Filling material multi-stage mixing type negative carbon filling system and filling material multi-stage mixing type negative carbon filling method

Abstract

The invention relates to a filling material multi-stage mixing type negative carbon filling system and method, and the system comprises a ground batching module which is used for mixing aggregate with water to prepare low-concentration slurry; the conveying pipeline is used for conveying filling materials; the first mixing module is used for injecting a cementing material into the low-concentration slurry; the second mixing module is positioned at the downstream of the first mixing module and is used for injecting a water-retaining agent and carbon dioxide into the slurry injected with the cementing material, the water-retaining agent enables the slurry to be pasty, and the carbon dioxide reacts in the slurry; the control module is in communication connection with other modules and is used for controlling the material injection time and the injection amount; wherein the second mixing module is arranged at the rear section of the conveying pipeline; the first mixing module is disposed upstream of and proximate to the second mixing module. The filling process can dynamically adapt to complex pipeline working conditions due to the intelligent segmented regulation and control capacity of the system, and the utilization efficiency of the cementing material and the carbon dioxide is optimized while the conveying safety is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of mine backfilling technology, and in particular to a multi-stage mixed-infill negative carbon backfilling system and method. Background Technology

[0002] With the increasing depth and scale of underground mining, backfilling mining has been widely used in the fields of metallic and non-metallic minerals due to its ability to control ground pressure, reduce surface subsidence, and improve resource recovery. Backfilling mining typically utilizes solid waste such as tailings and waste rock to prepare backfill materials, which are then transported to the goaf through pipelines to allow it to acquire load-bearing capacity and overall stability within a certain period. Commonly used backfilling techniques in engineering include water-sand backfilling, high-concentration cement tailings backfilling, cemented backfilling, paste backfilling, and high-water-content material backfilling.

[0003] Existing mine backfilling systems mostly employ surface-based single-point preparation and single-stage mixing via pipeline transportation. Their basic structure includes: surface raw material silos, metering devices, mixers (or mixing tanks), slurry pools, delivery pumps, and long-distance pipelines; sometimes, they are equipped with additive feeding devices for water-reducing agents and other admixtures. The working principle involves mixing tailings (or aggregates), cementitious materials, and water at the surface in a single step to form a backfill slurry of the target concentration, which is then transported as a whole through pipelines to the underground goaf for shaping.

[0004] The existing filling process generally has the following problems: First, when high-concentration, high-viscosity slurry is transported over long distances, the resistance inside the pipe is large and the pumping pressure is high, which makes it easy to block the pipe at bends and high-level sections, increasing energy consumption and maintenance costs; Second, if the concentration is reduced to ensure safe transportation, the bleeding and segregation after filling the goaf will be large and obvious, making it difficult to form a good structure and sufficient early strength; Third, a high amount of cement is usually required to obtain the target strength, resulting in high filling costs and carbon emission levels. Summary of the Invention

[0005] To address the technical problems of easy pipe blockage during long-distance transportation and the difficulty in synergistically improving terminal filling quality and negative carbon effect in existing technologies, this invention provides a multi-stage mixed-injection negative carbon filling system and method. The technical solution is as follows:

[0006] On one hand, a multi-stage mixing negative carbon backfilling system is provided. The system includes: a ground batching module for mixing aggregates with water to prepare a low-concentration slurry; a conveying pipeline, with its inlet end connected to the ground batching module and its outlet end leading to the underground goaf for conveying backfill material; a first mixing module, located on the conveying pipeline, for injecting a cementing material into the low-concentration slurry; and a second mixing module, located on the conveying pipeline and downstream of the first mixing module, for injecting a water-retaining agent and carbon dioxide into the slurry after the cementing material has been injected. The water-retaining agent is injected to form a paste-like consistency in the slurry, and the carbon dioxide is injected to induce an in-situ carbonization reaction in the slurry to achieve carbon sequestration. A control module, communicatively connected to the ground batching module, the first mixing module, and the second mixing module, is used to control the timing and amount of material injection. The second mixing module is located downstream of the conveying pipeline to ensure that the water-retaining agent and carbon dioxide are fully mixed and form a paste-like structure before the slurry reaches the goaf. The first mixing module is located upstream of and close to the second mixing module.

[0007] On the other hand, a multi-stage mixed-infill negative carbon backfilling method is provided. This method includes: mixing aggregates with water on the ground to prepare a low-concentration slurry; pumping the low-concentration slurry into a conveying pipeline for transport; injecting a cementing material into the low-concentration slurry at a first position in the conveying pipeline; and injecting a water-retaining agent and carbon dioxide into the slurry containing the cementing material at a second position downstream of the first position in the conveying pipeline to form a paste. The timing and amount of injection of the cementing material, the water-retaining agent, and the carbon dioxide are controlled by a control module, and the second position is located downstream of the conveying pipeline to ensure that the water-retaining agent and carbon dioxide are fully mixed and form a paste structure before the slurry reaches the goaf. The first position is located close to the second position.

[0008] The beneficial effects of the technical solution provided by the embodiments of the present invention include at least the following: By constructing a filling system that integrates ground batching, multi-stage pipeline mixing, and intelligent control, the traditional technical problems are effectively solved. First, the system prepares a low-concentration slurry on the ground as a transport base and injects cementitious materials in batches along the middle and later sections of the pipeline, achieving a controllable transition from low to high transport resistance, fundamentally reducing the risk of long-distance pipeline blockage and pumping energy consumption. Second, a dedicated mixing module is set up in the later section of the pipeline to inject water-retaining agents and carbon dioxide in synergy, enabling the slurry to complete the paste transformation and initially fix carbon dioxide before reaching the goaf, ensuring that the terminal filling body has the characteristics of high density, low water bleeding, and providing conditions for subsequent mineralization reactions. Finally, the intelligent segmented control capability of the entire system enables the filling process to dynamically adapt to complex pipeline conditions, ensuring transport safety while optimizing the utilization efficiency of cementitious materials (especially alkaline industrial solid waste) and carbon dioxide, providing reliable equipment and methodological support for constructing a safe, high-quality, and carbon-negative filling system. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure of a multi-stage mixed-infill negative carbon filling system provided in an embodiment of the present invention;

[0011] Figure 2 This is a flowchart of a multi-stage mixed-infill negative carbon filling method provided by an embodiment of the present invention.

[0012] Explanation of reference numerals in the attached drawings: 100, Ground batching module; 101, First storage silo; 102, Conveying device; 103, Water supply unit; 104, First mixing unit; 105, Slurry pump; 200, Conveying pipeline; 300, First mixing module; 301, Second storage silo; 302, First metering pump; 303, First injection interface; 304, Second mixing unit; 400, Second mixing module; 401, Water-retaining agent storage tank; 402, Second metering pump; 403, Carbon dioxide storage tank; 404, Third metering pump; 405, Second injection interface; 406, Third mixing unit; 500, Control module; 600, Sensor; 700, Terminal forming module; 701, Terminal mixer; 702, Discharge port. Detailed Implementation

[0013] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0014] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0015] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning.

[0016] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0017] Please see Figure 1 This invention provides a multi-stage mixing negative carbon filling system for filling materials. The system includes a ground batching module 100, a conveying pipeline 200, a first mixing module 300, a second mixing module 400, and a control module 500. The system includes a ground batching module 100 for mixing aggregates with water to prepare a low-concentration slurry; a conveying pipeline 200 with its inlet end connected to the ground batching module 100 and its outlet end leading to the underground goaf for conveying filling material; a first mixing module 300 installed on the conveying pipeline 200 for injecting cementitious materials into the low-concentration slurry; and a second mixing module 400 installed on the conveying pipeline 200 and downstream of the first mixing module 300 for injecting a water-retaining agent and carbon dioxide into the slurry after the cementitious materials have been injected. The water-retaining agent is used to paste the slurry, and the carbon dioxide is used to induce in-situ carbonization in the slurry to achieve carbon sequestration. A control module 500 is communicatively connected to the ground batching module 100, the first mixing module 300, and the second mixing module 400. Figure 1 (The connection relationship is not shown in the figure), used to control the timing and amount of material injection; wherein, the second mixing module 400 is set at the rear section of the conveying pipeline 200 to ensure that the water-retaining agent and carbon dioxide are fully mixed and form a paste structure before the slurry reaches the goaf; the first mixing module 300 is set upstream of the second mixing module 400 and close to the second mixing module 400.

[0018] The core of this system lies in transforming the originally fixed pipeline transportation process into a "flow reactor" with dynamically adjustable properties along the route. The first mixing module 300 progressively increases the slurry concentration and structure in the middle stage, while the second mixing module 400 completes the paste formation and carbon dioxide fixation in the later stage, achieving a segmented process of "low-resistance transportation in the front, structural construction in the middle, and performance finalization in the rear." This design not only ensures the safety of long-distance transportation but also allows the hydration reaction of cementitious materials (especially solid wastes such as slag and steel slag) and the mineralization reaction of carbon dioxide to be efficiently initiated and continued into the goaf during transportation, thereby simultaneously improving the engineering performance and carbon sequestration efficiency of the backfill.

[0019] When setting up the first mixing module 300 and the second mixing module 400, the following two principles should be followed in selecting their specific locations: First, the filling material should be kept at a low concentration for the maximum possible distance (pipeline transport distance) to save pumping energy consumption, as well as to prevent pipe blockage and wear; Second, carbon dioxide should be sealed to the maximum extent, which requires that the location of the cementitious material mixing be set as far back as possible, but sufficient reaction pipeline length should be left for the subsequent mixing of carbon dioxide and water-retaining agent.

[0020] Optionally, the ground batching module 100 includes a first feeding unit, a water supply unit 103, a first mixing unit 104, and a slurry pump 105. The first feeding unit stores and supplies aggregates, including a first storage bin 101 for storing tailings or crushed stone aggregates and a conveying device 102; the water supply unit 103 supplies water; the first mixing unit 104 is connected to the first feeding unit and the water supply unit 103, and is used to mix the aggregates from the first feeding unit with the water from the water supply unit 103 to prepare a low-concentration slurry with a concentration of 20% to 30%; the slurry pump 105 is connected to the inlet end of the first mixing unit 104 and the conveying pipeline 200, and is used to pump the low-concentration slurry into the conveying pipeline 200.

[0021] The conveying device 102 can be, for example, a screw conveyor or a belt, and the control module 500 can control the conveying device 102 to feed materials precisely. The first mixing unit 104 can be, for example, a high-speed mixer, to fully mix the aggregate and water. The ground batching module 100 uses independent feeding, water supply, and mixing units to ensure the accuracy and uniformity of the low-concentration slurry (20%~30%) ratio. This concentration setting is the starting point for subsequent multi-stage process control, and its low viscosity characteristics are key to ensuring that the slurry can be smoothly pumped into the front of the long-distance pipeline by the slurry pump 105 and achieve low-resistance transportation. The modular design facilitates the storage, metering, and rapid preparation of raw materials, providing a fundamental guarantee for the continuous and stable operation of the entire filling system.

[0022] Optionally, the first mixing module 300 includes at least two cementitious material injection stations arranged sequentially along the conveying pipeline 200. These stations are used to inject cementitious material into the low-concentration slurry in batches, so that the slurry concentration increases to 70%–80% after flowing through the first mixing module 300. Each cementitious material injection station includes a second feeding unit, a first injection port 303, and a second stirring unit 304. The second feeding unit stores and supplies cementitious material and includes a second storage tank 301 and a first metering pump 302. The first injection port 303 connects the second feeding unit to the conveying pipeline 200 and is used to introduce the cementitious material into the slurry within the conveying pipeline 200. The second stirring unit 304 is located on a pipe section downstream of the first injection port 303 and is used to promote the mixing of the cementitious material and the slurry. The first mixing module 300 uses at least two cementitious material injection stations arranged along the pipeline, realizing the graded and segmented addition of cementitious material. This design avoids the risk of a sudden increase in slurry viscosity and pipe blockage caused by adding all the cementitious material at once. Each workstation is equipped with independent feeding, metering, injection, and mixing devices to ensure that the cementitious material can be accurately and uniformly mixed into the flowing slurry. Through multi-stage addition, the slurry concentration can be steadily increased from the initial 20%~30% to 70%~80%, and flocculation structure begins to form in the process, creating conditions for subsequent paste formation, while significantly reducing the impact on the front-end conveying resistance.

[0023] Optionally, there are two cementitious material injection stations; and along the conveying direction, the amount of cementitious material added at the first cementitious material injection station is less than that at the second cementitious material injection station. The two stations are limited to a "less at the beginning, more at the end" addition strategy, meaning the amount added at the first station is less than that at the second station. This strategy has significant technological implications: adding a small amount of cementitious material at the beginning can initially activate the slurry activity without significantly increasing the slurry viscosity, laying the groundwork for subsequent large-scale addition; while adding the majority of the cementitious material in the middle and later stages, when the slurry has already been conveyed a certain distance, the flow is relatively stable, and it is close to the paste-forming reaction zone, which is conducive to quickly building the strength framework of the filling body, reducing ineffective hydration of the material in the pipeline, and optimizing the matching between material utilization and process resistance distribution.

[0024] Optionally, the amount of cementitious material added at the first cementitious material injection station is 30%, and the amount added at the second cementitious material injection station is 70%. The specific implementation ratios of 30% and 70% for the two-stage addition are based on the results of extensive experimental and engineering simulation optimization. This ratio allocation most effectively balances the requirements for transport safety and structure formation: the initial addition of 30% is sufficient to activate the slurry and initiate hydration, while maintaining low flow resistance in the initial section of the pipeline; the subsequent 70% addition fully utilizes the remaining pipeline length, completing the construction of the main structure before the slurry enters the high-resistance later section, allowing the concentration to smoothly transition to the target range of 70%~80%, providing an ideal foundation for the paste formation and carbonization of the second mixing module 400.

[0025] Cementitious materials can primarily consist of alkaline industrial solid waste, such as slag powder, fly ash, and steel slag powder. These solid wastes are not only widely available and inexpensive, capable of replacing large amounts of cement and significantly reducing backfill carbon emissions and costs, but their rich calcium and magnesium content is also a key material basis for subsequent mineralization reactions with carbon dioxide to form stable carbonates. Using them as the primary cementitious material is a core prerequisite for transforming the entire backfill system from a "carbon source" to a "carbon sink," achieving the goal of "negative carbon."

[0026] Optionally, the second mixing module 400 includes at least two co-injection stations arranged sequentially along the conveying pipeline 200, for injecting water-retaining agent and carbon dioxide into the slurry after the cementitious material has been injected in batches. Each co-injection station includes a third feeding unit, a fourth feeding unit, a second injection interface 405, and a third mixing unit 406. The third feeding unit is used to store and supply water-retaining agent, and includes a water-retaining agent storage tank 401 and a second metering pump 402. The fourth feeding unit is used to store and supply carbon dioxide, and includes a carbon dioxide storage tank 403 and a third metering pump 404. The second injection interface 405 is used to introduce water-retaining agent and carbon dioxide into the conveying pipeline 200. The third mixing unit 406 is located downstream of the second injection interface 405.

[0027] The second mixing module 400 is equipped with at least two collaborative injection stations for injecting water-retaining agent and carbon dioxide in batches into the downstream pipeline. The rapid water absorption characteristics of the water-retaining agent can quickly adsorb free water in the slurry, transforming the slurry into a highly water-retaining paste in a short time, completely solving the problems of bleeding and segregation. The synchronously injected carbon dioxide can be encapsulated and fixed in the form of microbubbles by the formed gel network. This simultaneous synergy of "physical paste formation" and "chemical fixation" not only optimizes the physical properties of the final filling material, but more importantly, creates the optimal reaction microenvironment and residence conditions for the subsequent long-term and efficient mineralization reaction of carbon dioxide inside the filling material.

[0028] Optionally, multiple second injection ports 405 can be provided, for injecting water-retaining agent and carbon dioxide respectively. Figure 1 For the sake of simplicity, only one second injection interface 405 is shown.

[0029] Optionally, two co-injection stations are used; and along the conveying direction, the amount of water-retaining agent and carbon dioxide added at the first co-injection station is greater than that at the second co-injection station. Using two co-injection stations, with the first station adding more than the second (e.g., 70% initially, 30% later), is a refined process control strategy. The initial large-volume co-injection (70%) aims to quickly start up the main slurry section and complete the paste-like transformation, encapsulating and fixing most of the carbon dioxide; the second small-volume supplementary injection (30%) serves to "fine-tune" and "reinforce," ensuring the uniformity of the slurry cross-section and strengthening any localized weak areas that may be caused by uneven mixing or reaction. This "primary and secondary" addition method ensures the integrity and reliability of the paste-like transformation and carbon dioxide fixation effects.

[0030] Optionally, the water-retaining agent and carbon dioxide addition amounts are 70% at the first co-injection station and 30% at the second co-injection station. Adding 70% water-retaining agent and carbon dioxide at the first co-injection station allows for the rapid establishment of a dominant paste structure and locking in most of the carbon dioxide at the beginning of the pipeline, fully utilizing the longer residence time of the slurry in the later section of the pipeline (typically 5-15 minutes) to complete the main reaction. The remaining 30% is injected near the outlet, serving as a final guarantee for the quality of the final product, ensuring that the slurry achieves optimal uniformity and reaction completion before discharge. This proportional allocation matches the spatial distribution of the pipeline residence time, achieving an optimal combination of process efficiency and final effect.

[0031] Optionally, a sensor 600 is installed on the conveying pipeline 200; the control module 500 is communicatively connected to the sensor 600 and is configured to dynamically adjust the material injection timing and amount of the first mixing module 300 and / or the second mixing module 400 based on the pressure, flow rate, or slurry concentration signals along the pipeline collected by the sensor 600. By deploying pressure, flow rate, and concentration sensors 600 at key locations along the conveying pipeline 200 and feeding the signals back to the control module 500 in real time, the system possesses intelligent sensing and dynamic control capabilities. The control module 500 can adjust the cementitious material injection rate of the first mixing module 300 in real time according to changes in friction resistance, or optimize the synergistic injection parameters of the water-retaining agent and carbon dioxide in the second mixing module 400 according to the slurry state. This closed-loop control enables the system to adapt to different pipeline terrains, conveying distances, and raw material fluctuations, always keeping the slurry rheological state within the optimal range, thereby stably ensuring the dual goals of "low-resistance conveying" and "high-quality end products" under complex operating conditions.

[0032] Optionally, the system also includes a terminal forming module 700, located at the outlet end of the conveying pipeline 200. The terminal forming module 700 includes a terminal mixer 701 and a discharge port 702. The terminal mixer 701 is used for final mixing of the paste from the conveying pipeline 200. The discharge port 702 is connected downstream of the terminal mixer 701 and is used to discharge the mixed paste into the goaf. The terminal forming module 700 is located at the final outlet of the conveying pipeline 200, and its core function is to perform final homogenization and shaping before discharge. The terminal mixer 701 performs high-speed, short-range mixing of the paste from the pipeline, eliminating local unevenness that may be caused by pipeline flow and ensuring the uniformity of the discharged paste. Subsequently, the paste is smoothly discharged into the goaf through the discharge port 702. This module's design enhances the final quality of the product, enabling the filling material to begin its static, solidification, and long-term mineralization reaction process in the goaf in the most uniform state, playing a crucial role in ensuring the overall stability and final performance of the filling material.

[0033] Please see Figure 2This invention also provides a multi-stage mixed-injection method for negative carbon backfilling, comprising: S1, mixing aggregate with water on the ground to prepare a low-concentration slurry; S2, pumping the low-concentration slurry into a conveying pipeline 200 for transport; S3, injecting a cementitious material into the low-concentration slurry at a first position in the conveying pipeline 200; S4, injecting a water-retaining agent and carbon dioxide into the slurry containing the cementitious material at a second position downstream of the first position in the conveying pipeline 200. The water-retaining agent is injected to form a paste-like consistency in the slurry, and the carbon dioxide is injected to induce an in-situ carbonization reaction in the slurry to achieve carbon sequestration. The timing and amount of injection of the cementitious material, water-retaining agent, and carbon dioxide are controlled by a control module 500, and the second position is located downstream of the conveying pipeline 200 to ensure that the water-retaining agent and carbon dioxide are fully mixed and form a paste-like structure before the slurry reaches the goaf; the first position is positioned close to the second position. The core process of this method embodies the technological concept of "segmented control and synergistic effect." First, a low-concentration slurry is prepared to ensure safety at the starting point of transportation. Then, cementing materials are added in stages at the first location (middle section) of the pipeline to achieve a steady increase in slurry concentration and initial structural formation. Most importantly, at the second location further back, a water-retaining agent and carbon dioxide are injected synergistically. The water-retaining agent rapidly locks in water, turning the slurry into a paste and solving the problem of segregation and bleeding. Simultaneously, the three-dimensional network it forms effectively encapsulates carbon dioxide bubbles. This ensures that by the time the slurry reaches the goaf, it has become a uniform paste containing carbon dioxide, laying a perfect foundation for the subsequent long-term mineralization reaction of carbon dioxide within the filling body and the continuous development of the filling body's strength.

[0034] Optionally, the concentration of the low-concentration slurry is 20%~30%; the concentration of the slurry after the injection of the cementitious material is 70%~80%; the volume ratio of water-retaining agent to water is 1:(700~1000); and the volume ratio of carbon dioxide to water at room temperature and pressure is (0.6~1):1. This embodiment optimizes and limits the parameters of each key stage. The low-concentration slurry (20%~30%) ensures low-resistance transport; the slurry concentration after the addition of cementitious material at the first location (70%~80%) is a key node for forming a stable flocculated structure and possessing good reactivity; the addition ratio of water-retaining agent to water (1:700~1000) ensures that while achieving rapid and sufficient paste formation, excessive water-retaining agent is avoided, which would cause the slurry to become too viscous and affect transport; the volume ratio of carbon dioxide to water (0.6~1:1) provides a sufficient but not excessive carbon source, which can ensure significant carbon sequestration potential while avoiding damage to the paste structure due to excessive gas injection. These parameter ranges together constitute the optimal process window for achieving the safe, efficient, and carbon-negative effects of this invention.

[0035] In summary, the present invention has the following beneficial effects: (1) By preparing a low-concentration initial slurry on the ground and maintaining a low viscosity in the front section, the transport resistance is greatly reduced, the pumping pressure is significantly reduced, the blockage of pipe bends and high-level sections is basically eliminated, the transport process is smooth and stable, and the safety and continuity of long-distance pipeline transport are greatly improved. (2) In the middle and later sections, cementing materials and water-retaining agents are added in stages and in-situ carbonization is carried out in synergistically, so that the slurry is gradually transformed into a paste-like filling body with strong water retention, no bleeding, and no segregation. The filling body structure is more compact, the early strength is established faster, and the later strength and overall stability are significantly improved, effectively controlling ground pressure and reducing surface subsidence. (3) The amount of cement used is greatly reduced. The cementing materials are mainly alkaline industrial solid wastes such as steel slag, slag, and fly ash. With the in-situ carbonization reaction during the transport process, the emitted carbon dioxide is efficiently and permanently fixed in the filling body, so that the entire filling system changes from traditional positive emission to net negative emission, and at the same time, the large-scale resource utilization of industrial solid waste is realized. (4) Cement consumption is greatly reduced, industrial solid waste is utilized locally, transportation energy consumption and equipment maintenance costs decrease simultaneously, and the overall filling cost is significantly lower than that of traditional cemented filling process, making it more economical.

[0036] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0037] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0038] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0039] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0040] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0041] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0042] In the several embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0043] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0044] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0045] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-stage mixed-infill negative carbon filling system, characterized in that, The system includes: The ground-based batching module is used to mix aggregates with water to prepare low-concentration slurry; The conveying pipeline has its inlet end connected to the ground batching module and its outlet end leading to the underground goaf area for conveying filling material; The first mixing module is installed on the conveying pipeline and is used to inject cementitious materials into the low-concentration slurry. A second mixing module, located on the conveying pipeline and downstream of the first mixing module, is used to inject a water-retaining agent and carbon dioxide into the slurry after the cementitious material has been injected. The injection of the water-retaining agent is used to solidify the slurry, and the injection of the carbon dioxide is used to induce an in-situ carbonization reaction in the slurry to achieve carbon sequestration. The control module is communicatively connected to the ground batching module, the first mixing module, and the second mixing module, and is used to control the timing and amount of material injection. The second mixing module is located at the rear end of the conveying pipeline to ensure that the water-retaining agent and carbon dioxide are fully mixed and form a paste structure before the slurry reaches the goaf; the first mixing module is located upstream of and close to the second mixing module.

2. The multi-stage mixed-infill negative carbon filling system according to claim 1, characterized in that, The ground-based ingredient dispensing module includes: The first feeding unit is used to store and supply the aggregate, and includes a first storage bin for storing tailings or crushed stone aggregate and a conveying device. A water supply unit is used to supply the water; A first mixing unit, connected to the first feeding unit and the water supply unit, is used to mix aggregate from the first feeding unit with water from the water supply unit to prepare the low-concentration slurry with a concentration of 20% to 30%; and A slurry pump, connected to the inlet end of the first stirring unit and the conveying pipeline, is used to pump the low-concentration slurry into the conveying pipeline.

3. The multi-stage mixed-infill negative carbon filling system according to claim 1, characterized in that, The first mixing module includes at least two cementitious material injection stations arranged sequentially along the conveying pipeline, for injecting cementitious material into the low-concentration slurry in batches, so that the concentration of the slurry increases to 70% to 80% after flowing through the first mixing module; Each of the aforementioned cementitious material injection stations includes: The second feeding unit is used to store and supply the cementitious material, and includes a second storage bin and a first metering pump. A first injection port, connecting the second feeding unit and the conveying pipe, is used to introduce the cementitious material into the slurry within the conveying pipe; and The second mixing unit is located on the pipe section downstream of the first injection port and is used to promote the mixing of the cementitious material and the slurry.

4. The multi-stage mixed-infill negative carbon filling system according to claim 3, characterized in that, The number of cementitious material injection stations is two; and along the conveying direction, the amount of cementitious material added at the first cementitious material injection station is less than the amount of cementitious material added at the second cementitious material injection station.

5. The multi-stage mixed-infill negative carbon filling system according to claim 1, characterized in that, The second mixing module includes at least two coordinated injection stations arranged sequentially along the conveying pipeline, for injecting water-retaining agent and carbon dioxide into the slurry after the cementitious material has been injected in batches; Each of the aforementioned collaborative injection stations includes: The third feeding unit is used to store and supply water-retaining agent, and includes a water-retaining agent storage tank and a second metering pump. The fourth feeding unit is used to store and supply carbon dioxide, and includes a carbon dioxide storage tank and a third metering pump. A second injection port is used to introduce the water-retaining agent and carbon dioxide into the delivery pipeline; and The third stirring unit is located downstream of the second injection port.

6. The multi-stage mixed-infill negative carbon filling system according to claim 5, characterized in that, The number of the collaborative injection stations is two; and along the conveying direction, the amount of water-retaining agent and carbon dioxide added at the first collaborative injection station is greater than that at the second collaborative injection station.

7. The multi-stage mixed-infill negative carbon filling system according to claim 1, characterized in that, Sensors are installed on the conveying pipeline; The control module is communicatively connected to the sensor and is configured to: Based on the pipeline pressure, flow rate, or slurry concentration signals collected by the sensors, the timing and amount of material injection in the first mixing module and / or the second mixing module are dynamically adjusted.

8. The multi-stage mixed-infill negative carbon filling system according to claim 1, characterized in that, The system also includes a terminal forming module, which is located at the outlet end of the conveying pipeline; The terminal forming module includes: A terminal mixer is used for final mixing of the paste from the delivery pipe; as well as The discharge port, connected downstream of the end mixer, is used to discharge the stirred paste into the goaf area.

9. A method for multi-stage mixing of filling materials in negative carbon backfilling, characterized in that, The method includes: Aggregates are mixed with water on the ground to prepare a low-concentration slurry; The low-concentration slurry is pumped into the delivery pipeline for transport. At a first location in the conveying pipeline, a cementing material is injected into the low-concentration slurry; At a second location downstream of the first location on the delivery pipeline, a water-retaining agent and carbon dioxide are injected into the slurry into which the cementitious material has been injected. The injection of the water-retaining agent is used to make the slurry paste-like, and the injection of carbon dioxide is used to cause an in-situ carbonization reaction in the slurry to achieve carbon sequestration. The timing and amount of injection of the cementitious material, the water-retaining agent, and the carbon dioxide are controlled by a control module, and the second position is located at the rear section of the conveying pipeline to ensure that the water-retaining agent and carbon dioxide are fully mixed and form a paste structure before the slurry reaches the goaf; the first position is set close to the second position.

10. The multi-stage mixed-infill negative carbon filling method according to claim 9, characterized in that, The concentration of the low-concentration slurry is 20%~30%; the concentration of the slurry after the cementitious material has been injected is 70%~80%; the volume ratio of the water-retaining agent to water is 1:(700~1000); the volume ratio of carbon dioxide to water at room temperature and pressure is (0.6~1):1.

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