Process for continuous recycling of hot casting slag in LF ladle furnace

Abstract

The present invention discloses a process method for continuously recycling hot casting slag in an LF ladle furnace, comprising: S1, pre-deoxidation treatment of molten steel; S2, receiving hot casting slag from the pre-deoxidized molten steel in a refining-continuous casting span; S21, for a ladle that has not recycled overheated casting slag, its casting slag is directly poured into the surface of the molten steel; for a ladle that has recycled overheated casting slag, part of the casting slag needs to be poured out before recycling, and the remaining slag is directly poured into the surface of the molten steel; S22, after receiving the casting slag, the ladle is transported to the LF ladle furnace processing station, the molten steel is heated and slag is made, and when the temperature rises to above 1575°C, 0.85-1.75kg / t of lime is added to further adjust the slag. The present invention solves the problems of large slag amount, difficult slag adjustment and unstable desulfurization efficiency in the existing hot casting slag recycling process, increases the number of hot casting slag recycling times, and reduces costs.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking, and in particular to a process method for continuously recycling hot casting slag in an LF ladle furnace. Background Art

[0002] The casting slag produced by molten steel after LF refining is a high-basicity reducing slag. Due to its high CaO and Al2O3 content and low w(MnO+FeO), it has strong pre-melting property and high sulfur capacity. Therefore, in the recycling process, it can not only promote the rapid slagging and slagging in the early stage of the LF furnace, but also has good desulfurization function. In addition, the hot casting slag has high physical heat. Therefore, many steel companies use the casting slag in a hot state. The recycling of hot casting slag not only reduces the consumption of slag-making materials, but also improves the metal recovery rate.

[0003] In actual production, the hot casting slag recycled for the first time has a high sulfur capacity, and has good slagging and desulfurization effects. With the increase in the number of recycling times, the basicity of the hot slag decreases, the Al2O3 content in the slag increases, the Mannesmann index of the slag decreases, and the sulfur content in the slag accumulates in a cycle, which makes the sulfur capacity of the circulating slag smaller, resulting in a decrease in the LF refining desulfurization efficiency and unstable desulfurization; at the same time, with the change of slag composition during the recycling process of casting slag, the adsorption capacity of the refined slag for inclusions is also decreasing, which affects the cleanliness of the molten steel and increases the incidence of surface inclusion defects in the finished product; in addition, with the increase in the number of recycling times, the amount of ladle slag increases and the clearance above the molten steel decreases, which easily leads to slag overflow, affecting the safe and smooth production. The existence of the above problems limits the number of recycling times of hot slag in the refining process and the applicable steel types.

[0004] Therefore, how to control the slag amount in the casting slag recycling process and ensure that the recycled casting slag has a high sulfur capacity is a key technical problem that needs to be solved in the LF refining process of multiple furnaces continuously recycling hot casting slag.

[0005] In order to solve the problem that the number of times hot casting slag is limited due to the large amount of slag in the recycling process and unstable desulfurization efficiency, various manufacturers have also conducted a lot of research:

[0006] The invention patent with the publication number of "CN 106811576 B" discloses a method for hot recycling of converter slag. The amount of slag is not controlled during the converter tapping process. During the process of pouring converter slag into the ladle, a slag reducing agent is continuously added to the slag surface in the ladle. The high temperature zone formed by heating with the LF electrode is used to realize the chemical reaction between the slag reducing agent and the phosphorus, silicon, manganese and iron oxides in the slag. At the same time, bottom blowing and stirring are performed. The gas flow rate is 0.04-0.12Nm3 / h·t, and the stirring time is 5-20min. After the slag is fully reduced, the molten steel is alloyed according to the influence of the slag reduction on the phosphorus, silicon and manganese components of the molten steel and the requirements of the steel grade. After the pouring is completed, the hot casting slag is poured onto the surface of the molten iron after the slag is removed, and is added to the converter together with the molten iron. The present invention not only saves the alloy consumption and steel material consumption in the molten steel alloying process, but also saves the slag material consumption in the reduction and refining process, and realizes the hot recycling of converter slag.

[0007] The invention patent with the publication number "CN202010239300.0" discloses an energy-saving and emission-reduction method for recycling hot casting slag. Through comprehensive sorting and summarization of the feasibility analysis, process design, pros and cons analysis of recycling process points, process standard formulation, process operation formulation, and post-recycling effect analysis of hot casting slag recycling, a set of practical and feasible hot casting slag recycling methods has been developed. After recycling the casting slag, the molten steel recovery rate is increased, the consumption of auxiliary materials is reduced, and at the same time, the rapid slag formation of refining is promoted, the refining process time is shortened, and the refining efficiency is improved.

[0008] The invention patent with the publication number "CN201210500164.1" discloses a method for hot application of low-basicity casting slag in steelmaking. This method uses 5-7kg / t steel of low-basicity casting slag from the ladle in hot state and adds it into the converter along with the semi-steel, making full use of the heat of the molten casting slag, and can quickly form slag after 2 minutes of blowing, eliminating the addition of composite slag-making agents and heat-increasing agents in the conventional semi-steel smelting process, thereby reducing production costs. The slag-making system is coordinated to achieve rapid production of high-basicity slag under low temperature conditions, and the phosphorus content in the molten iron is quickly and efficiently removed from 0.35-0.80% during the normal smelting cycle to finally meet the target steel grade requirements. Steelmaking has basically achieved the full recycling of casting slag, reducing the environmental pressure and treatment costs of waste slag emissions, and has obvious environmental benefits.

[0009] The invention patent with the publication number of "CN201811557461.3" discloses a method for recycling hot casting slag in a ladle in a converter, which solves the problem that the casting slag and its own waste heat cannot be effectively utilized in the prior art. The method of the present invention comprises the following steps: returning the hot casting slag remaining in the ladle after the molten steel casting is completed to the converter steelmaking process for recycling and utilization; performing a slag removal operation after desulfurization pretreatment of the molten iron in the molten iron tank; transporting the molten iron tank to the molten steel receiving span behind the furnace, transporting the ladle with hot casting slag to the feed port of the molten iron tank and pouring it onto the surface of the molten iron, and then transporting the molten iron tank car back to the molten iron receiving span, and adding the molten iron into the converter for converter smelting. The method of the present invention is energy-saving, environmentally friendly, effective, and stable, and utilizes the casting slag of liquid continuous casting to realize the hot recycling of casting slag, which can reduce the consumption of steel materials, effectively utilize the sensible heat of slag, improve smelting efficiency, reduce steelmaking production costs, improve molten steel quality, and have obvious environmental benefits.

[0010] The above invention patents mainly reuse hot casting slag in converters, ladles or multiple processes. Although the LF refining process of hot casting slag reuse has high molten steel yield and thermal efficiency and simple process, the reuse process is affected by factors such as steel type, slag amount, desulfurization, etc., and its reuse times are limited. In order to increase the sulfur capacity of casting slag, some manufacturers add lime to adjust the slag when the casting slag is reused for the second and third time. However, in the actual slag adjustment process, due to the increase in slag amount after the casting slag is reused, it is difficult to control the amount of lime added for slag adjustment. A small amount of lime cannot achieve the purpose of slag adjustment. Too much addition not only increases the cost but also leads to an increase in slag amount, affecting subsequent reuse; in addition, due to the influence of the oxidizability of the initial slag, the increase in slag amount after the casting slag is reused leads to an increase in aluminum consumption in deoxidation slag making. Due to the above-mentioned difficulties in production, the number of hot casting slag reuse furnaces generally does not exceed three furnaces at present. Summary of the invention

[0011] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a process method for continuously recycling hot casting slag in LF ladle furnace. The present invention solves the problems of large slag amount, difficult slag adjustment and unstable desulfurization efficiency in the existing hot casting slag recycling process, increases the number of hot casting slag recycling times and reduces costs.

[0012] To achieve the above object, the present invention is implemented through the following technical solutions:

[0013] A process for continuously recycling hot casting slag in a LF ladle furnace, comprising:

[0014] S1. Pre-deoxidation treatment of molten steel;

[0015] S2. The pre-deoxidized molten steel is subjected to hot casting slag in the refining-continuous casting span:

[0016] S21. For the ladle that has not reused the overheated casting slag, the casting slag is directly poured onto the surface of the molten steel; for the ladle that has reused the overheated casting slag, part of the casting slag needs to be poured out before reuse, and then the remaining slag is directly poured onto the surface of the molten steel;

[0017] S22. After receiving the casting slag, the ladle is transported to the LF ladle furnace processing station to heat the molten steel and make slag. When the temperature rises to above 1575℃, 0.85-1.75kg / t of lime is added to further adjust the slag.

[0018] Preferably, in step S21, for the ladle that has reused the superheated casting slag, the method for controlling the amount of slag discharge of the casting slag is as follows: after the ladle mouth is tilted 90 degrees, the slag is flowed for 8 to 10 seconds.

[0019] Preferably, in step S22, the amount of lime added is 0.85-1.75‰ of steel.

[0020] Preferably, in step S1, the process of pre-deoxidation treatment of molten steel is:

[0021] S11, pre-adjusting slag for converter tapping: adding aluminum alloy for deoxidation after 1 / 3 of the steel is tapped; using the intense stirring effect of high-temperature molten steel during the tapping process, adding lime through the high-level silo when 2 / 3 of the steel is tapped; after adding lime, stirring with large argon gas at the bottom of the ladle, and continuing to blow argon and stir after the tapping is completed;

[0022] S12. After the ladle is transported to the argon station, aluminum iron is added to the surface of the ladle slag to further remove oxygen from the slag, and argon is blown and stirred at the bottom of the ladle at the same time.

[0023] Furthermore, in step S11, the amount of aluminum alloy added is 1-2‰ of the steel.

[0024] Furthermore, in step S11, the amount of lime added is 2-4‰ of steel.

[0025] Furthermore, in step S11, the argon blowing flow rate of the large argon gas stirring is 800-1200 L / min.

[0026] Furthermore, in step S11, after the steel is tapped, argon blowing and stirring are continued for ≥ 3 min.

[0027] Furthermore, in step S12, the amount of aluminum iron added is 0.5 to 1‰ of steel.

[0028] Furthermore, in step S12, argon is blown at the bottom of the ladle for stirring for 5 to 8 minutes, and the blowing argon flow rate is 500 to 700 L / min.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The hot casting slag continuous recycling process technology developed in the present invention solves the problems of reduced desulfurization efficiency due to reduced sulfur capacity and difficulty in slag adjustment and limited recycling times due to increased slag volume in continuous recycling of hot casting slag. The casting slag can be stably recycled in more than 5 furnaces, which not only meets the requirements of smooth production and molten steel quality, but also significantly reduces production costs. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation scheme of the present invention is described below in conjunction with specific examples, but it should not be understood as a limitation of this patent.

[0032] The experimental methods or test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0033] In order to solve the above problems existing in the existing hot casting slag recycling process, such as large slag amount, difficult slag adjustment and unstable desulfurization efficiency, the present invention adopts the following technical scheme: adding an appropriate amount of slag to carry out initial slag adjustment during the steelmaking process, and deoxidizing the slag at the argon station to ensure that the oxidation of the top slag is maintained at a low level and relatively stable before the casting slag is recycled; in order to ensure that the amount of LF refining slag is relatively stable during the continuous recycling process and the slag adjustment process is stable, part of the casting slag is poured out before the casting slag is recycled to reduce the amount of recycled slag.

[0034] The main technical features and technical parameters are as follows:

[0035] (1) In order to reduce the influence of the initial slag oxidizability on the slag adjustment after the casting slag is recycled, an appropriate amount of slag is added during the steelmaking process for slag adjustment, and the slag is deoxidized at the argon station. The main process methods are as follows:

[0036] 1) Pre-adjust slag during converter tapping: add aluminum alloy for deoxidation after 1 / 3 of the steel is tapped, with the amount added being 1-2 kg / t of steel; utilize the intense stirring effect of high-temperature molten steel during the tapping process, and add lime through the high-level silo when 2 / 3 of the steel is tapped from the converter, with the amount of lime added being 2-4 kg / t of steel; after adding lime, stir with large argon gas at the bottom of the ladle, with the argon blowing flow rate being 800-1200 L / min. After the tapping is completed, continue blowing argon for ≥3 min;

[0037] 2) After the ladle is transported to the argon station, aluminum iron is added to the surface of the ladle slag to further remove oxygen from the slag. The amount of aluminum iron added is 0.5-1.0 kg / t steel. At the same time, argon is blown and stirred at the bottom of the ladle for 5-8 minutes, and the argon blowing flow rate is 500-700 L / min.

[0038] Ensuring that TFe≤2% in the top slag before recycling the casting slag has the following benefits:

[0039] Can promote early desulfurization: Since the hot casting slag is a reducing slag with low oxidizability (TFe≤2%), after the casting slag is recycled, the oxidizability of the top slag is still low and basically remains stable, which can promote rapid desulfurization in the early stage;

[0040] It can save aluminum consumption: after the casting slag is recycled, the top slag has low oxidation, and there is no need to add aluminum iron or only a small amount of aluminum to deoxidize the slag, and the aluminum consumption is low; if the top slag has high oxidation or is unstable before the casting slag is recycled, the top slag will also have high oxidation or be unstable after the casting slag is recycled. After recycling, aluminum iron needs to be added to the slag surface for slag deoxidation. Due to the large amount of slag, the deoxidation aluminum consumption increases.

[0041] (2) In order to avoid the continuous reuse of casting slag, which will lead to an increase in slag volume and affect the recovery, and a decrease in sulfur capacity and affect the desulfurization effect, part of the slag is poured out before the casting slag is reused to ensure that the slag volume in the refining process is relatively stable, and the slag is adjusted after the casting slag is reused; the main process methods are as follows:

[0042] 1) The molten steel after pre-deoxidation and slagging receives hot casting slag in the refining-continuous casting span: the casting slag of the ladle that has not been reused is directly poured into the surface of the molten steel; the ladle that has been reused is poured out of part of the casting slag and the remaining slag is directly poured into the surface of the molten steel;

[0043] 2) For the ladle that has reused the overheated casting slag, pour out half of the casting slag into the slag pot before reusing the hot casting slag again to avoid a substantial increase in the amount of slag from the reused furnace; the amount of slag poured out is controlled according to the slag flow time after the ladle mouth is tilted 90°, that is, the slag flow is 8 to 10 seconds after the ladle mouth is tilted 90°.

[0044] 3) After the casting slag is recovered, the molten steel is heated to form slag. When the temperature rises to above 1575°C, 0.85-1.75 kg / t of lime is added to further adjust the slag.

[0045] Based on the above process, the present invention has applied the method of the present invention on a 150t ladle furnace.

[0046] Example 1

[0047] The first recycling of casting slag, recycling steps:

[0048] (1) Receive the casting slag heat, the converter end temperature is 1645°C, the end [O] is 630ppm, and aluminum alloy is added for deoxidation after 1 / 3 of the converter is tapped. The amount of aluminum alloy added is 1.0kg / t steel. When 2 / 3 of the converter is tapped, lime is added through the high-level silo by utilizing the intense stirring effect of the high-temperature molten steel during the tapping process. The amount of lime added is 2.0kg / t steel. After adding lime, the bottom of the ladle is stirred with large argon gas. The argon blowing flow rate is 800L / min. After the tapping is completed, argon blowing and stirring are continued for 3min.

[0049] (2) After the ladle is transported to the argon station, aluminum iron is added to the surface of the ladle slag to further remove oxygen from the slag. The amount of aluminum iron added is 0.5 kg / t steel. At the same time, argon is blown at the bottom of the ladle for 5 minutes and stirred. The argon blowing flow rate is 600 L / min.

[0050] (3) The molten steel is transferred to the LF furnace and receives the hot slag from the end of the casting heat in the refining-continuous casting span;

[0051] (4) According to the recorded feedback, the casting slag was not reused in the casting furnace; the casting slag of the casting furnace was directly poured into the surface of the molten steel in the receiving furnace of the casting slag by the crane;

[0052] (5) After receiving the casting slag, the ladle is transported to the LF treatment station, the molten steel is heated to 1575°C for slag making, and 0.85kg / t of lime is added for further slag adjustment;

[0053] (6) LF refining is carried out according to the steel grade composition control requirements for desulfurization and alloying. After refining, soft argon is blown for 8 minutes at a flow rate of 300L / min.

[0054] After refining, slag samples and steel samples were taken for chemical composition and TO analysis. The results are shown in the following table:

[0055]

[0056] Example 2

[0057] The casting slag is recycled for the second time. The recycling steps are as follows:

[0058] (1) Receive the casting slag heat, the converter end temperature is 1651°C, the end [O] is 643ppm, and aluminum alloy is added for deoxidation after 1 / 3 of the converter is tapped. The amount of aluminum alloy added is 1.35kg / t steel. When 2 / 3 of the converter is tapped, lime is added through the high-level silo by utilizing the intense stirring effect of the high-temperature molten steel during the tapping process. The amount of lime added is 3.15kg / t steel. After adding lime, the bottom of the ladle is stirred with large argon gas. The argon blowing flow rate is 1100L / min. After the tapping is completed, argon blowing and stirring are continued for 4min.

[0059] (2) After the ladle is transported to the argon station, aluminum iron is added to the surface of the ladle slag to further remove oxygen from the slag. The amount of aluminum iron added is 0.72 kg / t steel. At the same time, argon is blown at the bottom of the ladle for 6 minutes, and the argon flow rate is 700 L / min;

[0060] (3) The molten steel is transferred to the LF furnace and receives the hot slag from the end of the casting heat in the refining-continuous casting span;

[0061] (4) According to the feedback from the records, the casting slag has been reused in the previous heat after casting, and part of the slag needs to be poured out for recycling the casting slag in this heat; the slag is poured out after the mouth of the big bag tank is tilted 90° by the driving crane, and the slag pouring time is 8s;

[0062] (5) After the slag pouring is completed, the remaining cast slag is directly poured onto the surface of the molten steel in the furnace receiving the cast slag;

[0063] (6) After receiving the casting slag, the ladle is transported to the LF processing station to heat the molten steel to make slag. When the temperature rises to 1578°C, 1.05kg / t of lime is added to further adjust the slag;

[0064] (7) LF refining is carried out according to the steel grade composition control requirements for desulfurization and alloying. After refining, soft argon is blown for 8.5 minutes at a flow rate of 280L / min.

[0065] After refining, slag samples and steel samples were taken for chemical composition and TO analysis. The results are shown in the following table:

[0066]

[0067] Example 3

[0068] The casting slag is recycled for the fifth time. The recycling steps are as follows:

[0069] (1) Receive the casting slag heat, the converter end temperature is 1648°C, the end [O] is 610ppm, and aluminum alloy is added for deoxidation after 1 / 3 of the converter is tapped. The amount of aluminum alloy added is 2.00kg / t steel. When 2 / 3 of the converter is tapped, lime is added through the high-level silo by utilizing the intense stirring effect of the high-temperature molten steel during the tapping process. The amount of lime added is 3.75kg / t steel. After adding lime, the bottom of the ladle is stirred with large argon gas. The argon blowing flow rate is 1200L / min. After the tapping is completed, argon blowing and stirring are continued for 4.5min.

[0070] (2) After the ladle is transported to the argon station, aluminum iron is added to the surface of the ladle slag to further remove oxygen from the slag. The amount of aluminum iron added is 0.80 kg / t steel. At the same time, argon is blown and stirred at the bottom of the ladle for 5.5 minutes, and the blowing flow rate is 650 L / min;

[0071] (3) The molten steel is transferred to the LF furnace and receives the hot slag from the end of the casting heat in the refining-continuous casting span;

[0072] (4) According to the record feedback, the casting slag has been reused in the previous heat after casting, and part of the slag needs to be poured out for recycling the casting slag in this heat; the slag is poured after the mouth of the big bag tank is tilted 90° by the driving crane, and the slag pouring time is 10s;

[0073] (5) After the slag pouring is completed, the remaining cast slag is directly poured onto the surface of the molten steel in the furnace receiving the cast slag;

[0074] (6) After receiving the casting slag, the ladle is transported to the LF treatment station to heat the molten steel and slag. When the temperature rises to 1580°C, 1.75kg / t of lime is added to further adjust the slag;

[0075] (7) LF refining is carried out according to the steel grade composition control requirements for desulfurization and alloying. After refining, soft argon is blown for 8 minutes at a flow rate of 250L / min.

[0076] After refining, slag samples and steel samples were taken for chemical composition and TO analysis. The results are shown in the following table:

[0077]

[0078] Example 4

[0079] The casting slag is recycled for the sixth time. The recycling steps are as follows:

[0080] (1) Receive the casting slag heat, the converter end temperature is 1655°C, the end [O] is 660ppm, and aluminum alloy is added for deoxidation after 1 / 3 of the converter is tapped. The amount of aluminum alloy added is 1.85kg / t steel. When 2 / 3 of the converter is tapped, lime is added through the high-level silo by utilizing the intense stirring effect of the high-temperature molten steel during the tapping process. The amount of lime added is 4.0kg / t steel. After adding lime, the bottom of the ladle is stirred with large argon gas. The argon blowing flow rate is 1100L / min. After the tapping is completed, argon blowing and stirring are continued for 5min.

[0081] (2) After the ladle is transported to the argon station, aluminum iron is added to the surface of the ladle slag to further remove oxygen from the slag. The amount of aluminum iron added is 1.0 kg / t steel. At the same time, argon is blown at the bottom of the ladle for 6 minutes, and the argon flow rate is 700 L / min;

[0082] (3) The molten steel is transferred to the LF furnace and receives the hot slag from the end of the casting heat in the refining-continuous casting span;

[0083] (4) According to the feedback from the records, the casting slag has been reused in the previous heat after casting, and part of the slag needs to be poured out for recycling the slag in this heat. The slag is poured out after the mouth of the big bag tank is tilted 90° by the driving crane, and the slag pouring time is 9s;

[0084] (5) After the slag pouring is completed, the remaining cast slag is directly poured onto the surface of the molten steel in the furnace receiving the cast slag;

[0085] (6) After receiving the casting slag, the ladle is transported to the LF processing station to heat the molten steel and slag. When the temperature rises to 1577°C, 1.55kg / t of lime is added to further adjust the slag;

[0086] (7) LF refining is carried out according to the steel grade composition control requirements for desulfurization and alloying. After refining, soft argon is blown for 8 minutes at a flow rate of 200L / min.

[0087] After refining, slag samples and steel samples were taken for chemical composition and TO analysis. The results are shown in the following table:

[0088]

[0089] By performing chemical composition and TO analysis on the slag samples and steel samples taken after the refining of Examples 1-4, it can be seen that the S content in the slag sample after the fifth reuse of the casting slag can still reach 0.36%, and the S content in the steel sample is basically maintained at about 0.0025%. Although the S content in the slag sample after the sixth reuse of the casting slag is reduced, the S content in the steel sample can reach about 0.002%, which indicates that the desulfurization efficiency of the slag controlled by the process method of the present invention is still very stable after multiple reuses.

[0090] The above are only specific embodiments of the present invention. It should be pointed out that any changes or substitutions that can be easily thought of by any technician familiar with the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. The rest not described in detail are prior arts.

Claims

1. A process for continuously recycling hot casting slag in LF ladle furnace, characterized in that: include: S1. Pre-deoxidize the molten steel to ensure that TFe in the top slag before recycling the casting slag is ≤2%: S11, pre-adjusting slag during converter tapping: adding aluminum alloy for deoxidation after 1 / 3 of the steel is tapped, and the amount of aluminum alloy added is 1~2‰ of the steel; using the intense stirring effect of high-temperature molten steel during the tapping process, lime is added through the high-level silo when 2 / 3 of the steel is tapped from the converter, and the amount of lime added is 2~4‰ of the steel; after adding lime, a large amount of argon gas is used for stirring at the bottom of the ladle, and argon blowing and stirring are continued after the tapping is completed; S12, after the ladle is transported to the argon station, aluminum iron is added to the surface of the ladle slag to further remove oxygen from the slag, and argon is blown and stirred at the bottom of the ladle; S2. The pre-deoxidized molten steel is subjected to hot casting slag in the refining-continuous casting span: S21. For the ladle that has not reused the overheated casting slag, the casting slag is directly poured onto the surface of the molten steel; for the ladle that has reused the overheated casting slag, part of the casting slag needs to be poured out before reuse, and then the remaining slag is directly poured onto the surface of the molten steel; S22. After receiving the casting slag, the ladle is transported to the LF ladle furnace processing station to heat the molten steel and make slag. When the temperature rises to above 1575℃, lime is added to further adjust the slag. The amount of lime added is 0.85~1.75‰ of steel.

2. The process for continuously recycling hot casting slag in LF ladle furnace according to claim 1, characterized in that: In step S21, for the ladle that has reused the superheated casting slag, the method for controlling the slag discharge amount of the casting slag is as follows: after the ladle mouth is tilted 90 degrees, the slag is flowed for 8 to 10 seconds.

3. The process for continuously recycling hot casting slag in LF ladle furnace according to claim 1, characterized in that: In step S11, the argon blowing flow rate of the large argon gas stirring is 800~1200L / min.

4. The process for continuously recycling hot casting slag in LF ladle furnace according to claim 1 or 3, characterized in that: In step S11, after the steel is tapped, argon blowing and stirring are continued for ≥ 3 min.

5. The process for continuously recycling hot casting slag in LF ladle furnace according to claim 1, characterized in that: In step S12, the amount of aluminum iron added is 0.5~1‰ of steel.

6. The process for continuously recycling hot casting slag in LF ladle furnace according to claim 1 or 5, characterized in that: In step S12, argon is blown at the bottom of the ladle for stirring for 5 to 8 minutes, and the blowing argon flow rate is 500 to 700 L / min.

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