KR desulfurization slag sulfur fixation method based on electromagnetic pulse, sulfur fixation slag and application of sulfur fixation slag

Abstract

The invention discloses a KR desulfurization slag sulfur fixation method based on electromagnetic pulses, sulfur fixation slag and application of the sulfur fixation slag, and belongs to the technical field of high-temperature steel slag processing. The sulfur fixation method comprises the following steps: covering a displacer containing elemental Ba on the surface of hot KR desulfurization slag obtained by molten iron slagging-off treatment; electromagnetic pulse treatment is carried out on the KR desulfurization slag covered with the displacer containing the elemental Ba under the treatment conditions that the treatment time is 15-20 min, the pulse frequency is 300 kHz to 500 kHz, and the pulse intensity is 300 A to 600 A; and cooling the KR desulfurization slag subjected to electromagnetic pulse treatment to obtain the KR sulfur fixation slag. According to the sulfur fixation method, CaS containing the S element in the KR desulfurization slag is converted into more stable sulfide, and electromagnetic pulse treatment is assisted to accelerate the reaction rate, so that the problem of resulfurization during resource utilization of the KR desulfurization slag can be effectively relieved, and meanwhile, the process energy consumption of KR desulfurization slag treatment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature steel slag processing, and more specifically to a KR desulfurization slag desulfurization method based on electromagnetic pulse, desulfurization slag and application thereof. Background Art

[0002] Sulfur exists mainly in the form of iron sulfide in solid steel, which makes steel prone to "hot brittleness" under high temperature conditions and reduces the plasticity, processability and weldability of steel. With the increasing requirements for steel performance, hot metal desulfurization technology has developed into an indispensable and important link in the steel production process. At present, the KR method is mainly used in China for hot metal pre-desulfurization, that is, the agitator is inserted into the liquid surface of the hot metal ladle to a certain depth, and a vortex is generated by the rotation of the agitator head. Lime and other desulfurizers are drawn into the hot metal through the vortex, and fully combined with sulfur in the hot metal to generate CaS. The generated desulfurization slag floats on the surface of the hot metal to obtain KR desulfurization slag. Due to the agglomeration effect of lime, the mass ratio of calcium and sulfur in the desulfurization slag is about 10:1, which means that a large amount of incompletely reacted CaO is brought into the desulfurization slag.

[0003] The annual output of KR desulfurization slag exceeds 4.4 million tons, of which the CaO mass fraction exceeds 40%, the basicity is generally above 3.5, and the CaS mass fraction is between 1 and 2.5%. The traditional treatment method is mainly to recover the iron-containing part through magnetic separation, and the remaining tailings are usually treated in a pile, resulting in serious waste of resources and environmental pollution. Therefore, it is urgent to develop an effective recovery process.

[0004] However, directly reusing KR desulfurized slag in the smelting process is prone to resulfurization, thus limiting its recycling in the steelmaking process. The so-called resulfurization here refers to the phenomenon that the sulfur element that has been removed re-enters the molten steel during the steelmaking process, causing the sulfur content in the molten steel to rise again. Specifically, most of the S in the KR desulfurized slag exists in the form of CaS, and a small amount is combined to form sulfates and other forms. When these KR desulfurized slags are recycled to metallurgical reactors such as converters and electric furnaces, due to the high temperature or oxidizing atmosphere in the furnace, CaS and other sulfur-containing substances are prone to decomposition or oxidation reactions to release S, causing S to re-enter the molten steel.

[0005] Therefore, how to achieve effective resource utilization of KR desulfurization slag has become a research hotspot for existing metallurgical workers. For example, Zhao Zhongfu's "Feasibility Study on Recycling of KR Hot Metal Desulfurization Slag" conducted an experimental study on the characteristics of KR desulfurization slag. The paper shows that the feasibility of KR desulfurization slag can be applied to the KR desulfurization process of hot metal after adding appropriate new desulfurizers, but the recycling rate of KR desulfurization slag is relatively low. For another example, the application of Chinese patent publication number CN113373275A discloses a method for recycling KR desulfurization slag within a steel plant, by crushing KR desulfurization slag and performing magnetic separation to obtain slag iron and tailings; then the tailings are subjected to high-temperature oxidation treatment to obtain sulfur-containing flue gas and pre-melted slag; then the sulfur-containing flue gas is collected and processed, and the pre-melted slag is used as slag-making material for the early slag-making of the converter, so as to achieve the recycling of KR desulfurization slag within the steel plant, but the process energy consumption of this application is relatively high. Summary of the invention

[0006] In view of the technical problem in the prior art that KR desulfurization slag is prone to cause resulfurization of molten steel when it is recycled, the present invention provides a KR desulfurization slag solidification method based on electromagnetic pulse, solidification slag and application thereof, by converting CaS containing S element in the KR desulfurization slag into more stable sulfide, and assisting with electromagnetic pulse treatment to accelerate the reaction rate, thereby effectively alleviating the resulfurization problem during the resource utilization of KR desulfurization slag, improving the reuse rate of KR desulfurization slag, and reducing the process energy consumption of KR desulfurization slag treatment.

[0007] The first aspect of the present invention provides a KR desulfurization slag solidification method based on electromagnetic pulse, comprising: covering the surface of the hot KR desulfurization slag obtained by molten iron slag treatment with a replacement agent containing elemental Ba; subjecting the KR desulfurization slag covered with the replacement agent to electromagnetic pulse treatment, wherein the treatment conditions include: treatment time of 15 to 20 minutes, pulse frequency of 300kHz to 500kHz, and pulse intensity of 300A to 600A; cooling the KR desulfurization slag after the electromagnetic pulse treatment to obtain KR solid sulfur slag.

[0008] The technical principle of the present invention is as follows: a replacement agent containing elemental Ba is used to carry out a replacement reaction with CaS in KR desulfurization slag to form a more stable sulfide BaS, wherein the standard formation Gibbs free energy of CaS is -508kJ / mol, and the standard formation Gibbs free energy of BaS is -555kJ / mol, that is, the stability of BaS is higher than that of CaS. At the same time, the decomposition temperature of CaS is about 1500°C, and the decomposition temperature of BaS exceeds 1600°C, that is, BaS tends to exist more stably at high temperatures. Therefore, replacing CaS in KR slag with BaS can achieve deep solidification of the S element, and can reduce the resulfurization of molten steel caused by the resource utilization of KR slag. The corresponding replacement reaction equation is:

[0009] CaS+Ba=BaS+Ca

[0010] ΔG=-47139-29T

[0011] The above formula T is the thermodynamic temperature. The temperature of KR desulfurization slag after slagging is generally 1250-1350℃. Covering the surface of hot KR desulfurization slag with a replacement agent containing elemental Ba can make full use of the high temperature state of KR desulfurization slag obtained by slagging of molten iron KR pretreatment. However, at this time, the Gibbs free energy is only -91.3kJ~-94.2kJ. Due to the small Gibbs free energy of the reaction and the inactive mass transfer in the KR desulfurization slag, the replacement reaction rate is slow and cannot meet the requirements of KR desulfurization slag solid sulfur treatment. Therefore, an electromagnetic pulse external field is applied to promote the replacement reaction of Ba and CaS.

[0012] The mechanism of promoting the above replacement reaction by electromagnetic pulse treatment is:

[0013] (1) Induced current and eddy current effect: Under the action of electromagnetic pulses, the conductive Ba generates an induced current and generates Joule heat under the action of its internal resistance, which causes the local temperature around the Ba metal to rise, increasing the Gibbs free energy of the reaction, helping to form a more active reaction area and accelerating the replacement of CaS and Ba.

[0014] (2) Diffusion enhancement caused by high-frequency oscillation: The high-frequency oscillation of the electromagnetic pulse will induce continuous electron movement and electric field oscillation in the KR desulfurization slag, increase the energy of ions and electrons in the reactants, promote electron transfer between CaS and Ba; and help loosen the organizational structure of the KR desulfurization slag and enhance the material diffusion rate during the reaction process.

[0015] (3) Lattice defects and surface activation: Electromagnetic pulses can induce microstructural changes on the material surface and inside the lattice, promote the formation of lattice defects, dislocations and vacancies, increase the surface energy of the material, break the passivation layer and adsorption layer on the surface of Ba and CaS, and thus accelerate the replacement reaction.

[0016] It should be noted that the specific process parameters of the electromagnetic pulse treatment are particularly important in the present invention, and the range of the pulse frequency and pulse intensity of the electromagnetic pulse is selected based on the results of the hot test. When the parameters are too small, the replacement reaction rate cannot be significantly improved, and when the parameters are too large, it will cause the gasification of elemental Ba and the splashing of slag.

[0017] In summary, KR desulfurized slag is obtained by adding a replacement agent containing elemental Ba to the surface of the slag layer of the hot KR desulfurized slag and performing electromagnetic pulse treatment to promote the sulfur element in the KR desulfurized slag to generate BaS through replacement reaction. When the desulfurized KR desulfurized slag is used as a slag-making agent or desulfurizing agent, it can reduce the sulfur element in it from flowing back into the molten iron or molten steel, and then it can replace part of the lime, reduce the amount of lime added, and make full use of the unreacted CaO in the KR desulfurized slag.

[0018] Furthermore, the temperature of the hot KR desulfurization slag is greater than the melting point of the replacement agent. It should be noted that the melting point of metal Ba is 727°C, and the temperature of the hot KR desulfurization slag obtained after slagging of KR desulfurization molten iron is generally 1250°C to 1350°C, so that the replacement agent can be quickly melted under the heat transfer of the KR desulfurization slag, thereby increasing the mass transfer rate of the replacement reaction.

[0019] Furthermore, the density of the slag layer is less than the density of the displacer. The density of the displacer is 3.5-4.5 g / cm 3 , whose density is greater than that of KR slag, and the material containing elemental Ba slowly passes through the slag layer from top to bottom, providing favorable kinetic conditions for the replacement reaction of CaS.

[0020] Furthermore, the temperature of the hot KR desulfurization slag is greater than the melting point of the displacer, and the density of the slag layer is less than the density of the displacer.

[0021] Furthermore, the replacement agent is Ba alloy or metal Ba, wherein the Ba alloy includes Ba-Al, Ba-Mg, and Ba-Si alloy, and the particle size of the replacement agent is 2 to 4 mm; the calculation formula of the amount thereof is:

[0022]

[0023] In the formula: M 钡 M is the amount of metal Ba added; 渣 is the mass of slag; w s is the percentage of S in the slag; η 钡 The dosage formula is based on laboratory and industrial test results. If the dosage coefficient is too large, it will cause waste of metal Ba, and if it is too small, the sulfur fixation effect is not ideal.

[0024] Furthermore, the surface of the hot KR desulfurized slag is covered with a replacement agent containing elemental Ba, specifically, after the slagging is completed, the replacement agent containing elemental Ba is added to the surface of the slag layer by spraying through a rotating chute, and an inert gas is used as a carrier gas. It should be noted that the synergistic effect of spraying through a rotating chute and adding initial kinetic energy through the carrier inert gas is conducive to ensuring that the replacement agent can be evenly covered on the slag surface, increasing the reaction sites, and further improving the replacement rate and the utilization rate of Ba.

[0025] Furthermore, the surface of the hot KR desulfurization slag is covered with a replacement agent containing elemental Ba under an inert gas protection atmosphere, thereby preventing the elemental Ba in the material from reacting with O2 to generate BaO and losing its replacement capacity, and can further improve the mass transfer rate.

[0026] Furthermore, the surface of the hot KR desulfurization slag obtained by the molten iron slag treatment is covered with a replacement agent containing elemental Ba. The specific operation is: before the molten iron slag treatment, N2 is introduced into the slag pot at a rate of 5 to 10 Nm 3 / min, ventilation time 1 to 3min, add the hot KR desulfurized slag obtained by molten iron slag treatment into the slag pot. In the above operation, a large flow rate of N2 is used to quickly drain the O2 inside the slag pot.

[0027] Furthermore, after the slag removal is completed, the slag pot cover is closed and N2 is continuously introduced into the slag pot until the electromagnetic pulse treatment is completed. The N2 introduction speed is 0.3-0.8 Nm 3 / min; and / or the N2 used to maintain the inert atmosphere is blown into the slag pot through bottom blowing. In the above operation, after pouring the KR desulfurization slag, the N2 is introduced into the slag pot to maintain the inert atmosphere in the slag pot, thereby preventing the Ba in the replacement agent from being oxidized and further improving the mass transfer rate.

[0028] Furthermore, the KR desulfurization slag includes the following components in percentage by mass: CaO 30-60%, SiO2 5-20%, Al2O3 1-15%, MgO 5-20%, FeO 1-10%, and S 0.5-3%.

[0029] Furthermore, the KR desulfurization slag treated with electromagnetic pulses is cooled to obtain KR solid sulfur slag. Specifically, the KR desulfurization slag treated with electromagnetic pulses is slowly cooled to 800°C, then air-cooled to room temperature and the cooled KR desulfurization slag is crushed. After electromagnetic pulse treatment, there are still trace amounts of S elements scattered in the matrix in the KR desulfurization slag. The diffusion of S elements is one of the key links that affect the rate of replacement reaction. When the temperature is above 800°C, the S elements in the slag pot diffuse faster, which can increase the replacement ratio of CaS without consuming additional heat sources. Slow cooling can provide sufficient time for the migration and reaction of S elements. After electromagnetic pulse treatment, when the temperature is lower than 800°C, the material in the slag pot gradually turns into a solid state, and the replacement reaction is difficult to continue.

[0030] A second aspect of the present invention provides a KR desulfurization slag, which is prepared by any of the desulfurization methods described above.

[0031] The third aspect of the present invention provides an application of the KR desulfurization slag, or the KR desulfurization slag prepared by any of the desulfurization methods described above, in converter smelting or molten iron KR pretreatment.

[0032] Compared with the prior art, the technical solution provided by the present invention can achieve the following beneficial effects:

[0033] (1) The solid sulfur method of the present invention adds a replacement agent containing elemental Ba to the surface of the slag layer of the hot KR desulfurization slag, and uses a material containing elemental Ba as a replacement agent. Ba undergoes a replacement reaction with CaS in the KR desulfurization slag to generate BaS with greater stability. In addition, the surface of the hot KR desulfurization slag is covered with the replacement agent containing elemental Ba under an inert gas protection atmosphere, thereby preventing the Ba element in the replacement agent from reacting with O2 to generate BaO and losing its replacement ability, and can further increase the mass transfer rate, thereby promoting the replacement reaction. By converting CaS into BaS, the resulfurization problem caused by the decomposition of CaS in the traditional KR desulfurization slag under high temperature or oxidizing environment is avoided, which is conducive to the resource utilization of the solidified KR desulfurization slag.

[0034] (2) The desulfurization method of the present invention further adopts electromagnetic pulse treatment to increase the local temperature at the reaction interface of Ba and CaS, and the high-frequency pulse enhances the S migration rate inside the KR desulfurization slag, effectively improving the replacement reaction rate and limit. At the same time, compared with the traditional overall heating scheme, the electromagnetic pulse treatment technology improves energy utilization and effectively reduces process energy consumption and production costs.

[0035] (3) The sulfur fixation method of the present invention has a simple process flow. By covering the surface of the hot KR desulfurization slag obtained by slagging with molten iron with a replacement agent containing elemental Ba, the high-temperature waste heat of the KR desulfurization slag obtained after slagging is fully utilized. No water quenching is required, and the environmental pollution is small. No major changes are required to the existing desulfurization slag treatment process. It is easy to be integrated into the existing industrial production of KR desulfurization slag treatment process, and has good prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure when feeding materials into the slag pot in an embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of the structure when electromagnetic pulse treatment is performed on KR desulfurization slag in an embodiment of the present invention.

[0038] Figure 3 This is a comparison chart of the resulfurization effects of the KR desulfurized slag obtained in Example 1 of the present invention and the KR desulfurized slag that has not been subjected to desulfurization treatment when used in converter smelting.

[0039] Figure 4 This is a comparison chart of the desulfurization effects of the KR desulfurization slag obtained in Example 1 of the present invention, the KR desulfurization slag obtained in Comparative Example 5, and the desulfurization slag without KR addition, respectively applied in KR molten iron pretreatment.

[0040] Description of labels:

[0041] 1. Slag tank;

[0042] 2. Rotating chute;

[0043] 3. Electromagnetic generator. DETAILED DESCRIPTION

[0044] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with embodiments.

[0045] The "hot KR desulfurization slag" referred to in the following embodiments and comparative examples is "the KR desulfurization slag obtained immediately after the KR molten iron pretreatment slag is scraped". The temperature of the KR desulfurization slag obtained after the KR molten iron desulfurization slag is generally 1250℃~1350℃.

[0046] Example 1

[0047] This embodiment provides a KR desulfurization slag desulfurization method based on electromagnetic pulse. The KR desulfurization slag used is shown in Table 1. Its mass is 1740 kg and its density is 2.85 g / cm 3 The detailed composition is shown in Table 1 below. Ba-Al alloy is used as the replacement agent, in which the effective Ba content is 65% and the density is 4.1g / cm 3 , melting point is 620℃, particle size is 2-4mm. The steps of the desulfurization method of KR desulfurization slag are as follows:

[0048] (1) Before the slag removal in KR hot metal pretreatment, N2 is blown into the bottom of slag pot 1. The volume of the slag pot used is 8m 3 , control the bottom blowing N2 flow rate to 5Nm 3 / min, blowing time 3min, slag removal starts after oxygen in slag tank 1 is exhausted;

[0049] (2) After the slag removal, 130 kg of Ba-Al alloy was sprayed onto the surface of the KR desulfurized slag using N2 as the carrier gas. The spraying direction was controlled by the rotating chute 2 to ensure that the Ba-Al alloy was evenly distributed on the slag layer surface. The carrier N2 flow rate was 0.25 Nm 3 / min; spraying process reference Figure 1 As shown; after closing the slag tank cover, change the bottom blowing N2 flow rate to 0.5Nm 3 / min and maintain until the electromagnetic pulse treatment is completed; transfer the slag pot to the slag treatment workshop, turn on the electromagnetic generator 3 to perform electromagnetic pulse treatment on the KR desulfurization slag, the treatment time is 15min, the pulse frequency is 300kHz, the pulse intensity is 500A, and the electromagnetic pulse treatment process is referred to Figure 2 As shown;

[0050] (4) After the electromagnetic pulse treatment is completed, the N2 is stopped, and the temperature of the slag pot 1 is slowly lowered to 800°C. The KR desulfurized slag is poured into the slag field and air-cooled to room temperature. After crushing, the KR solid sulfur slag is obtained.

[0051] The mass of KR desulfurization slag obtained in this example is 1670 kg, and the N2 consumption of the whole process of the desulfurization method is 33.7 Nm 3 , consuming 7.4kWh of electricity.

[0052] Table 1 Composition of KR desulfurization slag used in Example 1

[0053]

[0054] Comparative Example 1

[0055] This comparative example provides a KR desulfurization slag desulfurization method based on electromagnetic pulse. The KR desulfurization slag used is shown in Table 1. The difference between this comparative example and Example 1 is that no electromagnetic pulse treatment is performed, and the slag pot 1 is slowly cooled to 800°C; other operations are basically the same as Example 1.

[0056] Comparative Example 2

[0057] This comparative example provides a KR desulfurization slag desulfurization method based on electromagnetic pulse. The KR desulfurization slag used is detailed in Table 1. The difference between this comparative example and Example 1 is that the parameters for electromagnetic pulse treatment are different. The electromagnetic generator 3 is turned on to perform electromagnetic pulse treatment on the KR desulfurization slag. The treatment time is 12 minutes, the pulse frequency is 600kHz, and the pulse intensity is 700A. Other operations are basically the same as Example 1.

[0058] Comparative Example 3

[0059] This comparative example provides a KR desulfurization slag desulfurization method based on electromagnetic pulse. The KR desulfurization slag used is detailed in Table 1. The difference between this comparative example and Example 1 is that the parameters for electromagnetic pulse treatment are different. The electromagnetic generator 3 is turned on to perform electromagnetic pulse treatment on the KR desulfurization slag. The treatment time is 25 minutes, the pulse frequency is 280kHz, and the pulse intensity is 280A. Other operations are basically the same as Example 1.

[0060] Comparative Example 4

[0061] This comparative example provides a KR desulfurization slag desulfurization method based on electromagnetic pulse. The KR desulfurization slag used is shown in Table 1. The difference between this comparative example and Example 1 is that: N2 is not introduced into the slag pot 1 before and after slag scraping, and N2 is not used as the carrier gas for spraying Ba-Al alloy; other operations are basically the same as Example 1.

[0062] Comparative Example 5

[0063] This comparative example provides a method for recycling KR desulfurization slag within a steel plant. The KR desulfurization slag used is shown in Table 1, and includes the following steps:

[0064] (1) During the slag discharge process of KR hot metal pretreatment, 15% of Fe2O3 and 25% of bauxite by weight of the slag are added to the KR hot metal pretreatment slag;

[0065] (2) After the slag is discharged from the KR molten iron pretreatment, oxygen is blown into the molten iron for treatment; the blowing device is inserted to a depth of 1 / 2 below the slag surface, and the oxygen flow rate is controlled to 250 Nm 3 / (ht slag), the oxygen blowing time is 8 minutes, and the oxygen temperature is maintained at 1150°C during the blowing process to obtain KR desulfurized slag after sulfur reduction.

[0066] Performance Test 1

[0067] The KR desulfurized slag obtained after treatment in Example 1, the KR desulfurized slag after treatment in Comparative Examples 1-4, and the KR desulfurized slag without solid sulfur treatment were respectively applied to converter smelting, and heats with similar S content in molten iron were selected for testing. The amount of KR desulfurized slag added was 10 kg / t steel to replace part of the slag-making agent, and the other operating conditions were the same. The effect of preventing backsulfurization is detailed in Table 2 and Figure 3 :

[0068] Table 2 Desulfurization effect applied to converter smelting

[0069]

[0070] From Table 2 and Figure 3 It can be seen that the untreated KR desulfurization slag is directly applied to converter smelting, which causes different degrees of resulfurization of molten steel in heats 1-5, while the KR desulfurization slag obtained after the treatment in Example 1 is applied to converter smelting, and the sulfur content of the molten iron is reduced in heats 1 and 3 when the sulfur content of the molten iron is relatively high. The resulfurization amount in heats 2, 4 and 5 when the sulfur content of the molten iron is relatively low is less than that of the untreated KR slag directly returned to the converter. Therefore, the KR desulfurization slag after sulfur fixation obtained by the treatment in Example 1 can be widely used in the converter steelmaking process to reduce the amount of slag-making materials such as lime and dolomite.

[0071] The KR sulfur-fixing slag obtained by the preparation methods of Comparative Examples 1-4 is less effective in preventing resulfurization in the converter smelting process than the sulfur-fixing slag obtained in Example 1.

[0072] Performance Test 2

[0073] The KR desulfurization slag obtained after the treatment of Example 1 and the KR desulfurization slag obtained after the treatment of Comparative Examples 1-5 were respectively used in the KR molten iron pretreatment process as a slag-making agent as the experimental group, and the slag-making agent without adding KR desulfurization slag was used as the control group; the molten iron ladle with similar S content was selected for the KR molten iron pretreatment test, and the KR desulfurization slag was added in an amount of 6kg / t steel to replace part of the slag-making agent. The rest of the operations of the experimental group and the comparative group were the same. The desulfurization effect comparison results are shown in Tables 3 and Figure 4 :

[0074] Table 3 Resulfurization effect applied to KR hot metal pretreatment

[0075]

[0076] From Table 3 and Figure 4 It can be seen that the desulfurization capacity of molten iron pretreatment using the KR desulfurization slag prepared in Example 1 as a slag-forming agent is almost the same as that of the control group without adding KR desulfurization slag as a slag-forming agent, while the sulfur content in the molten iron after pretreatment with the KR desulfurization slag obtained in Comparative Example 5 decreased less, indicating that the desulfurization capacity of the KR desulfurization slag prepared in Comparative Example 5 is significantly reduced. Therefore, the KR solid sulfur slag obtained by the preparation method of the present invention has a better desulfurization effect in the KR pretreatment process than that of Comparative Example 5, and can be reused in the KR pretreatment process.

[0077] The KR solid sulfur slag obtained by the preparation methods of Comparative Examples 1-4 is less effective in reducing the sulfur content of molten iron than the solid sulfur slag obtained in Example 1 when used in KR molten iron pretreatment, but the effects are not lower than those of Comparative Example 5.

[0078] Example 2

[0079] This embodiment provides a KR desulfurization slag desulfurization method based on electromagnetic pulse. The KR desulfurization slag used is shown in Table 4. Its mass is 2217 kg and its density is 2.87 g / cm 3 Ba-Al alloy is used as the replacement agent, with an effective Ba content of 55% and a density of 4.1g / cm 3 , the melting point is 620℃, and the particle size is 2-4mm. The steps of the sulfur fixation method are as follows:

[0080] Table 4 Composition of KR desulfurization slag used in Example 2

[0081]

[0082]

[0083] (1) Before the slag removal in KR hot metal pretreatment, N2 was blown into the bottom of slag pot 1. The volume of the slag pot used was 10m 3 , control the bottom blowing N2 flow rate to 10Nm 3 / min, blowing time 1.5min, slag removal starts after the oxygen in slag tank 1 is emptied;

[0084] (2) After the slag removal, 162.5 kg of Ba-Al alloy was sprayed onto the surface of the KR desulfurized slag using N2 as the carrier gas. The spraying direction was controlled by the rotating chute 2 to ensure that the Ba-Al alloy was evenly distributed on the slag layer surface. The carrier N2 flow rate was 0.3 Nm 3 / min; After closing the slag tank cover, change the bottom blowing N2 flow rate to 0.6Nm 3 / min and maintain until the electromagnetic pulse treatment is completed; transfer the slag pot to the slag treatment workshop, turn on the electromagnetic generator 3 to perform electromagnetic pulse treatment on the KR desulfurization slag, the treatment time is 20min, the pulse frequency is 400kHz, and the pulse intensity is 600A;

[0085] (3) After the electromagnetic pulse treatment is completed, the bottom blowing is stopped and N2 is introduced. The temperature of the slag pot 1 is slowly lowered to 800°C. The KR desulfurization slag is poured into the slag field and air-cooled to room temperature. After crushing, the KR solid sulfur slag is obtained.

[0086] The mass of KR desulfurization slag obtained in this example is 2107 kg, and the N2 consumption of the whole process of the desulfurization method is 37.2 Nm 3 , consuming 9.4kWh of electricity.

[0087] Example 3

[0088] This embodiment provides a KR desulfurization slag desulfurization method based on electromagnetic pulse. The KR desulfurization slag used is shown in Table 5. Its mass is 2035 kg and its density is 2.82. Ba-Mg alloy is used as a replacement agent. The effective Ba content is 70% and the density is 3.8 g / cm 3 , melting point is 650℃, particle size is 2-4mm. The steps of the sulfur fixation method are as follows:

[0089] Table 5 Composition of KR desulfurization slag used in Example 3

[0090]

[0091] (1) Before the slag removal in KR hot metal pretreatment, N2 was blown into the slag pot 1. The volume of the slag pot used was 10m 3 , control the bottom blowing N2 flow rate to 8Nm 3 / min, blowing time 1.5min, slag removal starts after the oxygen in slag tank 1 is emptied;

[0092] (2) After the slag removal, 130.6 kg of Ba-Mg alloy was sprayed onto the surface of the KR desulfurized slag using N2 as the carrier gas. The spraying direction was controlled by the rotating chute 2 to ensure that the Ba-Mg alloy was evenly distributed on the slag layer surface. The carrier N2 flow rate was 0.3 Nm 3 / min; After closing the slag tank cover, change the bottom blowing N2 flow rate to 0.8Nm 3 / min and maintain until the electromagnetic pulse treatment is completed; transfer the slag pot to the slag treatment workshop, turn on the electromagnetic generator 3 to perform electromagnetic pulse treatment on the KR desulfurization slag, the treatment time is 18min, the pulse frequency is 500kHz, and the pulse intensity is 300A;

[0093] (4) After the electromagnetic pulse treatment is completed, the N2 is stopped, and the temperature of the slag pot 1 is slowly lowered to 800°C. The KR desulfurized slag is poured into the slag field and air-cooled to room temperature. After crushing, the KR solid sulfur slag is obtained.

[0094] The mass of KR desulfurization slag obtained in this embodiment is 2107 kg, and the N2 consumption of the whole process of the desulfurization method is 36.8 Nm 3 , consuming 8.1kWh of electricity.

Claims

1. A KR desulfurization slag desulfurization method based on electromagnetic pulse, characterized in that: include: The surface of the hot KR desulfurization slag obtained by slagging treatment with molten iron is covered with a replacement agent containing elemental Ba; The KR desulfurization slag covered with the displacer is subjected to electromagnetic pulse treatment, and the treatment conditions include: treatment time of 15 to 20 minutes, pulse frequency of 300 to 500 kHz, and pulse intensity of 300 to 600A; The KR desulfurized slag treated by electromagnetic pulse is cooled to obtain KR sulfur-fixing slag.

2. The method for fixing sulfur in KR desulfurized slag based on electromagnetic pulse according to claim 1, characterized in that: The temperature of the hot KR desulfurization slag is greater than that of the displacing agent; and / or the slag layer density of the hot KR desulfurization slag is less than that of the displacing agent.

3. The method for fixing sulfur in KR desulfurized slag based on electromagnetic pulse according to claim 2, characterized in that: The replacement agent containing elemental Ba is Ba alloy or metal Ba, wherein the Ba alloy includes Ba-Al, Ba-Mg, Ba-Si alloy, and the particle size of the replacement agent is 2-4 mm; the calculation formula of its dosage is: In the formula: M 钡 M is the amount of metal Ba added; 渣 is the mass of slag; w s is the percentage of S in the slag; η 钡 For metal Ba purity.

4. The method for fixing sulfur in KR desulfurized slag based on electromagnetic pulse according to claim 1, characterized in that: The method of covering the surface of the hot KR desulfurized slag with a replacement agent containing elemental Ba is as follows: after the slagging is completed, the replacement agent containing elemental Ba is added to the surface of the slag layer by spraying through a rotating chute (2), and an inert gas is used as a carrier gas.

5. The KR desulfurization slag desulfurization method based on electromagnetic pulse according to any one of claims 1 to 4, characterized in that: The process of covering the surface of the hot KR desulfurization slag with the replacement agent containing elemental Ba is carried out under an atmosphere protected by an inert gas.

6. The method for fixing sulfur in KR desulfurized slag based on electromagnetic pulse according to claim 5, characterized in that: The specific operation of covering the surface of the hot KR desulfurization slag obtained by the molten iron slag treatment with a replacement agent containing elemental Ba is as follows: Before the molten iron is deslagging, N2 is introduced into the slag pot (1) at a rate of 5 to 10 Nm 3 / min, ventilation time 1 to 3min, the hot KR desulfurization slag obtained by molten iron slag treatment is added into the slag pot (1).

7. The method for fixing sulfur in KR desulfurized slag based on electromagnetic pulse according to claim 6, characterized in that: After the slag removal is completed, the slag pot cover is closed and N2 is continuously introduced into the slag pot (1) until the electromagnetic pulse treatment is completed. The N2 introduction speed is 0.3-0.8 Nm 3 / min; And / or the N2 used to maintain the inert atmosphere is blown into the slag pot (1) through bottom blowing.

8. The KR desulfurization slag desulfurization method based on electromagnetic pulse according to any one of claims 1 to 4, characterized in that: The KR desulfurization slag comprises the following components in percentage by mass: CaO 30-60%, SiO2 5-20%, Al2O3 1-15%, MgO 5-20%, FeO 1-10%, and S 0.5-3%.

9. A KR sulfur-fixing slag, characterized in that: The KR desulfurized slag is obtained by treating with the method described in any one of claims 1-8.

10. Use of the KR desulfurized slag as claimed in claim 9 or prepared by the desulfurization method as claimed in any one of claims 1 to 8 in converter smelting or molten iron KR pretreatment.

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