Method for preparing different grades of aggregates using slag

Abstract

The present application relates to the technical field of aggregate preparation, and discloses a preparation method for preparing different grades of aggregates from slag, which comprises the following preparation steps: 1) drying and scattering slag and cementitious materials, and mixing them by stirring to form a mixture; 2) placing the mixture on a rotating disc; the rotating disc is inclined to rotate, and an activator is sprayed through a spraying structure, so that the activator is mixed with the mixture, and the mixture is extruded by centrifugal force to form a granular semi-finished product; 3) vibrating and screening the granular semi-finished product to form a plurality of different grades of granular aggregates; 4) solidifying the aggregates; in the preparation step 1), the cementitious materials comprise Portland cement, calcium oxide solid waste, gypsum material, metal tailings and metakaolin; in the preparation step 2), the activator comprises early strength agent, water reducing agent, water glass and mud inhibitor; a large amount of waste slag can be effectively disposed of, and the slag can be prepared into unburned ceramics or synthetic sand, which has the advantages of energy saving and emission reduction.

Description

Technical Field

[0001] This invention patent relates to the technical field of aggregate preparation, and more specifically, to a method for preparing aggregates of different grades using slag and soil. Background Technology

[0002] In existing technologies, construction waste is generally disposed of through landfilling, which not only pollutes the environment but also incurs high transportation costs. Alternatively, construction waste is incinerated, which poses significant potential dangers to the environment and human health.

[0003] Currently, there are also methods for recycling construction waste, such as crushing and other means to directly crush and recycle it. However, the utilization rate is low and it is difficult to achieve the goal of energy conservation and emission reduction. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing aggregates of different grades using slag soil, aiming to solve the problem that the recycling of slag soil is difficult to achieve energy conservation and emission reduction in the existing technology.

[0005] This invention is achieved by using a method for preparing aggregates of different grades from slag and soil, comprising the following preparation steps: 1) Dry and break up the slag and cementitious material in sequence, and then mix the broken slag and cementitious material to form a powdery mixture. 2) The mixture is placed in a granulator, which has an inclined rotating disk with a rotating cavity with an opening at the top. The rotating cavity is arranged at an inclination in the same direction as the rotating disk. The mixture is placed in a rotating chamber, and the rotating disk is tilted and rotated. During the process of the mixture rotating centrifugally with the rotating disk in the rotating chamber, a solution of activator is sprayed into the rotating chamber through multiple spray heads. The activator is mixed with the mixture. After the mixture rotates with the rotating disk for a set time, it is squeezed by centrifugal force to form a granular semi-finished product. 3) After the granular semi-finished product is discharged from the rotating disc, it is screened by a vibration transmission structure and screened into granular aggregates of various grades. 4) Solidify the aggregate; In preparation step 1), the cementitious material includes silicate cement, calcium oxide solid waste, gypsum, metal tailings, and metakaolin; in preparation step 2), the activator includes an early strength agent, polycarboxylate superplasticizer mother liquor, water glass, and a mud inhibitor.

[0006] Furthermore, in the preparation step 1), the slag is formed by one or more of the following: silt, shield tunnel slag, or granite residual soil.

[0007] Furthermore, in the preparation step 4), the cured aggregate is spherical, and the surface of the aggregate has an uneven structure.

[0008] Furthermore, in the preparation step 4), the aggregate includes a slag clump formed from slag and a cementitious layer formed from cementitious material covering the outer periphery of the slag clump, the cementitious layer forming the outer surface of the aggregate.

[0009] Furthermore, in preparation step 4), the diameter of the aggregate is between 2.5 mm and 13 mm.

[0010] Furthermore, in preparation step 4), the content of slag in the aggregate is between 60% and 90% by mass percentage.

[0011] Furthermore, according to mass percentage, in preparation step 1), the cementitious material comprises 0-20% silicate cement, 30-50% calcium oxide solid waste, 20-50% gypsum, 0-15% metal tailings, and 0-8% metakaolin; the gypsum is one or more of desulfurized gypsum, phosphogypsum, or natural gypsum.

[0012] Furthermore, according to mass percentage, in preparation step 1), the activator comprises 0-5% early strength agent, 0-35% polycarboxylate superplasticizer mother liquor, 30%-70% water glass material and 0-15% mud inhibitor; the modulus of the water glass is 1.8-2.3.

[0013] Furthermore, the rotating cavity has an upwardly inclined bottom surface, the rotating cavity includes an upper cavity and a lower cavity, the upper cavity is located above the lower cavity, and the upper cavity and the lower cavity are inclinedly connected; a crossbeam is provided above the rotating cavity, a mounting bracket is connected to the crossbeam, and a scraper is connected to the mounting bracket, the scraper has scraping edges arranged in strips; The scraper is arranged above the upper cavity, the scraping edge is arranged facing the bottom surface and has a scraping interval between it and the bottom surface, and the scraping edge is arranged at an inclined cross with the radial direction of the rotating disk; a plurality of spray heads are arranged above the upper cavity, and the plurality of spray heads are arranged at intervals along the length direction of the scraping edge; along the rotation direction of the rotating disk, the plurality of spray heads are located in front of the scraper. The scraping edge forms two hard inclined blades. Along the rotation direction of the rotating disk, the two hard inclined blades are inclined forward in the same direction, and the inclination angle of the two hard inclined blades gradually increases. The scraping interval is formed between the hard inclined blades and the bottom surface, and an inclined interval is formed between the two hard inclined blades. The inclined interval is provided with an elastic inclined piece, which extends along the length of the hard inclined piece; the top of the elastic inclined piece is fixedly arranged, and there is an elastic interval between the bottom of the elastic inclined piece and the bottom surface. The elastic interval is smaller than the scraping interval, and the elastic inclined piece is arranged at intervals with the two hard inclined pieces. In the preparation step 2), during the process of the mixture rotating with the rotating disk in the rotating cavity, the mixture is scraped and spread thin by the two hard inclined blades through the scraping interval of the two hard inclined blades, and the mixture placed in the inclined interval is scraped and spread thin by the elastic inclined blades. After the mixture passes through the scraping interval, it mixes with the activator sprayed from the multiple spray heads to form a viscous substance.

[0014] Furthermore, the spray head has a spray cavity, a spray surface facing the bottom, a plurality of spray holes in the spray surface, and the spray cavity communicates with the outside through the spray holes; a rotating spray net is fitted around the outside of the spray surface, the spray net has a plurality of fine spray nozzles, the diameter of the fine spray nozzles is smaller than the diameter of the spray holes, and the fine spray nozzles and the spray holes are staggered. The spraying chamber is provided with an elastically expandable airbag. The upper part of the airbag is fixedly connected to the inner wall of the spraying chamber. The lower part of the airbag has an elastic surface. The elastic surface is arranged facing the spraying surface and has an expansion gap with the spraying surface. The elastic surface has multiple elastic holes. When the elastic surface is in its natural state, the plurality of elastic holes are arranged in a closed manner; when the elastic surface is in an expanded state, the elastic holes are opened. In preparation step 2), during the process of spraying the activator by the spray head, the activator is injected into the air bag under high pressure, the elastic surface expands and abuts against the spray surface, the elastic hole opens, and the activator passes through the elastic hole and is sprayed out through the spray hole; the spray net is impacted by the activator sprayed out of the spray hole, the spray net rotates relative to the spray head, and the activator is sprayed into the mixture in the rotating cavity through multiple spray nozzles.

[0015] Compared with existing technologies, the present invention provides a method for preparing aggregates of different grades using waste soil. This method involves drying and dispersing the waste soil and cementitious materials, then mixing them to form a powdery mixture. During the tilting and rotating process in an inclined rotating disk, the mixture is mixed with an activator. The centrifugal force of the tilting rotation is then used to form granular semi-finished products. These granular semi-finished products are then screened by vibration to form aggregates of different grades. Finally, the aggregates are solidified. This method can effectively utilize a large amount of waste soil and prepare it into non-fired ceramics or synthetic sand, offering advantages in energy conservation and emission reduction. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the preparation method for preparing aggregates of different grades using slag provided by the present invention. Figure 2 This is a front view schematic diagram of the rotating disk provided by the present invention; Figure 3 This is a three-dimensional schematic diagram of the two rigid tilting plates and the elastic tilting plate provided by the present invention; Figure 4 This is a front view schematic diagram of the spray head provided by the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0019] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0020] Reference Figure 1-4 The image shown is a preferred embodiment of the present invention.

[0021] The preparation method for different grades of aggregates using slag soil includes the following preparation steps: 1) Dry and break up the slag and cementitious material in sequence, and then mix the broken slag and cementitious material to form a powdery mixture. 2) The mixture is placed in a granulator. The granulator has an inclined rotating disk 100. The rotating disk 100 has a rotating cavity with an opening at the top. The rotating cavity is arranged inclined in the same direction as the rotating disk 100. The mixture is placed in the rotating chamber, and the rotating disk 100 is tilted and rotated. During the process of the mixture rotating in the rotating chamber with the rotating disk 100 tilting and centrifugally rotating, a solution of activator is sprayed into the rotating chamber through the spraying structure. The activator mixes with the mixture. After the mixture rotates with the rotating disk 100 for a set time, it is squeezed by centrifugal force to form a granular semi-finished product. 3) After the granular semi-finished product is discharged from the rotating disc 100, it is screened by the vibration transmission structure and screened into granular aggregates of various grades. 4) Solidify the aggregate; In preparation step 1), the cementitious material includes silicate cement, calcium oxide solid waste, gypsum, metal tailings, and metakaolin; in preparation step 2), the activator includes an early strength agent, a water-reducing agent, polycarboxylate superplasticizer mother liquor, water glass, and a mud inhibitor.

[0022] The above-mentioned method for preparing aggregates of different grades using waste soil involves drying and dispersing the waste soil and cementitious material, then mixing them to form a powdery mixture. This mixture is then mixed with an activator while rotating in an inclined rotating disk 100. The centrifugal force from the inclined rotation then forms granular semi-finished products. These granular semi-finished products are then screened by vibration to form aggregates of different grades. Finally, the aggregates are solidified. This method can effectively utilize large quantities of waste soil and prepare it into non-fired ceramics or synthetic sand, offering advantages in energy conservation and emission reduction.

[0023] The term "slag and soil" can encompass the slag and soil commonly found in coastal areas of China, such as silt, tunnel boring machine slag and residual granite soil. The resulting aggregate can be different grades of non-fired ceramsite and synthetic sand, and its composition consists of a small amount of cementing materials, activators and a large amount of slag and soil.

[0024] In preparation step 1), the slag is formed by one or more of the following: silt, shield tunnel slag, or granite residual soil.

[0025] In preparation step 4), the cured aggregate is spherical and has an uneven surface.

[0026] The prepared aggregate has a spherical or near-spherical appearance. The particle size of the spheres varies from 2.5mm to 5mm, 5mm to 13mm, or more than 13mm or less than 2.5mm. They have few sharp edges and corners, a relatively rough surface with concave and convex surfaces, and good cohesion. Their shell and core are composed of different materials, but the boundaries are not clear.

[0027] The prepared aggregate, after being cured in an environment with a relative humidity of over 85% for 28 days, has a compressive strength of 5MPa-15MPa, or after being steam-cured at a temperature of over 60-80℃ for over 2 days, has a compressive strength of 8MPa-15MPa.

[0028] The aggregate prepared and cured in an environment with a relative humidity of over 85% for 28 days has a crushing value of less than 15%, or it is steam-cured at a temperature of over 60-80℃ for more than 2 days to achieve a crushing value of less than 10%.

[0029] The aggregates prepared contain 60-90% slag and soil, including common types such as silt, tunnel boring machine slag, and granite residual soil, with organic matter content less than 15%.

[0030] In this embodiment, in preparation step 4), the aggregate includes a slag clump formed from slag and a cementitious layer formed from cementitious material covering the outer periphery of the slag clump, the cementitious layer forming the outer surface of the aggregate.

[0031] In preparation step 4), the diameter of the aggregate is between 2.5 mm and 13 mm.

[0032] In preparation step 4), the slag content in the aggregate is between 60% and 90% by mass percentage.

[0033] According to the mass percentage, in step 1), the cementitious material contains 0-20% silicate cement, 30%-50% calcium oxide solid waste, 20%-50% gypsum, 0-15% metal tailings, and 0-8% metakaolin; the gypsum is one or more of desulfurized gypsum, phosphogypsum, or natural gypsum.

[0034] According to the mass percentage, in preparation step 1), the activator contains 0-5% early strength agent, 0-35% polycarboxylate superplasticizer mother liquor, 30%-70% water glass material and 0-15% mud inhibitor; the modulus of the water glass is 1.8-2.3.

[0035] In this embodiment, the rotating cavity has a bottom surface 101 that is inclined upwards. The rotating cavity includes an upper cavity 102 and a lower cavity 103. The upper cavity 102 is located above the lower cavity 103, and the upper cavity 102 and the lower cavity 103 are inclinedly connected. A crossbeam is provided above the rotating cavity, and a mounting frame is connected to the crossbeam. A scraper 200 is connected to the mounting frame, and the scraper 200 has scraping edges arranged in a strip shape.

[0036] The scraper 200 is arranged above the upper cavity 102, with the scraping edge facing the bottom surface 101 and having a scraping interval between it and the bottom surface 101. The scraping edge and the radial direction of the rotating disk 100 are arranged at an inclined cross. Above the upper cavity 102, there are multiple spray heads 400 that spray activator into the upper cavity 102. The multiple spray heads 400 are arranged at intervals along the length direction of the scraping edge. Along the rotation direction of the rotating disk 100, the multiple spray heads 400 are located in front of the scraper 200.

[0037] The scraping process forms two hard inclined blades 201. Along the rotation direction of the rotating disk 100, the two hard inclined blades 201 are inclined forward in the same direction, and the inclination angle of the two hard inclined blades 201 gradually increases. The scraping interval is formed between the hard inclined blades 201 and the bottom surface 101, and an inclined interval 202 is formed between the two hard inclined blades 201. An elastic inclined piece 300 is provided in the inclined interval 202. The elastic inclined piece 300 extends along the length direction of the hard inclined piece 201. The top of the elastic inclined piece 300 is fixedly arranged. There is an elastic interval between the bottom of the elastic inclined piece 300 and the bottom surface 101. The elastic interval is smaller than the scraping interval. The elastic inclined piece 300 is arranged at intervals with the two hard inclined pieces 201. In preparation step 2), during the process of the mixture rotating with the rotating disk 100 in the rotating cavity, the mixture is scraped and spread thin by the two hard inclined plates 201 through the scraping interval of the two hard inclined plates 201, and the mixture placed in the inclined interval 202 is scraped and spread thin by the elastic inclined plate 300. After the mixture passes through the scraping interval, it mixes with the activator sprayed from multiple spray heads 400, forming a viscous consistency.

[0038] When the mixture is poured into the rotating cavity, it can be poured from the upper cavity 102. As the rotating disk 100 rotates, the mixture tilts and rotates with the rotating disk 100. The two hard inclined blades 201 scrape the mixture on the bottom surface 101, spreading and thinning the mixture through the scraping interval. In the process of passing through the inclined interval 202, the mixture is elastically scraped by the elastic inclined blades 300, further spreading and thinning the mixture.

[0039] The two hard inclined plates 201 are inclined in the same direction, and the inclination angle gradually increases. This makes it easier for the two hard inclined plates 201 to spread and thin the mixture, and also makes it easier for the mixture to pass through the scraping interval.

[0040] In this embodiment, the spray head 400 has a spray cavity, and the spray head 400 has a spray surface 401 facing the bottom surface 101. The spray surface 401 has a plurality of spray holes, and the spray cavity communicates with the outside through the spray holes. A rotating spray net is sleeved on the outside of the spray surface 401. The spray net has a plurality of spray nozzles. The diameter of the spray nozzles is smaller than the diameter of the spray holes, and the spray nozzles and spray holes are staggered. The spraying chamber is provided with an elastically expandable airbag 500. The upper part of the airbag 500 is fixedly connected to the inner wall of the spraying chamber. The lower part of the airbag 500 has an elastic surface 501. The elastic surface 501 is arranged facing the spraying surface 401 and has an expansion gap 502 between it and the spraying surface 401. The elastic surface 501 is provided with multiple elastic holes. When the elastic surface 501 is in its natural state, the multiple elastic holes are arranged in a closed manner; when the elastic surface 501 is in an expanded state, the elastic holes are opened. In preparation step 2), during the process of spraying the activator by the spray head 400, the activator is injected into the air bag 500 under high pressure. The elastic surface 501 expands and abuts against the spray surface 401. The elastic hole opens, and the activator passes through the elastic hole and is sprayed out through the spray hole. The spray net is impacted by the activator sprayed out of the spray hole, and the spray net rotates relative to the spray head 400. The activator is sprayed into the mixture in the rotating cavity through multiple spray nozzles.

[0041] By arranging multiple spray heads 400, the activator can be evenly sprayed onto the mixture passing through the scraping interval. The air bladder 500 inflates only after the activator injected into it reaches the set pressure, opening the elastic orifice. The high-pressure activator can then be sprayed outwards through the elastic orifice, spray holes, and spray nozzles. Furthermore, the spray net, impacted and rotating, disperses the sprayed activator into a mist, achieving a wide-area spray and more uniform application.

[0042] 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, and improvements 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 preparing aggregates of different grades using slag and soil, characterized in that, The preparation steps include the following: 1) Dry and break up the slag and cementitious material in sequence, and then mix the broken slag and cementitious material to form a powdery mixture. 2) The mixture is placed in a granulator, which has an inclined rotating disk with a rotating cavity with an opening at the top. The rotating cavity is arranged at an inclination in the same direction as the rotating disk. The mixture is placed in a rotating chamber, and the rotating disk is tilted and rotated. During the process of the mixture rotating centrifugally with the rotating disk in the rotating chamber, a solution of activator is sprayed into the rotating chamber through multiple spray heads. The activator is mixed with the mixture. After the mixture rotates with the rotating disk for a set time, it is squeezed by centrifugal force to form a granular semi-finished product. 3) After the granular semi-finished product is discharged from the rotating disc, it is screened by a vibration transmission structure and screened into granular aggregates of various grades. 4) Solidify the aggregate; In preparation step 1), the cementitious material includes silicate cement, calcium oxide solid waste, gypsum, metal tailings, and metakaolin; in preparation step 2), the activator includes an early strength agent, polycarboxylate superplasticizer mother liquor, water glass, and a mud inhibitor. In the preparation step 4), the solidified aggregate is spherical and the surface of the aggregate has an uneven structure; the aggregate includes a slag clump formed by slag and a cementitious layer formed by cementitious material covering the outer periphery of the slag clump, and the cementitious layer forms the outer surface of the aggregate. According to the mass percentage, in the preparation step 1), the cementitious material contains 0-20% silicate cement, 30%-50% calcium oxide solid waste, 20%-50% gypsum, 0-15% metal tailings, and 0-8% metakaolin; the gypsum is one or more of desulfurized gypsum, phosphogypsum, or natural gypsum. The rotating cavity has an upwardly inclined bottom surface. The rotating cavity includes an upper cavity and a lower cavity. The upper cavity is located above the lower cavity, and the upper cavity and the lower cavity are inclinedly connected. A crossbeam is provided above the rotating cavity. A mounting bracket is connected to the crossbeam. A scraper is connected to the mounting bracket. The scraper has scraping edges arranged in strips. The scraper is arranged above the upper cavity, the scraping edge is arranged facing the bottom surface and has a scraping interval between it and the bottom surface, and the scraping edge is arranged at an inclined cross with the radial direction of the rotating disk; a plurality of spray heads are arranged above the upper cavity, and the plurality of spray heads are arranged at intervals along the length direction of the scraping edge; along the rotation direction of the rotating disk, the plurality of spray heads are located in front of the scraper. The scraping edge forms two hard inclined blades. Along the rotation direction of the rotating disk, the two hard inclined blades are inclined forward in the same direction, and the inclination angle of the two hard inclined blades gradually increases. The scraping interval is formed between the hard inclined blades and the bottom surface, and an inclined interval is formed between the two hard inclined blades. The inclined interval is provided with an elastic inclined piece, which extends along the length of the hard inclined piece; the top of the elastic inclined piece is fixedly arranged, and there is an elastic interval between the bottom of the elastic inclined piece and the bottom surface. The elastic interval is smaller than the scraping interval, and the elastic inclined piece is arranged at intervals with the two hard inclined pieces. In the preparation step 2), during the process of the mixture rotating with the rotating disk in the rotating cavity, the mixture is scraped and spread thin by the two hard inclined blades through the scraping interval of the two hard inclined blades, and the mixture placed in the inclined interval is scraped and spread thin by the elastic inclined blades. After the mixture passes through the scraping interval, it mixes with the activator sprayed from the multiple spray heads to form a viscous substance. The spray head has a spray cavity and a spray surface facing the bottom. The spray surface has multiple spray holes, and the spray cavity communicates with the outside through the spray holes. A rotating spray net is fitted around the outside of the spray surface. The spray net has multiple fine spray nozzles, the diameter of which is smaller than the diameter of the spray holes, and the fine spray nozzles are staggered with the spray holes. The spraying chamber is provided with an elastically expandable airbag. The upper part of the airbag is fixedly connected to the inner wall of the spraying chamber. The lower part of the airbag has an elastic surface. The elastic surface is arranged facing the spraying surface and has an expansion gap with the spraying surface. The elastic surface has multiple elastic holes. When the elastic surface is in its natural state, the plurality of elastic holes are arranged in a closed manner; when the elastic surface is in an expanded state, the elastic holes are opened. In preparation step 2), during the process of spraying the activator by the spray head, the activator is injected into the air bag under high pressure, the elastic surface expands and abuts against the spray surface, the elastic hole opens, and the activator passes through the elastic hole and is sprayed out through the spray hole; the spray net is impacted by the activator sprayed out of the spray hole, the spray net rotates relative to the spray head, and the activator is sprayed into the mixture in the rotating cavity through multiple spray nozzles.

2. The method for preparing aggregates of different grades using slag soil as described in claim 1, characterized in that, In the preparation step 1), the slag is formed by one or more of the following: silt, shield tunnel slag, or granite residual soil.

3. The method for preparing aggregates of different grades using slag soil as described in claim 1, characterized in that, In preparation step 4), the diameter of the aggregate is between 2.5 mm and 13 mm.

4. The method for preparing aggregates of different grades using slag soil as described in claim 1, characterized in that, In preparation step 4), the slag content in the aggregate is between 60% and 90% by mass percentage.

5. The method for preparing aggregates of different grades using slag soil as described in claim 1, characterized in that, According to the mass percentage, in the preparation step 1), the activator contains 0-5% early strength agent, 0-35% polycarboxylate superplasticizer mother liquor, 30%-70% water glass material and 0-15% mud inhibitor; the modulus of the water glass is 1.8-2.3.

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