Application of coke scraps as carburant in converter steelmaking and use method

Abstract

The invention relates to the technical field of ferrous metallurgy, and discloses application of coke dust as a carburant in converter steelmaking and a use method, the coke dust is a byproduct of a coking plant, and the particle size of the coke dust is 0.1-5mm. According to the use method, after molten steel smelted through a converter is conveyed to an LF external refining procedure, an operator needs to sample and confirm arriving components of the molten steel, and when other components, except for the carbon content, of the molten steel all meet the requirements of finished products, the coke scrap carburant is added into the molten steel, so that the coke scrap carburant is added into the molten steel. According to the present invention, the new use of the coking by-product can be achieved, the coke scrap can be adopted as the recarburizing agent to perform molten steel recarburization in the external refining process, and the carbon yield of the coke scrap recarburizing agent is higher than 80% so as to replace the traditional recarburizing agent to complete molten steel recarburization and effectively reduce the smelting cost.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to an application and a use method of coke dust as a carburizer in converter steelmaking. Background Art

[0002] In the converter steelmaking process, oxygen is supplied by an oxygen lance to oxidize carbon, silicon and other elements in the molten iron to achieve the purpose of heating. At the same time, the carbon content in the molten steel after the converter smelting is completed will not be able to reach the finished carbon range required by the type of steel being made. Therefore, in order to ensure that the steelmaking composition meets the standards, the method of adding a recarburizer is usually used to increase the carbon content of the molten steel.

[0003] At present, most steel mills use graphite-based recarburizers to meet the composition requirements of steel grade design, because the fixed carbon content of this type of recarburizer is generally high. However, this type of recarburizer generally needs to be purchased from outside and is relatively expensive, which can easily lead to high steel melt recarburization costs and thus high smelting costs. Summary of the invention

[0004] The present invention provides an application and a method of using coke dust as a carburizer in converter steelmaking to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: Coke crumbs are used as a carburizer in converter steelmaking. Coke crumbs are used as a carburizer in converter steelmaking.

[0006] Preferably, the coke residue is a by-product of a coking plant.

[0007] Preferably, the particle size of the coke chips is 0.1-5 mm.

[0008] Preferably, the particle size of the coke chips is 0.1-1 mm.

[0009] Preferably, the fixed carbon content in the coke component is ≥83.3wt%, the ash content on a dry basis is ≤15wt%, the total moisture content is ≤0.5wt%, and the total sulfur content on a dry basis is ≤1.2wt%.

[0010] Preferably, the char component has a fixed carbon content of 94wt%, an ash content on a dry basis of 4.3wt%, a total moisture content of 0.5wt%, and a total sulfur content on a dry basis of 1.2wt%.

[0011] The technical solution of the present application also provides a method for using coke as a carburizer in converter steelmaking, and the method of use is as follows: Step S100: After the molten steel after converter smelting is transported to the LF refining process via a molten steel transfer vehicle, the operator takes samples to confirm the composition of the molten steel at the station; Step S200: After the sample components are detected, the elemental composition of the molten steel is adjusted by adding various alloys to make the various alloy element compositions meet the standards; Step S300, at this time, except for the carbon content, the other components of the molten steel have reached the finished product requirements, and then the weight of the coke recarburizer required to be added to the molten steel is calculated according to the carbon content in the sample; The weight calculation formula of the added coke recarburizer is: the amount of coke recarburizer added kg = (carbon content target component % - converter end point carbon content %) / (coke recarburizer carbon content % * coke recarburizer recovery rate %) * 1000; Step S400: After calculating the required amount of coke recarburizer, the operator opens the refining furnace cover and door, and adds the coke recarburizer into the molten steel in the ladle through the furnace door; Step S500: After the coke dust carburizer is added into the molten steel, the molten steel is stirred to obtain molten steel with a qualified carbon content.

[0012] Preferably, the specific steps for achieving the standard of various alloy element compositions in step S200 are: Step S201: After the sample composition is detected, it is compared with the target range of the finished steel composition; Step S202, adding ferromanganese alloy, ferrosilicon alloy, calcium wire alloy and aluminum wire alloy according to the comparison data; Step S203, stirring the molten steel after adding various alloy elements to make the composition of the molten steel uniform; Step S204: Confirm that the composition of various alloy elements meets the standards by sampling.

[0013] Preferably, the specific steps of obtaining molten steel with qualified carbon content in step S500 are: Step S501, after the coke recarburizer is added into the molten steel, it temporarily floats on the surface of the molten steel; Step S502, adjusting the argon blowing at the bottom of the ladle to the alloying model; Among them, the argon gas flow rate is 600L / min; Step S503, quickly stirring the molten steel to make the coke recarburizer melt and the molten steel composition uniform, so as to obtain molten steel with qualified carbon content.

[0014] Preferably, the carbon recovery rate of the coke crumb as a recarburizer in the converter steelmaking process is higher than 80%.

[0015] According to the above specific, after the molten steel completed by converter smelting is transported to the LF off-furnace refining process, the operator is required to take samples to confirm the composition of the molten steel at the station, and add various alloy elements accordingly to make the other components of the molten steel except the carbon content meet the requirements of the finished product, and then calculate the weight of the coke recarburizer required to be added to the molten steel according to the carbon content in the sample, and then add the coke recarburizer to the molten steel, and while the molten steel is rapidly stirred, argon is blown from the bottom of the ladle to adjust it to the alloying model, so that the coke recarburizer melts and the composition of the molten steel is uniform, so as to obtain molten steel with qualified carbon content.

[0016] By adopting the above technical solution, the beneficial effects achieved by the present invention are: In the present invention, through the method of adding coke crumb carburizer to molten steel, a new use of coking by-products can be achieved, so that the coke crumb can be used as a carburizer to carburize molten steel in the off-furnace refining process, and the carbon recovery rate of the coke crumb carburizer is increased to higher than 80%, so as to replace the traditional carburizer to complete the carburization of molten steel, and the cost is reduced by about 1.68 yuan / ton of steel, effectively reducing the smelting cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the method of use of the present invention. DETAILED DESCRIPTION

[0018] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0019] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure. Example

[0020] The invention provides the application of coke crumbs as a carburizer in converter steelmaking. The coke crumbs are applied as a carburizer in the converter steelmaking process.

[0021] As preferred in this embodiment, coke chips are a by-product of a coking plant.

[0022] As a preferred embodiment of this invention, the particle size of the coke chips is 0.1-5 mm.

[0023] As a preferred embodiment of this embodiment, the particle size of the coke chips is 0.1-1 mm.

[0024] As preferred in this embodiment, the fixed carbon content in the coke component is ≥83.3wt%, the ash content on a dry basis is ≤15wt%, the total moisture content is ≤0.5wt%, and the total sulfur content on a dry basis is ≤1.2wt%. The components of the coke recarburizer are shown in Table 1: Table 1

[0025] Furthermore, the screened material of the coking plant by-product is used as raw material, and the raw material is dried to a total moisture content of ≤0.5wt% by existing heating technology, and then the dried raw material is crushed into 1mm powder by a crusher, so that the coke can be used as a recarburizer to recarburize molten steel in the off-furnace refining process, wherein the fixed carbon content in the coke component is ≥83.3wt%. When it replaces the traditional recarburizer to complete the recarburization of molten steel, the overall carbon recovery rate is higher than 80%, and the cost is reduced by about 1.68 yuan / ton of steel, effectively reducing the production cost of steel.

[0026] Furthermore, when the moisture content of the coke recarburizer is too high, the fixing agent content in the coke recarburizer product will be significantly reduced and the ash content will be significantly increased. Therefore, this scheme limits the total moisture content requirement of the coke recarburizer to ≤0.5wt% to improve product quality.

[0027] As preferred in this embodiment, the fixed carbon content of the coke component is 94wt%, the ash content on a dry basis is 4.3wt%, the total moisture content is 0.5wt%, and the total sulfur content on a dry basis is 1.2wt%.

[0028] Furthermore, since the single particles of the coke recarburizer are loose, have low strength and density, in order to facilitate the storage and transportation of the coke recarburizer, and to facilitate the staff to add the coke recarburizer and control the cost, the packaging of the coke recarburizer is an external white woven bag of 30kg / bag, with a small transparent tape package of 6kg / bag inside, and the external white woven bag must be marked with specifications and names for easy use and transportation.

[0029] like Figure 1 As shown, the technical solution of the present application provides a method for using coke as a carburizer in converter steelmaking, and the method of use is as follows: Step S100: After the molten steel after converter smelting is transported to the LF refining process via a molten steel transfer vehicle, the operator takes samples to confirm the composition of the molten steel at the station; Step S200: After the sample components are detected, the elemental composition of the molten steel is adjusted by adding various alloys to make the various alloy element compositions meet the standards; Step S300, at this time, except for the carbon content, the other components of the molten steel have reached the finished product requirements, and then the weight of the coke recarburizer required to be added to the molten steel is calculated according to the carbon content in the sample; The weight calculation formula of the added coke recarburizer is: the amount of coke recarburizer added kg = (carbon content target component % - converter end point carbon content %) / (coke recarburizer carbon content % * coke recarburizer recovery rate %) * 1000; Step S400: After calculating the required amount of coke recarburizer, the operator opens the refining furnace cover and door, and adds the coke recarburizer into the molten steel in the ladle through the furnace door; Step S500: After the coke dust carburizer is added into the molten steel, the molten steel is stirred to obtain molten steel with a qualified carbon content.

[0030] As a preferred embodiment of the present invention, the specific steps for achieving the standard of various alloy element compositions in step S200 are: Step S201: After the sample composition is detected, it is compared with the target range of the finished steel composition; Step S202, adding ferromanganese alloy, ferrosilicon alloy, calcium wire alloy and aluminum wire alloy according to the comparison data; Step S203, stirring the molten steel after adding various alloy elements to make the composition of the molten steel uniform; Step S204: Confirm that the composition of various alloy elements meets the standards by sampling.

[0031] As preferred in this embodiment, the specific steps of obtaining molten steel with qualified carbon content in step S500 are: Step S501, after the coke recarburizer is added into the molten steel, it temporarily floats on the surface of the molten steel; Step S502, adjusting the argon blowing at the bottom of the ladle to the alloying model; Among them, the argon gas flow rate is 600L / min; Step S503, quickly stirring the molten steel to make the coke recarburizer melt and the molten steel composition uniform, so as to obtain molten steel with qualified carbon content.

[0032] As a preferred embodiment of the present invention, the carbon recovery rate of coke chips as a carburizer in the converter steelmaking process is higher than 80%.

[0033] In the above steps S300 and S400, the particle size of the coke recarburizer to be added is 0.1-5 mm. For example, the particle size of the coke recarburizer can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm or 4.5 mm.

[0034] According to the above method of use, in step S202, when ferromanganese alloy, ferrosilicon alloy, calcium wire alloy and aluminum wire alloy are added according to the comparison data, the order of adding the various alloys can be ferromanganese alloy, ferrosilicon alloy, aluminum wire alloy and calcium wire alloy.

[0035] According to the above method of use, in step S500, when adding the coke recarburizer, the flow rate of the argon gas blown from the bottom of the ladle needs to be adjusted to 600L / min, and then the molten steel is quickly stirred to make full contact with the coke recarburizer, thereby increasing the recarburization amount of the molten steel, enabling the coking by-products to realize new uses and ensuring the utilization rate of the coke.

[0036] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. Application of coke as a carburizer in converter steelmaking.

2. The use according to claim 1, characterized in that: The coke dust is a by-product of a coking plant.

3. The use according to claim 1, characterized in that: The particle size of the coke residue is 0.1-5 mm.

4. The use according to claim 3, characterized in that: The particle size of the coke chips is 0.1-1 mm.

5. The use according to claim 1, characterized in that: The coke residue component has a fixed carbon content of ≥83.3wt%, an ash content on a dry basis of ≤15wt%, a total moisture content of ≤0.5wt%, and a total sulfur content on a dry basis of ≤1.2wt%.

6. The use according to claim 5, characterized in that: The coke component has a fixed carbon content of 94 wt %, an ash content of 4.3 wt %, a total moisture content of 0.5 wt %, and a total sulfur content of 1.2 wt % on a dry basis.

7. The use according to any one of claims 1 to 6, characterized in that: The usage of coke recarburizer is as follows: Step S100: After the molten steel after converter smelting is transported to the LF refining process via a molten steel transfer vehicle, the operator takes samples to confirm the composition of the molten steel at the station; Step S200: After the sample components are detected, the elemental composition of the molten steel is adjusted by adding various alloys to make the various alloy element compositions meet the standards; Step S300, at this time, except for the carbon content, the other components of the molten steel have reached the finished product requirements, and then the weight of the coke recarburizer required to be added to the molten steel is calculated according to the carbon content in the sample; The weight calculation formula of the added coke recarburizer is: the amount of coke recarburizer added kg = (carbon content target component % - converter end point carbon content %) / (coke recarburizer carbon content % * coke recarburizer recovery rate %) * 1000; Step S400: After calculating the required amount of coke recarburizer, the operator opens the refining furnace cover and door, and adds the coke recarburizer into the molten steel in the ladle through the furnace door; Step S500: After the coke dust carburizer is added into the molten steel, the molten steel is stirred to obtain molten steel with a qualified carbon content.

8. The method for using the coke recarburizer according to claim 7, characterized in that: The specific steps for achieving the standard of various alloy element compositions in step S200 are: Step S201: After the sample composition is detected, it is compared with the target range of the finished steel composition; Step S202, adding ferromanganese alloy, ferrosilicon alloy, calcium wire alloy and aluminum wire alloy according to the comparison data; Step S203, stirring the molten steel after adding various alloy elements to make the composition of the molten steel uniform; Step S204: Confirm that the composition of various alloy elements meets the standards by sampling.

9. The method for using the coke recarburizer according to claim 7, characterized in that: The specific steps of obtaining molten steel with qualified carbon content in step S500 are: Step S501, after the coke recarburizer is added into the molten steel, it temporarily floats on the surface of the molten steel; Step S502, adjusting the argon blowing at the bottom of the ladle to the alloying model; Among them, the argon gas flow rate is 600L / min; Step S503, quickly stirring the molten steel to make the coke recarburizer melt and the molten steel composition uniform, so as to obtain molten steel with qualified carbon content.

10. The use according to claim 7, characterized in that: The carbon recovery rate of the coke dust as a carburizer in the converter steelmaking process is higher than 80%.

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