Zero-emission comprehensive treatment and resource utilization method for steel slag

Abstract

The invention discloses a steel slag zero-emission comprehensive treatment and resource utilization method which comprises the following steps: primarily screening a steel slag raw material with the particle size of 0-150 mm by adopting a vibrating screen with the screen mesh aperture of 5 mm, and sorting out steel slag with the particle size of 0-5 mm and steel slag with the particle size larger than 5 mm; the steel slag with the particle size larger than 5 mm is subjected to cone crushing, screening and shaping impact crushing treatment in sequence, specifically, screening is conducted after primary crushing, the steel slag with the particle size larger than 50 mm is returned to a cage and crushed again, secondary cone crushing is conducted on the steel slag with the particle size of 26.5-50 mm, the steel slag with the particle size of 5-26.5 mm is fed into an impact crusher to be shaped, and broken stones with the particle sizes of 5-10 mm, 10-16 mm, 16-26.5 mm and 26.5-31.5 mm are obtained. Through the procedures of primary screening of a vibrating screen, cone crushing and impact breaking shaping, washing mineral separation, powder selection screening and high-frequency screening, waste water circulation treatment and dust recovery are combined, the utilization rate of the steel slag is 100%, no waste is discharged, the waste water recycling rate is larger than or equal to 98%, the dust recovery rate is larger than or equal to 99%, and the problem of environmental pollution caused by traditional steel slag treatment is thoroughly solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource utilization, and in particular relates to a method for comprehensive zero-emission treatment and resource utilization of steel slag. Background Art

[0002] Steel slag is the main solid waste generated during the steelmaking process, and its output accounts for about 15%-20% of crude steel production. At present, hot pouring, hot stewing, roller crushing and other processes are commonly used for steel slag treatment. The main processes include steel slag cooling, crushing and screening, and magnetic separation to recover metallic iron. The remaining tailings are used for road base aggregate, cement admixture or landfill after aging. Some technologies achieve steel slag classification through water washing and screening to prepare coarse aggregate or machine-made sand of different particle sizes, or produce steel slag powder for concrete admixtures through grinding. However, existing steel slag treatment technologies mainly focus on the recovery of metallic iron and the simple resource utilization of tailings, and pay insufficient attention to the refined utilization of the full-size particle 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 processing faces new technical demands: Traditional processes rely on natural aging for more than six months to eliminate free calcium oxide, resulting in a long treatment cycle and significant site 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 specialized grading designs for high-performance building materials such as asphalt mixtures and cement-stabilized crushed stone. This makes it difficult for steel slag aggregate to meet high-standard road use requirements in key indicators such as anti-skid performance and durability. Furthermore, existing technologies fail to achieve high-value utilization of steel slag powder, have a low mineral powder replacement rate, and require large-scale mining of natural aggregates, 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, an embodiment of the present invention provides a method for comprehensive treatment and resource utilization of steel slag with zero emission, which solves the problems of traditional steel slag treatment such as long cycle, pollution, low utilization rate and insufficient high-value utilization.

[0005] To achieve the above object, the present invention provides the following technical solutions:

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

[0007] Full-size classification crushing and screening process

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

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

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

[0011] 5-26.5mm steel slag is shaped by impact crushing to produce four grades of crushed stone: 5-10mm, 10-16mm, 16-26.5mm, and 26.5-31.5mm, meeting the aggregate particle size requirements of different building materials products.

[0012] Fine processing of fine steel slag:

[0013] 0-5mm fine steel slag is selected by powder separator to produce 0-0.075mm steel slag powder (specific surface area ≥450m 2 / kg), as an anti-stripping agent for asphalt mixture;

[0014] The remaining steel slag is passed through a high-frequency sieve with a mesh size of 3mm to separate 0-3mm machine-made sand (stone powder content 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] Optimized, efficient ingredient regulation and closed-loop processing:

[0016] Water washing and gravity separation:

[0017] After shaping, the gravel is washed with industrial water (water temperature 25℃±5℃, treatment time ≥30min) to accelerate the reaction of free calcium oxide and make the f-CaO residual content ≤0.8%, without the need for traditional 6-month stacking and aging;

[0018] Gravity separation screening density <3.2g / cm 3 Impurities, retention density ≥3.2g / cm 3 High-density aggregate (crushing value ≤ 28%, Los Angeles abrasion loss ≤ 30%) is used to prepare high-performance asphalt mixture.

[0019] Whole-process pollutant control:

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

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

[0022] Preferably, resource-based products are prepared in a targeted manner:

[0023] Cement stabilized gravel:

[0024] according to

[0025] Aggregates of various grades are mixed 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, with a cement content of 4.0%, to prepare a road base material with a 7-day unconfined compressive strength of ≥3.5MPa.

[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 the fine aggregate is 0-2.36mm steel slag. A specific gradation is formed (9.5-16mm accounts for 47%, 4.75-9.5mm accounts for 26%, etc.). The oil-stone ratio is 5.5%, and 9% limestone powder and 0.3% fiber are added.

[0028] 0-0.075mm steel slag powder can replace mineral powder at a dosage of 1.5%-2.5% (such as replacing 2% in SMA mixture, reducing the amount of mineral powder from 10% to 8%), which can improve the adhesion between asphalt and aggregate, achieve a anti-slip value (BPN) ≥ 60, and a freeze-thaw splitting strength ratio ≥ 85%.

[0029] The technical effects and advantages of the zero-emission comprehensive treatment and resource utilization method of steel slag of the present invention are as follows:

[0030] 1. This invention has zero emissions throughout the entire process. Through the processes of vibrating screen initial screening, cone crushing and impact crushing shaping, water washing and mineral processing, powder screening and high-frequency screening, combined with wastewater recycling treatment and dust recovery, it achieves 100% utilization of steel slag without waste discharge, wastewater reuse rate ≥ 98%, and dust recovery rate ≥ 99%, completely eliminating the environmental pollution problems caused by traditional steel slag treatment.

[0031] 2. This invention has an efficient processing cycle. The water washing process accelerates the digestion of free calcium oxide, eliminating the need for stacking and aging for more than 6 months. It shortens the steel slag processing cycle from 90 days in traditional processes to less than 48 hours, significantly improving production efficiency.

[0032] 3. This invention makes high-value use of multiple products. -0.075mm steel slag powder replaces 1.5%-2.5% mineral powder in asphalt mixture, making the anti-skid swing value ≥60 and the freeze-thaw splitting strength ratio ≥85%, thereby improving the anti-skid performance and durability of the road; the cement-stabilized gravel prepared according to the ratio has a 7-day unconfined compressive strength of ≥3.5MPa, meeting the strength requirements of the road base; the dynamic stability of the steel slag-based asphalt mixture is ≥5000 times / mm, the residual stability is ≥85%, and it has excellent high-temperature stability and water damage resistance, reducing the risk of road rutting and cracking.

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

[0034] 5. This invention combines the adaptability of equipment and process stability with the spring cone crushing and impact crushing shaping process, which makes the crushing value of steel slag aggregate ≤28% and the Los Angeles abrasion loss ≤30%, meeting the requirements of the "Highway Engineering Aggregate Test Procedures". The equipment has strong versatility and controllable process parameters, which is convenient for industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention provides a flow chart of a method for comprehensive treatment and resource utilization of steel slag with zero emission. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of further restrictions, the elements defined by the sentence "include..." do not exclude the existence of other identical elements in the process, method, article or apparatus that includes the elements.

[0038] Example 1

[0039] refer to Figure 1 This embodiment provides a method for comprehensive treatment and resource utilization of steel slag with zero emission, which is used for full-process treatment of steel slag and resource utilization of all particle sizes. The specific implementation content includes:

[0040] Implementation purpose: 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 slag were processed using a ZSG-2060 vibrating screen (5mm mesh), and 3.5 tons of 0-5mm slag (35%) and 6.5 tons of >5mm slag (65%) were screened.

[0043] S2 crushing and shaping:

[0044] Steel slag >5mm is crushed once by CS440 spring cone crusher, and after screening, steel slag >50mm (1.2 tons) is returned to the cage for re-crushing, and steel slag 26.5-50mm (2.8 tons) is crushed twice by HPT300 cone crusher to 5-26.5mm.

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

[0046] S3 washing and mineral separation: After shaping, the crushed stone is washed with a drum stone washer (water temperature 25°C, water pressure 0.3MPa, time 30min), and the free calcium oxide (f-CaO) content is reduced from 4.2% to 0.7%. LTA type spiral chute gravity separation is used, and the screening density is less than 3.2g / cm 3 Steel slag (0.5 ton), retaining 6.1 tons of high-density aggregate.

[0047] S4 powder screening: 0-5mm steel slag is screened by T-Sepax powder separator to select 0.3 tons of 0-0.075mm steel slag powder (specific surface area 450m 2 / kg); the remaining 4.7 tons were screened through a high-frequency sieve (3mm aperture) to separate 3.2 tons of 0-3mm machine-made sand (stone powder content 6.8%) and 1.5 tons of 3-5mm crushed stone.

[0048] S5 wastewater dust treatment: washing wastewater (15m 3 ) is filtered through the tertiary sedimentation tank and then reused, and the dust removal device recovers 0.2 tons of dust (mixed with steel slag powder).

[0049] Implementation effect:

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

[0051] Aggregate properties: 10-16mm crushed stone density 3.5g / cm 3 , crushing value 25%, meeting the requirements of "Highway Engineering Aggregate Test Code" (JTGE42);

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

[0053] Example 2

[0054] This embodiment provides a method for comprehensive treatment and resource utilization of steel slag with zero emission for use in cement-stabilized gravel preparation. The specific implementation includes:

[0055] Implementation purpose: To verify the road performance of cement-stabilized crushed stone formula.

[0056] Implementation steps:

[0057] Raw material ratio: 0-3mm machine-made sand (2.3kg), 3-5mm gravel (0.5kg), 5-10mm gravel (1.4kg), 10-16mm gravel (2.0kg), 16-26.5mm gravel (2.5kg), 26.5-31.5mm gravel (1.3kg) in the mass ratio of 23:5:14:20:25:13, cement content 4.0% (0.4kg).

[0058] Mixing and compaction: Use a double-shaft forced mixer to mix, control the moisture content to 6.5%, and the maximum dry density is 2.45g / cm3 as determined by heavy compaction tests. 3 , prepare the specimens according to 98% compaction degree.

[0059] Implementation effect:

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

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

[0062] Example 3

[0063] This embodiment provides a method for comprehensive treatment and resource utilization of steel slag with zero emission, which is used for the preparation of SMA asphalt mixture (steel slag powder replaces mineral powder). The specific implementation content includes:

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

[0065] Implementation steps:

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

[0067] Asphalt mixture preparation: SBS modified asphalt (PG76-22) was used, with an oil-to-stone ratio of 5.8%, a mixing temperature of 175°C, and compaction to form Marshall specimens.

[0068] Implementation effect:

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

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

[0071] Reduced mineral powder usage: cost reduced by 5%.

[0072] Example 4

[0073] This embodiment provides a method for comprehensive treatment and resource utilization of steel slag with zero emission for optimizing asphalt mixture gradation. The specific implementation includes:

[0074] Implementation purpose: To verify the high temperature stability and durability of asphalt mixture with steel slag aggregate.

[0075] Implementation steps:

[0076] Gradation design: Mix by mass percentage: 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 5.5% oilstone ratio.

[0077] Performance test: The wheel rolling method is used to form rutting plate specimens, and the dynamic stability and residual stability are tested.

[0078] Implementation effect:

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

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

[0081] Density: 2.53g / cm 3, void ratio 4.2%, in line with SMA mixture design standards.

[0082] Example 5

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

[0084] Implementation purpose:

[0085] Verify the effectiveness of the water washing process instead of the traditional 6-month stacking aging.

[0086] Implementation steps:

[0087] Control group: The traditional process of piling steel slag for 6 months to naturally decompose 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 tested.

[0089] Implementation effect:

[0090] index Traditional stacking for 6 months Water washing process of the present invention f-CaO residual 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 a traditional hot stewing method for treating steel slag.

[0093] Implementation purpose: To compare the comprehensive performance of the present invention with that of the traditional steel slag treatment process.

[0094] Implementation steps:

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

[0096] Contrast effect:

[0097]

[0098]

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

[0100] Example 1 achieves a closed-loop process for steel slag treatment. Through 5mm primary screening, two-stage cone crushing + impact crushing and shaping (producing 5-31.5mm multi-grade gravel), 30min water washing to accelerate the digestion of free calcium oxide (f-CaO is reduced from 4.2% to 0.7%) and 3mm high-frequency screening (sorting out 0-3mm machine-made sand), combined with three-stage sedimentation reuse of wastewater (reuse rate 98%) and full dust recovery (recovery rate 99%), 100% utilization rate is achieved without waste discharge, completely solving the problem of traditional process wastewater discharge (6m 3 / ton of steel slag), dust pollution (5kg / ton of steel slag) and long-term stacking and aging (6 months).

[0101] Examples 2-4 focus on the performance of resource-based products: Cement-stabilized gravel prepared in a ratio of 23:5:14:20:25:13 has a 7-day unconfined compressive strength of 4.2 MPa (17% higher than the standard requirement) and a porosity of 12%, meeting the high-strength requirements of the road base; in the SMA asphalt mixture, 2% steel slag powder replaces mineral powder to increase the anti-slip value to 68 (standard ≥ 60), the freeze-thaw splitting strength ratio reaches 89% (77% when not mixed), and the cost is reduced by 5%; the dynamic stability of the optimized graded asphalt mixture reaches 6200 times / mm (standard ≥ 5000), the residual stability is 87%, and the high temperature stability and water damage resistance are excellent.

[0102] Example 5 further demonstrates the high efficiency of the water-washing process. A 30-minute treatment reduced the residual f-CaO content to 0.8% and controlled the free expansion rate to 0.3%. This represents a 99.7% reduction compared to the traditional 6-month natural aging cycle, significantly improving production efficiency. Comparative data shows that the traditional hot-stemming method achieves a mere 82% slag utilization rate, a 90-day treatment cycle, and a 5% higher asphalt mixture cost than the present invention. This highlights the combined advantages of the present invention in terms of "zero-emission treatment, high-value utilization of all particle sizes, and efficient production in a short process," providing an environmentally friendly, economical, and high-performance integrated solution for slag resource utilization.

[0103] The above embodiments may be implemented in whole or in part through software, hardware, firmware or any other combination. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product.

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

[0105] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0106] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited to this. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

[0107] Finally: 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 in the scope of protection of the present invention.

Claims

1. A method for comprehensive treatment and resource utilization of steel slag with zero emission, characterized in that: The steps include: S1: Using a vibrating screen with a mesh size of 5 mm to preliminarily screen the steel slag raw material with a particle size of 0-150 mm, the steel slag with a particle size of 0-5 mm and the steel slag with a particle size greater than 5 mm are separated; S2: The steel slag with a particle size of more than 5 mm is subjected to spring cone crushing, screening and shaping impact crushing in sequence: after the primary crushing, the steel slag with a particle size of more than 50 mm is screened and returned to the cage for re-crushing, the steel slag with a particle size of 26.5-50 mm is subjected to secondary cone crushing, and the steel slag with a particle size of 5-26.5 mm is sent to the impact crusher for shaping to obtain gravel with particle sizes of 5-10 mm, 10-16 mm, 16-26.5 mm and 26.5-31.5 mm; S3: Wash the shaped gravel and perform gravity separation: conventional industrial water is used for washing to clean the surface and accelerate the reaction of free calcium oxide; the gravity separation screening density is less than 3.2g / cm 3 Steel slag, retaining density ≥3.2g / cm 3 Aggregates are used to prepare asphalt mixtures; S4: The steel slag with a particle size of 0-5 mm is subjected to powder selection and high-frequency screening in sequence: the powder selection machine selects steel slag powder with a particle size of 0-0.075 mm as an anti-stripping agent, and the high-frequency screen has a mesh size of 3 mm, which selects machine-made sand with a particle size of 0-3 mm and crushed stone with a particle size of 3-5 mm. The former is used as fine aggregate for cement-stabilized crushed stone, and the latter is used as auxiliary aggregate for asphalt mixture; S5: The wastewater generated during the treatment process is reused after sedimentation and filtration, and the dust is recovered through the dust removal device, achieving zero emissions in the entire process and 100% utilization of steel slag.

2. The method for zero-emission comprehensive treatment and resource utilization of steel slag according to 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 26.5-50 mm into a particle size range of 5-26.5 mm.

3. The method for zero-emission comprehensive treatment and resource utilization of steel slag according to claim 1, characterized in that: The water washing process in step S3 does not require the steel slag to be stored for more than 6 months, and the expansion of the aggregate can be eliminated directly through pre-water washing.

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

5. The method for zero-emission comprehensive treatment and resource utilization of steel slag according to claim 1, characterized in that The formula of the cement stabilized gravel is 0-3mm:3-5mm:5-10mm:10-16mm:16-26.5mm:26.5-31.5mm Mix according to the mass ratio of 23:5:14:20:25:13, and the cement content is 4.0%.

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

7. A method for zero-emission comprehensive treatment and resource utilization of steel slag as described in claim 4, characterized in that: The steel slag powder with a particle size of 0-0.075 mm replaces 2% of the mineral powder in the SMA asphalt mixture, so that the amount of the mineral powder is adjusted from 10% to 8%.

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

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

0.

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

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