A process for resource utilization of KR desulfurization residue

Abstract

This invention relates to the field of metallurgical solid waste resource utilization, and a KR desulfurization slag resource utilization process, comprising: (1) removing slag from molten iron to obtain pre-desulfurization slag and molten iron after slag removal; granulating and cooling the pre-desulfurization slag and removing iron with a magnetic drum to obtain iron particles and pre-desulfurization slag tailings; returning the iron particles to the blast furnace for utilization; and preparing the pre-desulfurization slag tailings into slag powder; (2) performing KR desulfurization on the molten iron after slag removal obtained in step (1), followed by slag removal to obtain desulfurization slag; performing primary and secondary crushing on the desulfurization slag to obtain secondary crushed desulfurization slag; and returning the secondary crushed desulfurization slag to the sintering process for reuse. This method can achieve 100% resource utilization of KR desulfurization slag, effectively recover resources such as iron and calcium, reduce carbon dioxide emissions, eliminate environmental hazards, and has good economic and social benefits.

Description

Technical Field

[0001] This invention relates to the field of metallurgical solid waste resource utilization, specifically to a KR desulfurization slag resource utilization process. Background Technology

[0002] The main desulfurization process for molten iron in domestic steel enterprises is the KR process, which primarily uses quicklime (CaO) as the desulfurizing agent. KR desulfurization slag is a byproduct of the KR process, with a production rate of approximately 7-10 kg / t of molten iron. It contains a large amount of valuable elements such as iron and calcium, as well as small amounts of harmful elements such as sulfur. Currently, the main treatment process for KR desulfurization slag in China is the "drip irrigation method." This involves slowly dripping water into the high-temperature KR desulfurization slag in a slag pot for about 24 hours, allowing the slag to be fully pulverized and cooled. After treatment by the "drip irrigation method," the KR desulfurization slag is then processed by magnetic separation to recover the iron. The remaining tailings are mainly stockpiled. This treatment process has two main drawbacks: first, because the desulfurization slag contains iron and sulfur, SO2 and H2S are generated during the "drip irrigation" cooling process, impacting the environment; second, the large-scale stockpiling of tailings not only occupies land resources but also poses environmental hazards.

[0003] The proposed method, "A Method for Internal Recycling of KR Desulfurization Slag in a Steel Plant," with application number 202110514292.0, mainly includes: crushing KR desulfurization slag and then performing magnetic separation to obtain slag iron and tailings; then subjecting the tailings to high-temperature oxidation desulfurization treatment, specifically heating the tailings to 1200–1350℃ and holding for 10–40 minutes to obtain sulfur-containing flue gas and pre-melted slag; further collecting and treating the sulfur-containing flue gas, and using the pre-melted slag as slag-forming material for early-stage slag formation in the converter, thus realizing the internal recycling of KR desulfurization slag in the steel plant. This process requires high-temperature desulfurization treatment of the tailings before utilization, resulting in high energy consumption.

[0004] The proposed method, "A Method for Efficient Resource Utilization of KR Desulfurization Slag," with application number 202010107303.9, mainly includes: firstly, crushing the desulfurization slag to a specified particle size, then obtaining slag iron and tailings through magnetic separation. The slag iron is returned to the steelmaking process to replace scrap steel recycling; the tailings are further ground to replace quicklime in sintering dry or semi-dry desulfurization processes, ultimately achieving full utilization of the desulfurization slag. This process requires further grinding of the tailings to replace quicklime in sintering dry or semi-dry desulfurization processes. Due to the poor grindability of steel slag, further grinding results in high energy consumption. Furthermore, because the calcium oxide content of the desulfurization slag is lower than that of the quicklime used for desulfurization, its desulfurization effect on sintering flue gas needs further verification.

[0005] The proposed method for comprehensive treatment of KR desulfurization slag, application number 202010107302.4, mainly includes: firstly, crushing the desulfurization slag to a specified particle size, and then obtaining slag iron and tailings through magnetic separation. The slag iron is returned to the steelmaking process to replace scrap steel for reuse; the tailings participate in sintering ore blending, replacing sintering iron-containing raw materials and fluxes in a certain proportion. This process uses the slag iron obtained from magnetic separation to replace scrap steel in the steelmaking process. However, because the desulfurization slag iron has a high sulfur content, it easily increases the sulfur content in molten steel, affecting the quality of the molten steel. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of high energy consumption and impact on product quality in existing KR desulfurization slag treatment technologies, and to provide a resource utilization process for KR desulfurization slag. This method can achieve 100% resource utilization of KR desulfurization slag, effectively recover resources such as iron and calcium, reduce carbon dioxide emissions, eliminate environmental hazards, and has good economic and social benefits.

[0007] To achieve the above objectives, the present invention provides a process for the resource utilization of KR desulfurization slag, which includes the following steps:

[0008] (1) Remove slag from molten iron to obtain slag before desulfurization and molten iron after slag removal. Granulate and cool the slag before desulfurization and remove iron with a magnetic drum to obtain iron particles and tailings of the slag before desulfurization. Return the iron particles to the blast furnace for use and prepare the tailings of the slag before desulfurization into slag powder. The magnetic field strength on the surface of the magnetic drum is 1800-2400GS and the rotation speed is 10-50r / min.

[0009] (2) The molten iron obtained after slag removal in step (1) is subjected to KR desulfurization, followed by slag removal to obtain desulfurized slag. The desulfurized slag is subjected to primary crushing and secondary crushing to obtain secondary crushed desulfurized slag. The secondary crushed desulfurized slag is returned to the sintering process for reuse. Among them, the material with a particle size greater than 5mm in the secondary crushed desulfurized slag does not exceed 1% of the total weight of the secondary crushed desulfurized slag, and the material with a particle size less than 0.075mm does not exceed 10% of the total weight of the secondary crushed desulfurized slag.

[0010] In step (1) of this invention, in order to improve the desulfurization efficiency, it is necessary to remove the slag from the molten iron before desulfurizing it. The specific operation of removing the slag from the molten iron is to use a slag remover to remove the floating slag on the surface of the molten iron.

[0011] In step (1) of this invention, granulation cooling is carried out using the INBA method. This method has a high treatment efficiency for desulfurization slag and the treated desulfurization slag has stable performance, which is beneficial for preparing slag powder and ensuring its performance.

[0012] In this invention, a magnetic drum is used to remove iron, and the process conditions are controlled within the above-mentioned range. The obtained iron particles have a TFe content ≥ 85wt% and an iron particle size < 120mm; the MFe content in the desulfurization tailings is < 1wt%.

[0013] Further, the desulfurization tailings obtained in step (1) are dried and then ground to a specific surface area greater than 400 m². 2 / kg, and slag powder can be obtained.

[0014] In step (2) of this invention, the KR desulfurization is a conventional operation in the field. The specific steps are: adding a desulfurizing agent to the molten iron after slag removal obtained in step (1), and then performing KR mechanical stirring; wherein the desulfurizing agent used is a conventional desulfurizing agent used in the field, and KR mechanical stirring is also a conventional operation process in the field.

[0015] In step (2), after the KR desulfurization is completed, the specific operation of slag removal is also as follows: use a slag remover to remove the floating slag on the surface of the molten iron.

[0016] In the preferred case, the reason for performing primary and secondary crushing on the desulfurization slag in step (2) is that primary crushing is for molten desulfurization slag, and its purpose is to prevent the molten desulfurization slag from sticking together to form large clumps, which is not conducive to subsequent processing. During the primary crushing process, the desulfurization slag can also be cooled. Secondary crushing is for cold desulfurization slag, and its purpose is to ensure that the slag can meet the requirements for subsequent re-sintering after processing.

[0017] Further in step (2), the desulfurization slag is subjected to primary crushing to obtain primary crushed desulfurization slag, and then the primary crushed desulfurization slag is subjected to secondary crushing to obtain secondary crushed desulfurization slag.

[0018] Furthermore, in step (2), the material with a particle size greater than 200mm in the desulfurization slag after primary crushing does not exceed 10% of the total weight of the desulfurization slag after primary crushing, so as to be used as raw material to enter the secondary crushing system for processing.

[0019] In step (2), the temperature of the desulfurization slag after primary crushing is ≤65℃.

[0020] In step (2), in the preferred case, different crushing methods are used in the primary crushing and secondary crushing according to the material characteristics. Specifically, the primary crushing method is roller crushing; the secondary crushing method is hammering or rod milling.

[0021] In step (2) of this invention, the particle size of the desulfurization slag after secondary crushing is controlled within a certain range in order to meet the requirements for sintering utilization.

[0022] This method allows the desulfurization slag obtained after secondary crushing to be returned to the sintering process for reuse, with the sulfur dioxide concentration at the outlet of the sintering flue gas desulfurization system not exceeding 35 mg / m³. 3 It meets the requirements for ultra-low emissions.

[0023] The molten iron after slag removal in step (2) of this invention is used in the steelmaking process of converter or electric furnace.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1) This technology combines the characteristics of KR desulfurization process and classifies and utilizes the slag produced before and after KR desulfurization according to their different characteristics, so as to achieve 100% resource utilization of KR desulfurization slag.

[0026] 2) This technology, combined with the steelmaking process, enables the recovery and utilization of resources such as iron and calcium in KR desulfurization slag, and effectively controls the impact of sulfur in the desulfurization slag on the system.

[0027] 3) Compared with existing technologies, this technology avoids high-temperature desulfurization and fine grinding of desulfurization slag and tailings, thus saving energy. Attached Figure Description

[0028] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0030] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] The resource utilization process of KR desulfurization slag in this invention is as follows: Figure 1 As shown, the present invention will be described in detail below through embodiments.

[0032] Example 1

[0033] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 88.37wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 0.88wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 1800GS and the rotation speed is 16r / min.

[0034] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (the primary crushing method is roller crushing) on ​​the desulfurized slag to a particle size of less than 200 mm to obtain primary crushed desulfurized slag. Then perform secondary crushing (the secondary crushing method is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 5 mm to obtain secondary crushed desulfurized slag (based on the total weight of the secondary crushed desulfurized slag as 100 wt%). The main chemical components of the desulfurization slag after secondary crushing are: TFe 26.00wt%, MFe 24.78wt%, CaO 44.35wt%, MgO 1.38wt%, Al2O3 2.40wt%, SiO2 14.70wt%, S 1.51wt%, and P 0.07wt%. The desulfurization slag after secondary crushing is returned to the sintering process for reuse. The temperature of the desulfurization slag after primary crushing is ≤65℃.

[0035] Example 2

[0036] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 87.58wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 0.74wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 1900GS and the rotation speed is 13r / min.

[0037] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (the primary crushing method is roller crushing) on ​​the desulfurized slag to a particle size of less than 200 mm to obtain primary crushed desulfurized slag. Then perform secondary crushing (the secondary crushing method is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 5 mm to obtain secondary crushed desulfurized slag (based on the total weight of the secondary crushed desulfurized slag as 100 wt%). The main chemical components of the desulfurization slag after secondary crushing are: TFe 31.37wt%, MFe 26.17wt%, CaO 49.07wt%, MgO 1.33wt%, Al2O3 2.39wt%, SiO2 13.95wt%, S 1.60wt%, and P 0.04wt%. The desulfurization slag after secondary crushing is returned to the sintering process for reuse. The temperature of the desulfurization slag after primary crushing is ≤65℃.

[0038] Example 3

[0039] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 86.58wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 0.90wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 2000GS and the rotation speed is 10r / min.

[0040] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (the primary crushing method is roller crushing) on ​​the desulfurized slag to a particle size of less than 200 mm to obtain primary crushed desulfurized slag. Then perform secondary crushing (the secondary crushing method is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 5 mm to obtain secondary crushed desulfurized slag (based on the total weight of the secondary crushed desulfurized slag as 100 wt%). The main chemical components of the desulfurization slag after secondary crushing are: TFe 33.27wt%, MFe 26.18wt%, CaO 42.07wt%, MgO 1.41wt%, Al2O3 2.34wt%, SiO2 13.89wt%, S 1.46wt%, and P 0.04wt%. The desulfurization slag after secondary crushing is returned to the sintering process for reuse. The temperature of the desulfurization slag after primary crushing is ≤65℃.

[0041] Example 4

[0042] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 86.27wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 0.72wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 2000GS and the rotation speed is 20r / min.

[0043] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (primary crushing is roller crushing) on ​​the desulfurized slag to a particle size of less than 200 mm to obtain primary crushed desulfurized slag. Then perform secondary crushing (secondary crushing is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 5 mm to obtain secondary crushed desulfurized slag (with the total weight of the secondary crushed desulfurized slag as 100 wt%). The main chemical components of the desulfurization slag after secondary crushing are: TFe 40.20wt%, MFe 34.29wt%, CaO 28.60wt%, MgO 0.37wt%, Al2O3 1.32wt%, SiO2 5.77wt%, S 0.47wt%, and P 0.03wt%. The desulfurization slag after secondary crushing is returned to the sintering process for reuse. The temperature of the desulfurization slag after primary crushing is ≤65℃.

[0044] Example 5

[0045] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 85.69wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 0.58wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 2300GS and the rotation speed is 15r / min.

[0046] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (primary crushing is roller crushing) on ​​the desulfurized slag to a particle size of less than 200 mm to obtain primary crushed desulfurized slag. Then perform secondary crushing (secondary crushing is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 5 mm to obtain secondary crushed desulfurized slag (with the total weight of the secondary crushed desulfurized slag as 100 wt%). The main chemical components of the desulfurization slag after secondary crushing are: TFe 35.78wt%, MFe 28.04wt%, CaO 32.59wt%, MgO 0.79wt%, Al2O3 1.62wt%, SiO2 8.33wt%, S 0.92wt%, and P 0.04wt%. The desulfurization slag after secondary crushing is returned to the sintering process for reuse. The temperature of the desulfurization slag after primary crushing is ≤65℃.

[0047] Example 6

[0048] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 87.03wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 0.66wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 2300GS and the rotation speed is 10r / min.

[0049] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (primary crushing is roller crushing) on ​​the desulfurized slag to a particle size of less than 200 mm to obtain primary crushed desulfurized slag. Then perform secondary crushing (secondary crushing is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 5 mm to obtain secondary crushed desulfurized slag (with the total weight of the secondary crushed desulfurized slag as 100 wt%). The main chemical components of the desulfurization slag after secondary crushing are: TFe 28.61wt%, MFe 22.31wt%, CaO 40.64wt%, MgO 1.96wt%, Al2O3 2.60wt%, SiO2 9.81wt%, S 1.35wt%, and P 0.05wt%. The desulfurization slag after secondary crushing is returned to the sintering process for reuse. The temperature of the desulfurization slag after primary crushing is ≤65℃.

[0050] Comparative Example 1

[0051] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 76.54wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 2.33wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 3000GS and the rotation speed is 60r / min.

[0052] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (the primary crushing method is roller crushing) on ​​the desulfurized slag to a particle size of less than 200mm to obtain primary crushed desulfurized slag. Then, perform secondary crushing (the secondary crushing method is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 10mm to obtain secondary crushed desulfurized slag. Based on a total weight of 100wt%, the main chemical components of the desulfurization slag after secondary crushing are: TFe 27.12wt%, MFe 20.78wt%, CaO 40.26wt%, MgO 1.19wt%, Al2O3 2.37wt%, SiO2 9.88wt%, S 0.93wt%, and P 0.03wt%; wherein, the temperature of the desulfurization slag after primary crushing is ≤65℃.

[0053] Comparative Example 2

[0054] (1) Before desulfurizing the molten iron, the slag on the surface of the molten iron is removed by a slag remover to obtain the slag before desulfurization and the molten iron after slag removal. The slag before desulfurization is granulated and cooled by the INBA method, and then the iron is removed by magnetic drum to obtain iron particles (TFe content is 80.26wt%, particle size <120mm) and tailings of the slag before desulfurization (MFe content is 2.51wt%). The iron particles are returned to the blast furnace for use. The magnetic field strength on the surface of the magnetic drum is 1500GS and the rotation speed is 60r / min.

[0055] (2) Add desulfurizing agent to the molten iron obtained after slag removal in step (1), and then perform KR mechanical stirring. After the stirring is completed, use a slag remover to remove the floating slag on the surface of the molten iron to obtain desulfurized slag. Perform primary crushing (the primary crushing method is roller crushing) on ​​the desulfurized slag to a particle size of less than 200 mm to obtain primary crushed desulfurized slag. Then perform secondary crushing (the secondary crushing method is rod milling) on ​​the primary crushed desulfurized slag to a particle size of less than 2 mm to obtain secondary crushed desulfurized slag (based on the total weight of the secondary crushed desulfurized slag as 100 wt%). The main chemical components of the desulfurization slag after secondary crushing are: TFe 30.14wt%, MFe 23.53wt%, CaO 39.36wt%, MgO 2.07wt%, Al2O3 2.56wt%, SiO2 10.88wt%, S 1.07wt%, and P 0.04wt%. The desulfurization slag after secondary crushing is returned to the sintering process for reuse. The temperature of the desulfurization slag after primary crushing is ≤65℃.

[0056] Test Example 1

[0057] The desulfurization tailings obtained in step (1) of Examples 1-6 and Comparative Examples 1-2 were dried and then ground to a specific surface area greater than 400 m². 2 / kg, slag powder was obtained, and the activity index of slag powder was determined according to GB / T 18046-2008 "Granulated blast furnace slag powder for cement and concrete". The results are shown in Table 1.

[0058] Table 1

[0059]

[0060] Table 1 shows that the 7-day and 28-day activity indices of the slag powder prepared in Examples 1-6 all meet the S95 grade technical requirements of GB / T18046-2008 "Granulated Blast Furnace Slag Powder for Cement and Concrete". In Comparative Examples 1-2, due to the inadequate magnetic drum iron removal process, the MFe content in the pre-desulfurization tailings exceeded 1 wt%, affecting the performance indicators of the slag powder. Therefore, the 7-day and 28-day activity indices of the slag powder prepared in these examples did not meet the S95 grade technical requirements of GB / T 18046-2008 "Granulated Blast Furnace Slag Powder for Cement and Concrete".

[0061] Test Example 2

[0062] Taking the highest S content of 1.6 wt% in the desulfurization slag after secondary crushing obtained in Examples 1-6 and Comparative Examples 1-2 as an example, i.e., Example 2, combined with 300m 2The relevant process parameters of the sintering machine were used to calculate the impact of returning desulfurization slag to the sintering system on sulfur dioxide emissions. Specific processes and calculations are shown in Table 2.

[0063] Table 2

[0064]

[0065] As shown in Table 2 (where No. 1 in Table 2 refers to the sintering result using the desulfurization slag after secondary crushing in Example 2), the sulfur content of the desulfurization slag after secondary crushing is 1.6 wt%. When the proportion returned to sintering is 0.5 wt%, the sulfur dioxide concentration at the sintering flue gas outlet is 34.14 mg / m³. 3 Therefore, the desulfurization slag after secondary crushing in Example 2, which has the highest sulfur content, meets the ultra-low emission requirements for sintering flue gas. Similarly, the desulfurization slag after secondary crushing obtained in the other examples also meets the ultra-low emission requirements for sintering flue gas when used for sintering.

[0066] Test Example 3

[0067] The particle size analysis of the desulfurization slag after secondary crushing obtained in Examples 1-6 and Comparative Examples 1-2 in step (2) is shown in Table 3.

[0068] The sintering performance of the desulfurization slag after secondary crushing was verified by sintering cup test. The test process parameters are shown in Table 4, the sintering test mix ratio is shown in Table 5, and the sintering test results are shown in Table 6.

[0069] Table 3

[0070]

[0071]

[0072] Table 4

[0073]

[0074] Table 5

[0075]

[0076] Table 6

[0077]

[0078]

[0079] As shown in Table 6, when the desulfurization slag obtained from secondary crushing in Examples 1-6 was added to the sinter at a ratio of 1.0 wt%, it had virtually no impact on the performance of the sintered ore. Valuable elements such as iron and calcium in the desulfurization slag were effectively utilized during sintering. The desulfurization slag obtained from secondary crushing in Comparative Example 1 could not be used in sintering due to its large particle size. When the desulfurization slag obtained from secondary crushing in Comparative Example 2 was added to the sinter at a ratio of 1.0 wt%, its sintering performance decreased. The main reason for this was the uneven particle size distribution of the desulfurization slag obtained from Comparative Example 2 (as can be seen in Table 3), with particles of 0.15 mm and below accounting for 41.46 wt%. After being added to the sinter, this resulted in poor permeability of the sintering bed, thus affecting the sintering performance.

[0080] In summary, the desulfurization slag obtained after treatment using this method can be entirely utilized in sintering, effectively recovering valuable elements such as iron and calcium. Simultaneously, the sulfur dioxide emissions from the sintering flue gas system meet national ultra-low emission requirements. The obtained iron particles can be fully utilized in blast furnaces, converters, and electric furnaces. The desulfurization slag tailings are used to prepare S95-grade mineral powder, meeting national standards. This achieves 100% resource utilization of the desulfurization slag, setting a positive example for the green development of steel enterprises.

[0081] It should be understood that any parts not described in detail in this specification belong to the prior art.

[0082] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A process for the resource utilization of KR desulfurization slag, characterized in that, The KR desulfurization residue resource utilization process includes the following steps: (1) Remove slag from molten iron to obtain slag before desulfurization and molten iron after slag removal. Granulate and cool the slag before desulfurization and remove iron with a magnetic drum to obtain iron particles and tailings of the slag before desulfurization. Return the iron particles to the blast furnace for use and prepare the tailings of the slag before desulfurization into slag powder. The magnetic field strength on the surface of the magnetic drum is 1800-2400GS and the rotation speed is 10-50r / min. (2) The molten iron obtained after slag removal in step (1) is subjected to KR desulfurization, followed by slag removal to obtain desulfurized slag. The desulfurized slag is subjected to primary crushing and secondary crushing to obtain secondary crushed desulfurized slag. The secondary crushed desulfurized slag is returned to the sintering process for reuse. Among them, the material with a particle size greater than 5mm in the secondary crushed desulfurized slag does not exceed 1% of the total weight of the secondary crushed desulfurized slag, and the material with a particle size less than 0.075mm does not exceed 10% of the total weight of the secondary crushed desulfurized slag.

2. The KR desulfurization slag resource utilization process according to claim 1, characterized in that, In step (1), granulation cooling is performed using the INBA method.

3. The KR desulfurization slag resource utilization process according to claim 1 or 2, characterized in that, In step (1), the content of TFe in the iron particles is ≥85wt%, and the particle size of the iron particles is <120mm.

4. The resource utilization process for KR desulfurization slag according to claim 1 or 2, characterized in that, In step (1), the MFe content in the pre-desulfurization tailings is <1wt%.

5. The KR desulfurization slag resource utilization process according to claim 1, characterized in that, In step (1), the pre-desulfurization tailings are dried and then ground to a specific surface area greater than 400 m². 2 / kg, to obtain slag powder.

6. The KR desulfurization slag resource utilization process according to claim 1, characterized in that, In step (2), the desulfurization slag is subjected to primary crushing to obtain primary crushed desulfurization slag, and then the primary crushed desulfurization slag is subjected to secondary crushing to obtain secondary crushed desulfurization slag.

7. The KR desulfurization slag resource utilization process according to claim 6, characterized in that, In step (2), the material with a particle size greater than 200mm in the desulfurization slag after primary crushing does not exceed 10% of the total weight of the desulfurization slag after primary crushing.

8. The KR desulfurization slag resource utilization process according to claim 6 or 7, characterized in that, In step (2), the temperature of the desulfurization slag after primary crushing is ≤65℃.

9. The KR desulfurization slag resource utilization process according to claim 1 or 6, characterized in that, In step (2), the primary crushing method is roller crushing.

10. The KR desulfurization slag resource utilization process according to claim 1 or 6, characterized in that, In step (2), the secondary crushing method is hammering or rod milling.

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