Production line and method for preparing construction sand from coal gasification slag
By performing graded modification and adaptive crushing and shaping of coal gasification slag, combined with waste heat recovery design, the gradation and performance problems of coal gasification slag in building sand were solved, realizing efficient and continuous production and large-scale application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIFANG UNIV OF NATITIES
- Filing Date
- 2025-12-26
- Publication Date
- 2026-05-08
AI Technical Summary
In existing technologies, coal gasification slag has problems such as unreasonable gradation, low density, and high crushing index when used to prepare building sand. In addition, there is a lack of continuous production equipment for the entire process, making it difficult to apply on a large scale.
The coal gasification slag is classified into coarse slag and fine slag by a feeding and screening device, and then subjected to targeted modification treatment. Combined with mixing, adaptive crushing and shaping and drying and homogenization, and with the waste heat recovery design, the coal gasification slag is efficiently modified and continuously produced.
It effectively solves the problems of unreasonable gradation and insufficient performance of coal gasification slag, improves density and crushing index, and realizes that construction sand can be made without the need to blend natural sand or manufactured sand, thus greatly improving resource utilization and production efficiency.
Smart Images
Figure CN121990777A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solid waste resource utilization technology, specifically relating to a production line and method for preparing construction sand using coal gasification slag. Background Technology
[0002] Coal gasification slag refers to the solid residue discharged from the bottom of the gasifier after coal undergoes a partial oxidation reaction with gasifying agents such as steam and air in the gasifier. Currently, the main method of treating coal gasification slag is landfill, which not only occupies a large amount of land resources but also poses potential environmental risks. At the same time, the demand for natural sand and gravel from the construction industry continues to grow, and over-exploitation will lead to serious ecological and environmental problems. Therefore, converting coal gasification slag into construction sand, realizing "turning waste into treasure," has significant environmental and economic benefits.
[0003] In existing technologies, when coal gasification slag is used as construction sand, it is mostly used directly after simple dehydration. However, the slag itself suffers from performance defects such as unreasonable gradation, low apparent and bulk density, and high crushing index, making it difficult to use alone as construction sand. In practical engineering applications, it usually needs to be blended with natural or manufactured sand, and the mass content of the slag does not exceed 50%, limiting its application. Although some modification technologies have been proposed, these technologies are mostly limited to laboratory research or intermittent operation, lacking integrated continuous production equipment covering the entire process from pretreatment, modification, blending to finished product homogenization. This severely restricts the large-scale promotion and application of coal gasification slag in the construction sand field.
[0004] Therefore, there is an urgent need to develop an integrated technology and equipment that can effectively optimize the gradation and performance of gasification slag, while achieving low-energy consumption and continuous production of coal gasification slag for the preparation of construction sand, so as to better promote the industrial application of gasification slag sand.
[0005] In view of this, this invention is hereby proposed. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a production line and method for preparing construction sand using coal gasification slag. This invention primarily addresses the problems of substandard gradation and density, excessively high crushing index, limited admixture dosage, and lack of continuous production equipment for the entire process, hindering large-scale scalability of coal gasification slag construction sand. By classifying coal gasification slag according to particle size and specifically optimizing the performance of coarse and fine slag particles, followed by mixing, adaptive crushing and shaping, and drying homogenization, combined with a closed-loop heat utilization design for waste heat recovery, this invention achieves efficient modification and continuous production of coal gasification slag, producing standard-compliant construction sand while simultaneously improving resource utilization and reducing energy consumption.
[0007] The objective of this invention is achieved through the following technical solution: On one hand, the present invention provides a production line for preparing construction sand using coal gasification slag, comprising: The feeding and screening device separates coal gasification slag into coarse slag and fine slag during the feeding process. A coarse slag treatment line is used to perform impregnation enhancement and leaching treatment on the coarse slag. The coarse slag treatment line includes an impregnation enhancement device, a leaching device, and a residual liquid collection tank located below the leaching device, which are connected in sequence. A fine slag processing line is used to granulate the fine slag into coarser particles. The fine slag processing line includes a fine slag funnel for receiving fine slag, a disc granulator, and a conveying device connected to the discharge port of the disc granulator. The mixing chamber has its inlet connected to the outlet of the draining device and the outlet of the conveying device, respectively, and is used to mix the treated coarse slag with the granulated fine slag particles. The roller pressing and shaping device has its feed inlet located below the discharge outlet of the mixing chamber, and is used to adaptively crush and shape the mixed material. The drying and homogenizing device has its inlet located below the outlet of the roller forming device, and is used to dry and homogenize the crushed and shaped sand. The waste heat recovery device has a hot air duct connected at one end to the hot air outlet of the drying and homogenizing device and at the other end to the body of the roller forming device, forming a closed-loop heat utilization system that uses the waste heat from drying to preheat the crushed material.
[0008] Furthermore, the feeding and screening device includes an inclined first cylinder, the bottom surface of which is uniformly provided with screening holes of 2mm to 5mm in diameter, and a first stirring shaft driven by a first drive motor via a chain inside. The first stirring shaft is fixed with stirring blades that are in clearance fit with the inner wall of the first cylinder. A coarse slag transfer chamber is provided at the lower outlet of the first cylinder, and a first flow control valve is provided at the discharge port of the coarse slag transfer chamber. The fine slag funnel is positioned below the screening holes, and its interface size covers the projected area of the screening hole section.
[0009] Furthermore, the impregnation strengthening device includes a second cylindrical body arranged at an angle, inside which is a first auger driven by a second drive motor, and an inlet pipe for injecting strengthening liquid into the upper part of the second cylindrical body; The draining device includes an inclined third cylinder with a draining hole on its bottom surface and a second auger inside. The second auger is driven by a third drive motor and is used to transport and squeeze the coarse slag after it has been impregnated by the impregnation strengthening device to drain the liquid.
[0010] Furthermore, the coarse slag treatment line also includes a liquid replenishment device, which includes a main pipeline containing two parallel inlets and one outlet. The first inlet of the main pipeline is connected to the strengthening liquid tank via a replenishment pipe equipped with a first one-way valve and a first one-way pump; the second inlet is connected to the drain pipe of the residual liquid collection tank via a residual liquid pipe equipped with a second one-way valve; and the outlet of the main pipeline is connected to the inlet pipe of the wetting strengthening device.
[0011] Furthermore, the disc granulation apparatus includes: The inclined granulation disc consists of a disc and a protective frame located on the outer edge of the disc. The disc is driven to rotate by a fourth drive motor mounted on its back, causing the fine slag falling on the disc to roll and gather towards the protective frame under the action of centrifugal force. The housing of the fourth drive motor is hinged to the frame through a hinge rod, which is used to adjust the tilt angle of the granulation disc. The spray assembly includes a spray storage tank, a delivery pipe, and multiple spray heads evenly arranged above the granulation tray. A second one-way pump is installed on the delivery pipe to deliver liquid to each spray head and spray atomized liquid onto the fine slag in the granulation tray. Each spray head is equipped with a second flow control valve. A slide is located below the granulation disc and is hinged to the frame via a hydraulic rod to match the angle of the granulation disc. Protective baffles are provided on both sides of the slide.
[0012] Furthermore, the disc granulation device also includes a scraper mechanism, which includes a scraper frame located above the granulation disc. The scraper frame is fixedly connected to the housing of the fourth drive motor via a connector. The scraper frame is provided with a scraper, and the distance between the scraper and the disc is controlled by an adjustment knob.
[0013] Furthermore, the roller pressing and shaping device includes a first roller assembly with a fixed position and a second roller assembly that is parallel to and opposite to the first roller assembly and cooperates to extrude the mixture. The second roller assembly is elastically connected to the machine body and can adaptively adjust the elastic pressure according to the particle size change of the mixture to perform adaptive crushing and shaping of the mixture.
[0014] Furthermore, the first roll assembly includes a first roll, and the roll shafts on both sides of the first roll are rotatably connected to the first support member. The first support member is fixedly installed on a fixed support, and the fixed support is fixedly installed on the frame. The first roll is driven by a fifth drive motor fixedly installed on the frame. The second roll assembly includes a second roll. The roll surfaces of the second roll and the first roll are provided with interlocking concave and convex structures. The roll shafts on both sides of the second roll are rotatably connected to the second support member. The second support member is slidably disposed on a preset slide rail in the fixed support, and a spring is provided between the second support member and the fixed support. The second roll is driven by a sixth drive motor. The sixth drive motor is mounted on the frame. The frame is provided with a sliding groove corresponding to the mounting position of the sixth drive motor, and the sixth drive motor moves synchronously with the second support member.
[0015] Furthermore, the drying and homogenizing device includes a horizontally arranged fourth cylinder, which has a gasification slag inlet and a modified raw material inlet. Inside the fourth cylinder is a second stirring shaft driven by a seventh drive motor. The second stirring shaft has fan-shaped stirring blades that extend spirally toward the outlet. The bottom surface of the fourth cylinder is uniformly provided with air inlets. A hot air device installed at the bottom of the fourth cylinder sends hot air into the cylinder through the air inlets. A hot air outlet is provided at the top of the outlet, and the hot air outlet is connected to the hot air pipe of the waste heat recovery device.
[0016] On the other hand, the present invention also provides a method for preparing construction sand using coal gasification slag, employing the production line described above, and including the following steps: Step 1, Raw material screening: The coal gasification slag raw material is fed into the feeding screening device, and coarse slag and fine slag are screened out using the screening holes; Step 2, Coarse slag treatment: The coarse slag is sequentially passed through an impregnation and strengthening device for liquid impregnation and strengthening, and then through a leaching device for leaching. The leached liquid is collected in a residual liquid collection tank. Step 3, Fine slag treatment: The fine slag is fed into the disc granulator through the fine slag funnel to form fine slag particles, and then conveyed by the conveying device. Step 4, Mixing: Mix the coarse slag after dewatering with the fine slag particles after granulation in a mixing chamber; Step 5, Crushing and Shaping: The mixture is fed into a roller pressing and shaping device for crushing and shaping; Step 6, Drying and Homogenization: The crushed and shaped sand enters the drying and homogenization device, is mixed with the modified raw materials, and is uniformly dried and homogenized under the action of hot air drying and mechanical stirring to obtain qualified construction sand; Step 7, Waste Heat Recovery: The hot waste gas generated by the drying and homogenizing device is extracted by the waste heat recovery device and transported to the roller forming device for material preheating to complete the heat cycle.
[0017] Furthermore, in step 2, the liquid in the residual liquid collection tank is replenished to the wetting enhancement device through the liquid replenishment device.
[0018] Furthermore, in step 2, the strengthening liquid used for treating coarse slag is a mixture of sodium silicate solution with a modulus of 1.5 to 2 and a concentration of 32% to 38% and secondary F fly ash at a mass ratio of (1.8 to 2): 1.
[0019] Furthermore, in step 3, when treating the fine slag, the spraying liquid used is a mixture of sodium silicate solution with a modulus of 2.2 to 2.6 and a concentration of 40% to 44% and secondary or primary F fly ash at a mass ratio of (2.2 to 2.6): 1.
[0020] Furthermore, in step 5, the second roll assembly of the roll forming device applies pressure to the material through spring adjustment, applying a larger crushing force to the impregnated coarse slag particles and a smaller crushing force to the fine slag particles. This reduces the content of low-strength particles while also crushing the gasification slag to a similar target particle size range, further optimizing the particle size distribution.
[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention classifies coal gasification slag using a feeding and screening device (particles larger than the screening hole diameter are coarse slag, and those smaller are fine slag), resulting in coarse and fine slag. Both are then specifically modified. The coarse slag is infiltrated with a specific formula strengthening liquid to improve strength and reduce crushing index, while the fine slag is granulated with a specific spray liquid to complete the fine material composition. Subsequent proportional mixing and adaptive roller pressing to optimize gradation effectively solve the defects of unreasonable natural gradation in gasification slag and improve its key performance issues of low apparent density, low bulk density, and high crushing index. The modified sand can meet the construction sand standard without the need for compounding with natural or manufactured sand, significantly improving the resource utilization rate of coal gasification slag.
[0022] 2. This invention encompasses a fully integrated continuous production equipment for screening, grading and modification, mixing, shaping, drying and homogenization, replacing existing laboratory or intermittent operation modes. It is compatible with different types of coal gasification slag, such as coal-water slurry gasifiers and dry coal powder gasifiers, and the modification effect is stable and controllable. It provides reliable equipment support for the large-scale preparation of construction sand from coal gasification slag. Furthermore, the various devices are closely connected through transfer silos, conveying devices, etc., ensuring continuous and smooth material flow, making it suitable for large-scale, industrial production.
[0023] 3. The residual liquid in the coarse slag treatment line of this invention is recovered and reused by the replenishment device, reducing the waste of the fortification liquid raw material; the waste heat in the drying and homogenization process is used in a closed loop by the waste heat recovery device for preheating of the roller-forming material, which greatly reduces production energy consumption, while reducing the emission of hot exhaust gas, significantly improving resource utilization efficiency and reducing energy consumption and operating costs.
[0024] 4. The adaptive elastic pressure design of the roller pressing and shaping device of this invention can dynamically adjust the crushing force according to the particle size difference of the mixed materials, taking into account both the shaping of coarse slag and the particle integrity and strength of fine slag, and further optimizing the gradation; the drying and homogenizing device is equipped with a modified raw material inlet (redundant design, only used when the performance of modified sand does not meet the standards or there are special requirements for the performance of the final product), which can flexibly adjust the performance of sand and adapt to the index requirements of construction sand in different engineering scenarios, thereby improving the adaptability and practicality of the product. Attached Figure Description
[0025] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.
[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is a schematic diagram of the front structure of the production line for preparing construction sand using coal gasification slag according to the present invention. Figure 2 This is a schematic diagram of the back structure of the production line for preparing construction sand using coal gasification slag according to the present invention; Figure 3 This is a schematic diagram of the feeding and screening device in the production line of the present invention; Figure 4 This is a schematic diagram of the wetting enhancement device in the production line of the present invention; Figure 5 This is a front structural diagram of the coarse slag treatment line in the production line of the present invention; Figure 6 This is a schematic diagram of the back structure of the coarse slag treatment line in the production line of the present invention; Figure 7 This is a schematic diagram of the fine slag funnel structure in the production line of the present invention; Figure 8 This is a schematic diagram of the front structure of the disc granulation device in the production line of the present invention; Figure 9 This is a schematic diagram of the back structure of the disc granulation device in the production line of the present invention; Figure 10 This is a schematic diagram of the conveying device structure in the production line of the present invention; Figure 11 This is a schematic diagram of the transmission wheel frame structure of the conveying device in the production line of the present invention; Figure 12 This is a schematic diagram of the mixing chamber structure in the production line of the present invention; Figure 13This is a schematic diagram of the roller forming device in the production line of the present invention; Figure 14 This is a schematic diagram of the drying and homogenization device in the production line of the present invention; Figure 15 This is a schematic diagram of the connection structure between the waste heat recovery device, the roller forming device, and the drying and homogenizing device in the production line of the present invention. Figure 16 This is a schematic diagram of the internal metal perforated screen plate structure of the waste heat recovery device pipeline in the production line of the present invention.
[0028] in: 100 is the feeding and screening device; 101 is the first cylinder; 102 is the first drive motor; 103 is the chain; 104 is the first stirring shaft; 105 is the stirring blade; 106 is the coarse slag transfer bin; 107 is the first flow control valve; 108 is the raw material inlet; 1011 is the screening hole; 200 is the wetting enhancement device; 201 is the second cylinder; 202 is the second drive motor; 203 is the first auger; 204 is the liquid inlet pipe; 205 is the coarse slag inlet; 206 is the enhanced discharge outlet; 300 is the draining device; 301 is the third cylinder; 302 is the second auger; 303 is the third drive motor; 304 is the draining inlet; 305 is the draining outlet; 3011 is the draining hole; 400 is the residual liquid collection tank; 401 is the drain pipe; 500 is the replenishment device; 501 is the main pipeline; 502 is the replenishment pipe; 503 is the residual liquid pipe; 504 is the first check valve; 505 is the first check pump; 506 is the enhanced liquid tank; 507 is the second check valve. 600 is a fine-grained slag funnel; 700 is the disc granulation device; 701 is the granulation disc; 702 is the fourth drive motor; 703 is the hinge rod; 704 is the spray assembly; 705 is the slide rail; 706 is the scraper mechanism; 7011 is the disc; 7012 is the protective frame; 7041 is the spray storage tank; 7042 is the infusion pipe; 7043 is the spray head; 7044 is the second one-way pump; 7045 is the second flow control valve; 7061 is the scraper frame; 7062 is the scraper; 7063 is the adjustment knob; 800 is the conveying device; 801 is the conveyor belt; 802 is the drive wheel frame; 803 is the three-way baffle; 900 is the mixing chamber; 901 is the mixing inlet; 902 is the protective baffle; 903 is the mixing outlet; 904 is the mixing agitator. 1000 is the roll forming device; 1001 is the first roll assembly; 1002 is the second roll assembly; 1003 is the roll press inlet; 1004 is the roll press outlet; 1005 is the fixed support; 10011 is the first roll; 10012 is the first support member; 10013 is the fifth drive motor; 10021 is the second roll; 10022 is the second support member; 10023 is the spring; 10024 is the sixth drive motor; 10025 is the sliding groove; 10051 is the slide rail. 1100 is the drying and homogenization device; 1101 is the fourth cylinder; 1102 is the seventh drive motor; 1103 is the second stirring shaft; 1104 is the fan-shaped stirring blade; 1105 is the hot air device; 1106 is the hot air outlet; 1107 is the gasification slag inlet; 1108 is the modified raw material inlet; 1109 is the finished product outlet; 11011 is the air inlet. 1200 is a waste heat recovery device; 1201 is a hot air duct; 1202 is a blower; 1203 is a metal perforated screen plate; 1204 is a gas valve. Detailed Implementation
[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.
[0030] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example
[0031] Please see Figure 1 , Figure 2 The present invention provides a production line for preparing construction sand using coal gasification slag, comprising a feeding and screening device 100, an impregnation and strengthening device 200, a draining device 300, a residual liquid collection tank 400, a replenishment device 500, a fine slag funnel 600, a disc granulation device 700, a conveying device 800, a mixing bin 900, a roller pressing and shaping device 1000, a drying and homogenizing device 1100, and a waste heat recovery device 1200. These devices are connected to a customized material conveying path via mechanical connectors (such as frames), forming a complete processing system that enables coordinated operation throughout the entire process from raw material processing to finished product output.
[0032] The workflow of this production line is as follows: The feeding and screening device 100 first grades the coal gasification slag raw material, separating coarse and fine slag particles. The screened coarse slag particles then sequentially enter the wetting and strengthening device 200 for modification treatment, and then enter the leaching device 300 for dewatering. The dewatered liquid is collected in the residual liquid collection tank 400 for recycling. The replenishing device 500 provides a stable supply of strengthening liquid for the wetting process. The fine slag particles are buffered by the fine slag funnel 600 and then processed into fine slag particles with controllable particle size by the disc granulator 700. The dewatered coarse slag particles and the granulated fine slag particles are fed into a mixing system according to a preset ratio. The mixture in silo 900 is thoroughly stirred to form a preliminary continuous gradation. Under gravity, the mixture falls into the roller pressing and shaping device 1000 below, where it is crushed, shaped, and optimized for particle shape through an adaptive roller pressing system. The shaped sand enters the drying and homogenizing device 1100, where the moisture content is controlled and the performance is homogenized through the combined action of hot air drying and mechanical stirring, ultimately producing standard construction sand. The waste heat recovery device 1200 recovers the hot waste gas generated by the drying and homogenizing device 1100 and transports it to the roller pressing and shaping device 1000 for material preheating, thus constructing an efficient heat circulation system.
[0033] Specifically, the structure of the feeding and screening device 100 in this embodiment is as follows: Figure 3 As shown, its main body is tilted at an angle of 15° to 30° (within). Figure 1 The first cylinder 101 (viewed from left to right, higher than left) has a bucket-shaped raw material inlet 108 at its left end. This design facilitates smooth material entry into the cylinder and allows the material to slide down the cylinder wall under gravity, while providing sufficient screening residence time to ensure effective grading. Multiple screening holes 1011 are evenly distributed axially on the bottom surface of the first cylinder 101, with a hole diameter of 2mm to 5mm (preferably 3mm) and an opening rate controlled at 40% to 50%. The holes are arranged in a staggered pattern to improve screening efficiency. Inside the cylinder is a first stirring shaft 104, driven by a first drive motor 102 via a chain 103. Multiple sets of stirring blades 105 are mounted on the first stirring shaft 104. The blades are made of wear-resistant high-chromium cast iron, and their outer edges maintain a 2mm to 6mm operating gap with the inner wall of the first cylinder. The continuous rotation of the stirring blades breaks up clumps and prevents clogging, ensuring continuous and stable screening. The lower outlet of the first cylinder 101 is connected to a coarse slag transfer bin 106. The inlet cross-sectional dimensions of the coarse slag transfer bin 106 match the outlet parameters of the first cylinder 101, and a flange connection is used to ensure sealing performance. A first flow control valve 107 is installed at the lower discharge port of the coarse slag transfer bin 106 to achieve precise control of the discharge amount of coarse slag, providing a stable guarantee for the material ratio of subsequent processes.
[0034] like Figure 1 , Figure 2 and Figure 7As shown, in this embodiment, the fine slag funnel 600 is positioned directly below the screening hole 1011. Its interface size completely covers the projected area of the screening hole and extends outwards by 50mm to 100mm, ensuring that the fine slag falling through the screening hole 1011 can be completely collected, avoiding material loss. The inner wall of the fine slag funnel is polished, and the funnel's tilt angle is designed to be 45° to 60°. By reducing the frictional resistance of the inner wall and optimizing the tilt angle, the fine slag flows smoothly within the funnel, preventing accumulation and blockage.
[0035] like Figure 4 As shown, the wetting strengthening device 200 in this embodiment includes an inclination angle of 10° to 20° (within the range of 10° to 20°). Figure 1 The second cylinder 201, viewed from a lower left to a higher right perspective, has a coarse slag inlet 205 at its upper left end, which is sealed and connected to the outlet of the coarse slag transfer bin 106. A reinforced discharge outlet 206 is located at its lower right end, serving as a material output channel. A first auger 203 is installed inside the second cylinder 201, driven by a second drive motor 202 outside the cylinder, to achieve material conveying and mixing. Simultaneously, a liquid inlet pipe 204 is located at the upper part of the second cylinder 201 near the reinforced discharge outlet 206. This inlet pipe 204 is connected to a liquid replenishment device 500, allowing continuous injection of reinforcing liquid into the cylinder. The reinforcing liquid is generally a mixture of sodium silicate solution with a modulus of 1.5–2 and a concentration of 32%–38% and secondary F fly ash at a mass ratio of (1.8–2):1, used to improve the particle strength of the coarse slag and reduce crushing index and water absorption rate.
[0036] The working process and control parameters of the impregnation strengthening device 200 are as follows: First, the feed rate of the coarse slag is adjusted by the first flow control valve 107 of the coarse slag transfer bin 106, so that the coarse slag continuously enters the second cylinder 201 at a set flow rate. At the same time, the liquid replenishment device 500 injects strengthening liquid through the liquid inlet pipe 204 at a matched flow rate, ensuring that the liquid level in the cylinder is stably maintained within 1 / 3 to 1 / 2 of the cylinder diameter, providing a sufficient impregnation environment for the coarse slag. Under the spiral pushing action of the first auger 203, the coarse slag moves slowly along the inclined second cylinder 201, continuously soaking in the strengthening liquid for 5 to 10 minutes, completing deep impregnation and performance strengthening, effectively improving its physical properties. After this process, the moisture content of the coarse slag is controlled at 15% to 25%, and the compressive strength is increased by 30% to 50% compared with before treatment, laying a good foundation for the subsequent shaping process. Finally, the impregnated and strengthened coarse slag is directly transported to the next process's draining device 300 through the strengthening discharge port 206.
[0037] like Figure 5 , 6 As shown, in this embodiment, the draining device 300 is tilted at an angle of 10° to 15° (within...). Figure 1The third cylinder 301 (viewed from left to right, lower than left) serves as the carrier for dewatering coarse slag. A drain inlet 304 is located at the upper left end of the third cylinder 301, which is sealed and connected to the enhanced discharge outlet 206 of the wetting enhancement device 200; a drain outlet 305 is located at the lower right end, directly connected to the inlet of the mixing chamber 900. Drain holes 3011 are evenly distributed on the bottom wall of the third cylinder 301, with a diameter of 1mm to 3mm and a spacing of 10mm to 15mm, arranged in a matrix to ensure drain efficiency. A second auger 302 is installed inside the cylinder, driven by a third drive motor 303, with its spiral blades tightly fitted to the cylinder wall (gap ≤ 3mm). During operation, the coarse slag particles, after being soaked, enter the third cylinder 301. Under the spiral pushing and squeezing action of the second auger 302, excess liquid is forcibly squeezed out and discharged through the drain hole 3011. Simultaneously, with the help of the inclined angle of the third cylinder 301, the liquid flows rapidly to the lower collection area under the assistance of gravity, avoiding liquid accumulation inside the cylinder. Through this dual-action dewatering design, the moisture content of the coarse slag particles is further reduced from 15%–25% before treatment to 8%–12%, meeting the process requirements for material moisture content in subsequent mixing and shaping processes.
[0038] To achieve the recycling of the fortifying liquid, this embodiment includes a residual liquid collection tank 400 directly below the draining device 300. The tank's dimensions completely cover the projected area of the draining hole 3011 and extend outwards by 100mm to 200mm, forming a fully covered collection structure to ensure that all drained liquid is recovered without leakage. A drain pipe 401 is located at the bottom of the residual liquid collection tank 400, and the pipe outlet is connected to the inlet of the replenishment device 500. This allows the recovered fortifying liquid to be reused in the impregnation and fortification process, reducing auxiliary material consumption and processing costs, and improving the system's economic efficiency and environmental friendliness.
[0039] Furthermore, the replenishment device 500 in this embodiment includes a main pipeline 501, which is a three-way structure with two parallel inlets and one outlet. The first inlet is connected to the strengthening liquid tank 506 via a replenishment pipe 502. The replenishment pipe 502 is sequentially equipped with a first one-way valve 504 and a first one-way pump 505, and the outlet side of the first one-way pump 505 is also equipped with a one-way valve, forming a bidirectional backflow prevention protection to avoid reverse backflow of residual liquid. The second inlet is connected to the drain pipe 401 of the residual liquid collection tank 400 via a residual liquid pipe 503, which is equipped with a second one-way valve 507. The outlet of the main pipeline 501 is sealed and connected to the inlet pipe 204 of the wetting strengthening device 200. During operation, the liquid recovered in the residual liquid collection tank 400 is used first. When the recovered liquid storage is insufficient to meet process requirements, the first one-way pump 505 is activated to replenish new fortifying liquid from the fortifying liquid tank 506. The first one-way valve 504, the second one-way valve 507, and the one-way valve on the pump body's outlet side work together to ensure the single and stable flow of liquid and effectively prevent backflow. This replenishment system can increase liquid utilization by 35% to 45% and significantly reduce auxiliary material consumption costs.
[0040] The structure of the disc granulation device 700 in this embodiment is as follows: Figure 8 , 9 As shown, the granulation disc 701 is tilted and consists of a disc 7011 and an annular protective frame 7012 fixed to the outer edge of the disc 7011. The surface of the disc 7011 is made of a rough and wear-resistant material. The disc 7011 is driven to rotate by a fourth drive motor 702 mounted on its back, causing the fine slag falling onto the disc surface to roll and gather towards the protective frame 7012 under centrifugal force. The front end of the housing of the fourth drive motor 702 is hinged to the frame, and the rear end is connected to the frame via a hinge rod 703. By adjusting the extension length of the hinge rod 703, the tilt angle of the granulation disc 701 can be flexibly adjusted. Increasing the tilt angle causes the fine slag particles with smaller diameters to detach from the disc surface due to the larger tilt angle and gravity, resulting in smaller diameter particles. Conversely, decreasing the tilt angle prolongs the rolling distance and residence time, causing larger diameter particles to detach from the disc surface. The specific tilt angle can be flexibly adjusted according to the actual granulation effect. A slide rail 705 is installed below the granulation disc 701. This slide rail is hinged to the frame via a hydraulic rod and can be synchronously adjusted to match the angle of the granulation disc 701, ensuring that the slide rail 705 and the disc surface 7011 maintain the same angle. The formed fine slag particles slide into the slide rail 705 from the lower edge of the protective frame 7012. Protective baffles are provided on both sides of the slide rail 705 to prevent the particles from scattering and ensure that they enter the conveying device 800 in an orderly manner. Actual measurements show that the fine slag particle forming rate can reach over 90%.
[0041] Furthermore, the disc granulation device 700 is also equipped with a spray assembly 704, which includes a spray storage tank 7041, a delivery pipe 7042, and multiple spray heads 7043 evenly distributed above the granulation disc 701. A second one-way pump 7044 is installed on the delivery pipe 7042 to transport the spray liquid (the spray liquid is a mixture of sodium silicate solution with a modulus of 2.2 to 2.6 and a concentration of 40% to 44% and secondary or primary F fly ash at a mass ratio of (2.2 to 2.6): 1) to each spray head 7043 and atomize it onto the surface of the fine slag; each spray head 7043 is equipped with a second flow control valve 7045, which can precisely adjust the spray volume to maintain suitable humidity for the fine slag to enhance adhesion and improve the granulation strength of the fine slag.
[0042] In addition, the disc granulation device 700 also includes a scraper mechanism 706, which consists of a scraper frame 7061 and a scraper 7062 located above the granulation disc 701. The scraper frame 7061 is fixed to the housing of the fourth drive motor 702 via a connector, and always maintains a non-contact state with the granulation disc 701 to avoid operational interference. The scraper 7062 is mounted on the scraper frame 7061, and its distance from the disc surface can be controlled by adjusting the knob 7063. After granulation is completed, the raw material input is stopped and the granulation disc 701 is allowed to idle. Adjusting the scraper 7062 to contact the disc surface removes residual fine slag adhering to the disc surface, ensuring the subsequent granulation effect. At the same time, the removed fine slag can be reused in the production of construction sand.
[0043] The structure of the conveying device 800 in this embodiment is as follows: Figure 10 , 11 As shown, the device mainly consists of a conveyor belt 801, a drive wheel frame 802, and a three-way baffle 803. The conveyor belt 801 has a roughened surface treated by sandblasting to increase friction. The drive wheel frame 802 adopts a concave frame structure, naturally forming a concave cross-section on the bearing surface of the conveyor belt 801, which can laterally limit the particles and effectively prevent them from rolling off during transport. The three-way baffle 803 is fixed at the feed inlet of the conveyor device 800, and its enclosure range matches the discharge port of the chute 705, ensuring that all fine slag particles discharged from the chute 705 fall into the bearing area of the conveyor belt 801. The speed of the conveyor belt 801 can be steplessly adjusted within a set range to adapt to the feeding requirements of the subsequent mixing chamber 900, smoothly conveying the formed fine slag particles into the mixing chamber 900. Actual operation verification shows that the material loss rate of this conveyor device is less than 2%, ensuring efficient material utilization.
[0044] like Figure 1 , 2As shown in Figure 12, in this embodiment, the mixing chamber 900 is horizontally positioned below the draining device 300 and to the right of the conveying device 800. A protective baffle 902 with a height of 200mm to 300mm is provided around the mixing inlet 901 of the mixing chamber 900 to collect and guide the coarse slag particles transported downwards by the draining device 300 and the fine slag particles transported laterally by the conveying device 800. Inside the mixing chamber 900, there is a stirring shaft driven by a drive motor. A fan-shaped mixing blade 904 facing the mixing outlet 903 is installed on the stirring shaft. The mixing blade 904 maintains a small operating gap with the inner wall of the chamber. The mixing time is 3 to 5 minutes to ensure that the coarse and fine slag particles are fully and evenly mixed. The mixed material is discharged through the mixing outlet 903 and enters the roller pressing and shaping device 1000.
[0045] It should be noted that the roller pressing and shaping device 1000 in this embodiment includes a first roller assembly 1001 with a fixed position and a second roller assembly 1002 that is parallel to and cooperates with the first roller assembly 1001 to extrude the mixture. The second roller assembly 1002 is elastically connected to the machine body and can adaptively adjust the elastic pressure according to the particle size change of the mixture to perform adaptive crushing and shaping of the mixture.
[0046] Specifically, such as Figure 13 As shown, the roller pressing and shaping device 1000 adopts a "top-in, bottom-out" material flow design. Its feed end is connected to the mixing outlet 903 of the mixing bin 900. The roller press feed inlet 1003 is located directly below the mixing outlet 903, and adopts a bucket-shaped structure with an inclination angle of 50° to 60°, which can effectively guide the material to flow smoothly and avoid accumulation and blockage. The roller press outlet 1004 is located at the bottom of the device and is used for directional discharge of the crushed and shaped material. The core working unit of the device is the first roller assembly 1001 and the second roller assembly 1002 arranged in parallel and symmetrically. The specific structure and installation method of the two are as follows: The first roll assembly 1001 includes a first roll 10011, the roll shafts on both sides of the first roll 10011 are rotatably connected to the first support member 10012, the first support member 10012 is fixedly installed on the fixed support 1005, and the fixed support 1005 is fixedly installed on the frame; the end of the roll shaft of the first roll 10011 is connected to the output shaft of the fifth drive motor 10013 fixedly installed on the frame, providing continuous power for the stable rotation of the roll.
[0047] The roller shafts on both sides of the second roll 10021 are rotatably connected to the second support member 10022. The second support member 10022 is slidably disposed on a pre-set slide rail 10051 within the fixed support 1005. A spring 10023 is provided between the second support member 10022 and the fixed support 1005. The pressure adjustment range of the spring 10023 is 5kN to 20kN (below 5kN will cause the roll to be below the crushing strength of the gasified slag being processed, while above 20kN will cause the crushing force of the roll to be much greater than that of the gasified slag being processed). The crushing strength of the slag is such that the crushed particle size is too small to become powder. The extrusion strength can be adaptively adjusted according to the particle characteristics and particle size distribution of the material. The second roll 10021 is driven by the sixth drive motor 10024. The sixth drive motor 10024 is mounted on the frame through a mounting base. The frame is provided with a sliding groove 10025 corresponding to the mounting base position of the sixth drive motor 10024 to ensure that the sixth drive motor 10024 can move synchronously and smoothly with the second support 10022, which is adapted to the adaptive displacement adjustment requirements of the roll.
[0048] During operation, the mixed material enters the gap between the two rollers through the roller press feed inlet 1003. Based on the difference in physical properties between coarse and fine slag particles, the second roller 10021 automatically adjusts its position through the elastic extension and contraction of the spring 10023. When large coarse slag particles enter the roller gap, the compression of the spring 10023 increases, and the rolling pressure increases simultaneously, achieving effective crushing and particle shape optimization of the coarse slag. When small fine slag particles pass through, the compression of the spring 10023 decreases, and the rolling pressure decreases, avoiding excessive crushing of the fine slag. The shaped material is discharged through the roller press discharge outlet 1004, and its particle size can be stably controlled within the set target range to meet the gradation requirements of construction sand.
[0049] The structure of the drying and homogenizing device 1100 in this embodiment is as follows: Figure 14 As shown, it includes a horizontally arranged fourth cylinder 1101, the left end of which (with Figure 1(From a perspective) The upper part is provided with a gasification slag inlet 1107 and a modified raw material inlet 1108. The modified raw material inlet 1108 is a redundant design and is only used when the performance of the modified sand does not meet the standards or when there are special requirements for the performance of the final product. Generally, the modified raw materials are standard sand, fly ash, mineral powder, etc., which are used to adjust the product performance. The gasification slag inlet 1107 is connected to the roller press outlet 1004. The upper part of the right end of the cylinder is the hot air outlet 1106, and the lower part is the finished product outlet 1109. The cylinder is equipped with a second stirring shaft 1103 driven by a seventh drive motor 1102. The second stirring shaft 1103 is equipped with fan-shaped stirring blades 1104 that extend spirally towards the discharge port. The bottom surface of the fourth cylinder 1101 is uniformly provided with air inlet holes 11011 with a diameter of less than 2mm. The bottom of the fourth cylinder 1101 is equipped with a hot air device 1105 (which can be a gas-fired hot air furnace). The hot air outlet of the hot air device 1105 is matched with the air inlet hole 11011. The high-temperature hot air generated by the device enters the cylinder through the air inlet hole 11011 to dry the wet material. During the drying process, the fan-shaped stirring blades 1104 driven by an external motor agitate the wet material, making the wet material dry evenly and greatly improving the drying efficiency. When the wet material is completely dried, the strength of the crushed sand reaches the strength standard of construction sand. Finally, qualified construction sand products are output through the finished product outlet 1109. The high-temperature waste gas generated during the drying process is extracted by the blower 1202 of the waste heat recovery device 1200 through the hot air outlet 1106 and used to preheat the mixed gasification slag in the roller pressing and shaping device 1000, thus completing the recycling of heat.
[0050] like Figure 15 , 16 As shown, the waste heat recovery device 1200 in this embodiment includes a hot air duct 1201, a blower 1202, a metal perforated screen plate 1203, and a gas valve 1204. The hot air duct 1201 is covered with insulation material on its outer wall. One end is connected to the hot air outlet 1106 of the drying and homogenizing device 1100, and the other end is connected to the body of the roller forming device 1000. The blower 1202 is installed on the hot air duct 1201 to draw the high-temperature exhaust gas generated by the drying and homogenizing device 1100 into the roller forming device 1000 in one direction. The gas valve 1204 is used to regulate the hot air flow and pressure. The hot air duct 1201 is equipped with metal perforated screen plates 1203 at the connection points with the body of the roller forming device 1000, the hot air outlet 1106 of the drying and homogenizing device 1100, and the blower 1202. The screen plates have a mesh size of 150 to 250 mesh, which can effectively filter the fine particles entrained in the exhaust gas and prevent the particles from entering the blower and causing damage.
[0051] During operation, blower 1202 draws in the high-temperature exhaust gas discharged from drying and homogenizing device 1100 and sends it into the machine body of roller forming device 1000 through hot air duct 1201. The high-temperature exhaust gas raises the internal temperature of roller forming device 1000 while significantly reducing the humidity inside the machine. The mixture before crushing is preheated in this environment, and the moisture content can be further reduced, which is beneficial to improving crushing efficiency and product quality. This waste heat recovery system can improve the overall drying efficiency by about 15-25%, realizing the cascade utilization of energy.
[0052] Based on the above-mentioned production line, this invention also provides a method for preparing construction sand using coal gasification slag, specifically including the following steps: Step 1: Sieving The coal gasification slag raw material is fed into the feeding and screening device 100 via a conveying device. Inside the first cylinder 101, the raw material is evenly dispersed and moved forward by the continuous stirring and conveying action of the first stirring shaft 104 and the stirring fan blades 105. Fine slag particles with a diameter smaller than the sieve aperture 1011 pass through the sieve holes and fall into the fine slag funnel 600 below, while coarse slag particles with a diameter larger than the sieve aperture are intercepted and continue to be conveyed, and finally discharged quantitatively through the coarse slag transfer bin 106 and the first flow control valve 107.
[0053] Step 2: Coarse Slag Treatment The coarse slag discharged from the feeding and screening device 100 enters the wetting and strengthening device 200. Inside the second cylinder 201, the coarse slag is fully contacted and wetted by the strengthening liquid injected through the inlet pipe 204 during the conveying process of the first auger 203, completing the strengthening treatment. The wetted coarse slag enters the draining device 300. Under the rotational conveying and squeezing action of the second auger 302, excess liquid is discharged through the draining hole 3011, and the moisture content of the coarse slag is reduced to 8-12%. The drained liquid is collected by the residual liquid collection tank 400. Through the replenishment device 500, the recovered liquid in the residual liquid collection tank 400 and / or the new strengthening liquid in the strengthening liquid tank 506 can be replenished to the wetting and strengthening device 200.
[0054] Step 3: Fine slag treatment Fine slag discharged from the fine slag funnel 600 is quantitatively added to the disc granulator 700. Under the centrifugal force generated by the rotation of the granulation disc 701, the fine slag gathers towards the edge of the disc. Simultaneously, the spray nozzles 7043 of the spray assembly 704 spray atomized strengthening liquid onto the disc surface. Under the combined action of centrifugal force, disc surface friction, and liquid adhesion, the fine slag gradually rolls into spherical particles with a diameter of 2mm to 5mm. The formed particles overflow from the edge of the disc, slide out through the slide 705, and are conveyed to the mixing chamber 900 via the conveying device 800. After granulation, residual fine slag on the disc surface can be removed by the scraper 7062.
[0055] Step 4: Mix The coarse slag particles after leachate treatment and the granulated fine slag particles are respectively fed into the mixing chamber 900. Inside the mixing chamber 900, the coarse slag particles and fine slag particles are thoroughly mixed in a predetermined ratio by the action of the stirring mechanism.
[0056] Step 5: Crushing and Shaping The mixed material enters the roll forming device 1000. As the material passes through the gap between the first roll 10011 and the second roll 10021, the second roll assembly 1002, under the action of the spring 10023, adaptively adjusts the rolling pressure according to the particle size and strength of the material. A larger crushing force is applied to coarse slag particles with higher strength, while a smaller crushing force is applied to fine slag particles with lower strength, achieving differentiated crushing. The particle size of the crushed and shaped material is controlled within the target range.
[0057] Step 6: Drying and homogenization The crushed and shaped sand enters the drying and homogenizing device 1100. Inside the fourth cylinder 1101, the second stirring shaft 1103 drives the fan-shaped stirring blades 1104 to stir and propel the sand. A hot air device 1105 installed at the bottom of the fourth cylinder 1101 continuously supplies hot air into the cylinder through the air inlet 11011 to dry the sand. Simultaneously, corrective raw materials added through the corrective raw material inlet 1108 are thoroughly mixed with the sand. The moisture content of the dried and homogenized sand is less than 1%.
[0058] Step 7: Waste Heat Recovery The high-temperature exhaust gas generated by the drying and homogenizing device 1100 is drawn by the blower 1202 of the waste heat recovery device 1200 through the hot air outlet 1106, and then transported to the interior of the roller forming device 1000 through the hot air duct 1201 for preheating the mixed materials. The metal perforated screen plate 1203 installed at the connection of the hot air duct can filter fine particles in the exhaust gas.
[0059] Preferably, in step 2, the replenishment device 500 preferentially uses the recovered liquid in the residual liquid collection tank 400, and uses new reinforcement liquid when the recovered liquid is insufficient.
[0060] To further verify the processing effect of the present invention on gasification slag and sand, this embodiment uses the above-mentioned production line and corresponding method to conduct a performance comparison experiment, as follows: Raw materials: Two different batches of gasification slag from a coal-water slurry gasifier (denoted as gasification slag A and gasification slag B), and two different batches of gasification slag from a dry pulverized coal gasifier (denoted as gasification slag C and gasification slag D) were selected. All were raw industrial discharge slags without any pretreatment. Modifying reagents: Strengthening solution: a sodium silicate solution with a modulus of 2 and a concentration of 40% is mixed with secondary F fly ash at a mass ratio of 2:1, stirred evenly, and then set aside for later use; Spraying solution: a sodium silicate solution with a modulus of 2.2 and a concentration of 40% is mixed with secondary F fly ash at a mass ratio of 2.5:1, stirred evenly, and then set aside for later use. The above four types of gasification slag were processed through the production line of this invention, including screening, grading and modification, mixing, roller pressing and shaping, and drying and homogenization, to obtain processed gasification slag sand. Using each batch of raw slag as a control, particle size distribution, maximum single-stage crushing index, apparent density, loose bulk density, and porosity were tested and compared according to GB / T 14684-2022 "Construction Sand" standard. The results are shown in Tables 1 to 3 below. Table 1 Particle size distribution ratio Table 2 Comparison of Maximum Crushing Index for Single Stage Table 3 Comparison of Apparent Density, Loose Bulk Density, and Porosity Table 1 shows that the raw slag particles from the coal-water slurry gasifier are relatively coarse, belonging to the category of coarse sand, and have an uneven particle size distribution; the raw slag particles from the dry pulverized coal gasifier are relatively fine, belonging to the category of fine sand, and also have an uneven particle size distribution. After modification using the scheme of this invention, the particle size distribution of the four types of gasification slag all belong to the medium sand zone 2 category. The modification effect of different types of gasification slag is consistent, indicating that the modification effect of this invention on particle size distribution is stable and reliable.
[0061] As shown in Table 2, the maximum single-stage crushing index of the raw slag is 53% to 68%, which far exceeds the limit of ≤25% for Class II sand in GB / T 14684-2022. After modification, it is reduced to 17% to 21%, all of which meet the standard, with a reduction of more than 60%. The coarse slag wetting enhancement and roller pressing shaping work together to improve the particle strength.
[0062] As shown in Table 3, the raw slag, due to its large coarse particle porosity, had low apparent density and low bulk density, failing to meet the basic requirements for construction sand. After modification, the apparent density increased by over 25%, and the bulk density exceeded 1460 kg / m³. 3 The porosity has been optimized to 34%–38%, meeting the needs of engineering applications.
[0063] In summary, the production line and method of this invention have significant and stable modification effects on different types of gasification slag: the modified sand gradation reaches the medium sand zone 2, and the crushing index, apparent density and bulk density all meet the GB / T 14684-2022 standard. It can be used as construction sand without the need for compounding natural sand, which greatly improves the resource utilization rate of coal gasification slag.
[0064] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.
[0065] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.
Claims
1. A production line for preparing construction sand using coal gasification slag, characterized in that, include: The feeding and screening device (100) uses screening holes (1011) to screen coal gasification slag into coarse slag and fine slag; A coarse slag treatment line is used to perform wetting enhancement and leaching treatment on the coarse slag. The coarse slag treatment line includes a wetting enhancement device (200), a leaching device (300), and a residual liquid collection tank (400) connected in sequence below the leaching device (300). A fine slag processing line is used to granulate the fine slag to form fine slag particles. The fine slag processing line includes a fine slag funnel (600) for receiving fine slag, a disc granulator (700), and a conveying device (800) connected to the discharge port of the disc granulator (700). The mixing chamber (900) has its inlet connected to the outlet of the draining device (300) and the outlet of the conveying device (800) respectively, and is used to mix the treated coarse slag with the granulated fine slag particles. The roller pressing and shaping device (1000) has its feed inlet located below the discharge outlet of the mixing chamber (900) and is used to adaptively crush and shape the mixed material. The drying and homogenizing device (1100) has its inlet located below the outlet of the roller forming device (1000) and is used to dry and homogenize the crushed and shaped sand. The waste heat recovery device (1200) has a hot air duct (1201) connected at one end to the hot air outlet (1106) of the drying and homogenizing device (1100) and at the other end to the body of the roller pressing and shaping device (1000), forming a closed-loop heat utilization system that uses the waste heat from drying to preheat the crushed material.
2. The production line for preparing construction sand using coal gasification slag according to claim 1, characterized in that, The feeding and screening device (100) includes an inclined first cylinder (101), the bottom surface of which is uniformly provided with screening holes (1011) with a diameter of 2mm to 5mm, and the interior is provided with a first stirring shaft (104) driven by a first drive motor (102) through a chain (103). The first stirring shaft (104) is fixed with stirring blades (105) that are in clearance fit with the inner wall of the first cylinder (101). The lower outlet of the first cylinder (101) is provided with a coarse slag transfer chamber (106), and the outlet of the coarse slag transfer chamber (106) is provided with a first flow control valve (107). The fine slag funnel (600) is located below the screening hole (1011), and its interface size covers the projected area of the screening hole (1011) segment.
3. The production line for preparing construction sand using coal gasification slag according to claim 1, characterized in that, The wetting enhancement device (200) includes a second cylindrical body (201) arranged at an angle, inside which is a first auger (203) driven by a second drive motor (202), and an inlet pipe (204) for injecting enhancement liquid into the upper part of the second cylindrical body (201). The draining device (300) includes an inclined third cylinder (301) with a draining hole (3011) on its bottom surface and a second auger (302) inside. The second auger (302) is powered by a third drive motor (303) and is used to transport and squeeze the coarse slag after it has been impregnated by the impregnation strengthening device (200).
4. The production line for preparing construction sand using coal gasification slag according to claim 3, characterized in that, The coarse slag treatment line also includes a liquid replenishment device (500), which includes a main pipeline (501) containing two parallel inlets and one outlet. The first inlet of the main pipeline (501) is connected to the strengthening liquid tank (506) through a replenishment pipe (502) equipped with a first one-way valve (504) and a first one-way pump (505); the second inlet is connected to the drain pipe (401) of the residual liquid collection tank (400) through a residual liquid pipe (503) equipped with a second one-way valve (507); and the outlet of the main pipeline (501) is connected to the inlet pipe (204) of the immersion strengthening device (200).
5. The production line for preparing construction sand using coal gasification slag according to claim 1, characterized in that, The disc granulation device (700) includes: The inclined granulation disc (701) consists of a disc (7011) and a protective frame (7012) located on the outer edge of the disc (7011). The disc (7011) is driven to rotate by a fourth drive motor (702) mounted on its back, causing the fine slag falling on the disc (7011) to roll and gather towards the protective frame (7012) under the action of centrifugal force. The housing of the fourth drive motor (702) is hinged to the frame through a hinge rod (703) to adjust the tilt angle of the granulation disc (701). The spray assembly (704) includes a spray storage tank (7041), a delivery pipe (7042), and a plurality of spray heads (7043) evenly arranged above the granulation plate (701). A second one-way pump (7044) is installed on the delivery pipe (7042) for delivering liquid to each spray head (7043) and spraying atomized liquid onto the fine slag in the granulation plate (701). Each spray head (7043) is provided with a second flow control valve (7045). A slide (705) is located below the granulation disc (701) and is hinged to the frame via a hydraulic rod to match the angle of the granulation disc (701). Protective baffles are provided on both sides of the slide (705).
6. The production line for preparing construction sand using coal gasification slag according to claim 5, characterized in that, The disc granulation device (700) further includes a scraper mechanism (706), which includes a scraper frame (7061) located above the granulation disc (701). The scraper frame (7061) is fixedly connected to the housing of the fourth drive motor (702) via a connector. A scraper (7062) is provided on the scraper frame (7061), and the distance between the scraper (7062) and the disc (7011) is controlled by an adjusting knob (7063).
7. The production line for preparing construction sand using coal gasification slag according to claim 1, characterized in that, The roller pressing and shaping device (1000) includes a first roller assembly (1001) with a fixed position and a second roller assembly (1002) that is parallel to and cooperates with the first roller assembly (1001) to extrude the mixture. The second roller assembly (1002) is elastically connected to the machine body and can adaptively adjust the elastic pressure according to the particle size change of the mixture to perform adaptive crushing and shaping of the mixture.
8. The production line for preparing construction sand using coal gasification slag according to claim 7, characterized in that, The first roll assembly (1001) includes a first roll (10011), and the roll shafts on both sides of the first roll (10011) are rotatably connected to the first support member (10012). The first support member (10012) is fixedly installed on the fixed support (1005), and the fixed support (1005) is fixedly installed on the frame. The first roll (10011) is driven by a fifth drive motor (10013) fixedly installed on the frame. The second roll assembly (1002) includes a second roll (10021). Both the second roll (10021) and the first roll (10011) have interlocking convex and concave structures on their surfaces. The roll shafts on both sides of the second roll (10021) are rotatably connected to a second support member (10022). The second support member (10022) is slidably mounted on a pre-set slide rail (10051) within a fixed support (1005). A spring (10023) is provided between (10022) and the fixed support (1005). The second roll (10021) is driven by a sixth drive motor (10024). The sixth drive motor (10024) is mounted on the frame. The frame is provided with a sliding groove (10025) corresponding to the mounting position of the sixth drive motor (10024). The sixth drive motor (10024) moves synchronously with the second support (10022).
9. The production line for preparing construction sand using coal gasification slag according to claim 1, characterized in that, The drying and homogenizing device (1100) includes a horizontally arranged fourth cylinder (1101), which is provided with a gasification slag inlet (1107) and a modified raw material inlet (1108). Inside the cylinder is a second stirring shaft (1103) driven by a seventh drive motor (1102). The second stirring shaft (1103) is provided with fan-shaped stirring blades (1104) that extend spirally toward the discharge port. The bottom surface of the fourth cylinder (1101) is uniformly provided with air inlets (11011). A hot air device (1105) installed at the bottom of the fourth cylinder (1101) sends hot air into the cylinder through the air inlets (11011). A hot air outlet (1106) is provided at the upper part of the discharge port. The hot air outlet (1106) is connected to the hot air pipe (1201) of the waste heat recovery device (1200).
10. A method for preparing construction sand using coal gasification slag, characterized in that, The production line using any one of claims 1 to 9 includes the following steps: Step 1, Raw material screening: The coal gasification slag raw material is fed into the feeding screening device (100), and coarse slag and fine slag are screened out using the screening holes (1011); Step 2, coarse slag treatment: The coarse slag is sequentially passed through the impregnation strengthening device (200) for liquid impregnation strengthening and through the leaching device (300) for leaching. The leached liquid is collected in the residual liquid collection tank (400). Step 3, Fine slag treatment: The fine slag is fed into the disc granulator (700) through the fine slag funnel (600) to form fine slag particles, and then conveyed by the conveying device (800). Step 4, Mixing: Mix the coarse slag after dewatering with the fine slag particles after granulation in the mixing chamber (900); Step 5, Crushing and Shaping: The mixture is fed into the roller forming device (1000) for crushing and shaping; Step 6, Drying and Homogenization: The crushed and shaped sand enters the drying and homogenization device (1100), is mixed with the modified raw materials, and is uniformly dried and homogenized under the action of hot air drying and mechanical stirring to obtain qualified construction sand; Step 7, Waste Heat Recovery: The hot waste gas generated by the drying and homogenizing device (1100) is extracted by the waste heat recovery device (1200) and transported to the roller forming device (1000) for material preheating to complete the heat cycle.