Process control method of molten steel online decoppering treatment system

Abstract

The invention provides a process control method of a molten steel online decoppering treatment system, and relates to the technical field of steelmaking residual element purification. The process control method comprises the following steps: adding an online decoppering treatment system in a refining link of a refining furnace behind a steel-making furnace for a steel-making flow of a large scrap ratio BF-BOF-LF long flow or an EAF-LF short flow, and determining the copper content of outbound molten steel of the steel-making furnace or the refining furnace through a copper content detection method; the method comprises the following steps: establishing a graded decoppering model, grading according to the copper content of outbound molten steel, selecting decoppering treatment equipment and a control method of the grade decoppering model corresponding to the copper content to carry out decoppering treatment to obtain molten steel with the copper content controlled to be 0.1% or below and tail gas containing CuCl, and finally, carrying out green recycling on the tail gas containing CuCl through a purification and recovery device. The method is simple and convenient in process, simple to operate, convenient in device structure improvement, low in cost, high in efficiency and beneficial to industrial large-scale production, application and popularization.

Description

Technical Field

[0001] This invention relates to the technical field of residual element purification in steelmaking, and in particular to a process control method for an online copper removal system for molten steel. Background Technology

[0002] Currently, using 1 ton of recycled steel raw materials (commonly known as scrap steel) can save approximately 1.5-1.7 tons of iron ore and reduce CO2 emissions by 1.2-1.4 tons. Increasing the proportion of scrap steel in steelmaking and low-carbon production meet the major needs of the national "dual-carbon" strategy and are of great strategic significance for vigorously promoting low-carbon steelmaking and green circular development.

[0003] In high-scrap steel smelting processes, when steel billets with high residual copper content are hot-rolled at high temperatures under oxidizing atmospheres, Cu enrichment occurs at the grain boundaries beneath the iron oxide scale, causing hot cracking of the steel, a phenomenon known as "copper embrittlement." Therefore, GB / T 4223-2017 specifies the residual copper content of recycled steel raw materials. As residual copper accumulates during steel production and scrap steel recycling, excessively high residual copper content at a certain stage can prevent scrap steel from meeting the standards for furnace feed, leading to resource idleness and waste. Therefore, it is urgent to establish copper removal refining stations to specifically remove residual copper from molten steel, reducing the copper content in steel products and creating a virtuous cycle of green scrap steel utilization.

[0004] Currently, methods for removing sulfides include sulfide removal, ammonium salt removal, Ag phase removal, metal bath removal, and external electric field removal. However, most of these methods have technical drawbacks such as incompatibility with existing processes, conflict with steelmaking objectives, complex equipment, high cost, and low efficiency.

[0005] Chinese patent CN107130082A discloses a method for separating copper from high-copper iron materials, but it involves repeated copper removal and slag removal operations, which are complicated and the direct addition of copper removal agents results in low utilization efficiency, making it unsuitable for industrial production.

[0006] Chinese patent CN115652024A discloses a method for efficient copper removal in electric arc furnace steelmaking. Essentially, it involves directly injecting a certain amount of CaCl2-O2 jet into the molten pool. Due to the principle of selective oxidation, the oxygen in the gas-powder jet preferentially reacts with the iron element in the molten metal pool. Therefore, this method increases the iron loss in the molten metal pool to a certain extent and has limited copper removal efficiency.

[0007] Chinese patent CN259907Y discloses a method for removing copper from molten steel by applying an external electric field to a ladle. CN2579907 provides a device for removing copper from molten steel under the action of an electric field. This device can provide a special electric field, but it is cumbersome and does not match the working conditions on the production site. The long enrichment time slows down the production pace, which is contrary to the principle of fast-paced and high-efficiency steelmaking production.

[0008] Lu Zhihao of Northeastern University published his research on copper removal from molten iron using FeS-based copper removers and its electrochemical enhancement, first published on Wanfang Data on June 12, 2024. His work, while exploring the occurrence forms of copper and sulfur in sulfide slag and molten iron during copper removal from sulfide slag, discovered that the Na2S-FeS-Cu2S system in the copper-removing slag, as well as the copper- and sulfur-containing high-temperature molten iron after copper removal, can all be used as electrolytes for electrolyzing dissolved sulfides. Based on this, he innovatively combined copper removal from sulfide slag with electrochemical refining methods, proposing a new electrochemical refining method for copper removal in iron-based melts, achieving significantly better copper removal results than existing methods; however, this method is highly complex and difficult to operate, resulting in a relatively low copper removal rate.

[0009] Therefore, in the face of the gradually increasing demand for copper removal in steelmaking with high scrap ratios, it is urgent to study and seek a simple, efficient refining method with online copper removal capabilities. Summary of the Invention

[0010] The main objective of this invention is to address the technical problems in existing steel copper removal technologies, such as the inability to integrate the copper removal process online, the lack of a graded control mechanism, low copper recovery rates, and difficulty in adapting to different steelmaking processes. Therefore, a process control method for an online steel copper removal system is proposed, which not only improves the device structure but also designs the structure, composition, performance of the copper removal agent cored wire, and the wire feeding device. This improves the steel copper removal efficiency, reduces preparation costs, and achieves green utilization of scrap steel.

[0011] A process control method for an online copper removal system for molten steel includes: adding an online copper removal system to the refining stage of the refining furnace after the steelmaking furnace in steelmaking processes with a large scrap ratio (BF-BOF-LF long process or EAF-LF short process); determining the copper content of the molten steel exiting the steelmaking furnace or refining furnace using a copper content detection method; establishing a graded copper removal model; selecting the appropriate copper removal equipment and control method based on the copper content of the exiting molten steel; obtaining molten steel with a copper content controlled below 0.1% and tail gas containing CuCl; and finally, recycling the tail gas containing CuCl through a purification and recovery device.

[0012] Optionally, the steelmaking process includes long process production via blast furnace-converter with a scrap ratio of more than 50%, short process production via electric arc furnace with a scrap ratio of more than 70%, or other steelmaking furnace production with copper removal requirements.

[0013] Optionally, the steelmaking furnace is a converter, an electric arc furnace, or other steelmaking furnace that requires copper content indicators, and the refining furnace is an LF or other refining furnace; the copper content detection method is direct reading spectroscopy, inductively coupled plasma atomic emission spectrometry (ICP), chemical titration, or other copper content testing methods.

[0014] Optionally, the online copper removal system is set in the LF refining stage after BOF or EAF with a high scrap ratio, and the structure of VD, RH or other vacuum refining furnaces is modified; including designing and installing a ladle top cover adapted to the ladle for copper removal, and a refining station adapted to vacuum function; a copper removal agent cored wire feeding device is set on it, and a negative pressure exhaust device for the ladle is set on one side of it, and the purification and recovery device includes a tail gas buffer tank and a two-stage purification treatment device.

[0015] Optionally, vacuum refining furnaces such as VD or RH furnaces can be modified to enhance their copper removal capacity while maintaining their metallurgical functions such as degassing and inclusion removal. In actual production, copper removal treatment can be carried out according to the steel composition and smelting requirements. A cored wire composed of silicon oxide, iron oxide, and calcium chloride is arranged in a ring structure within the sheet metal and inserted downwards into the molten steel through the feeding hole in the top cover. This increases the contact area, achieving a highly efficient chlorination copper removal reaction. Through copper removal treatment of the molten steel, the green recycling of low-quality recycled steel raw materials can be realized.

[0016] Optionally, copper removal treatment can be incorporated into the high scrap ratio steelmaking process. This can be implemented by modifying the VD / RH ratio of a specific steel plant. In actual smelting, the decision to perform copper removal treatment can be made based on the target steel composition requirements, production needs, and smelting pace. Taking VD modification as an example, the existing square pit capable of holding a ladle can be used as a copper removal refining station. A ladle filled with molten steel is moved into the copper removal station, and the ladle cover, equipped with a portable wire feeding device and a negative pressure extraction device, is lowered from above.

[0017] Optionally, the established hierarchical copper removal model includes the following three intervals:

[0018] First-level processing: When the detected copper content is Cu≤0.1%, the system determines that the molten steel in this batch meets the composition requirements for high-quality steel, and no copper removal process is initiated. The molten steel is directly used for subsequent casting processes. This avoids unnecessary processes and energy consumption, and significantly reduces production costs.

[0019] Second range: When the detected copper content is between 0.1% and Cu, the system determines that physical copper removal is required. The specific steps of physical copper removal are as follows: the ladle containing molten steel is hoisted to a dedicated copper removal station, and the vacuum copper removal system is started directly without adding any chlorination copper removal agent. During this process, the pressure of the vacuum system is not a fixed value, but is dynamically calculated and set according to the initial copper content through a preset first function relationship, so as to achieve the optimal balance between copper removal efficiency and energy consumption.

[0020] The third interval: When the detected copper content is between 0.2% and Cu, ≤ 0.5%, the system determines that enhanced chemical copper removal is required. The specific steps for enhanced chemical copper removal are as follows: After the ladle is hoisted to the copper removal station, the appropriate mass of chlorinated copper removal agent is first added based on the initial copper content using a preset second function relationship. Subsequently, vacuum copper removal is performed simultaneously with the addition of the copper removal agent. The vacuum system pressure here is also optimized and set based on the initial copper content using an independent third function relationship to ensure that deep copper removal is achieved under the combined action of chemical reaction and physical vacuum, ultimately reducing the copper content below the target value.

[0021] Optionally, the vacuum pressure in the second interval is determined based on the initial copper content using a first functional relationship, the equation of which is:

[0022]

[0023] Where P is the vacuum pressure and x is the initial copper content;

[0024] The amount of copper-removing chloride added in the third zone is determined based on the initial copper content using the second functional relationship, and the vacuum pressure is determined based on the initial copper content using the third functional relationship.

[0025] The equation for the second functional relationship is:

[0026]

[0027] Where M is the amount of copper removal agent added, and x is the initial copper content;

[0028] The equation for the third functional relationship is:

[0029] .

[0030] Optionally, the copper-removing agent-coated wire used in the copper-removing agent cored wire feeding device has an outer iron sheet wrapping the copper-removing agent. This outer iron sheet effectively prevents the copper-removing agent from absorbing moisture and ensures that the copper-removing agent continuously reacts inside the molten steel. The cross-sectional structure is circular or elliptical with an inner and outer double-layer reaction interface. The main components of the copper-removing agent are copper trapping agent, oxidant, and ion donor. The copper trapping agent is silicon dioxide, accounting for 10-20% of the mass of the copper-removing agent, and is mainly distributed in the inner layer to trap residual copper elements in the molten steel. The oxidant is iron oxide, accounting for 30-40% of the mass of the copper-removing agent, and is mainly distributed in the inner layer. At the trapping and oxidation interface, the oxidant oxidizes the residual copper elements trapped by the copper trapping agent, forming Cu. + Ions continue to be transported outward through the ion exchange region; the ion donor is calcium chloride, which accounts for approximately 50-60% of the removal agent by mass, mainly distributed in the outer layer, providing Cl in the ion exchange region. - Negative ions maintain a chlorination environment in the ion exchange region, reacting with Cu at the vaporization interface. + Positive ions combine to generate (CuCl)3 gas molecules, maintaining the "electric neutrality" of the copper stripping agent-coated wire. This copper stripping agent-coated wire extends downward into the molten steel through the feeding hole of the top cover. With the addition of a tail gas purification device and the corresponding vacuum level, copper can be removed from the molten steel, while removing gases such as H2, N2, and Cl2, without increasing hydrogen, nitrogen, or chlorine in the molten steel.

[0031] Optionally, the internal structure of the copper-removing agent-coated wire is such that the copper trapping agent and oxidant are mainly distributed in the inner layer, while the ion donor is mainly distributed in the outer layer; the outer diameter of the cored wire is 15-25 mm, the thickness of the outer iron sheet is 1-2 mm, and the density of the removing agent is approximately 3000-4000 kg / m³. 3 .

[0032] Optionally, the copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire used extends downward into the molten steel through the feeding hole set in the top cover of the ladle, increasing the contact area between the copper stripping agent and the molten steel. The feeding speed of the copper stripping agent cored wire feeding device is 1-3m / s, and the feeding amount of cored wire is 5-10kg / t steel. The suction flow rate of the negative pressure suction device is 72-240Nm. 3 / h, typically around 80Nm 3 / h, under negative pressure evacuation conditions, low pressure or pseudo-vacuum conditions can be achieved in the enclosed area above the ladle at the copper removal station to reduce the partial pressure of gaseous products. While the pressure inside the ladle decreases, the copper removal reaction is continuously promoted. Furthermore, after the iron sheet of the cored wire melts, the copper scavenger in the removal agent efficiently captures residual copper elements in the molten steel, causing these residual copper elements to pass through the ion exchange zone to reach the capture interface, where they are oxidized to Cu by the oxidant. + Cu +It is enriched in the ion exchange region and transported outward. At the gasification interface, it combines with Cl- to generate (CuCl)3 gas molecules, and finally escapes from the gasification reaction interface into the gas phase, reducing the residual copper content in the molten steel.

[0033] Optionally, since the copper removal process is discontinuous, this technology allows all the exhaust gas from a single copper removal process to enter an exhaust gas buffer tank for two-stage purification. First, a primary purification stage is performed, followed by a secondary purification stage. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the exhaust gas meets harmless emission standards. This method does not generate additional waste gas, achieving pollution-free and waste-free green circular production. Specifically, the purification steps involve first extracting the exhaust gas containing CuCl gas for cooling, followed by condensation, precipitation, adsorption, and recovery in the recovery area.

[0034] Optionally, this technology can make the exhaust gas containing CuCl meet emission standards, while opening up a new route for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0035] Optionally, taking the modified VD copper removal process as an example, when the vacuum degree is controlled at 700-1000Pa, the copper removal rate ranges from 28-33%, the hydrogen content in the molten steel is 1-2ppm, the nitrogen content in the molten steel is 25-40ppm, and the chlorine content in the molten steel is less than 1ppm; when the vacuum degree is controlled at 70-100Pa, the copper removal rate ranges from 68-75%, the hydrogen content in the molten steel is 1-2ppm, the nitrogen content in the molten steel is 25-40ppm, and the chlorine content in the molten steel is less than 1ppm; when the vacuum degree is controlled at 30-50Pa, the copper removal rate ranges from 80-88%, the hydrogen content in the molten steel is 1-2ppm, the nitrogen content in the molten steel is 25-40ppm, and the chlorine content in the molten steel is less than 1ppm.

[0036] Optionally, the process control method of the online copper removal system for molten steel reduces the copper content of the molten steel by 50% when the vacuum degree reaches 100Pa, and reduces it by more than 70% when the vacuum degree reaches 30Pa; the online copper removal treatment time is 10-30min, and the copper removal efficiency reaches 50-80%; it is applicable to existing high scrap ratio steelmaking processes of 70-250t "EAF+LF+VD / VOD / RH", 70-250t "EAF+VD / VOD / RH", 70-250t "BOF+LF+VD / VOD / RH", and 70-250t "BOF+VD / VOD / RH".

[0037] Technical principle of the invention:

[0038] This invention uses a thermodynamically feasible vacuum chlorination reaction as its scientific basis, a hierarchical intelligent control model as its "brain" for precise and economical copper removal, and an integrated and modular online system engineering design and cored wire deep reaction technology as its efficient "body." Finally, a closed loop is completed through a tail gas resource recovery system, forming a complete, efficient, green, and industrially applicable online copper removal process control method for molten steel.

[0039] The above technical solution has at least the following advantages compared with the existing technology:

[0040] The above-mentioned solution proposes a process control method for an online copper removal system for molten steel, which can solve the technical problems in the existing technology of copper removal of molten steel, such as the inability to integrate the copper removal process online, the lack of a graded control mechanism, low copper recovery rate, and difficulty in adapting to different steelmaking processes.

[0041] This invention adds an online copper removal system to the refining stage of the refining furnace after the steelmaking furnace in steelmaking processes with large scrap ratios, such as the BF-BOF-LF long process or the EAF-LF short process. This allows the copper removal process to be seamlessly integrated with the existing steelmaking process, enabling precise online control of the copper content in molten steel.

[0042] This invention enables precise and differentiated control of the copper removal process by determining the copper content of molten steel exiting the steelmaking or refining furnace and establishing a graded copper removal model, effectively ensuring the stability and reliability of the copper removal effect.

[0043] This invention classifies molten steel by copper content and selects copper removal equipment and control methods that correspond to the copper content of each grade. This enables the copper removal process to be controlled on demand, achieving both efficiency and cost control.

[0044] This invention, through the selection of the composition and structure of the copper stripping agent cored wire and the structural design of the wire feeding device, enables the copper stripping agent to act precisely and efficiently on the reaction zone of molten steel, significantly improving the kinetic conditions and reaction efficiency of the copper stripping reaction.

[0045] This invention, through the two-stage purification device of the purification and recycling unit, enables the efficient separation, purification, and green recycling of CuCl-containing exhaust gas, achieving the dual goals of resource recovery and environmental compliance.

[0046] In summary, compared with traditional steel copper removal, the method of this invention improves the copper removal rate of molten steel in the steelmaking process by setting up an online copper removal treatment system, establishing a graded copper removal model, selecting the copper removal treatment equipment and control methods for the corresponding graded copper removal model, selecting the composition and structure of the copper removal agent cored wire and setting up the structure of the wire feeding device, and setting up a two-stage purification device. This method is simple in process, easy to operate, convenient to improve the device structure, low in cost, and high in efficiency, which is conducive to large-scale industrial production and application. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of a graded copper removal model of molten steel in the process control method of an online copper removal system for molten steel according to the present invention;

[0049] Figure 2 This is a schematic diagram of the apparatus for controlling the process of an online copper removal system for molten steel according to Embodiment 1 of the present invention;

[0050] Figure 3 This is a schematic diagram of the apparatus for controlling the process of an online copper removal system for molten steel according to Embodiment 2 of the present invention;

[0051] Figure 4 This is a schematic diagram of the internal structure of the cored wire containing the copper removal agent in the process control method of the online copper removal treatment system for molten steel according to the present invention, wherein: mark 1 is the gasification interface, mark 2 is the ion exchange zone, mark 3 is the trapping and oxidation interface, mark 4 is the copper trapping and oxidation zone, and mark 5 is the outer iron sheet.

[0052] Figure 5 This is a schematic diagram of the tail gas purification technology of the process control method of the online copper removal treatment system for molten steel according to the present invention;

[0053] The annotations in the attached figures are explained as follows:

[0054] 1. Copper stripping station; 2. Steel ladle; 3. Molten steel to be treated; 4. Steel ladle top cover; 5. Copper stripping agent cored wire feeding device; 6. Cored wire wrapped with copper stripping agent; 7. Negative pressure exhaust device; 8. Tail gas buffer tank; 9. Connecting valve; 10. Primary purification device; 11. Secondary purification transfer device; 12. Ascending pipe; 13. Lifting air jet pipe; 14. Vacuum chamber; 15. Vacuum chamber outer wall; 16. Downcomer pipe. Detailed Implementation

[0055] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0056] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0057] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0058] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0059] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0060] A process control method for an online copper removal system for molten steel includes: adding an online copper removal system to the refining stage of the refining furnace after the steelmaking furnace in steelmaking processes with a large scrap ratio (BF-BOF-LF long process or EAF-LF short process); determining the copper content of the molten steel exiting the steelmaking furnace or refining furnace using a copper content detection method; establishing a graded copper removal model; selecting the appropriate copper removal equipment and control method based on the copper content of the exiting molten steel; obtaining molten steel with a copper content controlled below 0.1% and tail gas containing CuCl; and finally, recycling the tail gas containing CuCl through a purification and recovery device.

[0061] Specifically, the steelmaking process includes long-process production using blast furnaces and converters with a scrap ratio of over 50%, short-process production using electric arc furnaces with a scrap ratio of over 70%, or other steelmaking furnaces that require copper removal.

[0062] Specifically, the steelmaking furnace is a converter, an electric arc furnace, or other steelmaking furnace that requires copper content indicators, and the refining furnace is an LF or other refining furnace; the copper content detection method is direct reading spectroscopy, inductively coupled plasma atomic emission spectrometry (ICP), chemical titration, or other copper content testing methods.

[0063] Specifically, the online copper removal system is installed in the LF refining stage after BOF or EAF with a high scrap ratio, and the structure of VD, RH or other vacuum refining furnaces is modified; including the design and installation of a ladle top cover adapted to the ladle for copper removal, and a refining station adapted to vacuum function; a copper removal agent cored wire feeding device is installed on it, and a negative pressure exhaust device for the ladle is installed on one side of it; the purification and recovery device includes a tail gas buffer tank and a two-stage purification treatment device.

[0064] Specifically, vacuum refining furnaces such as VD or RH furnaces are modified to enhance their copper removal capabilities while maintaining their metallurgical functions such as degassing and inclusion removal. In actual production, copper removal can be performed based on the steel composition and smelting requirements. A cored wire, composed of silicon oxide, iron oxide, and calcium chloride, is arranged in a ring structure within the sheet metal and inserted into the molten steel through the feeding hole in the top cover. This increases the contact area, achieving a highly efficient chlorination-based copper removal reaction. Through copper removal from the molten steel, the green recycling of low-quality recycled steel raw materials is realized.

[0065] Specifically, copper removal treatment is incorporated into the high scrap ratio steelmaking process. For a particular steel plant's VD / RH conversion, the decision to perform copper removal can be made based on the target steel composition requirements, production needs, and smelting pace. Taking VD conversion as an example, the existing square pit capable of holding a ladle is used as a copper removal refining station. A ladle filled with molten steel is moved into the copper removal station, and the ladle cover, equipped with a portable wire feeding device and a negative pressure extraction device, is lowered from above.

[0066] Specifically, the established graded copper removal model includes the following three intervals:

[0067] First interval: When the detected copper content is Cu≤0.1%, the system determines that the molten steel in this batch has met the composition requirements of high-quality steel, and no copper removal process is initiated. The molten steel is directly used for subsequent casting processes. This avoids unnecessary processes and energy consumption, and significantly reduces production costs.

[0068] Second range: When the detected copper content is between 0.1% and Cu, the system determines that physical copper removal is required. The specific steps of physical copper removal are as follows: the ladle containing molten steel is hoisted to a dedicated copper removal station, and the vacuum copper removal system is started directly without adding any chlorination copper removal agent. During this process, the pressure of the vacuum system is not a fixed value, but is dynamically calculated and set according to the initial copper content through a preset first function relationship, so as to achieve the optimal balance between copper removal efficiency and energy consumption.

[0069] The third interval: When the detected copper content is between 0.2% and Cu, ≤ 0.5%, the system determines that enhanced chemical copper removal is required. The specific steps for enhanced chemical copper removal are as follows: After the ladle is hoisted to the copper removal station, the appropriate mass of chlorinated copper removal agent is first added based on the initial copper content using a preset second function relationship. Subsequently, vacuum copper removal is performed simultaneously with the addition of the copper removal agent. The vacuum system pressure here is also optimized and set based on the initial copper content using an independent third function relationship to ensure that deep copper removal is achieved under the combined action of chemical reaction and physical vacuum, ultimately reducing the copper content below the target value.

[0070] Optionally, the vacuum pressure in the second interval is determined based on the initial copper content using a first functional relationship, the equation of which is:

[0071]

[0072] Where P is the vacuum pressure and x is the initial copper content;

[0073] The amount of copper-removing chloride added in the third zone is determined based on the initial copper content using the second functional relationship, and the vacuum pressure is determined based on the initial copper content using the third functional relationship.

[0074] The equation for the second functional relationship is:

[0075]

[0076] Where M is the amount of copper removal agent added, and x is the initial copper content;

[0077] The equation for the third functional relationship is:

[0078] .

[0079] In particular, such as Figure 4 As shown, the copper-removing agent cored wire used in the copper-removing agent cored wire feeding device consists of an outer iron sheet 5 wrapping the copper-removing agent. This outer iron sheet 5 effectively prevents the copper-removing agent from absorbing moisture and ensures that the copper-removing agent can continuously react inside the molten steel. The cross-sectional structure is a circular or elliptical shape with an inner and outer double-layer reaction interface. The main components of the copper-removing agent are copper trapping agent, oxidant, and ion donor. The copper trapping agent is silicon dioxide, accounting for 10-20% of the mass of the copper-removing agent, and is mainly distributed in the inner layer to trap residual copper elements in the molten steel. The oxidant is iron oxide, accounting for 30-40% of the mass of the copper-removing agent, and is mainly distributed in the inner layer. At the trapping and oxidation interface 3, it oxidizes the residual copper elements trapped by the copper trapping agent, forming Cu. +Ions continue to be transported outward through ion exchange zone 2; the ion donor is calcium chloride, which accounts for approximately 50-60% of the removal agent by mass, mainly distributed in the outer layer, and provides Cl in ion exchange zone 2. - Negative ions maintain a chlorination environment in ion exchange zone 2, allowing Cu to react with ions at the vaporization interface 1. + Positive ions combine to generate (CuCl)3 gas molecules, maintaining the "electric neutrality" of the copper stripping agent-coated wire. This copper stripping agent-coated wire extends downward into the molten steel through the feeding hole of the top cover. With the addition of a tail gas purification device and the corresponding vacuum level, copper can be removed from the molten steel, while removing gases such as H2, N2, and Cl2, without increasing hydrogen, nitrogen, or chlorine in the molten steel.

[0080] Specifically, the internal structure of the copper-removing agent-coated wire is such that the copper trapping agent and oxidant are mainly distributed in the inner layer, while the ion donor is mainly distributed in the outer layer; the outer diameter of the cored wire is 15-25 mm, the thickness of the outer iron sheet is 1-2 mm, and the density of the removing agent is approximately 3000-4000 kg / m³. 3 .

[0081] In particular, such as Figure 4 As shown, the copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire used extends downward into the molten steel through the feeding hole set in the top cover of the ladle, increasing the contact area between the copper stripping agent and the molten steel. The feeding speed of the copper stripping agent cored wire feeding device is 1-3m / s, and the feeding amount of cored wire is 5-10kg / t steel. The suction flow rate of the negative pressure suction device is 72-240Nm. 3 / h, typically around 80Nm 3 / h, under negative pressure pumping conditions, low pressure or pseudo-vacuum conditions can be achieved in the enclosed area above the ladle at the copper removal station to reduce the partial pressure of gaseous products. While the pressure inside the ladle decreases, the copper removal reaction continues to proceed. Furthermore, after the iron sheet of the cored wire melts, the copper catching agent in the removal agent is located in the copper catching and oxidation zone 4, efficiently capturing residual copper elements in the molten steel. This causes the residual copper elements to pass through the ion exchange zone 2 to reach the catching interface, where they are oxidized to Cu by the oxidant. + Cu + It is enriched in ion exchange zone 2 and transported outward. It combines with Cl- at the gasification interface to generate (CuCl)3 gas molecules, and finally escapes from the gasification reaction interface into the gas phase, reducing the residual copper content in the molten steel.

[0082] In particular, such as Figure 5As shown, since the copper removal process is discontinuous, this technology allows all the tail gas from a single copper removal process in the ladle to enter a tail gas buffer tank for two-stage purification. First, a primary purification stage is performed, followed by a secondary purification stage. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the tail gas meets harmless emission standards. This method does not emit additional waste gas, achieving pollution-free and waste-free green circular production. Specifically, the purification steps involve first extracting the tail gas containing CuCl gas for cooling, followed by condensation, precipitation, adsorption, and recovery in the recovery area.

[0083] In particular, this technology enables tail gas containing CuCl to meet emission standards, while also opening up a new route for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0084] Specifically, taking the modified VD copper removal process as an example, when the vacuum degree is controlled at 700-1000Pa, the copper removal rate ranges from 28-33%, the hydrogen content in the molten steel is 1-2ppm, the nitrogen content in the molten steel is 25-40ppm, and the chlorine content in the molten steel is less than 1ppm; when the vacuum degree is controlled at 70-100Pa, the copper removal rate ranges from 68-75%, the hydrogen content in the molten steel is 1-2ppm, the nitrogen content in the molten steel is 25-40ppm, and the chlorine content in the molten steel is less than 1ppm; when the vacuum degree is controlled at 30-50Pa, the copper removal rate ranges from 80-88%, the hydrogen content in the molten steel is 1-2ppm, the nitrogen content in the molten steel is 25-40ppm, and the chlorine content in the molten steel is less than 1ppm.

[0085] Specifically, the process control method of the online copper removal system for molten steel reduces the copper content of the molten steel by 50% when the vacuum degree reaches 100Pa, and reduces it by more than 70% when the vacuum degree reaches 30Pa; the online copper removal time is 10-30 minutes, and the copper removal efficiency reaches 50-80%; it is applicable to existing high scrap ratio steelmaking processes of 70-250t "EAF+LF+VD / VOD / RH", 70-250t "EAF+VD / VOD / RH", 70-250t "BOF+LF+VD / VOD / RH", and 70-250t "BOF+VD / VOD / RH".

[0086] In the following embodiments, such as Figure 1 As shown, the established hierarchical copper removal model includes the following three intervals:

[0087] First interval: When the detected copper content is Cu≤0.1%, the system determines that the molten steel in this batch has met the composition requirements of high-quality steel, and no copper removal process is initiated. The molten steel is directly used for subsequent casting processes. This avoids unnecessary processes and energy consumption, and significantly reduces production costs.

[0088] Second range: When the detected copper content is between 0.1% and Cu, the system determines that physical copper removal is required. The specific steps of physical copper removal are as follows: the ladle containing molten steel is hoisted to a dedicated copper removal station, and the vacuum copper removal system is started directly without adding any chlorination copper removal agent. During this process, the pressure of the vacuum system is not a fixed value, but is dynamically calculated and set according to the initial copper content through a preset first function relationship (F1), thereby achieving the optimal balance between copper removal efficiency and energy consumption.

[0089] The third interval: When the detected copper content is between 0.2% and Cu ≤ 0.5%, the system determines that enhanced chemical copper removal is required. The specific steps of enhanced chemical copper removal are as follows: After the ladle is hoisted to the copper removal station, the appropriate mass of chlorinated copper removal agent is first added based on the initial copper content using a preset second function relationship (F2); subsequently, vacuum copper removal is performed simultaneously with the addition of the copper removal agent. The vacuum system pressure here is also optimized and set based on the initial copper content using an independent third function relationship (F3) to ensure that deep copper removal is achieved under the combined action of chemical reaction and physical vacuum, ultimately reducing the copper content below the target value.

[0090] The vacuum pressure in the second zone is determined based on the initial copper content using the first functional relationship, which is:

[0091]

[0092] Where P is the vacuum pressure and x is the initial copper content;

[0093] The amount of copper-removing chloride added in the third zone is determined based on the initial copper content using the second functional relationship, and the vacuum pressure is determined based on the initial copper content using the third functional relationship.

[0094] The equation for the second functional relationship is:

[0095]

[0096] Where M is the amount of copper removal agent added, and x is the initial copper content;

[0097] The equation for the third functional relationship is:

[0098] .

[0099] Example 1

[0100] A process control method for an online copper removal system for 90t molten steel, the process control method for the online copper removal system for molten steel includes:

[0101] S1. For the long-process steelmaking process of BF-BOF-LF with a high scrap ratio, an online copper removal system is added to the refining stage of the refining furnace after the steelmaking furnace. This online copper removal system is installed in the LF refining stage after the high scrap ratio BOF, and the VD vacuum refining furnace undergoes structural modifications. Figure 2 As shown, the system includes a copper stripping station 1, a ladle cover 4 adapted to the ladle 2 for copper stripping, a refining station 3 with vacuum capability, a ladle cover 4 for copper stripping, a refining station 3 containing molten steel to be processed, a copper stripping agent cored wire feeding device 5 for feeding copper stripping agent cored wire 6, a negative pressure exhaust device 7 for the ladle, and a purification and recovery device including a tail gas buffer tank 8, a connecting valve 9, and a two-stage purification treatment device. The two-stage purification treatment device includes a primary purification device 10 and a secondary purification device 11.

[0102] The copper content of molten steel exiting the steelmaking furnace or refining furnace is determined by inductively coupled plasma atomic emission spectrometry (ICP). The steelmaking process is a 50% blast furnace-converter long process.

[0103] S2. Establish a graded copper removal model. Based on the copper content of the molten steel leaving the station, select the copper removal equipment and control method corresponding to the copper content of the graded copper removal model to carry out copper removal treatment to obtain molten steel with copper content controlled below 0.1% and tail gas containing CuCl.

[0104] In this embodiment, the copper content of the BOF molten steel is 0.08%; therefore, the first interval is selected, wherein: the copper-removing agent cored wire used in the copper-removing agent cored wire feeding device is a copper-removing agent wrapped in an outer iron sheet, and the cross-sectional structure is an elliptical shape with an inner and outer double-layer reaction interface; the main components of the copper-removing agent are copper catching agent, oxidant, and ion donor; the copper catching agent is silicon dioxide, accounting for 10% of the mass of the removal agent, mainly distributed in the inner layer; the oxidant is iron oxide, accounting for 50% of the mass of the removal agent, mainly distributed in the inner layer; the ion donor is calcium chloride, accounting for 40% of the mass of the removal agent, mainly distributed in the outer layer; the outer diameter of the copper-removing agent cored wire is 15mm, the thickness of the outer iron sheet is 1mm, and the density of the removal agent is approximately 4000kg / m³. 3 ;

[0105] The copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire is inserted into the molten steel through the feeding hole in the top cover. The feeding speed of the copper stripping agent cored wire feeding device is 2m / s, and the feeding amount of cored wire is 5kg / t of steel. The vacuum pump has a flow rate of 150Nm. 3 / h;

[0106] S3. Finally, the tail gas containing CuCl is recycled in a green manner through a purification and recovery device. Specifically, all the tail gas containing CuCl is put into the tail gas buffer tank and a two-stage purification process is set up. First, a primary purification is carried out, followed by a secondary purification. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the tail gas meets the standards for being harmless and can be discharged. This method does not emit additional waste gas and achieves green circular production with no pollution and no waste discharge.

[0107] The technology in this embodiment enables the exhaust gas containing CuCl to meet emission standards, while also opening up a new path for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0108] In this embodiment, when the vacuum degree is controlled at 700Pa, the copper removal rate is 28%, the hydrogen content in the molten steel is less than 1ppm, the nitrogen content in the molten steel is 40ppm, and the chlorine content in the molten steel is less than 1ppm.

[0109] In this embodiment, the copper content in the molten steel can be reduced by up to 33%.

[0110] Example 2

[0111] A process control method for an online copper removal system for 120t molten steel, the process control method for the online copper removal system for molten steel includes:

[0112] S1. For the long-process steelmaking process of BF-BOF-LF with a high scrap ratio, an online copper removal system is added to the refining stage of the refining furnace after the steelmaking furnace. The online copper removal system is set in the LF refining stage after the BOF with a high scrap ratio. The VD vacuum refining furnace is modified in terms of its structure. This includes designing and installing a ladle top cover that is compatible with the ladle for copper removal, and a refining station that is compatible with vacuum function. A copper removal agent cored wire feeding device is installed on it, and a negative pressure exhaust device for the ladle is installed on one side of it. The purification and recovery device includes a tail gas buffer tank and a two-stage purification treatment device.

[0113] The copper content of molten steel exiting the steelmaking furnace or refining furnace is determined by inductively coupled plasma atomic emission spectrometry (ICP). The steelmaking process is a 50% blast furnace-converter long process.

[0114] S2. Establish a graded copper removal model. Based on the copper content of the molten steel leaving the station, select the copper removal equipment and control method corresponding to the copper content of the graded copper removal model to carry out copper removal treatment to obtain molten steel with copper content controlled below 0.1% and tail gas containing CuCl.

[0115] In this embodiment, the copper content of the molten steel in the BOF is 0.15%; therefore, the second interval is selected, wherein: the copper-coated wire used in the copper-coated wire feeding device is a copper-coated wire with an outer iron sheet wrapping the copper-coated agent, and the cross-sectional structure is a circle with an inner and outer double-layer reaction interface; the main components of the copper-coated agent are copper catching agent, oxidant, and ion donor; the copper catching agent is silicon dioxide, which accounts for 10% of the mass of the copper-coated agent and is mainly distributed in the inner layer; the oxidant is iron oxide, which accounts for 35% of the mass of the copper-coated agent and is mainly distributed in the inner layer; the ion donor is calcium chloride, which accounts for 55% of the mass of the copper-coated agent and is mainly distributed in the outer layer;

[0116] The copper stripping agent has an outer diameter of 15mm for the cored wire, an outer iron sheet thickness of 1mm, and a stripping agent density of approximately 3500kg / m³. 3 ;

[0117] The copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire is inserted into the molten steel through the feeding hole in the top cover. The feeding speed of the copper stripping agent cored wire feeding device is 1.00m / s, and the feeding amount of cored wire is 7.5kg / t of steel. The vacuum pump has a flow rate of 170Nm. 3 / h;

[0118] S3. Finally, the tail gas containing CuCl is recycled in a green manner through a purification and recovery device. Specifically, all the tail gas containing CuCl is put into the tail gas buffer tank and a two-stage purification process is set up. First, a primary purification is carried out, followed by a secondary purification. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the tail gas meets the standards for being harmless and can be discharged. This method does not emit additional waste gas and achieves green circular production with no pollution and no waste discharge.

[0119] The technology in this embodiment enables the exhaust gas containing CuCl to meet emission standards, while also opening up a new path for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0120] In this embodiment, the vacuum level is controlled at 70 Pa, the copper removal rate is 68%, the hydrogen content in the molten steel is less than 1 ppm, the nitrogen content in the molten steel is 35 ppm, and the chlorine content in the molten steel is less than 1 ppm.

[0121] In this embodiment, the copper content in the molten steel can be reduced by up to 75%.

[0122] Example 3

[0123] A process control method for an online copper removal system for 150t molten steel, the process control method for the online copper removal system for molten steel includes:

[0124] S1. For the long-process steelmaking process of BF-BOF-LF with a high scrap ratio, an online copper removal system is added to the refining stage of the refining furnace after the steelmaking furnace. The online copper removal system is set in the LF refining stage after the BOF with a high scrap ratio. The VD vacuum refining furnace is modified in terms of its structure. This includes designing and installing a ladle top cover that is compatible with the ladle for copper removal, and a refining station that is compatible with vacuum function. A copper removal agent cored wire feeding device is installed on it, and a negative pressure exhaust device for the ladle is installed on one side of it. The purification and recovery device includes a tail gas buffer tank and a two-stage purification treatment device.

[0125] The copper content of molten steel exiting the steelmaking furnace or refining furnace is determined by inductively coupled plasma atomic emission spectrometry (ICP). The steelmaking process is a 50% blast furnace-converter long process.

[0126] S2. Establish a graded copper removal model. Based on the copper content of the molten steel leaving the station, select the copper removal equipment and control method corresponding to the copper content of the graded copper removal model to carry out copper removal treatment to obtain molten steel with copper content controlled below 0.1% and tail gas containing CuCl.

[0127] In this embodiment, the copper content of the BOF molten steel is 0.3%; therefore, the third interval is selected, wherein: the copper-coated wire used in the copper-coated wire feeding device is a copper-coated wire with an outer iron sheet wrapping the copper-coated agent, and the cross-sectional structure is a circle with an inner and outer double-layer reaction interface; the main components of the copper-coated agent are copper catching agent, oxidant, and ion donor; the copper catching agent is silicon dioxide, accounting for 10% of the mass of the copper-coated agent, mainly distributed in the inner layer; the oxidant is iron oxide, accounting for 30% of the mass of the copper-coated agent, mainly distributed in the inner layer; the ion donor is calcium chloride, accounting for 60% of the mass of the copper-coated agent, mainly distributed in the outer layer;

[0128] The copper stripping agent has an outer diameter of 15mm for the cored wire, an outer iron sheet thickness of 1mm, and a stripping agent density of approximately 3200kg / m³. 3 ;

[0129] The copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire is inserted into the molten steel through the feeding hole in the top cover. The feeding speed of the copper stripping agent cored wire feeding device is 1.67m / s, and the feeding amount of cored wire is 10kg / t of steel. The vacuum pump has a flow rate of 190Nm. 3 / h;

[0130] S3. Finally, the tail gas containing CuCl is recycled in a green manner through a purification and recovery device. Specifically, all the tail gas containing CuCl is put into the tail gas buffer tank and a two-stage purification process is set up. First, a primary purification is carried out, followed by a secondary purification. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the tail gas meets the standards for being harmless and can be discharged. This method does not emit additional waste gas and achieves green circular production with no pollution and no waste discharge.

[0131] The technology in this embodiment enables the exhaust gas containing CuCl to meet emission standards, while also opening up a new path for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0132] In this embodiment, the vacuum level is controlled at 30 Pa, the copper removal rate is within the range of 80%, the hydrogen content in the molten steel is less than 1 ppm, the nitrogen content in the molten steel is 30 ppm, and the chlorine content in the molten steel is less than 1 ppm.

[0133] In this embodiment, the copper content in the molten steel can be reduced by up to 88%.

[0134] Example 4

[0135] A process control method for an online copper removal system for 70t molten steel, the process control method for the online copper removal system for molten steel includes:

[0136] S1. For the high scrap ratio EAF-LF short-process steelmaking process, an online copper removal system is added to the refining stage of the refining furnace after the steelmaking furnace. This online copper removal system is installed in the LF refining stage after the high scrap ratio EAF, and the RH vacuum refining furnace undergoes structural modifications. Figure 3 As shown, the system includes a ladle 2 containing molten steel 3 to be processed, a refining station adapted to vacuum function, a copper stripping agent cored wire feeding device 5 for feeding copper stripping agent cored wire 6, a negative pressure exhaust device 7 for the ladle, and a purification and recovery device including a tail gas buffer tank 8, a connecting valve 9, and a two-stage purification treatment device; the two-stage purification treatment device includes a primary purification device 10 and a secondary purification device 11.

[0137] A riser pipe 12 and a faller pipe 16 are provided above the ladle 2. A vacuum chamber 14 is provided on the riser pipe 12 and the faller pipe 16. A lifting gas injection pipe 13 is provided at the surface of the molten steel 3 on the outer wall 15 of the vacuum chamber 14.

[0138] The copper content of molten steel exiting the steelmaking furnace or refining furnace is determined by direct reading spectroscopy; the steelmaking process is a short-process electric arc furnace production with a scrap steel ratio of more than 70%.

[0139] S2. Establish a graded copper removal model. Based on the copper content of the molten steel leaving the station, select the copper removal equipment and control method corresponding to the copper content of the graded copper removal model to carry out copper removal treatment to obtain molten steel with copper content controlled below 0.1% and tail gas containing CuCl.

[0140] In this embodiment, the copper content of the molten steel in EAF is 0.2%; therefore, the third interval is selected, wherein: the copper-coated wire used in the copper-coated wire feeding device is a copper-coated wire with an outer iron sheet wrapping the copper-coated agent, and the cross-sectional structure is a circle with an inner and outer double-layer reaction interface; the main components of the copper-coated agent are copper catching agent, oxidant, and ion donor; the copper catching agent is silicon dioxide, which accounts for 10% of the mass of the copper-coated agent and is mainly distributed in the inner layer; the oxidant is iron oxide, which accounts for 30% of the mass of the copper-coated agent and is mainly distributed in the inner layer; the ion donor is calcium chloride, which accounts for 60% of the mass of the copper-coated agent and is mainly distributed in the outer layer;

[0141] The copper stripping agent has an outer diameter of 15mm for the cored wire, an outer iron sheet thickness of 1mm, and a stripping agent density of approximately 3200kg / m³. 3 ;

[0142] The copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire is inserted into the molten steel through the feeding hole in the top cover. The feeding speed of the copper stripping agent cored wire feeding device is 1.5m / s, and the feeding amount of cored wire is 10kg / t of steel. The vacuum pump has a flow rate of 180Nm. 3 / h;

[0143] S3. Finally, the tail gas containing CuCl is recycled in a green manner through a purification and recovery device. Specifically, all the tail gas containing CuCl is put into the tail gas buffer tank and a two-stage purification process is set up. First, a primary purification is carried out, followed by a secondary purification. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the tail gas meets the standards for being harmless and can be discharged. This method does not emit additional waste gas and achieves green circular production with no pollution and no waste discharge.

[0144] The technology in this embodiment enables the exhaust gas containing CuCl to meet emission standards, while also opening up a new path for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0145] In this embodiment, the vacuum level is controlled at 45 Pa, the copper removal rate is 73%, the hydrogen content in the molten steel is less than 1 ppm, the nitrogen content in the molten steel is 30 ppm, and the chlorine content in the molten steel is less than 1 ppm.

[0146] In this embodiment, the copper content in the molten steel can be reduced by up to 81%.

[0147] Example 5

[0148] A process control method for an online copper removal system for 180t molten steel, the process control method for the online copper removal system for molten steel includes:

[0149] S1. For the high scrap ratio EAF-LF short-process steelmaking process, an online copper removal system is added to the refining stage of the refining furnace after the steelmaking furnace. The online copper removal system is set in the LF refining stage after the high scrap ratio EAF, and the RH vacuum refining furnace is modified in terms of device structure. This includes designing and installing a ladle top cover adapted to the ladle for copper removal, and a refining station adapted to vacuum function. A copper removal agent cored wire feeding device is installed on it, and a negative pressure exhaust device for the ladle is installed on one side. The purification and recovery device includes a tail gas buffer tank and a two-stage purification treatment device.

[0150] The copper content of molten steel exiting the steelmaking furnace or refining furnace is determined by direct reading spectroscopy; the steelmaking process is a short-process electric arc furnace production with a scrap steel ratio of more than 70%.

[0151] S2. Establish a graded copper removal model. Based on the copper content of the molten steel leaving the station, select the copper removal equipment and control method corresponding to the copper content of the graded copper removal model to carry out copper removal treatment to obtain molten steel with copper content controlled below 0.1% and tail gas containing CuCl.

[0152] In this embodiment, the copper content of the molten steel in EAF is 0.25%; therefore, the selected range is [number missing]. The copper-coated wire used in the copper-coated wire feeding device is a copper-coated wire with an outer iron sheet covering the copper-coated agent, and its cross-sectional structure is a circle with an inner and outer double-layer reaction interface. The main components of the copper-coated agent are copper catching agent, oxidant, and ion donor. The copper catching agent is silicon dioxide, accounting for 20% of the mass of the copper-coated agent, mainly distributed in the inner layer; the oxidant is iron oxide, accounting for 35% of the mass of the copper-coated agent, mainly distributed in the inner layer; and the ion donor is calcium chloride, accounting for 45% of the mass of the copper-coated agent, mainly distributed in the outer layer.

[0153] The copper stripping agent has an outer diameter of 15mm for the cored wire, an outer sheet thickness of 1mm, and a stripping agent density of approximately 2900kg / m³. 3 ;

[0154] The copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire is inserted into the molten steel through the feeding hole in the top cover. The feeding speed of the copper stripping agent cored wire feeding device is 1.5m / s, and the feeding amount of cored wire is 8.5kg / t of steel. The vacuum pump has a flow rate of 200Nm. 3 / h;

[0155] S3. Finally, the tail gas containing CuCl is recycled in a green manner through a purification and recovery device. Specifically, all the tail gas containing CuCl is put into the tail gas buffer tank and a two-stage purification process is set up. First, a primary purification is carried out, followed by a secondary purification. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the tail gas meets the standards for being harmless and can be discharged. This method does not emit additional waste gas and achieves green circular production with no pollution and no waste discharge.

[0156] The technology in this embodiment enables the exhaust gas containing CuCl to meet emission standards, while also opening up a new path for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0157] In this embodiment, the vacuum level is controlled at 67 Pa, the copper removal rate is 69%, the hydrogen content in the molten steel is less than 1 ppm, the nitrogen content in the molten steel is 30 ppm, and the chlorine content in the molten steel is less than 1 ppm.

[0158] In this embodiment, the copper content in the molten steel can be reduced by up to 74%.

[0159] Example 6

[0160] A process control method for an online copper removal system for 210t molten steel, the process control method for the online copper removal system for molten steel includes:

[0161] S1. For the high scrap ratio EAF-LF short-process steelmaking process, an online copper removal system is added to the refining stage of the refining furnace after the steelmaking furnace. The online copper removal system is set in the LF refining stage after the high scrap ratio EAF, and the RH vacuum refining furnace is modified in terms of device structure. This includes designing and installing a ladle top cover adapted to the ladle for copper removal, and a refining station adapted to vacuum function. A copper removal agent cored wire feeding device is installed on it, and a negative pressure exhaust device for the ladle is installed on one side. The purification and recovery device includes a tail gas buffer tank and a two-stage purification treatment device.

[0162] The copper content of molten steel exiting the steelmaking furnace or refining furnace is determined by direct reading spectroscopy; the steelmaking process is a short-process electric arc furnace production with a scrap steel ratio of more than 70%.

[0163] S2. Establish a graded copper removal model. Based on the copper content of the molten steel leaving the station, select the copper removal equipment and control method corresponding to the copper content of the graded copper removal model to carry out copper removal treatment to obtain molten steel with copper content controlled below 0.1% and tail gas containing CuCl.

[0164] In this embodiment, the copper content of the molten steel in EAF is 0.4%; therefore, the third interval is selected, wherein: the copper-coated wire used in the copper-coated wire feeding device is a copper-coated wire with an outer iron sheet wrapping the copper-coated agent, and the cross-sectional structure is a circle with an inner and outer double-layer reaction interface; the main components of the copper-coated agent are copper catching agent, oxidant, and ion donor; the copper catching agent is silicon dioxide, accounting for 10% of the mass of the copper-coated agent, mainly distributed in the inner layer; the oxidant is iron oxide, accounting for 25% of the mass of the copper-coated agent, mainly distributed in the inner layer; the ion donor is calcium chloride, accounting for 65% of the mass of the copper-coated agent, mainly distributed in the outer layer;

[0165] The copper stripping agent has an outer diameter of 15mm for the cored wire, an outer iron sheet thickness of 1mm, and a stripping agent density of approximately 2700kg / m³. 3 ;

[0166] The copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire is inserted into the molten steel through the feeding hole in the top cover. The feeding speed of the copper stripping agent cored wire feeding device is 2m / s, and the feeding amount of cored wire is 10kg / t of steel. The vacuum pump has a flow rate of 240Nm. 3 / h;

[0167] S3. Finally, the tail gas containing CuCl is recycled in a green manner through a purification and recovery device. Specifically, all the tail gas containing CuCl is put into the tail gas buffer tank and a two-stage purification process is set up. First, a primary purification is carried out, followed by a secondary purification. The purification process consists of three steps: condensation, precipitation, and adsorption. After two stages of purification, the tail gas meets the standards for being harmless and can be discharged. This method does not emit additional waste gas and achieves green circular production with no pollution and no waste discharge.

[0168] The technology in this embodiment enables the exhaust gas containing CuCl to meet emission standards, while also opening up a new path for the production of CuCl / CuCl2 crystals from steel and chemical industries.

[0169] In this embodiment, the vacuum level is controlled at 14 Pa, the copper removal rate is within the range of 90%, the hydrogen content in the molten steel is less than 1 ppm, the nitrogen content in the molten steel is 20 ppm, and the chlorine content in the molten steel is less than 1 ppm.

[0170] In this embodiment, the copper content in the molten steel can be reduced by up to 93%.

[0171] As can be seen from Examples 1-6, with the increase of the tonnage of molten steel processed, under the same process parameters, the reduction in copper content of molten steel increases accordingly, with an increase of at least 33% and a maximum increase of up to 93%.

[0172] The above-mentioned solution proposes a process control method for an online copper removal system for molten steel, which can solve the technical problems in the existing technology of copper removal of molten steel, such as the inability to integrate the copper removal process online, the lack of a graded control mechanism, low copper recovery rate, and difficulty in adapting to different steelmaking processes.

[0173] This invention adds an online copper removal system to the refining stage of the refining furnace after the steelmaking furnace in steelmaking processes with large scrap ratios, such as the BF-BOF-LF long process or the EAF-LF short process. This allows the copper removal process to be seamlessly integrated with the existing steelmaking process, enabling precise online control of the copper content in molten steel.

[0174] This invention enables precise and differentiated control of the copper removal process by determining the copper content of molten steel exiting the steelmaking or refining furnace and establishing a graded copper removal model, effectively ensuring the stability and reliability of the copper removal effect.

[0175] This invention classifies molten steel by copper content and selects copper removal equipment and control methods that correspond to the copper content of each grade. This enables the copper removal process to be controlled on demand, achieving both efficiency and cost control.

[0176] This invention, through the selection of the composition and structure of the copper stripping agent cored wire and the structural design of the wire feeding device, enables the copper stripping agent to act precisely and efficiently on the reaction zone of molten steel, significantly improving the kinetic conditions and reaction efficiency of the copper stripping reaction.

[0177] This invention, through the two-stage purification device of the purification and recycling unit, enables the efficient separation, purification, and green recycling of CuCl-containing exhaust gas, achieving the dual goals of resource recovery and environmental compliance.

[0178] In summary, compared with traditional steel copper removal, the method of this invention improves the copper removal rate of molten steel in the steelmaking process by setting up an online copper removal treatment system, establishing a graded copper removal model, selecting the copper removal treatment equipment and control methods for the corresponding graded copper removal model, selecting the composition and structure of the copper removal agent cored wire and setting up the structure of the wire feeding device, and setting up a two-stage purification device. This method is simple in process, easy to operate, convenient to improve the device structure, low in cost, and high in efficiency, which is conducive to large-scale industrial production and application.

[0179] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0180] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0181] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0182] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A process control method for an online copper removal system for molten steel, characterized in that, The process control method of the online copper removal system for molten steel includes: adding an online copper removal system to the refining stage of the refining furnace after the steelmaking furnace in steelmaking processes with a large scrap ratio (BF-BOF-LF long process or EAF-LF short process); determining the copper content of the molten steel leaving the steelmaking furnace or refining furnace through copper content detection methods; establishing a graded copper removal model; classifying the molten steel according to its copper content; selecting the copper removal equipment and control method corresponding to the copper content of the graded copper removal model; obtaining molten steel with a copper content controlled below 0.1% and tail gas containing CuCl; and finally, recycling the tail gas containing CuCl through a purification and recovery device.

2. The process control method for the online copper removal system for molten steel according to claim 1, characterized in that, Steelmaking processes include long-process production using blast furnaces and converters with a scrap ratio exceeding 50%, short-process production using electric arc furnaces with a scrap ratio exceeding 70%, or other steelmaking furnaces with copper removal requirements.

3. The process control method for the online copper removal system for molten steel according to claim 1, characterized in that, The steelmaking furnace is a converter, an electric arc furnace, or other steelmaking furnace that requires copper content indicators; the refining furnace is an LF or other refining furnace; the copper content detection method is direct reading spectroscopy, inductively coupled plasma atomic emission spectrometry (ICP), chemical titration, or other copper content testing methods.

4. The process control method for the online copper removal system for molten steel according to claim 1, characterized in that, The online copper removal system is set in the LF refining stage after BOF or EAF with a high scrap steel ratio, and the equipment structure of VD, RH or other vacuum refining furnaces is modified. The system includes the design and installation of a ladle top cover adapted to the ladle for copper removal processing, which is equipped with a copper removal agent core wire feeding device and a negative pressure exhaust device for the ladle on one side. The purification and recovery device includes an exhaust gas buffer tank and a two-stage purification treatment device.

5. The process control method for the online copper removal system for molten steel according to claim 1, characterized in that, The established hierarchical copper removal model includes the following three intervals: First interval: When the detected copper content is Cu≤0.1%, the system determines that the molten steel in this batch has met the composition requirements of high-quality steel, and no copper removal process is initiated. The molten steel is directly used for the subsequent casting process. Second range: When the detected copper content is between 0.1% and Cu, the system determines that physical copper removal is required. The specific steps of physical copper removal are as follows: the ladle containing molten steel is hoisted to a dedicated copper removal station, and the vacuum copper removal system is started directly without adding any chlorination copper removal agent. Third interval: When the detected copper content is 0.2% < Cu ≤ 0.5%, the system determines that enhanced chemical copper removal is required. The specific steps of enhanced chemical copper removal are as follows: After the ladle is hoisted to the copper removal station, the appropriate mass of chlorinated copper removal agent is first added according to the initial copper content; then, vacuum copper removal is performed at the same time as adding the copper removal agent.

6. The process control method for the online copper removal system for molten steel according to claim 5, characterized in that, The vacuum pressure in the second zone is determined based on the initial copper content using the first functional relationship, which is: Where P is the vacuum pressure and x is the initial copper content; The amount of copper-removing chloride added in the third zone is determined based on the initial copper content using the second functional relationship, and the vacuum pressure is determined based on the initial copper content using the third functional relationship. The equation for the second functional relationship is: Where M is the amount of copper removal agent added, and x is the initial copper content; The equation for the third functional relationship is: 。 7. The process control method for the online copper removal system for molten steel according to claim 4, characterized in that, The copper-stripping agent cored wire used in the copper-stripping agent feeding device consists of an outer layer of iron sheet wrapping the copper-stripping agent, with a cross-sectional structure of a circular or elliptical shape with an inner and outer double-layer reaction interface. The main components of the copper-stripping agent are a copper collector, an oxidant, and an ion donor. The copper collector is silicon dioxide, and its mass percentage in the copper-stripping agent is 10-20%. The oxidant is iron oxide, and its mass percentage in the copper-stripping agent is 30-40%. The ion donor is calcium chloride, and its mass percentage in the copper-stripping agent is approximately 50-60%.

8. The process control method for the online copper removal system for molten steel according to claim 7, characterized in that, The internal structure of the copper-removing agent-coated wire consists of copper trapping agents and oxidants mainly distributed in the inner layer, and ion donors mainly distributed in the outer layer. The outer diameter of the cored wire is 15-25 mm, the thickness of the outer iron sheet is 1-2 mm, and the density of the copper-removing agent is approximately 3000-4000 kg / m³. 3 .

9. The process control method for the online copper removal system for molten steel according to claim 8, characterized in that, The copper stripping agent cored wire feeding device is installed 10cm off-center from the top cover of the ladle. The copper stripping agent cored wire used is inserted downwards into the molten steel through the feeding hole set in the top cover. The feeding speed of the copper stripping agent cored wire feeding device is 1-3m / s, and the feeding amount of cored wire is 5-10kg / t of steel. The suction flow rate of the negative pressure suction device is 72-240Nm. 3 / h.

10. The process control method for the online copper removal system for molten steel according to claim 1, characterized in that, The process control method of the online copper removal system for molten steel shows that when the vacuum degree reaches 100Pa, the copper content in the molten steel is reduced by 50%; when the vacuum degree reaches 30Pa, the copper content in the molten steel is reduced by more than 70%. The online copper removal treatment time is 10-30 minutes, and the copper removal efficiency reaches 50-80%. It is applicable to existing high scrap ratio steelmaking processes with 70-250t "EAF+LF+VD / VOD / RH", 70-250t "EAF+VD / VOD / RH", 70-250t "BOF+LF+VD / VOD / RH", and 70-250t "BOF+VD / VOD / RH".

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