furnace molten iron decarburization treatment method based on converter LT fly ash is characterized by comprising the following steps: mixing converter LT dedusting ash serving as a decarbonizer with molten iron discharged from a blast furnace, oxidizing carbon in the molten iron to achieve the decarbonization effect, and reducing carbon-containing dust generated by temperature drop of the molten iron;
the processing method comprises the following steps: before the molten iron from the blast furnace, paving a powdery decarbonizing agent in a molten iron ditch connecting a molten iron outlet of the blast furnace with a torpedo car, so that the molten iron flows through the powdery decarbonizing agent and reacts to realize decarbonization;
after molten iron is poured into a converter or a ladle of a steel plant from the torpedo car, the blocky decarbonizing agent is filled to the bottom of the torpedo car, so that the decarbonizing agent is preheated by means of the waste heat of the torpedo car in the process of returning the torpedo car from the steel plant to the steel plant, and the heat loss of the molten iron caused by directly mixing the decarbonizing agent with the molten iron of the blast furnace is reduced.
2. The method for decarbonizing molten iron in a blast furnace according to claim 1, wherein said LT fly ash comprises: comprises 0.060 to 0.075 percent of S and SiO by mass percent2 1.50％-2.90％、Al2O3 0.02％-0.05％、CaO 6.00％-9.10％、MgO 3.5％-5.0％、MnO 0.40％-0.55％、P2O50.15 to 0.25 percent of iron, 27.0 to 32.0 percent of FeO, 56.00 to 63.40 percent of Tfe total iron, 1.00 to 2.00 percent of C and Fe2O350.0% -55.00% and the rest is 1.00% -3.00% of the undetected part.
3. The method for decarbonizing molten iron of a blast furnace according to claim 1, wherein the amount of fly ash of the converter LT used is 2 to 5% by mass of the molten iron.
4. The method for decarbonizing molten iron of a blast furnace according to claim 1, wherein the converter LT fly ash is mixed with the molten iron discharged from the blast furnace in a powdery or lump form; the size of the block is 0.3-5 cm.
5. The method for decarbonizing molten iron of a blast furnace according to claim 1, wherein converter LT fly ash is mixed with fine iron ore powder to form a decarbonizer, and the decarbonizer is mixed with molten iron discharged from the blast furnace; the iron ore concentrate powder contains 50-67 wt% of total iron TFe.
6. The method for decarbonizing the blast furnace molten iron according to any one of claims 1 to 5, wherein the molten iron temperature is 1330 ℃ to 1500 ℃ when the molten iron from the blast furnace is subjected to mixed decarbonization by using the converter LT fly ash or the mixture of the converter LT fly ash and the iron concentrate powder.
7. The method for decarbonizing molten iron in a blast furnace according to claim 1, comprising:
s1, briquetting: fully mixing converter LT fly ash or a mixture of the converter LT fly ash and iron ore concentrate powder with a binder and water for pulping, pressing into blocks and drying to obtain a block decarbonizer;
mixing the converter LT fly ash and iron concentrate powder to prepare a powdery decarbonizer;
s2, filling the blocky decarbonizing agent to the bottom of the emptied torpedo ladle car, and preheating the decarbonizing agent by using the waste heat of the torpedo ladle car;
s3, before the molten iron from the blast furnace, paving a powdery decarbonizing agent into a molten iron ditch connecting a molten iron outlet of the blast furnace with a torpedo ladle car, so that the molten iron from the blast furnace reacts with the decarbonizing agent to realize decarbonization in the process of flowing through the molten iron ditch and entering the torpedo ladle car;
and after the molten iron is poured backwards to the torpedo ladle car, the molten iron is contacted with a blocky decarbonizer which is filled at the bottom of the torpedo ladle car in advance and reacts, so that decarbonization is further realized.
8. The method for decarbonizing the blast furnace molten iron according to claim 7, wherein the binder is an inorganic binder, and the amount of the binder added is 5 to 8 percent of the mass of the converter LT fly ash or the mixture of the converter LT fly ash and the iron ore concentrate powder in step S1.
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| CN102010933A (en) * | 2010-11-05 | 2011-04-13 | 钢铁研究总院 | Molten iron dephosphorization agent manufactured by using converter dry-method dust-removal ash as raw material |
| CN103320562A (en) * | 2013-06-21 | 2013-09-25 | 山西太钢不锈钢股份有限公司 | Method for smelting molten iron from dedusting ash |
| CN107012284A (en) * | 2017-03-02 | 2017-08-04 | 新兴铸管股份有限公司 | The Application way of converter dust-removing ash |
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| JP6036172B2 (en) * | 2012-03-29 | 2016-11-30 | Ｊｆｅスチール株式会社 | Method of refining hot metal in converter |
| CN105886953A (en) * | 2015-01-15 | 2016-08-24 | 马锐 | Smelting technology for magnesium type stainless steel |
| CN113293260A (en) * | 2021-04-27 | 2021-08-24 | 宁夏钢铁(集团)有限责任公司 | Efficient dephosphorization process method using fly ash as converter slagging agent |
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| CN102010933A (en) * | 2010-11-05 | 2011-04-13 | 钢铁研究总院 | Molten iron dephosphorization agent manufactured by using converter dry-method dust-removal ash as raw material |
| CN103320562A (en) * | 2013-06-21 | 2013-09-25 | 山西太钢不锈钢股份有限公司 | Method for smelting molten iron from dedusting ash |
| CN107012284A (en) * | 2017-03-02 | 2017-08-04 | 新兴铸管股份有限公司 | The Application way of converter dust-removing ash |
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