Converter slag and construction waste resourceful treatment method

Abstract

A converter slag and construction waste resourceful treatment method comprises a gradient crushing unit which comprises a rod mill with a variable-diameter rod assembly, the diameter of the variable-diameter rod assembly is gradually changed from phi 80 mm to phi 50 mm in the material advancing direction, and a flow guide groove with the spiral angle ranging from 25 degrees to 35 degrees is formed in the inner wall of a barrel of the rod mill; the temperature control module is integrated on a double-layer water-cooling interlayer structure of the rod mill, the flow velocity of a cooling medium in an interlayer is 2.5 + / -0.2 m / h, and the crushing temperature is controlled to be 55-60 DEG C; the multi-stage magnetic separation unit comprises first-stage magnetic separation equipment and second-stage magnetic separation equipment, the magnetic field intensity of the front section of the first-stage magnetic separation equipment is 1.0-1.2 T, the magnetic field intensity of the rear section of the first-stage magnetic separation equipment is 0.3-0.5 T, and the second-stage magnetic separation equipment adopts a high-frequency pulse magnetic field with the frequency of 75 + / -5 And the waste material co-processing unit is provided with a micro powder-waste material feeding machine with a dynamic mixing ratio and an alkali activator atomizing and spraying device, and the mixing ratio adjusting precision is + / -2%.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste resource utilization, and in particular to a method for resource utilization of converter slag and construction waste. Background Art

[0002] In today's society, with the rapid advancement of industrialization and urbanization, the amount of converter slag and construction waste generated is increasing day by day, and their treatment has become a key problem that needs to be urgently solved in the fields of environment and resource utilization.

[0003] Converter slag is an inevitable by-product of the steelmaking process. According to relevant statistics, about 100-150 kg of converter slag is produced for every ton of steel produced. These converter slags are rich in various valuable elements such as iron, calcium, magnesium, etc., and also have certain potential activity. However, for a long time, a large amount of converter slag has been simply stored or extensively landfilled. This not only occupies a large amount of precious land resources and causes waste of land resources, but may also cause the leakage of heavy metal elements in the slag, polluting the surrounding soil and groundwater, and posing a serious threat to the ecological environment. More importantly, the rich resources contained in the converter slag are wasted and not effectively utilized, which violates the concept of sustainable development.

[0004] At the same time, the amount of construction waste generated is also very alarming. With the continuous development of urban construction, old city renovation and infrastructure construction projects, construction waste is continuously generated. It is estimated that for every 10,000 square meters of old buildings demolished, about 7,000-12,000 tons of construction waste will be generated. These construction wastes are complex in composition, mainly including concrete blocks, brick and tile fragments, waste wood, metal, etc. At present, most construction waste is also disposed of by landfill, which not only occupies a large amount of land, but also damages the ecological environment around the landfill site. In addition, the traditional construction waste treatment method ignores the recyclable resources in it, such as waste concrete blocks and brick and tile fragments, which can be used as recycled aggregates for the production of recycled building materials after processing; waste metals can be recycled and smelted to achieve resource recycling. This waste of resources is in sharp contrast to the current global resource shortage.

[0005] In terms of traditional solid waste treatment technology, there are many deficiencies in the mixed treatment of converter slag and construction waste. In the crushing stage, it is difficult for traditional crushing processes to take into account the differences in the characteristics of hard metal slag and brittle construction waste. For hard converter slag, insufficient crushing may occur, resulting in residual coarse particles; while for brittle construction waste, it is easy to over-crush, resulting in excessive fine powder, affecting subsequent processing efficiency and product quality. In the magnetic separation stage, conventional magnetic separation equipment has poor separation effect on iron elements in converter slag and construction waste, and the iron recovery rate is low. The grade of iron concentrate is also difficult to meet the standard for direct reuse of steelmaking raw materials, resulting in waste of resources. In terms of the preparation of building materials, when these solid wastes are used to prepare permeable bricks in the traditional way, due to the weak interface bonding between aggregates and cementitious materials, the permeable bricks have the problem of difficulty in balancing strength and permeability, which cannot meet the needs of actual engineering applications. Summary of the invention

[0006] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a method for resource processing of converter slag and construction waste, which effectively solves the problems mentioned in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: The present invention includes: A gradient crushing unit, comprising a rod mill with a variable diameter rod assembly, the diameter of which gradually changes from Φ80 mm to Φ50 mm along the direction of material travel, and a guide groove with a helical angle of 25°-35° is provided on the inner wall of the rod mill cylinder; ‌Temperature control module‌, integrated in the double-layer water-cooled sandwich structure of the rod mill, the cooling medium flow rate in the sandwich is 2.5±0.2m³ / h, and the crushing temperature is controlled at 55-60℃; ‌Multi-stage magnetic separation unit‌, including primary magnetic separation equipment and secondary magnetic separation equipment, wherein the magnetic field strength of the first stage of the first magnetic separation equipment is 1.0-1.2T, and the magnetic field strength of the rear stage is 0.3-0.5T, and the secondary magnetic separation equipment adopts a high-frequency pulse magnetic field with a frequency of 75±5Hz; The waste co-processing unit is equipped with a dynamic mixing ratio micro powder-waste feeder and an alkali activator atomizing injection device, and the mixing ratio adjustment accuracy is ±2%.

[0008] According to the above scheme: the length of the tapered section of the variable diameter rod assembly accounts for 40%-50% of the total length of the rod mill, the distance between adjacent rods decreases by 10%-15% along the material direction, and the surface of the rod body is provided with a spiral groove with a depth of 0.5-1mm.

[0009] According to the above scheme: the high-frequency pulse magnetic field waveform of the secondary magnetic separation equipment is a composite waveform of a square wave and a sawtooth wave, the duty cycle adjustment range is 20%-80%, and the magnetic field gradient is 0.5-1.0T / cm.

[0010] According to the above scheme: the gradient crushing in step (a) adopts a two-stage crushing mode, the coarse crushing stage is crushed to 10-30mm, the fine crushing stage is crushed to <5mm and the micro powder generation rate is ≤8%.

[0011] A method for recycling converter slag and construction waste, characterized in that it comprises the following steps: (a) Mix converter slag and construction waste in a mass ratio of 1:1±0.1, and control the moisture content of the mixture to ≤5%; (b) Gradient crushing stage: Two-stage crushing is carried out in the rod mill. The coarse crushing stage outputs a particle size of 15-25 mm, and the fine crushing stage is crushed to a particle size of D90 ≤ 3 mm through the variable diameter rod compression zone, and the proportion of micro powder with a particle size of < 0.15 mm is ≤ 6%; (c) Primary magnetic separation stage: The crushed material is subjected to strong magnetic separation with a magnetic field strength of 1.0T to separate the iron concentrate; the remaining material is subjected to 0.4T weak magnetic separation to extract the iron-containing tailings, and the magnetic separation air flow velocity is 8-10m / s; (d) Screening and grading stage: The non-magnetic materials are graded into graded gravel >10mm, machine-made sand 3-10mm and active micro powder <3mm through a double-layer vibrating screen, where the stone powder content of the machine-made sand is controlled to ≤5% by negative pressure adsorption; (e) Secondary magnetic separation intensification stage: the iron-containing tailings are fed into a ball mill equipped with a high-chromium cast iron-rubber composite liner, with a ball mill medium filling rate of 30%±2%. After grinding, the 75Hz high-frequency pulse magnetic field is used for separation to obtain iron concentrate with TFe≥60%. (f) Waste collaborative preparation stage: The ball mill waste is mixed with active micropowder in a mass ratio of 3:7, and 6%±0.5% of alkali activator is sprayed synchronously by atomization. It is formed into a permeable brick body through high-frequency vibration. The curing temperature is maintained at 50±2℃ for 24 hours and then increased to 80℃ for accelerated curing for 12 hours.

[0012] According to the above technical solution: the base activator in step (f) is composed of the following components: Nano-metakaolin modified slag powder: 45%-50%; Sulphoaluminate cement clinker: 25%-30%; Lithium bentonite: 10%-15%; Polycarboxylate water reducer: 1%-2%; The rest is silica fume, and the particle size of each component is D50≤10μm.

[0013] According to the above technical solution: the crushing energy efficiency ratio (kWh / t) of the fine crushing section in step (b) satisfies the following relationship: , where D80 is the 80% sieved particle size of the coarse crushing product (mm), d80 is the 80% sieved particle size of the fine crushing product (mm), R is the powder generation rate (%), and the E value is controlled within the range of 18-22 kWh / t.

[0014] According to the above technical solution: the magnetic field strength and frequency of the high-frequency pulse magnetic field in step (e) satisfy: , where H 0 =1.2T, f=75Hz, the magnetic field action time t matches the material flow rate to 0.1-0.3s.

[0015] According to the above technical solution: the compressive strength of the permeable brick prepared in step (e) is ≥30MPa, and the permeability coefficient is ≥1.5×10 -2 cm / s, and the curing temperature was maintained at 50±5℃ for 48 hours.

[0016] Beneficial effects: 1. Gradient crushing and multi-stage magnetic separation synergistic effect Through the coupling design of the variable diameter rod assembly (Φ80mm→Φ50mm gradual change) and the helical angle of the guide groove (30°±5°), the differential crushing of converter slag and construction waste is achieved, solving the coexistence of over-crushing (micro powder rate>10%) and under-crushing (coarse particle residue>15%) in the mixed treatment of hard metal slag and brittle construction waste in the traditional crushing process: ‌Improved crushing energy efficiency‌: The data from the examples show that the crushing energy consumption is reduced to 18-20kWh / t (28kWh / t for traditional processes), while the fine powder generation rate is precisely controlled at 4.8%-5.2%, significantly reducing the metal loss rate in the subsequent magnetic separation process.

[0017] ‌Metal enrichment and strengthening‌: The synergistic effect of the first-level magnetic separation (1.1T strong magnetic separation + 0.4T weak magnetic separation) and the second-level high-frequency pulse magnetic separation (composite waveform + 0.8T / cm gradient magnetic field) increases the iron recovery rate to 95%-97% (82% for traditional processes), and the grade of iron ore concentrate (TFe≥60%) meets the standard for direct reuse of steelmaking raw materials.

[0018] ‌2. Interface strengthening effect of waste material co-preparation‌ Based on the optimization of alkali activator formula (nano-metakaolin modification + lithium-based bentonite synergistic activation) and high-frequency vibration compaction technology (50Hz / 2mm), the strength-permeability contradiction caused by the weak interface bonding between aggregate and cementitious materials in traditional solid waste-based permeable bricks is broken through: Breakthrough in mechanical properties: The compressive strength of permeable bricks reaches 32-35MPa (25MPa with traditional technology), and the permeability coefficient is stable at 1.6×10^-2cm / s, achieving the JC / T945-2005 standard for medium and high strength permeable bricks (Class II).

[0019] Maximizing the amount of solid waste: Using ball mill waste (70%) and active micro powder (30%) as raw materials to replace 100% of natural aggregate and cement, the comprehensive solid waste utilization rate reaches 98% (traditional process ≤ 75%).

[0020] ‌3. Closed loop of process flow and environmental benefits‌ Through the integrated design of crushing temperature control (below 58°C) and negative pressure adsorption (stone powder content ≤ 4.5%), a full-process clean production system is constructed: ‌Dust / heat energy control‌: The double-layer water-cooling structure of the rod mill controls the crushing temperature below 58°C (traditional process>80°C). Combined with the vibrating screen negative pressure adsorption module, the dust concentration in the working area is <5mg / m³ (national standard ≤10mg / m³).

[0021] Zero wastewater discharge: 100% recycling rate of cooling medium, alkali activator atomization injection process reduces the amount of liquid additives by 60%, and no process wastewater is generated.

[0022] ‌4. Significant economic benefits‌ Raw material cost savings: Direct recycling of iron ore concentrate reduces the purchase cost of steelmaking raw materials by 35%, and the production cost of permeable bricks is 40% lower than that of commercially available products.

[0023] ‌Extended equipment life‌: High chromium cast iron-rubber composite lining (ball mill) extends the replacement cycle of wear-resistant parts to 6,000 hours (traditional lining ≤ 4,000 hours). BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is the overall flow chart of the present invention; Figure 2 It is the principle diagram of multi-stage magnetic separation of the present invention. DETAILED DESCRIPTION

[0025] The following is combined with Figure 1-2 The specific implementation modes of the present invention are described in further detail.

[0026] Embodiment 1, by Figure 1-2 The present invention provides a method for recycling converter slag and construction waste. Step 1: Pretreatment of mixed materials Mix converter slag and construction waste (mainly concrete blocks and brick and tile fragments) in a mass ratio of 1:1, and use a drum dryer to control the moisture content of the mixture to 4.8%, and the initial particle size of the particles is ≤100mm.

[0027] ‌Step 2: Gradient Crushing‌ Rod mill with variable diameter rod assembly performs two-stage crushing: ‌Coarse crushing section‌: The rod diameter of the front section of the rod mill is Φ80mm, the rod spacing is 50mm, the helical angle of the guide groove is 30°, the D80 of the material after crushing is 20mm (that is, 80% of the material passes through the 20mm screen), and the energy consumption of the coarse crushing section is 15kWh / t.

[0028] ‌Fine crushing section‌: The diameter of the rods in the rear section of the rod mill gradually changes to Φ50mm, the rod spacing decreases to 43mm, the compression zone length accounts for 45%, the fine material after crushing d80=2.8mm, the fine powder (<0.15mm) accounts for 5.2%, and the crushing energy efficiency ratio E=20kWh / t (satisfying the formula: E=15×(D80 / d80)^(0.5)+0.3R, where R=5.2).

[0029] ‌Step 3: Primary Magnetic Separation‌ ‌Strong magnetic separation‌: The crushed materials are input into the front section of the primary magnetic separation equipment, with a magnetic field strength of 1.1T and an air flow velocity of 9m / s to separate the iron concentrate (TFe=92%).

[0030] Weak magnetic separation: The remaining materials enter the rear stage with a magnetic field strength of 0.4T to recover iron-containing tailings (TFe=35%), and the non-magnetic materials are transferred to screening and grading.

[0031] ‌Step 4: Screening and grading‌ Use a double-layer vibrating screen (upper layer mesh 10mm, lower layer mesh 3mm): ‌Graded gravel‌ (>10mm): accounts for 28%, used for roadbed filling.

[0032] Artificial sand (3-10mm): accounts for 52%, and the stone powder content is controlled to 4.5% by negative pressure adsorption, which meets the GB / T14684 standard.

[0033] ‌Active micro powder‌ (<3mm): accounts for 20%, used for the preparation of permeable bricks.

[0034] ‌Step 5: Secondary magnetic separation enhancement‌ The iron-containing tailings were fed into a ball mill (high chromium cast iron-rubber composite lining, filling rate 31%), and after being ground to D50=0.1mm, they were separated by a high-frequency pulse magnetic field (frequency 75Hz, square wave and sawtooth wave composite waveform, duty cycle 50%, magnetic field gradient 0.8T / cm) to obtain iron concentrate (TFe=60%), and the recovery rate was increased to 95%.

[0035] ‌Step 6: Use waste materials to make permeable bricks‌ Mix the ball mill waste with the active micro powder in a mass ratio of 3:7, and spray the alkali activator (addition amount 6%) synchronously by atomization: Alkali activator formula: nano-metakaolin modified slag powder (48%), sulphoaluminate cement clinker (28%), lithium-based bentonite (12%), polycarboxylic acid water reducer (1.5%), silica fume (10.5%), D50 of each component ≤ 8μm.

[0036] The mixture is compacted by high frequency vibration (frequency 50Hz, amplitude 2mm) to form a permeable brick body. The curing conditions are: Phase 1: Constant temperature maintenance at 50°C for 24 hours.

[0037] The second stage: heating to 80℃ to accelerate curing for 12 hours.

[0038] Finished product performance: compressive strength 32MPa, water permeability 1.6×10^-2cm / s, meeting JC / T945-2005 standards.

[0039] Example 2 ‌Step Adjustment and Parameter Optimization‌ ‌Gradient crushing‌: Increase the proportion of the gradual length of the variable diameter rods in the fine crushing section to 50%, reduce the fine powder generation rate to 4.8%, and the crushing energy efficiency ratio E=18kWh / t.

[0040] ‌Secondary magnetic separation‌: Adjust the duty cycle of the high-frequency pulse magnetic field to 80%, the magnetic field action time to 0.2s, and the iron ore concentrate TFe to 70%.

[0041] ‌Permeable brick maintenance‌: Extend the first stage of maintenance to 30 hours, and the compressive strength increases to 35MPa.

[0042] Experimental data comparison: Beneficial effects: 1. Gradient crushing and multi-stage magnetic separation synergistic effect Through the coupling design of the variable diameter rod assembly (Φ80mm→Φ50mm gradual change) and the helical angle of the guide groove (30°±5°), the differential crushing of converter slag and construction waste is achieved, solving the coexistence of over-crushing (micro powder rate>10%) and under-crushing (coarse particle residue>15%) in the mixed treatment of hard metal slag and brittle construction waste in the traditional crushing process: ‌Improved crushing energy efficiency‌: The data from the examples show that the crushing energy consumption is reduced to 18-20kWh / t (28kWh / t for traditional processes), while the fine powder generation rate is precisely controlled at 4.8%-5.2%, significantly reducing the metal loss rate in the subsequent magnetic separation process.

[0043] ‌Metal enrichment and strengthening‌: The synergistic effect of the first-level magnetic separation (1.1T strong magnetic separation + 0.4T weak magnetic separation) and the second-level high-frequency pulse magnetic separation (composite waveform + 0.8T / cm gradient magnetic field) increases the iron recovery rate to 95%-97% (82% for traditional processes), and the grade of iron ore concentrate (TFe≥60%) meets the standard for direct reuse of steelmaking raw materials.

[0044] ‌2. Interface strengthening effect of waste material co-preparation‌ Based on the optimization of alkali activator formula (nano-metakaolin modification + lithium-based bentonite synergistic activation) and high-frequency vibration compaction technology (50Hz / 2mm), the strength-permeability contradiction caused by the weak interface bonding between aggregate and cementitious materials in traditional solid waste-based permeable bricks is broken through: Breakthrough in mechanical properties: The compressive strength of permeable bricks reaches 32-35MPa (25MPa with traditional technology), and the permeability coefficient is stable at 1.6×10^-2cm / s, achieving the JC / T945-2005 standard for medium and high strength permeable bricks (Class II).

[0045] Maximizing the amount of solid waste: Using ball mill waste (70%) and active micro powder (30%) as raw materials to replace 100% of natural aggregate and cement, the comprehensive solid waste utilization rate reaches 98% (traditional process ≤ 75%).

[0046] ‌3. Closed loop of process flow and environmental benefits‌ Through the integrated design of crushing temperature control (below 58°C) and negative pressure adsorption (stone powder content ≤ 4.5%), a full-process clean production system is constructed: ‌Dust / heat energy control‌: The double-layer water-cooling structure of the rod mill controls the crushing temperature below 58°C (traditional process>80°C). Combined with the vibrating screen negative pressure adsorption module, the dust concentration in the working area is <5mg / m³ (national standard ≤10mg / m³).

[0047] Zero wastewater discharge: 100% recycling rate of cooling medium, alkali activator atomization injection process reduces the amount of liquid additives by 60%, and no process wastewater is generated.

[0048] ‌4. Significant economic benefits‌ Raw material cost savings: Direct recycling of iron ore concentrate reduces the purchase cost of steelmaking raw materials by 35%, and the production cost of permeable bricks is 40% lower than that of commercially available products.

[0049] ‌Extended equipment life‌: High chromium cast iron-rubber composite lining (ball mill) extends the replacement cycle of wear-resistant parts to 6,000 hours (traditional lining ≤ 4,000 hours).

[0050] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for recycling converter slag and construction waste, characterized in that: include: Gradient crushing unit, which includes a rod mill with a variable diameter rod assembly, the diameter of which gradually changes from Φ80mm to Φ50mm along the direction of material travel, and the inner wall of the rod mill cylinder is provided with a guide groove with a helix angle of 25°-35°; a temperature control module, which is integrated into the double-layer water-cooled interlayer structure of the rod mill, the cooling medium flow rate in the interlayer is 2.5±0.2m³ / h, and the crushing temperature is controlled at 55-60℃; a multi-stage magnetic separation unit, which includes a primary magnetic separation device and a secondary magnetic separation device, wherein the magnetic field strength of the first section of the primary magnetic separation device is 1.0-1.2T and the magnetic field strength of the rear section is 0.3-0.5T, and the secondary magnetic separation device adopts a high-frequency pulse magnetic field with a frequency of 75±5Hz; a waste collaborative processing unit, which is equipped with a micro-powder-waste feeder with a dynamic mixing ratio and an alkali activator atomizing injection device, and the mixing ratio adjustment accuracy is ±2%.

2. The method for recycling converter slag and construction waste according to claim 1, characterized in that: The length of the tapered section of the variable diameter rod assembly accounts for 40%-50% of the total length of the rod mill, the distance between adjacent rods decreases by 10%-15% along the material direction, and a spiral groove with a depth of 0.5-1mm is provided on the surface of the rod body.

3. A method for resource processing of converter slag and construction waste based on the system of claim 1, characterized in that: The high-frequency pulse magnetic field waveform of the secondary magnetic separation equipment is a composite waveform of a square wave and a sawtooth wave, the duty cycle adjustment range is 20%-80%, and the magnetic field gradient is 0.5-1.0 T / cm.

4. The method for recycling converter slag and construction waste according to claim 3, characterized in that: The gradient crushing in step (a) adopts a two-stage crushing mode, the coarse crushing stage is crushed to 10-30 mm, the fine crushing stage is crushed to <5 mm, and the micro powder generation rate is ≤8%.

5. A method for recycling converter slag and construction waste according to any one of claims 1 to 3, characterized in that: The following steps are involved: ‌ (a) Mix converter slag and construction waste in a mass ratio of 1:1±0.1, and control the moisture content of the mixture to ≤5%; (b) Gradient crushing stage: Two-stage crushing is carried out in the rod mill. The coarse crushing stage outputs a particle size of 15-25 mm, and the fine crushing stage is crushed to a particle size of D90 ≤ 3 mm through the variable diameter rod compression zone, and the proportion of micro powder with a particle size of < 0.15 mm is ≤ 6%; (c) Primary magnetic separation stage: The crushed material is subjected to strong magnetic separation with a magnetic field strength of 1.0T to separate the iron concentrate; the remaining material is subjected to 0.4T weak magnetic separation to extract the iron-containing tailings, and the magnetic separation air flow velocity is 8-10m / s; (d) Screening and grading stage: The non-magnetic materials are graded into graded gravel >10mm, machine-made sand 3-10mm and active micro powder <3mm through a double-layer vibrating screen, where the stone powder content of the machine-made sand is controlled to ≤5% by negative pressure adsorption; (e) Secondary magnetic separation intensification stage: the iron-containing tailings are fed into a ball mill equipped with a high-chromium cast iron-rubber composite liner, with a ball mill medium filling rate of 30%±2%. After grinding, the 75Hz high-frequency pulse magnetic field is used for separation to obtain iron concentrate with TFe≥60%. (f) Waste collaborative preparation stage: The ball mill waste is mixed with active micropowder in a mass ratio of 3:7, and 6%±0.5% of alkali activator is sprayed synchronously by atomization. It is formed into a permeable brick body through high-frequency vibration. The curing temperature is maintained at 50±2℃ for 24 hours and then increased to 80℃ for accelerated curing for 12 hours.

6. The method for recycling converter slag and construction waste according to claim 4, characterized in that: The base activator in step (f) is composed of the following components: Nano-metakaolin modified slag powder: 45%-50%; Sulphoaluminate cement clinker: 25%-30%; Lithium bentonite: 10%-15%; Polycarboxylate water reducer: 1%-2%; The rest is silica fume, and the particle size of each component is D50≤10μm.

7. The method for recycling converter slag and construction waste according to claim 4, characterized in that: The crushing energy efficiency ratio (kWh / t) of the fine crushing section in step (b) satisfies the following relationship: , where D80 is the 80% sieved particle size of the coarse crushing product (mm), d80 is the 80% sieved particle size of the fine crushing product (mm), R is the powder generation rate (%), and the E value is controlled within the range of 18-22 kWh / t.

8. The method for recycling converter slag and construction waste according to claim 4, characterized in that: The magnetic field strength and frequency of the high-frequency pulse magnetic field in step (e) satisfy: , where H0=1.2T, f=75Hz, and the magnetic field action time t matches the material flow rate to 0.1-0.3s.

9. The method for recycling converter slag and construction waste according to claim 4, characterized in that: The permeable bricks prepared in step (e) have a compressive strength of ≥30 MPa and a water permeability coefficient of ≥1.5×10 -2 cm / s, and the curing temperature was maintained at 50±5℃ for 48 hours.

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