Coal gangue resourceful treatment method
By classifying and analyzing the particle size distribution of coal gangue, the problem of pollution from coal gangue stockpiling has been solved, achieving efficient resource utilization and improving the comprehensive utilization rate and economic benefits of coal gangue.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 山西低碳环保产业集团有限公司
- Filing Date
- 2026-02-11
- Publication Date
- 2026-05-15
AI Technical Summary
The large-scale stockpiling of coal gangue has led to environmental pollution. The existing utilization rate of coal gangue resources is low, and there is a lack of efficient comprehensive utilization methods.
By performing primary crushing and screening of coal gangue, and classifying it based on density and calorific value, high-calorific-value, medium-calorific-value, and low-calorific-value coal gangue groups are obtained. Furthermore, by classifying it based on content analysis, coal gangue groups of preset element categories are obtained, thereby achieving resource classification and reuse.
It has improved the comprehensive utilization rate of coal gangue, reduced environmental pollution, realized an efficient and flexible resource reuse method, and enhanced economic benefits.
Smart Images
Figure CN122032989A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of environmental protection, and in particular to a method for the resource utilization of coal gangue. Background Technology
[0002] Coal gangue is a solid waste generated during coal mining and washing processes.
[0003] In recent years, with the increasing total coal production, the large-scale stockpiling of coal gangue not only occupies land, but also causes air, water and soil pollution due to spontaneous combustion and leaching. There are illegal stockpiling and dumping of coal gangue in many places, which has led to pollution of surrounding water bodies, soil and air environment, and poses significant hidden dangers to the production, life and health of residents along the line.
[0004] In the existing technology, the comprehensive utilization of coal gangue is mainly based on single industries such as landfill, building material utilization and calcination of kaolin. Due to the differences in the physical and chemical properties of coal gangue in different regions and the impact of the downturn in the building material market, the utilization of coal gangue resources is relatively low. Summary of the Invention
[0005] The purpose of this application is to provide a method for the resource-based treatment of coal gangue, which can systematically treat coal gangue, improve the comprehensive utilization rate of coal gangue, and reduce environmental pollution.
[0006] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a method for the resource utilization of coal gangue, comprising: The raw coal gangue is subjected to primary crushing and screening to obtain a first-size coal gangue group, a second-size coal gangue group, and a third-size coal gangue group; wherein the particle size of the first-size coal gangue group is greater than that of the second-size coal gangue group, which is greater than that of the third-size coal gangue group. The first, second, and third sized coal gangue groups are graded based on density and calorific value to obtain high-calorific-value coal gangue groups, medium-calorific-value coal gangue groups, and low-calorific-value coal gangue groups; wherein the high-calorific-value and medium-calorific-value coal gangue groups are used for heating and / or power generation and reuse. The low-calorific-value coal gangue group is subjected to content analysis and classification to obtain coal gangue groups of preset element categories for reuse.
[0007] Optionally, the step of classifying the first, second, and third coal gangue groups based on density and net lower heating value to obtain high-calorific-value coal gangue groups, medium-calorific-value coal gangue groups, and low-calorific-value coal gangue groups includes: The first-sized coal gangue group is classified by calorific value to obtain a high-calorific-value coal gangue group and the first coal gangue residue, wherein the lower heating value of the high-calorific-value coal gangue group is greater than the lower heating value of the first coal gangue residue. The first coal gangue residue and the second grade coal gangue group are subjected to secondary crushing and screening to obtain a fourth grade coal gangue group and a fifth grade coal gangue group; wherein, the particle size of the fourth grade coal gangue group is larger than that of the fifth grade coal gangue group; wherein, the particle size range of the second grade coal gangue group and the fourth grade coal gangue group is the same, and the particle size range of the third grade coal gangue group and the fifth grade coal gangue group is the same. The fourth-grade coal gangue group is classified using a heavy medium cyclone device to obtain high-calorific-value coal gangue group, medium-calorific-value coal gangue group, and low-calorific-value coal gangue group. The third and fifth grade coal gangue groups are classified by a wind-powered composite dry separator to obtain the medium-calorific-value coal gangue group and the low-calorific-value coal gangue group. Optionally, the step of classifying the first-sized coal gangue group by calorific value to obtain a high-calorific-value coal gangue group and the first coal gangue residue includes: The first feature sequence is obtained by extracting multi-level features from the first particle size coal gangue group. Based on the first feature sequence, the predicted values of fixed carbon content and ash content are obtained by processing through a prediction model. The multi-level features include multiple features such as atomic number, density feature, and texture feature. The moisture content of the first-sized coal gangue group was obtained using a microwave moisture meter. The near-infrared spectrum of the first-size coal gangue group is obtained using a near-infrared spectrometer. The spectral characteristics are obtained as the second feature sequence based on the near-infrared spectrum. The predicted value of volatile matter content is obtained by using a preset third prediction model based on the second feature sequence. The received basis lower heating value is obtained by using a preset coal quality industrial analysis calculation model based on the predicted values of the fixed carbon content, the ash content, the moisture content, and the volatile matter content. Based on a first preset threshold, the received low-calorific-value ...
[0008] Optionally, the prediction model includes a preset first prediction model and a preset second prediction model, wherein the preset first prediction model is used to predict the fixed carbon content and the preset second prediction model is used to predict the ash content; both the preset first prediction model and the preset second prediction model adopt a pre-trained regression prediction model. The step of extracting multi-level features from the first particle size coal gangue group to obtain the first feature sequence includes: The high-energy X-ray intensity array of high-energy X-rays penetrating the first-size coal gangue group and the low-energy X-ray intensity array of low-energy X-rays penetrating the first-size coal gangue group were obtained based on the dual-energy X-ray transmission imaging sorting machine. For each pixel, the transmittance of high-energy X-rays for each pixel is obtained based on the high-energy X-ray intensity array, and the transmittance of low-energy X-rays for each pixel is obtained based on the low-energy X-ray intensity array. For each pixel, the attenuation coefficient ratio is obtained based on the ratio of the transmittance of high-energy X-rays to the transmittance of low-energy X-rays, and the equivalent atomic number is obtained based on the lookup table of the attenuation coefficient ratio and the equivalent atomic number. The equivalent atomic number array and / or the average value of the atomic number array for each pixel are used as features in the first feature sequence.
[0009] Optionally, the preset third prediction model is one of a pre-trained partial least squares regression model, a support vector regression model, and a random forest regression model; the step of obtaining spectral features as the second feature sequence based on the near-infrared spectrum includes: The near-infrared spectrum is preprocessed to obtain a preprocessed signal, and the principal component score sequence of the preprocessed signal is obtained by principal component analysis as a second feature sequence. Optionally, the heavy medium cyclone device includes a first stage heavy medium cyclone separator and a second stage heavy medium cyclone separator. The step of classifying the fourth-sized coal gangue group using the heavy medium cyclone device to obtain high-calorific-value coal gangue group, medium-calorific-value coal gangue group, and low-calorific-value coal gangue group includes: The fourth-grade coal gangue group is mixed with the first suspension and transported to the first stage heavy medium cyclone separator. The mixture output from the overflow port of the first stage heavy medium cyclone separator is used as the high-calorific-value coal gangue group. The mixture output from the underflow port of the first stage heavy medium cyclone separator is used as the second coal gangue residue. The residual coal gangue and the second suspension are mixed and transported to the second stage heavy medium cyclone separator. The mixture output from the overflow port of the first stage heavy medium cyclone separator is used as the medium calorific value coal gangue group; the mixture output from the underflow port of the second stage heavy medium cyclone separator is used as the low calorific value coal gangue group; wherein, the density of the first suspension is less than the density of the second suspension.
[0010] Optionally, the preset elemental categories of coal gangue groups include a first material group, a second material group, a third material group, a fourth material group, and a fifth material group. The step of performing content analysis and grading on the low-calorific-value coal gangue groups to obtain coal gangue groups of the preset elemental categories for reuse includes: When the low-calorific-value coal gangue flows through the detection point, the Fe, Si, Al, S, and Ca element contents are obtained using an X-ray fluorescence spectrometer. The low-calorific-value coal gangue is graded according to the content of Fe, Si, Al, S, and Ca to obtain the first material group, the second material group, the third material group, the fourth material group, and the fifth material group; wherein: The first material group is used to indicate that the Fe2O3 content of the material is higher than the corresponding threshold and the S element content is higher than the corresponding threshold; the first material group is used for valuable recycling; The second material group is used to indicate that the aluminum-silicon ratio of the material is higher than the corresponding threshold; the second material group is used to prepare chemical materials. The third material group is used to indicate that the Ca element content of the material is higher than the corresponding threshold; the third material group is used to prepare calcium-based materials; The fourth material is used to indicate that the silicon-to-aluminum ratio of the material is higher than a corresponding threshold; the fourth material is used to prepare building materials. The fifth material is used to indicate that the material does not belong to any of the first material group, the second material group, the third material group, and the fourth material group.
[0011] Optionally, after classifying the low-calorific-value coal gangue group according to the Fe, Si, Al, S, and Ca element contents to obtain the first material group, the second material group, the third material group, the fourth material group, and the fifth material group; the method further includes: The fifth material group is processed through a screening process to obtain a first particle size material, a second particle size material, and a third particle size material; the particle size of the first particle size material is larger than the particle size of the second particle size material, which is larger than the particle size of the third particle size material. The first particle size material and the third particle size material are mixed in a first preset ratio to form an ecological restoration backfill layer material. The second particle size material is mixed with loess in a second preset ratio to obtain the ecological restoration sealing layer material; The third-grade material is modified to obtain the ecological restoration planting layer material.
[0012] Optionally, the process of modifying the third-sized material to obtain the ecological restoration planting layer material includes: The third-grade material and the lime are added to the mixer; water is taken according to the preset liquid-solid ratio, aluminum powder foaming agent and the heavy metal curing agent are added to the water and stirred evenly and added to the mixer in multiple batches. After stirring evenly, the material is poured out and cured to obtain porous material. Add 0.2%~0.4% microbial inoculant to the porous material, and after aerobic fermentation, obtain the planting layer material by crushing and sieving.
[0013] Optionally, the porous material is composed of the following components in the following mass ratio: The third particle size consists of 90%~95% lime, 0~5% aluminum powder foaming agent, 1.5%~2% heavy metal curing agent, and the remainder is water. The preset liquid-solid ratio is 0.6~0.9.
[0014] Optionally, in the step of performing primary crushing and screening on the raw coal gangue to obtain the first-size coal gangue group, the second-size coal gangue group and the third-size coal gangue group, a three-layer heavy-duty vibrating screen is used for screening, with the top layer screen having a 50mm aperture and the middle layer screen having a 10mm aperture. In the step of obtaining the fourth and fifth coal gangue groups by secondary crushing and screening of the first coal gangue residue and the second coal gangue group, a double-layer heavy-duty vibrating screen with a screen aperture of 10mm is used for screening.
[0015] Optionally, the density of the first suspension is set to 1.45 g / cm³. 3 The density of the second suspension was set to 1.85 g / cm³. 3 .
[0016] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a method for the resource utilization of coal gangue. The method involves primary crushing and multi-size screening to classify the raw coal gangue according to particle size, providing homogenized raw materials for subsequent precise sorting. Based on density and net calorific value (LCV) based on the received basis, the material is further separated into three groups: high calorific value, medium calorific value, and low calorific value. This allows the high and medium calorific value components to be reused as fuel for energy recovery. By performing content analysis and classification on the low calorific value coal gangue group, resource classification based on specific elements or mineral composition is achieved, making resource reuse more flexible and efficient, thus improving efficiency and reducing costs. The embodiments of this application can systematically process coal gangue, improve its comprehensive utilization rate, and reduce environmental pollution. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 A schematic flowchart of a coal gangue resource utilization method provided in an embodiment of this application; Figure 2 This is a schematic flowchart of a coal gangue resource utilization method provided in another embodiment of this application. Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] It should be noted that the terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented, for example, in orders other than those illustrated or described herein.
[0021] It should be noted that "at the time of..." in the embodiments of this application can be either at the instant when a certain situation occurs, or for a period of time after the occurrence of a certain situation. The embodiments of this application do not make specific limitations on this.
[0022] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0023] In one exemplary embodiment, such as Figure 1 As shown, a method for the resource utilization of coal gangue is provided. This method is executed by computer equipment, specifically by a terminal or server alone, or by both a terminal and a server. It includes the following steps 101 to 103. Wherein: Step 101: The raw coal gangue is subjected to primary crushing and screening to obtain a first-size coal gangue group, a second-size coal gangue group, and a third-size coal gangue group; wherein the particle size of the first-size coal gangue group is greater than that of the second-size coal gangue group, which is greater than that of the third-size coal gangue group. As one embodiment, after crushing with a jaw crusher, heavy hammer crusher, and impact crusher, the raw coal gangue is screened using a three-layer heavy-duty vibrating screen. The top layer screen has a 50mm aperture, and the middle layer screen has a 10mm aperture. This primary crushing and screening process divides the raw coal gangue into three sizes: >50mm, 10~50mm, and <10mm. The coal gangue >50mm is the first size group, the coal gangue 10~50mm is the second size group, and the coal gangue <10mm is the third size group.
[0024] Step 102: Based on density and calorific value, the first-size coal gangue group, the second-size coal gangue group, and the third-size coal gangue group are graded to obtain high-calorific-value coal gangue group, medium-calorific-value coal gangue group, and low-calorific-value coal gangue group; among them, the high-calorific-value coal gangue group and the medium-calorific-value coal gangue group are used for heating and / or power generation reuse; Specifically, based on density and calorific value classification, the materials of each particle size are further separated into three groups: high calorific value, medium calorific value, and low calorific value. The high calorific value and medium calorific value components can be reused as fuel for energy recovery, while the low calorific value coal gangue group is further processed in step 103.
[0025] Specifically, the processing method for this step is determined by both the received lower heating value and density. Generally, the heating value of high-calorific-value coal gangue is greater than that of medium-calorific-value coal gangue, which is greater than that of low-calorific-value coal gangue.
[0026] Step 103: Perform content analysis and classification on the low-calorific-value coal gangue group to obtain coal gangue groups of preset element categories for reuse.
[0027] Specifically, resource classification based on their specific elements or mineral composition (such as silicon-rich, aluminum-rich, iron-rich, etc.) provides the possibility for diversified and high-value-added reuse pathways such as valuable component recovery, chemical material preparation, and building material preparation.
[0028] By implementing steps 101 to 103 above, the raw coal gangue is classified by particle size through primary crushing and multi-size screening, providing homogenized raw materials for subsequent precise sorting. Based on density and net calorific value (NDV) based on the received basis, the material is further separated into three groups: high calorific value, medium calorific value, and low calorific value. This allows the high and medium calorific value components to be reused as fuel for energy recovery. By performing content analysis and classification on the low calorific value coal gangue group, resource classification based on its specific elemental or mineral composition is achieved, making resource reuse more flexible and efficient, thus improving efficiency and reducing costs. This embodiment of the application can systematically process coal gangue, improve its comprehensive utilization rate, and reduce environmental pollution.
[0029] As an exemplary embodiment, such as Figure 2 Another embodiment of this application provides a schematic flowchart of a method for the resource utilization of coal gangue, which will be further described below based on steps 101 to 103.
[0030] To provide an intelligent method for obtaining high-calorific-value coal gangue groups, medium-calorific-value coal gangue groups, and low-calorific-value coal gangue groups, step 102 may be replaced by steps 301 to 304: Step 301: The first-sized coal gangue group is classified by calorific value to obtain the high-calorific-value coal gangue group and the first coal gangue residue. The lower heating value of the high-calorific-value coal gangue group is greater than the lower heating value of the first coal gangue residue. Specifically, the calorific value of the first-stage coal gangue group is classified based on the machine learning module to obtain the high-calorific-value coal gangue group and the first coal gangue residue.
[0031] Step 302: The first coal gangue residue and the second coal gangue group are subjected to secondary crushing and screening to obtain a fourth coal gangue group and a fifth coal gangue group; wherein the particle size of the fourth coal gangue group is larger than that of the fifth coal gangue group; wherein the particle size range of the second coal gangue group and the fourth coal gangue group is the same, and the particle size range of the third coal gangue group and the fifth coal gangue group is the same. As one embodiment, after crushing with a jaw crusher, a heavy hammer crusher, and an impact crusher, the material is screened using a double-layer heavy-duty vibrating screen with a screen aperture of 10mm. The first coal gangue residue and the second coal gangue group are subjected to secondary crushing and screening to obtain two groups: 10~50mm (fourth coal gangue group) and <10mm (fifth coal gangue group). Step 303: The fourth-grade coal gangue group is classified by heavy medium cyclone equipment to obtain high-calorific-value coal gangue group, medium-calorific-value coal gangue group and low-calorific-value coal gangue group. Specifically, heavy medium cyclone equipment includes two-stage series or single-stage multi-section heavy medium cyclone, such as a first-stage heavy medium cyclone and a second-stage heavy medium cyclone. The fourth-sized coal gangue group is mixed with the first suspension and transported to the first stage heavy medium hydrocyclone. The mixture output from the overflow port of the first stage heavy medium hydrocyclone is taken as the high-calorific-value coal gangue group. The mixture output from the underflow port of the first stage heavy medium hydrocyclone is taken as the second coal gangue residue. The second coal gangue residue is mixed with the second suspension and transported to the second stage heavy medium hydrocyclone. The mixture output from the overflow port of the second stage heavy medium hydrocyclone is taken as the medium-calorific-value coal gangue group. The mixture output from the underflow port of the second stage heavy medium hydrocyclone is taken as the low-calorific-value coal gangue group. The density of the first suspension is less than that of the second suspension.
[0032] Specifically, the material and suspension enter the hydrocyclone tangentially under pressure. In the strong centrifugal force field, particles with a density higher than the sorting density (gangue) are thrown against the wall of the hydrocyclone and discharged from the bottom outlet; particles with a density lower than the sorting density (gangue with calorific value) gather towards the center and are discharged from the overflow outlet.
[0033] Specifically, the suspension is prepared by mixing magnetite powder (Fe3O4) with water, and a density range of 1.3~2.0 g / cm³ can be achieved. 3 The density of the suspension is the separation density of the heavy medium cyclone separator.
[0034] In one embodiment, the density of the first suspension is set to 1.45 g / cm³. 3 The density of the second suspension was set to 1.85 g / cm³. 3 .
[0035] Step 304: The third-grade coal gangue group and the fifth-grade coal gangue group are classified by a wind-powered composite dry separator to obtain medium-calorific-value coal gangue group and low-calorific-value coal gangue group.
[0036] Specifically, the wind-powered composite dry separator includes an inclined vibrating bed with a perforated plate and a vibrator driven by a variable frequency motor, which causes directional vibration of the bed. After the material is fed into the bed, it begins to fluidize under the action of the rising airflow, causing the material bed to expand and loosen. At the same time, the vibration of the bed causes the particles to "drill" according to density. Under the combined action of the "wind" and "vibration," the material achieves precise stratification according to density in the longitudinal (depth) direction of the bed: low-density (rich coal) material floats to the top, and high-density (rich gangue) material sinks. The stratified material moves towards the discharge end under the combined action of the bed's inclination angle and the vibration direction. By setting an adjustable-height dividing scraper at the discharge end, low-density products (medium-calorific-value coal gangue group) can be scraped out from the top, and high-density products (low-calorific-value coal gangue group) can be discharged from the bottom.
[0037] Specifically, by controlling the effective sorting density within the sorting machine, the lower heating value (LCV) of low-density products is consistently guaranteed to be greater than 800 kcal / kg, while the LCV of high-density products is less than 800 kcal / kg. Among these parameters, air pressure and vibration frequency are the main parameters for coordinated adjustment to control sorting accuracy; the height of the scraper is the final fine-tuning parameter for the LCV.
[0038] As one example, the sorting density point is set at 1.50 g / cm³. 3 ~1.60g / cm 3 Preferably, the concentration can be set to 1.55 g / cm³. 3 .
[0039] Specifically, according to steps 301 to 304, the received basis lower heating value of the high calorific value coal gangue group is greater than 1200 kcal / kg, the received basis lower heating value of the medium calorific value coal gangue group is not greater than 1200 kcal / kg but greater than 800 kcal / kg, and the received basis lower heating value of the low calorific value coal gangue group is not greater than 800 kcal / kg.
[0040] Specifically, high-calorific-value coal gangue is used for combustion power generation or heating and sold directly as a product. Medium-calorific-value coal gangue: using coal gangue decarbonization technology (invention patent name: a pure combustion low-calorific-value coal gangue three-stage separation fluidized bed boiler, patent number: ZL202010860663.6), the waste heat generated is used to produce steam or drive a steam turbine for power generation, and the ash and slag produced by decarbonization enter the building materials or ecological channels (subsequent step 6.3).
[0041] As another embodiment, in order to provide an implementation method for classifying the received basis lower heating value of the first-size coal gangue group based on a machine learning module, step 301 includes the following steps 401-404: Step 401: Extract multi-level features from the first-size coal gangue group to obtain the feature sequence; the multi-level features include multiple features such as atomic number, density features, and texture features; As one embodiment, the atomic number can be obtained through a specific actuator (dual-energy X-ray transmission imaging sorter); As one example, the density characteristics are estimated by combining the overall attenuation of X-rays (typically based on high-energy data) with the geometric dimensions (area of the region) to determine the bulk density of the particles.
[0042] As one embodiment, the texture features include one or more of color, brightness, texture roughness, and contrast, and are obtained according to feature extraction methods in existing image processing techniques.
[0043] Specifically, as a classification criterion, coal is usually black or dark brown, while gangue is gray, white, or yellow. Gangue may exhibit crystalline or layered textures, which helps in determining the mineral type.
[0044] To provide a method for obtaining atomic numbers, the following steps 501-504 can be used in this step: Step 501: Based on the dual-energy X-ray transmission imaging sorting machine, obtain the high-energy X-ray intensity array of high-energy X-rays penetrating the first-size coal gangue group and the low-energy X-ray intensity array of low-energy X-rays penetrating the first-size coal gangue group. Specifically, the dual-energy X-ray transmission imaging sorting machine includes a dual-energy X-ray linear array detector and a transport mechanism. The dual-energy X-ray linear array detector (which consists of thousands of tiny detection pixels arranged in a row) is set under the transport belt to obtain the radiation intensity array after high-energy and low-energy X-rays penetrate the material. Step 502: For each pixel, obtain the high-energy X-ray transmittance of each pixel based on the high-energy X-ray intensity array, and obtain the low-energy X-ray transmittance of each pixel based on the low-energy X-ray intensity array. Specifically, for each pixel, the ratio of the intensity of high-energy X-rays after penetrating the material to the initial intensity of high-energy X-rays is the transmittance of high-energy X-rays, and the ratio of the intensity of low-energy X-rays after penetrating the material to the initial intensity of low-energy X-rays is the transmittance of low-energy X-rays. Step 503: For each pixel, obtain the attenuation coefficient ratio based on the ratio of the transmittance of high-energy X-rays to the transmittance of low-energy X-rays, and obtain the equivalent atomic number (Zeff) based on the lookup table of the attenuation coefficient ratio and the equivalent atomic number (Zeff).
[0045] Specifically, coal (rich in C, H, and O) has a lower Zeff (0-6), while gangue minerals (containing Si, Al, Fe, etc.) have a higher Zeff (>12). Step 504: The equivalent atomic number (i.e., the atomic number array) of each pixel and / or the average value of the atomic number array are used as part of the feature sequence of the region.
[0046] Step 402: Obtain the fixed carbon content and ash content by processing the feature sequence through a prediction model; Specifically, ash content is used to express the percentage of the total substance after the ash residue remains; fixed carbon content is used to express the percentage of the total substance after heating under air-isolated conditions (i.e., after measuring volatile matter and deducting ash content). As one embodiment, the prediction model includes a preset first prediction model and a preset second prediction model; wherein, the preset first prediction model is used to predict the fixed carbon content, and the preset second prediction model is used to predict the ash content; Specifically, the feature sequence is input into a preset first prediction model to obtain the fixed carbon content output by the preset first prediction model, and the feature sequence is input into a preset second prediction model to obtain the ash content output by the preset second prediction model.
[0047] Furthermore, the preset first prediction model and the preset second prediction model can be one of the pre-trained regression prediction models (such as random forest, gradient booster or neural network).
[0048] As part of the training process for the preset first prediction model, several first-grade coal gangue groups are taken as samples. Based on the feature sequence in step 401 above, a fixed carbon content is obtained through experiments or existing calculation methods. The fixed carbon content is used as a label, and the feature sequence and the corresponding label are used as a training set to train the preset regression prediction model to obtain the preset first prediction model. As part of the training process for the preset second prediction model, the first-size coal gangue group is taken as a sample. Based on the feature sequence in step 401 above, the ash content is obtained through experiments or existing calculation methods. The ash content is used as a label, and the feature sequence and the corresponding label are used as a training set to train the preset regression prediction model to obtain the preset second prediction model. Step 403: Obtain the moisture content of the first particle size coal gangue group using a microwave moisture meter; Specifically, the moisture content can be directly obtained by scanning the material using an online microwave moisture meter (non-contact type).
[0049] Specifically, the linear microwave moisture meter is positioned above the belt conveyor. It includes a microwave transmitter, a receiver, and an internal processor. The meter continuously scans the passing material. The microwave transmitter emits microwaves of a specific frequency onto the material on the belt. The receiver detects the energy attenuation and phase shift of the microwaves after they penetrate the material (or are reflected from the material surface). Based on the attenuation and phase shift, the internal processor calculates the moisture content of the material in real time using a preset material-moisture calibration curve.
[0050] Step 404: Obtain the near-infrared spectrum of the first-sized coal gangue group based on the near-infrared spectrometer, obtain the spectral features as the second feature sequence based on the near-infrared spectrum, and obtain the predicted value of volatile matter content based on the second feature sequence through a preset third prediction model. Specifically, the near-infrared spectrum is preprocessed to obtain a preprocessed signal, and the preprocessed signal is used to obtain the principal component score sequence as the second feature sequence through principal component analysis; the second feature sequence is input into a preset third prediction model to obtain the predicted value of the volatile matter content.
[0051] As one embodiment, the preprocessing step includes sequentially filtering the near-infrared spectrum, calculating the first derivative, and performing standard normal variable transformation to obtain the preprocessed signal; For example, an SG (Savitzky-Golay) smoothing filter can be used for filtering; the purpose of this processing is to filter out high-frequency random noise.
[0052] Specifically, the first derivative is used to eliminate baseline drift and feature enhancement, and the standard normal transformation is used to standardize the signal.
[0053] Specifically, the third prediction model is pre-trained and selected from one of the following: partial least squares regression model, support vector regression model, and random forest regression model. Principal component analysis (PCA) is a statistical method that uses orthogonal linear transformations to convert a set of potentially correlated high-dimensional variables into a few linearly uncorrelated low-dimensional variables. The transformed variables are called principal components, which can preserve the variation information in the original dataset to the greatest extent.
[0054] Specifically, as a training method for the preset third prediction model, several samples of the first-size coal gangue group are obtained, and the second feature sequence is obtained according to the above preprocessing method. The volatile matter content of the first-size coal gangue group is obtained by actual measurement as its label. The second feature sequence and the corresponding label are used as the training set. The preset third prediction model is obtained by training one of the preset partial least squares regression model, support vector regression model and random forest regression model according to the training set.
[0055] Step 405: Obtain the received basis lower heating value based on the predicted values of the fixed carbon content, the ash content, the moisture content, and the volatile matter content through a preset coal quality industrial analysis calculation model. Specifically, the lower heating value is the heat released when a unit mass of fuel is completely burned under constant pressure and specific conditions, with the water in the combustion products remaining in a steam state (20°C).
[0056] Specifically, the coal quality industrial analysis calculation model is a system based on fundamental data of coal "industrial analysis." Through a series of formulas and correlations, it calculates and predicts various key characteristic indicators of coal during industrial utilization. It is a core and practical existing model in industries such as coal, power, metallurgy, and chemicals.
[0057] As one implementation method, the coal quality industrial analysis and calculation model adopts the national standard empirical model, specifically including: Qnet,ar=0.358FCar+0.393Var-0.023Aar-0.024Mar; Where Qnet,ar is the lower heating value on the received basis, FCar is the predicted value of fixed carbon content, Aar is the predicted value of ash content, Mar is the moisture content, and Var is the predicted value of volatile matter content.
[0058] Step 406: Based on the first preset threshold, threshold screening is performed on the received low heating value to obtain the high heating value coal gangue group and the first coal gangue residue. The received low heating value of the high heating value coal gangue group is greater than the first preset threshold, and the received low heating value of the first coal gangue residue is not greater than the first preset threshold.
[0059] As one embodiment, the first preset threshold can be set to 1200 kcal / kg (approximately 5.02 MJ / kg).
[0060] Furthermore, based on the judgment by the first preset threshold, the corresponding first-grade coal gangue can be diverted to different channels by triggering the actuator (high-pressure air gun) to complete the classification of high-calorific-value coal gangue group and first coal gangue residue.
[0061] As one embodiment, step 103 is replaced by steps 601 to 606: Step 601: When the low-calorific-value coal gangue flows through the detection point, the Fe, Si, Al, S and Ca content are obtained using an X-ray fluorescence spectrometer. Specifically, X-ray irradiation of the coal gangue surface excites inner-shell electrons, producing characteristic X-ray fluorescence. Energy dispersive spectroscopy (EDS) analysis is used to determine the elemental composition and content. The characteristic peak for Fe is located at 6.4 keV (Kα line). The characteristic peak for Si is at 1.74 keV. The characteristic peak for Al is at 1.49 keV. The characteristic peak for S is at 2.31 keV. The characteristic peak for Ca is at 3.69 keV. Fluorescence intensity is converted to percentage content using calibration curves (using standard samples with known compositions).
[0062] Furthermore, a whiteness meter can be used for auxiliary analysis. The content of minerals such as kaolinite and quartz in coal gangue is related to whiteness. A high whiteness value may indicate a high content of silicon and aluminum (such as kaolinite). Combining spectral data can cross-validate and improve the accuracy of mineral phase analysis.
[0063] Step 602: Based on the Fe, Si, Al, S, and Ca content, the low-calorific-value coal gangue is graded to obtain a first material group, a second material group, a third material group, a fourth material group, and a fifth material group. Specifically: the first material group indicates that the Fe2O3 content and S content of the material are both above a corresponding threshold; the first material group is used for valuable recycling. The second material group indicates that the aluminum-to-silicon ratio of the material is above a corresponding threshold; the second material group is used for preparing chemical materials. The third material group indicates that the Ca content of the material is above a corresponding threshold; the third material group is used for preparing calcium-based materials. The fourth material group indicates that the silicon-to-aluminum ratio of the material is above a corresponding threshold; the fourth material group is used for preparing building materials. The fifth material group indicates that the material does not belong to any of the first, second, third, or fourth material groups.
[0064] Specifically, the first material group is used for valuable recycling, mainly for recovering pyrite. The second material group is used for preparing chemical materials, such as preparing coal-series kaolin, extracting alumina, and preparing molecular sieves. The third material group is used for preparing calcium-based materials, such as producing soil conditioners (to neutralize acidity) and desulfurizing agents. The fourth material is used to indicate that the silicon-to-aluminum ratio of the material is higher than a corresponding threshold. The fourth material is used for preparing building materials, such as producing high-quality sintered bricks, ceramsite, and cement admixtures.
[0065] Specifically, if there is a classification conflict, the material will be assigned to a specific group based on its priority. As one embodiment, the above priorities from high to low are: first material group, second material group, third material group, fourth material group and fifth material group.
[0066] For example, in order to implement the above priority processing steps, step 602 can be replaced by the following steps: Step 701: Obtain the Fe2O3 content based on the Fe element content, and determine whether the first condition is met based on the Fe2O3 content and the S element content; the first condition includes: the Fe2O3 content is greater than a first preset content value and the S element content is greater than a second preset content value. Specifically, the Fe2O3 content is obtained by converting the Fe element content using the ratio of the molecular weight of Fe2O3 to Fe. That is, according to the formula, the Fe2O3 content is equal to 1.4297 times the Fe element content. As one embodiment, the first preset content value is set to 15%, and the second preset content value is set to 3%.
[0067] Step 702: If the first condition is met, classify the material flowing through the detection point into the first material group and divert it to the first diversion channel; Specifically, the first diversion channel includes pyrite, which is used for the valuable recovery of precious metals; Step 703: If the first condition is not met, obtain the aluminum-silicon ratio based on the ratio of Al element content to Si element content, and determine whether the aluminum-silicon ratio is greater than the first preset ratio; if the aluminum-silicon ratio is greater than the first preset ratio, classify the material flowing through the detection point into the second material group and divert it to the second diversion channel. As one embodiment, the first preset ratio is set to 0.5; Specifically, coal gangue with a high aluminum-to-silicon ratio can be used to generate materials, such as coal-based kaolin, alumina extraction, and molecular sieve preparation.
[0068] Step 704: If the aluminum-silicon ratio is not greater than the first preset ratio, determine whether the Ca element content is greater than the third preset content value; if the Ca element content is greater than the third preset content value, classify the material flowing through the detection point into the third material group and divert it to the third diversion channel. Furthermore, before step 704, the method further includes: obtaining a third preset content value based on the preset content and preset ratio of CaO; As an example, the content of CaO in the third material group is required to be greater than 10%, and the CaO content (%) ≈ Ca element content (%) × 1.4, so the Ca element content should be > 7.1%, and the third preset content value is set to 7.1%.
[0069] Step 705: If the Ca content is not greater than the third preset content value, obtain the silicon-aluminum ratio based on the ratio of Si content to Al content, and determine whether the silicon-aluminum ratio is greater than the second preset ratio value; if the silicon-aluminum ratio is greater than the second preset ratio value, classify the material flowing through the detection point into the fourth material group and divert it to the fourth diversion channel. Specifically, the second preset ratio is set in the range of 2.5 to 3.5. Coal gangue with a high silicon-to-aluminum ratio can be used for building materials, such as for producing gangue bricks, ceramsite, cement clinker and other building materials. The products are used in urban renewal projects in counties, rural roads and other construction projects.
[0070] Step 706: If the silicon-to-aluminum ratio is not greater than the second preset ratio, classify the material flowing through the detection point into the fifth material group and divert it to the fifth diversion channel; Specifically, the fifth material group will process the unusable ash, residue, and raw low-value coal gangue produced after the screening process described above.
[0071] Step 603: The fifth material group is processed by a screening process to obtain the first particle size material, the second particle size material and the third particle size material; the particle size of the first particle size material is larger than the particle size of the second particle size material and the particle size of the third particle size material. Specifically, this step involves further screening to obtain the first-size material, the second-size material, and the third-size material; Furthermore, a three-stage vibrating screen can be used, with the top screen mesh having an aperture of 20mm, the middle screen mesh having an aperture of 5mm, the second-stage material having a particle size range of 20mm to 50mm, the third-stage material having a particle size range of 5mm to 20mm, and the third-stage material having a particle size range of less than 5mm.
[0072] Step 604: Mix the first particle size material and the third particle size material in a first preset ratio to form the ecological restoration backfill material; Specifically, the first-grade material and the third-grade material are mixed in a ratio of 6~8:2~4 to obtain backfill material. The backfill material can be used as filling material to restore land function and is mainly used for filling and landform reshaping in coal subsidence areas.
[0073] Specifically, the backfill material for ecological restoration is generally located at the bottom layer, directly covering the original waste slag or unstable substrate. It is mainly used to prevent the roots and water of the upper plant layer from directly contacting the lower layer of potentially polluting slag (such as heavy metals or acids), and can provide a solid and flat foundation for the entire restoration structure. At the same time, it has the characteristics of coarse particles and high permeability, which can achieve stable drainage.
[0074] Step 605: The second-sized material is mixed with loess in a second preset ratio to obtain the ecological restoration sealing layer material; Specifically, the second preset ratio is set within the range of 5~6:4~5.
[0075] Specifically, the ecological restoration sealing layer material is located above the backfill layer and below the planting layer. This serves to retain the effective moisture needed for plant growth in the upper planting layer and to prevent harmful gases such as methane that may be produced by materials like coal ore from spreading to the surface.
[0076] Step 606: Modify the third-grade material to obtain the ecological restoration planting layer material.
[0077] Specifically, the ecological restoration sealing layer material is located on the top layer, which can provide a growth substrate, restore the ecology, retain water and stabilize the soil, and provide physical covering protection for the sealing layer below, preventing ultraviolet radiation, drastic temperature changes and mechanical damage, thus extending its service life.
[0078] Specifically, the preparation of ecological restoration planting layer materials shall be carried out according to the following steps: Step 801: Prepare a porous material based on the third particle size distribution. The porous material is composed of the following components in the following mass ratio: The third particle size consists of 90%~95% lime, 0~5% aluminum powder foaming agent, 1.5%~2% heavy metal curing agent, and the remainder is water, with a preset liquid-solid ratio of 0.6~0.9. Porous materials are prepared using the following methods: Add the third-grade material and lime to the mixer; take water according to the preset liquid-solid ratio, add aluminum powder foaming agent and heavy metal curing agent to the water, stir evenly and add to the mixer in multiple batches. After stirring evenly, pour out the material and cure it at 120℃~150℃ for 12 hours to obtain porous material. Specifically, sodium dihydrogen phosphate is used as the heavy metal curing agent. During the preparation and curing of porous materials, coal gangue, fly ash, and lime form a composite system, creating a neutral to alkaline environment that is conducive to the heavy metal curing reaction (sodium dihydrogen phosphate reacts with heavy metals such as Cr, Pb, and Ni in the material to form insoluble phosphate precipitates, which passivate the heavy metals in the material). At the same time, the Ca, Si, and Al system in the material reacts to form calcium silicate gel (C~S~H), which greatly increases the difficulty of the migration and diffusion of heavy metal ions to the outside world and reduces the risk of heavy metal leaching.
[0079] Step 802: Add 0.2%~0.4% microbial inoculant to the porous material and ferment it aerobically for 15~30 days. During the fermentation process, stir and moisturize appropriately. After crushing and screening, obtain the planting layer material.
[0080] Specifically, adding microbial agents using one or more of Bacillus mucilaginosus and arbuscular mycorrhizal fungi can degrade elements such as nitrogen, phosphorus, and potassium in materials into effective nitrogen, phosphorus, and potassium that can be absorbed by plants.
[0081] Furthermore, as an ecological restoration material, it also has the following functions: Ecological restoration backfill materials, ecological restoration sealing materials, and ecological restoration planting materials can be used for filling and landform reshaping in coal mining subsidence areas, serving as filling materials to restore land function.
[0082] Ecological restoration planting layer materials can be used for mine slope restoration and revegetation. Specifically, they serve as substrate soil for vegetation restoration.
[0083] Ecological restoration backfill material and ecological restoration sealing material can be used as roadbed filler, that is, for the roadbed construction of low-grade highways within the county.
[0084] This application provides a method for the resource utilization of coal gangue, which includes the following technical advantages: Based on the differences in physical properties and economic efficiency of sorting technology caused by variations in coal gangue particle size, this application's embodiments creatively construct a three-level particle size classification-sorting matching system: For the first-order coal gangue group (>50mm large particles), multi-level feature sequences (atomic number, density, texture, etc.) are obtained through component detection. These multi-level feature sequences are then used to directly predict the core indicators determining the received-by-basis lower heating value—fixed carbon content and ash content. Finally, a mature coal quality industrial analysis and calculation model is used to accurately calculate the received-by-basis lower heating value. Intelligent sorting based on pattern recognition is employed, fully utilizing its abundant information to provide a more fundamental prediction of the received-by-basis lower heating value, a more scientific calculation path, and significantly improved accuracy. This enables the recovery of high-value blocky fuels and avoids ineffective crushing energy consumption.
[0085] For medium-sized coal gangue (critical particle size of 10-50mm), heavy medium cyclone separation is used to fully utilize the principle that the particle separation efficiency is the highest in this particle size range according to density to achieve precise separation of high-calorific-value and medium-calorific-value fuels and gangue, thus ensuring the value of core products. Fine-grained coal gangue (third-grade and fifth-grade coal gangue, with fine particles <10mm) is classified and screened using a wind-powered composite dry separator, fundamentally avoiding the generation of coal slurry water and achieving the separation of fine-grained materials with the lowest environmental and operating costs.
[0086] When the low-calorific-value coal gangue flows through the detection point, the Fe, Si, Al, S, and Ca element contents are obtained using an X-ray fluorescence spectrometer. Using the chemical element content as the criterion, the low-calorific-value coal gangue is "turned from waste into treasure" and guided to the most economically valuable utilization path according to its internal composition differences.
[0087] For the final remaining material (fifth material group) after multiple sorting processes, the mixed components of the fifth material group are separated into three grades according to particle size through screening. The different particle sizes are then used in preset proportions to construct the backfill layer, sealing layer, and planting layer of the ecological restoration material.
[0088] This application provides a multi-level, multi-process synergistic sorting method. It innovatively employs a multi-stage cascade process, including pre-sorting based on the received low calorific value, particle size adaptation sorting, and fine composition sorting. For materials of different particle sizes and characteristics, it matches optimal technologies such as heavy media sorting and airflow sorting to create a synergistic effect and maximize overall sorting efficiency. Based on the deep coupling of particle size engineering principles, this application ensures that each technology functions within its most suitable and economical particle size range, thereby achieving synergistic optimization of sorting efficiency, economic benefits, and environmental benefits at the system level.
[0089] This application also provides an application scenario in which the above-described coal gangue resource utilization method is applied.
[0090] Specifically, the coal gangue resource utilization method provided in this embodiment can be applied to a coal gangue resource utilization system. This system includes multiple grading modules / systems connected by transport channels. Each grading module may be a specific actuator (e.g., implementing step 304 by using a wind-powered composite dry separator) or a microprocessor integrated with an actuator (e.g., implementing step 301 by using a dual-energy X-ray transmission imaging sorting machine, imaging equipment, and a microprocessor as a grading module / system). Each grading module / system completes its corresponding grading task, and the different graded materials are transported to the next grading module / system via the transport channels, thereby providing an intelligent management platform to realize the coal gangue resource utilization method provided in this application.
[0091] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0092] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. In summary, the content of this specification should not be construed as a limitation of this application.
Claims
1. A method for the resource utilization of coal gangue, characterized in that, The method for resource utilization of coal gangue includes: The raw coal gangue is subjected to primary crushing and screening to obtain a first-size coal gangue group, a second-size coal gangue group, and a third-size coal gangue group; wherein the particle size of the first-size coal gangue group is greater than that of the second-size coal gangue group, which is greater than that of the third-size coal gangue group. The first, second, and third granular coal gangue groups are graded based on density and net calorific value to obtain high-calorific-value, medium-calorific-value, and low-calorific-value coal gangue groups; wherein the high-calorific-value and medium-calorific-value coal gangue groups are used for heating and / or power generation. The low-calorific-value coal gangue group is subjected to content analysis and classification to obtain coal gangue groups of preset element categories for reuse.
2. The method for resource utilization of coal gangue according to claim 1, characterized in that, The method of classifying the first, second, and third particle size coal gangue groups based on density and calorific value to obtain high-calorific-value coal gangue groups, medium-calorific-value coal gangue groups, and low-calorific-value coal gangue groups includes: The first-sized coal gangue group is classified by calorific value to obtain a high-calorific-value coal gangue group and the first coal gangue residue, wherein the lower heating value of the high-calorific-value coal gangue group is greater than the lower heating value of the first coal gangue residue. The first coal gangue residue and the second-sized coal gangue group are subjected to secondary crushing and screening to obtain a fourth-sized coal gangue group and a fifth-sized coal gangue group; wherein the particle size of the fourth-sized coal gangue group is larger than that of the fifth-sized coal gangue group; wherein the particle size range of the second-sized coal gangue group and the fourth-sized coal gangue group is the same, and the particle size range of the third-sized coal gangue group and the fifth-sized coal gangue group is the same. The fourth-grade coal gangue group is classified using a heavy medium cyclone device to obtain high-calorific-value coal gangue group, medium-calorific-value coal gangue group, and low-calorific-value coal gangue group. The third and fifth grade coal gangue groups are graded using a wind-powered composite dry separator to obtain the medium-calorific-value coal gangue group and the low-calorific-value coal gangue group.
3. The method for resource utilization of coal gangue according to claim 2, characterized in that, The step of classifying the first-sized coal gangue group by calorific value to obtain a high-calorific-value coal gangue group and the first coal gangue residue includes: The first feature sequence is obtained by extracting multi-level features from the first particle size coal gangue group. Based on the first feature sequence, the predicted values of fixed carbon content and ash content are obtained by processing through a prediction model. The multi-level features include multiple features such as atomic number, density feature, and texture feature. The moisture content of the first-sized coal gangue group was obtained using a microwave moisture meter. The near-infrared spectrum of the first-sized coal gangue group is obtained using a near-infrared spectrometer. The spectral features are obtained as a second feature sequence based on the near-infrared spectrum. The predicted value of volatile matter content is obtained by using a preset third prediction model based on the second feature sequence. The received basis lower heating value is obtained by using a preset coal quality industrial analysis calculation model based on the predicted values of the fixed carbon content, the ash content, the moisture content, and the volatile matter content. Based on a first preset threshold, the received low-calorific-value ...
4. The method for resource utilization of coal gangue according to claim 3, characterized in that, The prediction model includes a preset first prediction model and a preset second prediction model. The preset first prediction model is used to predict the fixed carbon content, and the preset second prediction model is used to predict the ash content. Both the preset first prediction model and the preset second prediction model use pre-trained regression prediction models. The step of extracting multi-level features from the first particle size coal gangue group to obtain the first feature sequence includes: The high-energy X-ray intensity array of high-energy X-rays penetrating the first-size coal gangue group and the low-energy X-ray intensity array of low-energy X-rays penetrating the first-size coal gangue group were obtained based on the dual-energy X-ray transmission imaging sorting machine. For each pixel, the transmittance of high-energy X-rays for each pixel is obtained based on the high-energy X-ray intensity array, and the transmittance of low-energy X-rays for each pixel is obtained based on the low-energy X-ray intensity array. For each pixel, the attenuation coefficient ratio is obtained based on the ratio of the transmittance of high-energy X-rays to the transmittance of low-energy X-rays, and the equivalent atomic number is obtained based on the lookup table of the attenuation coefficient ratio and the equivalent atomic number. The equivalent atomic number array and / or the average value of the atomic number array for each pixel are used as features in the first feature sequence.
5. The method for resource utilization of coal gangue according to claim 3, characterized in that, The preset third prediction model is one of a pre-trained partial least squares regression model, a support vector regression model, and a random forest regression model; the step of obtaining spectral features as the second feature sequence based on the near-infrared spectrum includes: The near-infrared spectrum is preprocessed to obtain a preprocessed signal, and the principal component score sequence of the preprocessed signal is obtained by principal component analysis as a second feature sequence.
6. The method for resource utilization of coal gangue according to claim 2, characterized in that, The heavy medium cyclone device includes a first stage heavy medium cyclone separator and a second stage heavy medium cyclone separator. The step of classifying the fourth-sized coal gangue group using the heavy medium cyclone device to obtain high-calorific-value coal gangue group, medium-calorific-value coal gangue group, and low-calorific-value coal gangue group includes: The fourth-grade coal gangue group is mixed with the first suspension and transported to the first stage heavy medium cyclone separator. The mixture output from the overflow port of the first stage heavy medium cyclone separator is used as the high-calorific-value coal gangue group. The mixture output from the underflow port of the first stage heavy medium cyclone separator is used as the second coal gangue residue. The residual coal gangue and the second suspension are mixed and transported to the second stage heavy medium cyclone separator. The mixture output from the overflow port of the first stage heavy medium cyclone separator is used as the medium calorific value coal gangue group; the mixture output from the underflow port of the second stage heavy medium cyclone separator is used as the low calorific value coal gangue group; wherein, the density of the first suspension is less than the density of the second suspension.
7. The method for resource utilization of coal gangue according to claim 1, characterized in that, The pre-defined elemental categories of coal gangue include a first material group, a second material group, a third material group, a fourth material group, and a fifth material group. The step of performing content analysis and grading on the low-calorific-value coal gangue to obtain coal gangue groups of the pre-defined elemental categories for reuse includes: When the low-calorific-value coal gangue flows through the detection point, the Fe, Si, Al, S, and Ca element contents are obtained using an X-ray fluorescence spectrometer. The low-calorific-value coal gangue is graded according to the content of Fe, Si, Al, S, and Ca to obtain the first material group, the second material group, the third material group, the fourth material group, and the fifth material group; wherein: The first material group is used to indicate that the Fe2O3 content of the material is higher than the corresponding threshold and the S element content is higher than the corresponding threshold; the first material group is used for valuable recycling. The second material group is used to indicate that the aluminum-silicon ratio of the material is higher than the corresponding threshold; the second material group is used to prepare chemical materials. The third material group is used to indicate that the Ca element content of the material is higher than the corresponding threshold; the third material group is used to prepare calcium-based materials; The fourth material is used to indicate that the silicon-to-aluminum ratio of the material is higher than a corresponding threshold; the fourth material is used to prepare building materials. The fifth material is used to indicate that the material does not belong to any of the first material group, the second material group, the third material group, and the fourth material group.
8. The method for resource utilization of coal gangue according to claim 7, characterized in that, After classifying the low-calorific-value coal gangue group according to the Fe, Si, Al, S, and Ca element contents to obtain the first material group, the second material group, the third material group, the fourth material group, and the fifth material group; the method further includes: The fifth material group is processed through a screening process to obtain a first particle size material, a second particle size material, and a third particle size material; the particle size of the first particle size material is larger than the particle size of the second particle size material, which is larger than the particle size of the third particle size material. The first particle size material and the third particle size material are mixed in a first preset ratio to form an ecological restoration backfill layer material. The second particle size material is mixed with loess in a second preset ratio to obtain the ecological restoration sealing layer material; The third-grade material is modified to obtain the ecological restoration planting layer material.
9. The method for resource utilization of coal gangue according to claim 8, characterized in that, The process of modifying the third-grade material to obtain the ecological restoration planting layer material includes: The third-grade material and the lime are added to the mixer; water is taken according to the preset liquid-solid ratio, aluminum powder foaming agent and the heavy metal curing agent are added to the water and stirred evenly and added to the mixer in multiple batches. After stirring evenly, the material is poured out and cured to obtain porous material. Add 0.2%~0.4% microbial inoculant to the porous material, and after aerobic fermentation, obtain the planting layer material by crushing and sieving; The porous material is composed of the following components in the following mass ratio: The third particle size consists of 90%~95% lime, 0~5% aluminum powder foaming agent, 1.5%~2% heavy metal curing agent, and the remainder is water. The preset liquid-solid ratio is 0.6~0.
9.
10. The method for resource utilization of coal gangue according to claim 2, characterized in that, In the step of obtaining the first-grade coal gangue group, the second-grade coal gangue group and the third-grade coal gangue group by primary crushing and screening of the raw coal gangue, a three-layer heavy-duty vibrating screen is used for screening, with the top layer screen having a 50mm aperture and the middle layer screen having a 10mm aperture. In the step of obtaining the fourth and fifth coal gangue groups by secondary crushing and screening of the first coal gangue residue and the second coal gangue group, a double-layer heavy-duty vibrating screen with a screen aperture of 10mm is used for screening.