A steel slag zero-discharge comprehensive treatment and resource utilization method

Abstract

The application discloses a kind of steel slag zero discharge comprehensive treatment and resource utilization method, comprising the following steps: using vibrating screen to 0-150mm steel slag raw materials are initially screened, the screen mesh aperture of vibrating screen is 5mm, separate 0-5mm particle size steel slag and greater than 5mm particle size steel slag;Greater than 5mm particle size steel slag is successively cone crushing, screening and shaping impact break processing: after once crushing, screening, greater than 50mm particle size steel slag is returned to cage and broken again, 26.5-50mm particle size steel slag is twice cone crushing, 5-26.5mm particle size steel slag is sent into impact break shaping, and 5-10mm, 10-16mm, 16-26.5mm, 26.5-31.5mm particle size crushed stone is obtained, the present application, zero discharge in whole process, by vibrating screen initial screening, cone crushing and impact break shaping, water washing ore dressing, powder screening and high-frequency screening process, combined with waste water recycling and dust recovery, realize 100% utilization rate of steel slag and no waste discharge, waste water reuse rate is greater than or equal to 98%, dust recovery rate is greater than or equal to 99%, completely eliminate the environmental pollution problem of traditional steel slag treatment.

Description

Technical Field

[0001] This invention belongs to the field of resource utilization technology, and in particular relates to a method for the comprehensive treatment and resource utilization of steel slag with zero discharge. Background Technology

[0002] Steel slag is a major solid waste generated during steel smelting, accounting for approximately 15%-20% of crude steel production. Currently, steel slag treatment commonly employs processes such as hot pouring, hot simmering, and roller crushing. The main processes include steel slag cooling, crushing and screening, magnetic separation to recover metallic iron, and the remaining tailings being aged and used as road base aggregate, cement admixtures, or landfill disposal. Some technologies achieve steel slag grading through washing and screening to prepare coarse aggregates or manufactured sand of different particle sizes, or produce steel slag powder through grinding for use in concrete admixtures. However, existing steel slag treatment technologies mainly focus on metallic iron recovery and simple resource utilization of tailings, with insufficient attention paid to the refined utilization of all particle size components of steel slag and the environmental friendliness of the treatment process.

[0003] With the development of green building materials and the circular economy, steel slag treatment faces new technological demands: traditional processes rely on natural aging for more than 6 months to dissolve free calcium oxide, resulting in long processing cycles and large land occupation; wastewater and dust generated during washing and crushing lack effective recycling, easily causing secondary pollution, and the comprehensive utilization rate of steel slag is generally below 90%; resource-based products are concentrated in low-value-added coarse aggregates, lacking dedicated gradation designs for high-performance building materials such as asphalt mixtures and cement-stabilized crushed stone, making it difficult for steel slag aggregates to meet high-standard road use requirements in key indicators such as skid resistance and durability. Furthermore, existing technologies have not achieved high-value utilization of steel slag powder, the mineral powder substitution rate is low, and large-scale mining of natural aggregates is still necessary, failing to fully realize the economic and environmental value of steel slag as a high-quality solid waste resource. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a method for comprehensive treatment and resource utilization of steel slag with zero discharge, which solves the problems of long cycle, pollution, low utilization rate and insufficient high-value utilization of traditional steel slag treatment.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for the comprehensive treatment and resource utilization of steel slag with zero discharge, the core technical features of which include:

[0007] Full-size grading crushing and screening process

[0008] Primary screening and separation: A vibrating screen with a screen aperture of 5mm is used to screen the 0-150mm steel slag raw material, accurately separating the 0-5mm fine steel slag (accounting for about 35%) and the >5mm coarse steel slag (accounting for about 65%), providing a basis for subsequent differentiated processing.

[0009] Multi-stage crushing of coarse steel slag:

[0010] >5mm coarse steel slag is crushed once by a spring cone crusher and then screened; >50mm steel slag is returned to the cage for further crushing; 26.5-50mm steel slag is crushed twice by a cone crusher to a particle size range of 5-26.5mm.

[0011] Steel slag with a diameter of 5-26.5mm is shaped by an impact crusher to produce four grades of crushed stone: 5-10mm, 10-16mm, 16-26.5mm, and 26.5-31.5mm, to meet the aggregate particle size requirements of different building materials.

[0012] Fine steel slag refining:

[0013] Fine steel slag of 0-5mm is separated into steel slag powder of 0-0.075mm (specific surface area ≥450m²) by an air classifier. 2 / kg), as an anti-stripping agent for asphalt mixtures;

[0014] The remaining steel slag is passed through a high-frequency screen with a screen size of 3mm to separate 0-3mm manufactured sand (stone powder content of 5%-8%) and 3-5mm crushed stone. The former is used as cement-stabilized crushed stone fine aggregate, and the latter is used as auxiliary aggregate for asphalt mixture.

[0015] Preferred high-efficiency component regulation and closed-loop processing:

[0016] Water washing and gravity separation:

[0017] After shaping, the crushed stone is washed with industrial water (water temperature 25℃±5℃, treatment time ≥30min) to accelerate the reaction of free calcium oxide, so that the f-CaO residue is ≤0.8%, eliminating the need for the traditional 6-month stockpiling and aging process.

[0018] Gravity separation screens remove minerals with a density <3.2 g / cm³ 3 Impurities, with a retention density ≥3.2 g / cm³ 3 High-density aggregates (crushing value ≤28%, Los Angeles abrasion loss ≤30%) are used to prepare high-performance asphalt mixtures.

[0019] Full-process pollutant control:

[0020] The washing wastewater is 100% reused after three-stage sedimentation and filtration treatment, with a recycling rate of ≥98%.

[0021] Dust generated during the crushing and screening process is recovered by a pulse dust collector (recovery rate ≥99%) and mixed into steel slag powder for unified utilization, achieving zero discharge of wastewater and dust.

[0022] Preferred method: Targeted preparation of resource-based products:

[0023] Cement-stabilized crushed stone:

[0024] according to

[0025] A road base material with a 7-day unconfined compressive strength ≥3.5MPa was prepared by mixing aggregates of various grades in a mass ratio of 0-3mm:3-5mm:5-10mm:10-16mm:16-26.5mm:26.5-31.5mm = 23:5:14:20:25:13 and adding 4.0% cement.

[0026] Steel slag-based asphalt mixture:

[0027] The main coarse aggregate is 10-16mm crushed stone, the auxiliary aggregate is 26.5-31.5mm crushed stone, and it is mixed with 0-2.36mm steel slag fine material to form a specific gradation (9.5-16mm accounts for 47%, 4.75-9.5mm accounts for 26%, etc.), with an oil-aggregate ratio of 5.5%, and 9% limestone mineral powder and 0.3% fiber are added.

[0028] 0-0.075mm steel slag powder is used to replace mineral powder at a dosage of 1.5%-2.5% (e.g., 2% in SMA mixture, reducing the mineral powder dosage from 10% to 8%), thereby improving the adhesion between asphalt and aggregate, achieving a slip resistance value (BPN) ≥60, and a freeze-thaw splitting strength ratio ≥85%.

[0029] The technical effects and advantages of the present invention regarding a method for the comprehensive treatment and resource utilization of steel slag with zero discharge are as follows:

[0030] 1. This invention achieves zero emissions throughout the entire process. Through primary screening with vibrating screen, shaping with cone crusher and impact crusher, water washing and beneficiation, powder screening and high-frequency screening, combined with wastewater recycling and dust recovery, it achieves 100% utilization of steel slag with no waste discharge. The wastewater reuse rate is ≥98% and the dust recovery rate is ≥99%, completely eliminating the environmental pollution problems of traditional steel slag treatment.

[0031] 2. This invention features a highly efficient processing cycle. The water washing process accelerates the decomposition of free calcium oxide, eliminating the need for more than 6 months of stockpiling and aging. This reduces the steel slag processing cycle from 90 days in the traditional process to less than 48 hours, significantly improving production efficiency.

[0032] 3. This invention enables the high-value utilization of multiple products. -0.075mm steel slag powder replaces 1.5%-2.5% mineral powder in asphalt mixtures, resulting in a skid resistance value ≥60 and a freeze-thaw splitting strength ratio ≥85%, thus improving the road's skid resistance and durability. The cement-stabilized crushed stone prepared according to the specified ratio has an unconfined compressive strength of ≥3.5MPa after 7 days, meeting the strength requirements of the road base layer. The steel slag-based asphalt mixture exhibits a dynamic stability of ≥5000 cycles / mm, a residual stability of ≥85%, and excellent high-temperature stability and water damage resistance, reducing the risk of rutting and cracking of the road surface.

[0033] 4. This invention saves costs and resources. The full-size graded utilization of steel slag reduces the mining of natural aggregates and lowers the cost of asphalt mixtures by 3%-5%. The use of manufactured sand in cement-stabilized crushed stone replaces natural sand, alleviating the pressure of sand shortage in construction and realizing the resource utilization of solid waste and sustainable resource utilization.

[0034] 5. This invention features equipment adaptability and process stability, combining spring cone crushing and impact crushing shaping processes, resulting in a steel slag aggregate crushing value of ≤28% and Los Angeles abrasion loss of ≤30%, meeting the requirements of the "Specifications for Testing Aggregates in Highway Engineering". The equipment is highly versatile, the process parameters are controllable, and it is easy to promote industrialization. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a method for the comprehensive treatment and resource utilization of steel slag with zero discharge proposed in this invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0038] Example 1

[0039] refer to Figure 1 This embodiment provides a method for the comprehensive treatment and resource utilization of steel slag with zero discharge, applicable to the entire process of steel slag treatment and the resource utilization of all particle sizes. Specific implementation details include:

[0040] Objective: To verify the feasibility of the entire process of steel slag from screening and crushing to resource utilization, and to confirm the output efficiency and performance indicators of products of various particle sizes.

[0041] Implementation steps:

[0042] S1 Primary Screening: 10 tons of 0-150mm converter steel slag were processed using a ZSG-2060 vibrating screen (5mm screen size), resulting in 3.5 tons of 0-5mm steel slag (35%) and 6.5 tons of >5mm steel slag (65%).

[0043] S2 fragmentation and reshaping:

[0044] Steel slag >5mm is crushed once by a CS440 spring cone crusher. After screening, steel slag >50mm (1.2 tons) is returned to the crusher for further crushing. Steel slag 26.5-50mm (2.8 tons) is crushed a second time to 5-26.5mm by an HPT300 cone crusher.

[0045] 5-26.5mm steel slag (6.1 tons) is shaped by VSI-9526 impact crusher and screened to obtain: 5-10mm (1.4 tons), 10-16mm (2.0 tons), 16-26.5mm (2.5 tons), and 26.5-31.5mm (1.3 tons) crushed stone.

[0046] S3 Water Washing Beneficiation: After shaping, the crushed stone is washed in a drum washing machine (water temperature 25℃, water pressure 0.3MPa, time 30min), reducing the free calcium oxide (f-CaO) content from 4.2% to 0.7%; LTA type spiral chute gravity separation is used to remove particles with a density <3.2g / cm³. 3 Steel slag (0.5 tons), retain 6.1 tons of high-density aggregate.

[0047] S4 air classifier screening: 0-5mm steel slag is separated into 0.3 tons of 0-0.075mm steel slag powder (specific surface area 450m²) by the T-Sepax air classifier. 2 / kg); the remaining 4.7 tons were separated by a high-frequency screen (3mm aperture) to produce 3.2 tons of 0-3mm manufactured sand (stone powder content 6.8%) and 1.5 tons of 3-5mm crushed stone.

[0048] S5 wastewater and dust treatment: washing wastewater (15m³) 3 After being filtered through a three-stage sedimentation tank, the material is reused, and the dust removal device recovers 0.2 tons of dust (mixed with steel slag powder).

[0049] Implementation results:

[0050] Steel slag utilization rate: 100% (no waste discharge);

[0051] Aggregate properties: 10-16mm crushed stone density 3.5g / cm³ 3 The crushing value is 25%, which meets the requirements of the "Specifications for Testing Aggregates in Highway Engineering" (JTGE42);

[0052] Wastewater reuse rate: 98%, dust recovery rate: 99%.

[0053] Example 2

[0054] This embodiment provides a method for the comprehensive treatment and resource utilization of steel slag with zero emissions, used in the preparation of cement-stabilized crushed stone. Specific implementation details include:

[0055] Purpose of the implementation: To verify the road performance of cement-stabilized crushed stone formulation.

[0056] Implementation steps:

[0057] Raw material ratio: Mix 0-3mm manufactured sand (2.3kg), 3-5mm crushed stone (0.5kg), 5-10mm crushed stone (1.4kg), 10-16mm crushed stone (2.0kg), 16-26.5mm crushed stone (2.5kg), and 26.5-31.5mm crushed stone (1.3kg) by mass ratio of 23:5:14:20:25:13, with cement admixture of 4.0% (0.4kg).

[0058] Mixing and compaction: A twin-shaft forced mixer was used for mixing, and the moisture content was controlled at 6.5%. The maximum dry density was determined to be 2.45 g / cm³ through heavy compaction tests. 3 Specimens were prepared with a compaction degree of 98%.

[0059] Implementation results:

[0060] 7-day unconfined compressive strength: 4.2 MPa (superior to the 3.5 MPa required by the "Technical Specifications for Construction of Highway Pavement Base Course" JTG / TF20);

[0061] Porosity after compaction: 12%, with good water stability.

[0062] Example 3

[0063] This embodiment provides a method for the comprehensive treatment and resource utilization of steel slag with zero discharge, used in the preparation of SMA asphalt mixtures (steel slag powder replacing mineral powder). Specific implementation details include:

[0064] Objective: To verify the anti-stripping effect and proportion feasibility of steel slag powder in SMA asphalt mixtures.

[0065] Implementation steps:

[0066] Aggregate proportion: 10-16mm steel slag (47% main aggregate) and 26.5-31.5mm steel slag (13% auxiliary aggregate) prepared in Example 1 are used, along with manufactured sand and mineral powder. The steel slag powder content is 2% (replacing 2% of the original 10% mineral powder and adjusting it to 8% limestone mineral powder).

[0067] Asphalt mixture preparation: SBS modified asphalt (PG76-22) was used, with an asphalt-aggregate ratio of 5.8%, a mixing temperature of 175℃, and Marshall specimens were compacted.

[0068] Implementation results:

[0069] Anti-slip pendulum value (BPN): 68 (20℃), which is better than the standard requirement (≥60);

[0070] Freeze-thaw splitting strength ratio: 89% (77% without steel slag powder), adhesion grade improved to level 5 (boiling water method);

[0071] Reduced mineral powder usage: Cost reduction of 5%.

[0072] Example 4

[0073] This embodiment provides a method for the comprehensive treatment and resource utilization of steel slag with zero discharge, used for the optimization of asphalt mixture gradation. Specific implementation details include:

[0074] Objective: To verify the high-temperature stability and durability of asphalt mixtures with steel slag aggregate proportions.

[0075] Implementation steps:

[0076] Grading design: Mixed by mass percentage of 47% 9.5-16mm steel slag, 26% 4.75-9.5mm steel slag, 7% 2.36-4.75mm steel slag, 11% 0-2.36mm steel slag, 9% limestone powder, 0.3% fiber, and an oil-aggregate ratio of 5.5%.

[0077] Performance testing: The wheel rolling method was used to form rutted slab specimens, and the dynamic stability and residual stability were tested.

[0078] Implementation results:

[0079] Dynamic stability: 6200 cycles / mm (better than the 5000 cycles / mm required by the "Code for Construction and Quality Acceptance of Urban Road Engineering" CJJ1);

[0080] Residual stability: 87% (standard requirement ≥85%), excellent resistance to water damage;

[0081] Density: 2.53 g / cm³ 3The porosity is 4.2%, which meets the SMA mixture design standard.

[0082] Example 5

[0083] This embodiment provides a method for the comprehensive treatment and resource utilization of steel slag with zero discharge, which can be used to shorten the treatment cycle of water washing processes. The specific implementation content includes:

[0084] Purpose of implementation:

[0085] Verify the effectiveness of the water washing process as a replacement for the traditional 6-month storage and aging process.

[0086] Implementation steps:

[0087] Control group: Steel slag was piled up using traditional methods for 6 months, allowing for the natural digestion of f-CaO;

[0088] Experimental group: Washed with water (30 min) according to step S3 of the present invention, and the f-CaO content and expansion rate were detected.

[0089] Implementation results:

[0090] f-CaO residue 1.8％ 0.8％ Free expansion rate 0.5％ 0.3％ Processing cycle 180 days 0.5 days

[0091] Comparative Example 1

[0092] This comparative example provides information on the traditional hot slag treatment method for steel slag.

[0093] Purpose of implementation: To compare the overall performance of the present invention with that of traditional steel slag treatment processes.

[0094] Implementation steps:

[0095] The existing hot braising process of a steel plant is adopted: after the steel slag is poured, it is sprayed with water and braising for 72 hours, then screened, crushed and naturally piled up for 3 months, and the wastewater is discharged after neutralization treatment.

[0096] Comparison results:

[0097]

[0098]

[0099] Compared with Examples 1-5 and Comparative Example 1, Examples 1-5 of the present invention, through full-process process verification and resource-based product performance testing, have constructed a technical system of "zero-emission treatment - full particle size utilization - high-performance application" for steel slag, achieving a significant breakthrough in environmental protection, efficiency, and product performance compared with the traditional hot quenching method.

[0100] Example 1 achieves a closed-loop process for steel slag treatment. This involves a 5mm primary screen, two-stage cone crusher + impact crusher shaping (producing multi-stage crushed stone ranging from 5-31.5mm), 30-minute water washing to accelerate the decomposition of free calcium oxide (f-CaO reduced from 4.2% to 0.7%), and 3mm high-frequency screening (separating 0-3mm manufactured sand). Combined with three-stage wastewater sedimentation and reuse (98% reuse rate) and complete dust recovery (99% recovery rate), 100% utilization is achieved with no waste discharge, completely solving the wastewater discharge problem of traditional processes (6m³). 3 The pain points include (5 kg / ton of steel slag), dust pollution (5 kg / ton of steel slag), and long-term storage and aging (6 months).

[0101] Examples 2-4 focus on the performance of resource-based products: Cement-stabilized crushed stone prepared with a mix ratio of 23:5:14:20:25:13 achieved an unconfined compressive strength of 4.2 MPa after 7 days (17% exceeding the specification requirement) and a porosity of 12%, meeting the high strength requirements of road base courses; In SMA asphalt mixtures, 2% steel slag powder replaced mineral powder, increasing the anti-skid pendulum value to 68 (specification ≥60), and the freeze-thaw splitting strength ratio to 89% (77% without additives), while reducing costs by 5%; The optimized gradation of the asphalt mixture achieved a dynamic stability of 6200 cycles / mm (specification ≥5000), a residual stability of 87%, and excellent high-temperature stability and resistance to water damage.

[0102] Example 5 further confirms the high efficiency of the water washing process. A 30-minute treatment can reduce the residual f-CaO content to 0.8% and control the free expansion rate to 0.3%, shortening the traditional 6-month natural aging cycle by 99.7%, significantly improving production efficiency. Comparative data shows that the traditional hot-quenching method has a steel slag utilization rate of only 82%, a processing cycle of up to 90 days, and an asphalt mixture cost 5% higher than that of this invention. This highlights the comprehensive advantages of this invention in "zero-emission treatment - high-value utilization of all particle sizes - short-process, high-efficiency production," providing an environmentally friendly, economical, and high-performance integrated solution for steel slag resource utilization.

[0103] The above embodiments can be implemented in whole or in part by software, hardware, firmware or other arbitrary combinations. When implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product.

[0104] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0105] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0106] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0107] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for the comprehensive treatment and resource utilization of steel slag with zero discharge, characterized in that, Includes the following steps: S1: A vibrating screen is used to perform a preliminary screening of steel slag raw materials with a particle size of 0-150mm. The screen mesh size of the vibrating screen is 5mm, and steel slag with a particle size of 0-5mm and steel slag with a particle size of >5mm are separated. S2: Steel slag with a particle size >5mm is subjected to spring cone crushing, screening, and shaping impact crushing in sequence: after primary crushing and screening, steel slag with a particle size >50mm is returned to the cage for further crushing, steel slag with a particle size of 26.5-50mm is subjected to secondary cone crushing, and steel slag with a particle size of 5-26.5mm is fed into the impact crusher for shaping to obtain crushed stone with particle sizes of 5-10mm, 10-16mm, 16-26.5mm, and 26.5-31.5mm. S3: The shaped crushed stone is washed with water and subjected to gravity separation: Water washing uses conventional industrial water to clean the surface and accelerate the reaction of free calcium oxide; gravity separation removes stones with a density <3.2 g / cm³. 3 The steel slag retains a density ≥3.2 g / cm³. 3 Aggregates are used to prepare asphalt mixtures; S4: Steel slag with a particle size of 0-5mm is sequentially classified by an air classifier and screened by a high frequency: the air classifier selects steel slag powder with a particle size of 0-0.075mm as an anti-stripping agent, and the high frequency screen has a screen aperture of 3mm to separate manufactured sand with a particle size of 0-3mm and crushed stone with a particle size of 3-5mm. The former is used as fine aggregate in cement-stabilized crushed stone, and the latter is used as auxiliary aggregate in asphalt mixture. S5: Wastewater generated during the treatment process is reused after sedimentation and filtration, and dust is recovered through a dust removal device, achieving zero emissions throughout the entire process and 100% utilization of steel slag.

2. The method for comprehensive treatment and resource utilization of steel slag with zero discharge as described in claim 1, characterized in that, The screening operation after the secondary cone crushing in step S2 crushes the steel slag with a particle size of 26.5-50mm to a particle size range of 5-26.5mm.

3. The method for comprehensive treatment and resource utilization of steel slag with zero discharge as described in claim 1, characterized in that, In step S3, the water washing process does not require the steel slag to be stockpiled for more than 6 months. The expansion of the aggregate is eliminated directly through pre-washing.

4. The method for comprehensive treatment and resource utilization of steel slag with zero discharge as described in claim 1, characterized in that, In step S4, the amount of steel slag powder with a particle size of 0-0.075mm in the asphalt mixture is 1.5%-2.5%, replacing an equal mass of mineral powder.

5. The method for comprehensive treatment and resource utilization of steel slag with zero discharge as described in claim 1, characterized in that... The formula for the cement-stabilized crushed stone is 0-3mm:3-5mm:5-10mm:10-16mm:16-26.5mm:26.5-31.5mm. The mixture is prepared in a mass ratio of 23:5:14:20:25:13, with a cement content of 4.0%.

6. The method for comprehensive treatment and resource utilization of steel slag with zero discharge as described in claim 1, characterized in that, In step S3, the steel slag coarse aggregate used in the asphalt mixture includes crushed stone with a particle size of 10-16mm and a particle size of 26.5-31.5mm, wherein the crushed stone with a particle size of 10-16mm serves as the main coarse aggregate and the crushed stone with a particle size of 26.5-31.5mm serves as auxiliary aggregate.

7. The method for comprehensive treatment and resource utilization of steel slag with zero discharge as described in claim 4, characterized in that, The steel slag powder with a particle size of 0-0.075mm replaces 2% of the mineral powder in the SMA asphalt mixture, thereby adjusting the mineral powder content from 10% to 8%.

8. The method for comprehensive treatment and resource utilization of steel slag with zero discharge as described in claim 1, characterized in that, In step S3, the steel slag aggregate proportions used to prepare the asphalt mixture are as follows: 47% steel slag with a particle size of 9.5-16mm, 26% steel slag with a particle size of 4.75-9.5mm, 7% steel slag with a particle size of 2.36-4.75mm, and 11% steel slag with a particle size of 0-2.36mm, combined with 9% limestone powder and 0.3% fiber, with an asphalt-aggregate ratio of 5.5%.

9. The steel slag aggregate prepared by the comprehensive treatment and resource utilization method for zero-emission steel slag as described in any one of claims 1-8, characterized in that, Includes crushed stone with a particle size of 5-31.5 mm and manufactured sand with a particle size of 0-3 mm, wherein the density of the crushed stone is ≥3.2 g / cm³. 3 The crushing value is ≤28%, and the Los Angeles abrasion loss is ≤30%; the stone powder content of the manufactured sand is 5%-8%, and the fineness modulus is 2.3-3.

0.

10. The steel slag-based asphalt mixture prepared by the comprehensive treatment and resource utilization method for zero-emission steel slag as described in any one of claims 1-8, characterized in that, The asphalt mixture comprises the following components and their mass percentages: 47% steel slag with a particle size of 9.5-16mm, 26% steel slag with a particle size of 4.75-9.5mm, 7% steel slag with a particle size of 2.36-4.75mm, 11% steel slag with a particle size of 0-2.36mm, 9% limestone powder, 0.3% fiber, and an asphalt-aggregate ratio of 5.5%. The dynamic stability of the asphalt mixture is ≥5000 cycles / mm, the residual stability is ≥85%, and the anti-skid sway value (BPN) is ≥60.

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