Process for uniformly adding rare earth in electroslag remelting process of rare earth reducing slag system
By using batch addition of rare earth oxides and reducing agents during the remelting of rare earth reducing slag-based electroslag, the problem of uneven distribution of rare earth elements is solved, the utilization rate of rare earth and steel quality is improved, and the production cost is reduced.
Patent Information
- Application Number
- CN202411265468.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-01-14
AI Technical Summary
During the remelting of rare earth reduction slag-based electroslag, the distribution of rare earth elements in the steel ingot is uneven, resulting in low rare earth recovery and unstable steel quality.
By mixing rare earth oxides and reducing agents in batches during the electroslag remelting process, we ensure the stability of the refining slag components, use Ca-Si alloy to reduce rare earth oxides, calculate and determine the time and amount of slag replenishment to ensure rare earth The elements are evenly distributed.
The uniform distribution of rare earth elements in steel is achieved, the utilization rate of rare earth elements, the metallurgical quality and mechanical properties of steel are improved, and the production cost is reduced.
Smart Images
Figure CN119307730A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of electroslag remelting, in particular to a process for uniformly adding rare earth in a rare earth reduction slag system electroslag remelting process. Background Art
[0002] The electroslag remelting process is a metallurgical method that uses the high temperature generated by the current passing through the high-resistance refined slag to perform secondary refining on the consumable electrode. During the smelting process, the bottom of the consumable electrode gradually melts and forms metal droplets at the tip. The droplets fall and react with the refined slag during the process of passing through the slag layer to achieve the purpose of purifying the molten steel. The refined molten steel is rapidly solidified in a certain direction under the action of the water-cooled crystallizer. In this process, the macro-segregation of the steel ingot is effectively improved, but dendrite micro-segregation still exists.
[0003] Rare earth modification can effectively refine the solidification structure, thereby achieving the purpose of inhibiting segregation and refining primary carbides. Compared with other rare earth addition processes, the rare earth slag electroslag remelting reduction method can not only overcome the low and unstable rare earth recovery rate, but also the rare earth does not come into contact with air, which can avoid secondary oxidation and reduce the number of rare earth inclusions in the steel. Studies have shown that the use of traditional electroslag methods for rare earth reduction slag refining will lead to the uneven rare earth element content in the steel ingot, with "high at the bottom and low at the top". Summary of the invention
[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a process for uniformly adding rare earths during rare earth reducing slag electroslag remelting to solve the problems raised in the above-mentioned background technology. The present invention can ensure the stability of the slag composition during the experiment, make the rare earth elements in the remelted steel ingot evenly distributed, enhance the effect of the rare earth elements, and improve the utilization rate of the rare earth elements.
[0005] In order to achieve the above object, the present invention is implemented by the following technical scheme: a process for uniformly adding rare earth during rare earth reduction slag electroslag remelting, comprising the following steps:
[0006] S1: The traditional electroslag remelting process is used to smelt with rare earth reduction slag system, and the volatiles of the refined slag are collected at the furnace mouth fume hood;
[0007] S2: Analyze the volatiles obtained in step S1 to obtain their composition;
[0008] S3: After the electroslag remelting is completed, three slag shell samples are taken from the electroslag ingot from bottom to top at equal distances to detect the content of rare earth oxides in the slag, and three steel samples are taken to detect the content of rare earth elements in the steel. The influence of the change of rare earth slag content on the change of rare earth element content in steel during the electroslag remelting process is calculated.
[0009] S4: Use rare earth oxide slag system with reducing agent to measure the melting rate of consumable electrode under stable production state, and determine the time required from the start of smelting to the end of smelting.
[0010] Furthermore, the target composition of the refined slag is set at 48-56wt.% CaF2-18-28wt.% Al2O3-8-17wt.% La2O3, the total amount of refined slag is to make the slag layer thickness 140-200mm, the initial composition of the refined slag is 48-56wt.% CaF2-18-28wt.% Al2O3-8-17wt.% La2O3 (50%), and the slag supplement is composed of the remaining lanthanum oxide and the CaSi alloy reducing agent consumed by the La2O3 in the corresponding reduction target refined slag.
[0011] Furthermore, the target mass M of the refined slag is calculated according to the size of the electroslag ingot to be produced. i And composition:
[0012] M i =ρ slag ~H~πr 2
[0013] Where: slag -slag density, H-slag layer thickness, r-inner diameter of crystallizer.
[0014] Further, according to the calculated refined slag target mass M i Calculate the initial slag mass M s and composition, slag filling (M b ) The composition and quality are determined according to the S3 test quality, where:
[0015] M s =M i -M b
[0016] Furthermore, according to the target quality M of the refined slag i Calculate the mass M of the reducing agent Ca-Si alloy by the composition h :
[0017]
[0018] in: -Mass percentage of La2O3 in slag, w Ca -Mass percentage of Ca in Ca-Si alloy.
[0019] Furthermore, in step S1, the start time of slag filling is determined to be when the consumable electrode is inserted into the molten pool to start refining, the end time of slag filling is determined to be when electroslag remelting shrinkage feeding starts, and the interval of slag filling is divided into 24 equal parts.
[0020] Furthermore, the slag composition is La2O3-(Ca-Si), and the calculated reducing agent mass (M h ) and the total mass of refined slag are divided into 24 portions and added into the molten pool at regular intervals.
[0021] Furthermore, slag is replenished periodically at the gap between the electrode and the inner wall of the crystallizer.
[0022] Beneficial effects of the present invention:
[0023] 1. The rare earth uniform addition process in the rare earth reduction slag system electroslag remelting process uses Ca-Si alloy to reduce the rare earth oxide electroslag system in the electroslag remelting smelting process, which can enhance the effect of rare earth elements and improve the utilization rate of rare earth elements.
[0024] 2. This process uses a method of mixing rare earth oxides and reducing agents and adding them in batches during the electroslag remelting process to ensure the stability of the refined slag composition during the refining process, so that the rare earth element content diffused from the slag to the molten steel during the reaction between the metal droplets and the slag is stable, ensuring the uniform distribution of rare earths in the steel, thereby effectively improving the metallurgical quality and mechanical properties of the steel.
[0025] 3. The rare earth uniform addition process during the rare earth reduction slag system electroslag remelting process is optimized on the basis of the original refined slag system, so that the production cost changes little. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a flow chart of a process for uniformly adding rare earths in a rare earth reduction slag system electroslag remelting process of the present invention;
[0027] Figure 2 A schematic diagram of the slag filling position in the process provided by the present invention;
[0028] In the figure: 1. Water-cooled crystallizer wall; 2. Feeding position; 3. Consumable electrode. DETAILED DESCRIPTION
[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.
[0030] See also Figure 1 and Figure 2 The present invention provides the following technical solution: a process for uniformly adding rare earths during rare earth reduction slag electroslag remelting, comprising the following steps:
[0031] S1: Use the traditional electroslag remelting process to use rare earth reduction slag system for smelting, calculate the electrode melting rate during the stable smelting process, and take the volatiles of the refined slag at the furnace mouth fume hood;
[0032] S2: After the electroslag remelting, three slag shell samples are taken from the electroslag ingot from bottom to top at equal distances to detect the rare earth oxide content in the slag, and three steel samples are taken to detect the rare earth element content in the steel. Combined with step S1, the influence of the change of rare earth slag content during electroslag remelting on the change of rare earth element content in steel is calculated;
[0033] S3: Calculate the target mass, initial mass and total slag replenishment of the rare earth reduction electroslag system according to the electroslag ingot mass and the crystallizer size;
[0034] S4: batching the refined slag according to the calculated initial mass, baking it in an oven, and then weighing and proportioning the supplementary slag;
[0035] S5: The crystallizer, graphite electrode and consumable electrode 3 are prepared, the baked initial refined slag is loaded into the crystallizer, and the power is turned on to start slagging;
[0036] S6: After slagging is completed, the graphite electrode is pulled out and the consumable electrode 3 is replaced to start smelting;
[0037] S7: When the consumable electrode 3 smelting starts, add the first batch of slag filling material, and Figure 1 Add some slag filler at the marked position until the smelting is finished and the slag filler is completely added to the molten pool when shrinkage compensation begins.
[0038] S8: Start shrinkage compensation. After shrinkage compensation is completed, wait for cooling and demoulding. During the demoulding process, take the slag shells at the upper, middle and lower parts of the electroslag ingot for inspection.
[0039] S9: After demoulding, the electroslag ingot is buried in sand for cooling, and then steel samples are cut from the upper and lower sections of the electroslag ingot for testing.
[0040] In this embodiment, in step S1, the target composition of the refined slag is set at 48-56wt.%CaF2-18-28wt.%Al2O3-8-17wt.%La2O3. In steps S1-S2, XRD and XRF are used to detect and analyze the components and contents of volatiles and slag shells. In step S2, ICP-AES is used to determine the La element content in the steel. In step S3, the total slag volume of the refined slag needs to be calculated in combination with the cross-sectional area of the crystallizer to ensure that the slag layer thickness is 140-200mm, and the specific needs need to be considered in combination with the type of smelting steel, the size of the electroslag ingot, the size of the crystallizer and other factors. In step S4, the slag drying temperature should be between 700 and 1000°C, and the slag drying time should be between 5 and 10 hours. In step S5, when graphite electrodes are used for slag smelting, the furnace port voltage is 40-60V, and the current is about 8000-9500A. To ensure that the slag composition is uniform, the slag smelting time must be at least 30 minutes. In step S7, during the smelting process, the furnace port voltage is gradually reduced from 55V to 40V, and the current is reduced from 8000-9000A to 7000-8000A.
[0041] Example 1
[0042] This embodiment is based on the 1t H13 steel electroslag remelting process, and the details are as follows:
[0043] (1) The dimensions of the crystallizer are 300 mm in lower diameter, 340 mm in lower diameter, 1500 mm in crystallizer height, and 220 mm in refining slag layer thickness.
[0044] M i =2316.2×0.22×3.14×0.15 2 =36kg
[0045] M h =36×0.18×40 / (977.4×0.255)=1.04kg
[0046] After calculation, the amount of slag required for 1t H13 steel crystallizer is 36kg. The composition of the rare earth reduction slag system is shown in Table 1. The mass of Ca-Si alloy used to reduce lanthanum oxide is 1.04kg. The smelting is carried out by the traditional electroslag remelting process, and the total smelting time is 200 minutes. The test results of slag volatiles and slag shell are shown in Table 2.
[0047] Table 1: Rare earth reduction slag kg
[0048] <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[La2O3]]> 20.16 8.64 7.2
[0049] Table 2: Slag volatiles and slag shell test results wt.%
[0050] Test substances <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[AlF3]]> <![CDATA[La2O3]]> Slag Volatile 43.2 10.8 35.6 10.4 upper slag shell 51.8 35.1 - 13.1 Middle slag shell 52.0 32.8 15.2 lower slag shell 52.9 30.3 - 16.8
[0051] (2) The La content in the upper and lower ingots was found to be 82 ppm and 103 ppm respectively.
[0052] (3) According to the smelting speed and the change law of refined slag, the initial refined slag composition is designed as shown in Table 3, and the supplementary slag composition is a mixture of 3.6 kg La2O3 and 1.04 kg Ca-Si alloy.
[0053] Table 3: Rare earth reduction initial slag composition kg
[0054]
[0055]
[0056] (4) The refined slag is batched according to the calculated initial mass and baked in an oven at 800°C for 4 hours, and then the slag filler is weighed and proportioned.
[0057] (5) The crystallizer, graphite electrode and consumable electrode 3 are prepared, the baked initial refined slag is loaded into the crystallizer, and the power is turned on to start slagging. The furnace port voltage is 48V, the current is 9500A, and the slagging time is set to 35 minutes.
[0058] (6) After slagging is completed, the graphite electrode is pulled out and replaced with the consumable electrode 3 to start smelting. The consumable electrode 3 is placed vertically at the center of the cross section of the crystallizer.
[0059] (7) At the beginning of the smelting of consumable electrode 3, add the first batch of 194g of mixed slag material, and stir it along the consumable electrode 3 every 9 minutes. Figure 1 Mark the position, add part of the circulating slag material at the four intersections of the mutually perpendicular diameters between the consumable electrode 3 and the inner wall of the crystallizer until the smelting is finished and the slag material is completely added to the molten pool when the shrinkage feeding starts.
[0060] (8) During the smelting process, the furnace mouth voltage is reduced by 1V and the current is reduced by 100A every 20 minutes.
[0061] (9) After the shrinkage compensation is completed, the power supply is stopped and the electroslag ingot is demoulded after cooling with the furnace for 30 minutes.
[0062] (10) During the demoulding process, the slag shells at the upper, middle and lower parts and the upper and lower ends of the steel ingot were tested. The slag shell test results are shown in Table 4. The upper end of the steel ingot [La] = 95 ppm, and the lower end [La] = 100 ppm.
[0063] Table 4: Slag shell detection results wt.%
[0064] Test substances <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[La2O3]]> upper slag shell 61.5 25.8 12.7 Middle slag shell 61.8 25.6 12.6 lower slag shell 62.2 26.7 11.1
[0065] Example 2
[0066] This embodiment provides a process for uniformly adding rare earths during the electroslag remelting process of rare earth reduction slag, based on the electroslag remelting process of 1.5t H13 steel, and is specifically as follows:
[0067] (1) The dimensions of the crystallizer are 330 mm in lower diameter, 370 mm in lower diameter, 1500 mm in crystallizer height, and 260 mm in refining slag layer thickness.
[0068] M i =2573.5×0.26×3.14×0.165 2 =51kg
[0069] M h =51×0.18×40 / (977.4×0.283)=1.33kg
[0070] After calculation, the slag required for a 1.5t H13 steel crystallizer is 51kg. The composition of the rare earth reduction slag system is shown in Table 1. The mass of the Ca-Si alloy used to reduce lanthanum oxide is 1.33kg. The smelting is carried out using the traditional electroslag remelting process, and the total smelting time is 260 minutes. The test results of the slag volatiles and slag shell are shown in Table 2.
[0071] Table 1: Rare earth reduction slag kg
[0072] <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[La2O3]]> 28.56 12.24 10.2
[0073] Table 2: Slag volatiles and slag shell test results wt.%
[0074] Test substances <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[AlF3]]> <![CDATA[La2O3]]> Slag Volatile 42.5 11.3 35.4 10.8 upper slag shell 52.6 34.8 - 12.6 Middle slag shell 54.6 26.9 - 18.5 lower slag shell 55.1 28.3 - 16.6
[0075] (2) The La content in the upper and lower ingots was detected to be 79 ppm and 105 ppm respectively.
[0076] (3) According to the smelting speed and the change law of refined slag, the initial refined slag composition is designed as shown in Table 3, and the supplementary slag composition is a mixture of 5.1 kg La2O3 and 1.33 kg Ca-Si alloy.
[0077] Table 3: Rare earth reduction initial slag composition kg
[0078] <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[La2O3]]> 28.56 12.24 5.1
[0079] (4) The refined slag is batched according to the calculated initial mass and baked in an oven at 700°C for 6 hours, and then the slag filler is weighed and proportioned.
[0080] (5) The crystallizer, graphite electrode and consumable electrode 3 are prepared, the baked initial refined slag is loaded into the crystallizer, and the power is turned on to start slagging. The furnace port voltage is 61V, the current is 9500A, and the slagging time is set to 35 minutes.
[0081] (6) After slagging is completed, the graphite electrode is pulled out and replaced with the consumable electrode 3 to start smelting. The consumable electrode 3 is placed vertically at the center of the cross section of the crystallizer.
[0082] (7) At the beginning of the smelting of consumable electrode 3, add the first batch of 268g of mixed slag material, and stir it along the surface every 11 minutes. Figure 1 Mark the position, add part of the circulating slag material at the four intersections of the mutually perpendicular diameters between the consumable electrode 3 and the inner wall of the crystallizer until the smelting is finished and the slag material is completely added to the molten pool when the shrinkage feeding starts.
[0083] (8) During the smelting process, the furnace mouth voltage is reduced by 1V and the current is reduced by 100A every 20 minutes.
[0084] (9) After the shrinkage compensation is completed, the power supply is stopped and the electroslag ingot is demoulded after cooling with the furnace for 40 minutes.
[0085] (10) During the demolding process, the slag shells at the upper, middle and lower parts and the upper and lower ends of the steel ingot were tested. The slag shell test results are shown in Table 4. The upper end of the steel ingot [La] = 97 ppm, and the lower end [La] = 102 ppm.
[0086] Table 4: Slag shell detection results wt.%
[0087] Test substances <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[La2O3]]> upper slag shell 60.9 26.1 13.0 Middle slag shell 61.6 25.9 12.5 lower slag shell 62.1 26.2 11.7
[0088] Example 3
[0089] This embodiment provides a process for uniformly adding rare earths during the electroslag remelting process of rare earth reduction slag, based on the electroslag remelting process of 1t H13 steel, and is specifically as follows:
[0090] (1) The dimensions of the crystallizer are 300 mm in lower diameter, 340 mm in lower diameter, 1500 mm in crystallizer height, and 220 mm in refining slag layer thickness.
[0091] M i =2573.5×0.22×3.14×0.15 2 =40kg
[0092] M h =40×0.18×40 / (977.4×0.283)=1.04kg
[0093] After calculation, the amount of slag required for 1t H13 steel crystallizer is 40kg. The composition of the rare earth reduction slag system is shown in Table 1. The mass of Ca-Si alloy used to reduce lanthanum oxide is 1.04kg. The smelting is carried out by traditional electroslag remelting process, the total smelting time is 240 minutes, and the slag shell detection results are shown in Table 2.
[0094] Table 1: Rare earth reduction slag kg
[0095] <![CDATA[CaF2]]> <![CDATA[Al2O3]]> MgO <![CDATA[La2O3]]> 19.6 9.6 3.6 7.2
[0096] Table 2: Slag volatiles and slag shell test results wt.%
[0097] Test substances <![CDATA[CaF2]]> <![CDATA[Al2O3]]> MgO <![CDATA[La2O3]]> upper slag shell 49.9 33.6 6.7 9.8 Middle slag shell 49.8 31.8 6.1 12.3 lower slag shell 48.1 29.9 8.5 13.5
[0098] (2) The La content in the upper and lower ingots was detected to be 110 ppm and 135 ppm respectively.
[0099] (3) According to the smelting speed and the change law of refined slag, the initial refined slag composition is designed as shown in Table 3, and the supplementary slag composition is a mixture of 3.6 kg La2O3 and 1.04 kg Ca-Si alloy.
[0100] Table 3: Rare earth reduction initial slag composition kg
[0101] <![CDATA[CaF2]]> <![CDATA[Al2O3]]> MgO <![CDATA[La2O3]]> 19.6 9.6 3.6 3.6
[0102] (4) The refined slag is batched according to the calculated initial mass and baked in an oven at 700°C for 6 hours, and then the slag filler is weighed and proportioned.
[0103] (5) The crystallizer, graphite electrode and consumable electrode 3 are prepared, the baked initial refined slag is loaded into the crystallizer, and the power is turned on to start slagging. The furnace port voltage is 52V, the current is 9500A, and the slagging time is set to 35 minutes.
[0104] (6) After slagging is completed, the graphite electrode is pulled out and replaced with the consumable electrode 3 to start smelting. The consumable electrode 3 is placed vertically at the center of the cross section of the crystallizer.
[0105] (7) At the beginning of the smelting of consumable electrode 3, add the first batch of 194g of mixed slag material, and stir it along the consumable electrode 3 every 8 minutes. Figure 1 Mark the position, add part of the circulating slag material at the four intersections of the mutually perpendicular diameters between the consumable electrode 3 and the inner wall of the crystallizer until the smelting is finished and the slag material is completely added to the molten pool when the shrinkage feeding starts.
[0106] (8) During the smelting process, the furnace mouth voltage is reduced by 1V and the current is reduced by 100A every 20 minutes.
[0107] (9) After the shrinkage compensation is completed, the power supply is stopped and the electroslag ingot is demoulded after cooling with the furnace for 30 minutes.
[0108] (10) During the demolding process, the slag shells at the upper, middle and lower parts and the upper and lower ends of the steel ingot were tested. The slag shell test results are shown in Table 4. The upper end of the steel ingot [La] = 115 ppm, and the lower end [La] = 120 ppm.
[0109] Table 4: Slag shell detection results wt.%
[0110] Test substances <![CDATA[CaF2]]> <![CDATA[Al2O3]]> <![CDATA[La2O3]]> upper slag shell 61.5 25.8 12.7 Middle slag shell 61.8 25.6 12.6 lower slag shell 62.2 26.7 11.1
[0111] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention.
[0112] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.
Claims
1. A process for uniformly adding rare earths during rare earth reduction slag electroslag remelting, characterized in that: The following steps are involved: S1: The traditional electroslag remelting process is used to smelt with rare earth reduction slag system, and the volatiles of the refined slag are collected at the furnace mouth fume hood; S2: Analyze the volatiles obtained in step S1 to obtain their composition; S3: After the electroslag remelting, three slag shell samples were taken from the electroslag ingot from bottom to top at equal distances to detect the rare earth oxide content in the slag, and three steel samples were taken to detect the rare earth element content in the steel. The influence of the change of rare earth slag content during the electroslag remelting process on the change of rare earth element content in the steel was calculated; S4: Use rare earth oxide slag system with reducing agent to measure the melting rate of consumable electrode under stable production state, and determine the time required from the start of smelting to the end of smelting.
2. The process for uniformly adding rare earths during electroslag remelting of rare earth reduction slag according to claim 1, characterized in that: The target composition of the refined slag is set at 48-56wt.% CaF2-18-28wt.% Al2O3-8-17wt.% La2O3, the total amount of refined slag is to make the slag layer thickness 140-200mm, the initial composition of the refined slag is 48-56wt.% CaF2-18-28wt.% Al2O3-8-17wt.% La2O3 (50%), and the slag supplementation composition is the remaining lanthanum oxide and the CaSi alloy reducing agent consumed by the La2O3 in the corresponding reduction target refined slag.
3. The process for uniformly adding rare earths during electroslag remelting of rare earth reduction slag according to claim 2, characterized in that: Calculate the target quality M of refined slag according to the size of electroslag ingot to be produced i And composition: M i =ρ slag ~H~πr 2 Where: slag -slag density, H-slag layer thickness, r-inner diameter of crystallizer.
4. The process for uniformly adding rare earths during rare earth reduction slag electroslag remelting according to claim 3, characterized in that: According to the calculated refined slag target mass M i Calculate the initial slag mass M s and composition, slag filling (M b ) The composition and quality are determined according to the S3 test quality, where: M s =M i -M b 。 5. The process for uniformly adding rare earths during rare earth reduction slag electroslag remelting according to claim 4, characterized in that: According to the target quality M of refined slag i Calculate the mass M of the reducing agent Ca-Si alloy by the composition h : in: -Mass percentage of La2O3 in slag, w Ca -Mass percentage of Ca in Ca-Si alloy.
6. The process for uniformly adding rare earths during rare earth reduction slag electroslag remelting according to claim 1, characterized in that: In step S1, the starting time of slag filling is determined to be when the consumable electrode is inserted into the molten pool to start refining, the ending time of slag filling is determined to be when electroslag remelting and shrinkage feeding start, and the interval of slag filling is divided into 24 equal parts.
7. The process for uniformly adding rare earth during rare earth reduction slag electroslag remelting according to claim 6, characterized in that: The slag composition is La2O3-(Ca-Si), and the calculated reducing agent mass (M h ) and the total mass of refined slag are divided into 24 portions and added into the molten pool at regular intervals.
8. The process for uniformly adding rare earths during rare earth reduction slag electroslag remelting according to claim 1, characterized in that: The slag is replenished periodically in the gap between the electrode and the inner wall of the crystallizer.