Multi-source solid waste backfill slurry and preparation method therefor

Abstract

The present invention relates to the technical field of green backfill mining in coal mines. Disclosed are a multi-source solid waste backfill slurry and a preparation method therefor. Raw materials for the multi-source solid waste backfill slurry include: a multi-source solid waste material, a waterborne epoxy resin, a curing agent, a waterborne acrylic resin, and polyacrylic acid. Raw materials for the multi-source solid waste material include: tailings, desulfurized gypsum, fly ash, and gasification slag. The raw materials used in the present invention are all green and environmentally friendly raw materials, various types of solid waste materials feature low costs, and the entire preparation process requires no addition of cement, effectively reducing the cost of backfill mining in coal mines; moreover, efficiently and rationally utilizing various types of solid waste materials reduces surface accumulation, and vigorously promotes the green mining process of coal, thereby providing a brand-new green backfill approach for cemented backfill mining, and achieving significant social and economic benefits in ensuring safe and low-cost mining of mines.

Description

A multi-source solid waste backfill slurry and its preparation method Technical Field

[0001] This invention relates to the field of green backfilling mining technology in coal mines, and in particular to a multi-source solid waste backfilling slurry and its preparation method. Background Technology

[0002] Against the backdrop of ever-increasing energy demand, coal, as a conventional energy source with abundant reserves, wide distribution, and relatively low price, plays a vital role in numerous industries such as power generation, metallurgy, building materials, and chemicals. However, with the continuous development of coal resources, a series of serious problems have gradually emerged. The occurrence of goafs in mines often leads to surface subsidence and unstable mine pressure. Surface subsidence and collapse in goafs can easily trigger major disasters such as mine instability, posing a serious threat to the safety of the mining area and its surroundings. At the same time, the utilization of coal generates a large amount of industrial solid waste, which not only occupies valuable land resources but also causes significant pollution to the ecological environment.

[0003] To address the problem of mining subsidence, mine backfilling technology has emerged. Mine backfilling requires large quantities of high-quality backfill materials, and currently, existing backfill materials mainly consist of slurries made from mixtures of gangue, cement, and fly ash. However, cement, as a commonly used cementitious material, is relatively expensive, and its extensive use would undoubtedly significantly increase the cost of mine backfilling. Furthermore, cement production generates large amounts of carbon dioxide, which is detrimental to environmental protection. Additionally, the mechanical properties of backfill materials using cement as a cementing material need improvement. Therefore, developing an economical backfill material with excellent mechanical properties is an urgent priority.

[0004] Moreover, with rapid industrial development and continuous urban evolution, the output of industrial solid waste is increasing daily. The massive accumulation of these industrial solid waste materials not only occupies vast amounts of land resources but also becomes a serious source of pollution, causing enormous harm to the environment and ecosystem. How to achieve the rational utilization of industrial solid waste has become a critical issue that urgently needs to be addressed.

[0005] In conclusion, if an economical, efficient, and environmentally friendly mine backfill material that does not use cement can be developed using industrial solid waste as the main raw material, it will have great development prospects. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-source solid waste backfill slurry and its preparation method to solve the problems existing in the prior art. The multi-source solid waste backfill slurry uses tailings, desulfurized gypsum, and gasification slag as aggregates, and water-based epoxy resin and its curing agent, water-based acrylic resin, polyacrylic acid, and fly ash as cementing materials. It fully utilizes multi-source solid waste materials and combines the excellent properties of water-based epoxy resin, water-based acrylic resin, and polyacrylic acid to obtain a low-cost, high-performance backfill slurry, providing an economical, efficient, and environmentally friendly solution for mine backfilling. The multi-source solid waste backfill slurry uses various industrial solid waste materials as its main components, enabling efficient utilization of multi-source solid waste to achieve optimal rationality in solid waste backfilling.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] One of the technical solutions of the present invention is a multi-source solid waste filling slurry, the raw materials of which include: multi-source solid waste materials, water-based epoxy resin, curing agent, water-based acrylic resin and polyacrylic acid;

[0009] The raw materials of the multi-source solid waste material, by mass percentage, include: tailings 38-45%, desulfurized gypsum 18-24%, fly ash 19-24%, and gasification slag 11-15%.

[0010] The sum of the mass of the water-based epoxy resin and the curing agent is 7.5-12.5% ​​of the mass of the multi-source solid waste material;

[0011] The mass of the water-based acrylic resin is 2-5% of the mass of the multi-source solid waste material;

[0012] The mass of the polyacrylic acid is 0.5-1% of the mass of the multi-source solid waste material.

[0013] The filling slurry of this invention uses a multi-source solid waste material composed of tailings, desulfurized gypsum, fly ash, and gasification slag as its main raw materials. Tailings generally exhibit a regular blocky structure with a rough surface and high specific surface area. Its large particle size makes it the most abundant solid waste material in the filling slurry. Tailings not only provide skeletal support but also, due to its surface microstructure, facilitates the effective adhesion of hydration cementitious substances such as water-based epoxy resin, thereby improving the overall bonding strength and structural stability of the filling body. Desulfurized gypsum generally exhibits an irregular plate-like or sheet-like structure. This structure allows it to interlock and overlap within the filling slurry system, providing structural stability and filling capacity. Furthermore, its large specific surface area allows for better physical adsorption and chemical reactions with other substances (such as cementing materials), promoting the solidification and hardening process and enhancing the overall strength and durability of the material. Fly ash typically exhibits a spherical microstructure with a smooth, porous surface, allowing it to adsorb more hydration products and improve the strength and durability of the backfill. Gasification slag, on the other hand, displays an irregular blocky, porous structure with a rough surface. These characteristics contribute to the good filling, adsorption, strength support, and chemical reactivity of gasification slag in backfill, enhancing its performance. The use of these multi-source solid waste materials lays the foundation for the excellent mechanical properties of backfill prepared using backfill slurry. Furthermore, the synergistic effect of waterborne epoxy resin and its curing agent in the backfill slurry effectively improves the performance of the solid waste materials. Waterborne epoxy resin plays a crucial role in bonding and reinforcing in the backfill slurry. Its excellent bonding properties enable it to tightly bind various solid waste materials together, forming a robust backfill structure. Simultaneously, waterborne epoxy resin also improves the water resistance, corrosion resistance, and durability of the backfill. The waterborne epoxy resin curing agent, used in conjunction with the waterborne epoxy resin, promotes the curing reaction of the epoxy resin, forming a stable three-dimensional network structure, further enhancing the strength and stability of the filling material. Waterborne acrylic resin exhibits excellent adhesion to solid waste materials such as tailings, gasification slag, desulfurization gypsum, and fly ash, assisting the waterborne epoxy resin in strengthening the bond between aggregates and cementitious materials, thus better reducing voids within the filling material. Polyacrylic acid provides even greater anchoring for particles, resulting in higher stability of the bonded material and further reducing porosity and cracks within the filling material, thereby further improving its performance. This multi-source solid waste filling slurry fully utilizes various solid waste materials and works synergistically with waterborne epoxy resin and its curing agent, waterborne acrylic resin, and polyacrylic acid. It minimizes the amount of waterborne epoxy resin and its curing agent used without introducing additional activators, significantly reducing filling costs. Especially under specific dosage ranges and concentration conditions, the specific combination and ratio of raw materials work together to further enhance the comprehensive properties of the filling material, such as compressive strength. This invention provides a low-cost, high-performance filling grout without the use of cement.

[0014] Furthermore, the raw materials of the multi-source solid waste filling slurry also include a defoamer; the mass of the defoamer is 2% of the sum of the masses of the multi-source solid waste material, waterborne epoxy resin, curing agent, waterborne acrylic resin and polyacrylic acid dry matter.

[0015] Furthermore, the defoamer comprises organosilicon and tributyl phosphate; the mass ratio of the organosilicon and the tributyl phosphate is 1:2.

[0016] Organosilicon, as a defoamer, can effectively eliminate bubbles generated during the preparation process, improving the density and uniformity of the filling material prepared from multi-source solid waste filling slurry, thereby enhancing the performance of the filling material. Tributyl phosphate, as a defoamer, works synergistically with organosilicon to ensure that the filling slurry maintains good performance during the preparation process, further reducing the impact of bubbles on the quality of the filling material.

[0017] More preferably, the raw materials of the multi-source solid waste filling slurry include: multi-source solid waste materials, water-based epoxy resin, curing agent, water-based acrylic resin, polyacrylic acid and defoamer;

[0018] The sum of the mass of the waterborne epoxy resin and the curing agent is 7.5-10% of the mass of the multi-source solid waste material;

[0019] The mass of the water-based acrylic resin is 4-5% of the mass of the multi-source solid waste material;

[0020] The mass of the polyacrylic acid is 0.75% of the mass of the multi-source solid waste material;

[0021] The mass of the defoamer is 2% of the sum of the masses of the multi-source solid waste material, waterborne epoxy resin, curing agent, waterborne acrylic resin, and polyacrylic acid dry matter.

[0022] Regarding the dosage of waterborne epoxy resin and its curing agent, excessive addition will lead to excessively high costs, while insufficient addition will affect the performance of the filling material. To save costs and meet practical application requirements, it is recommended to incorporate 7.5-12.5% ​​by mass of waterborne epoxy resin and its curing agent into the multi-source solid waste material; more preferably, the incorporation amount is 7.5-10%.

[0023] Furthermore, the tailings have a particle size ≤ 2.5 mm.

[0024] Furthermore, the mass percentage of the component with a particle size ≤ 4.75 mm in the gasification slag is higher than 98%.

[0025] Furthermore, the curing agent is a curing agent for water-based epoxy resin.

[0026] Furthermore, the waterborne epoxy resin is a bisphenol type epoxy resin, and the curing agent includes amine curing agents and / or acid anhydride curing agents.

[0027] The second technical solution of the present invention: The preparation method of the above-mentioned multi-source solid waste backfill slurry includes the following steps:

[0028] After uniformly mixing the multi-source solid waste material, water-based epoxy resin, curing agent, water-based acrylic resin and polyacrylic acid, water is added to make the mass concentration of the multi-source solid waste filling slurry 69-76%, and the mixture is stirred evenly to obtain the multi-source solid waste filling slurry.

[0029] And / or, after uniformly mixing the multi-source solid waste material, water-based epoxy resin, curing agent, water-based acrylic resin, polyacrylic acid and defoamer, water is added to the mass concentration of the multi-source solid waste filling slurry to 69-76%, and the mixture is stirred evenly to obtain the multi-source solid waste filling slurry.

[0030] More preferably, water is added to bring the mass concentration of the multi-source solid waste backfill slurry to 73-76%.

[0031] The third technical solution of the present invention: the application of the above-mentioned multi-source solid waste backfill slurry in mine backfilling.

[0032] The present invention discloses the following technical effects:

[0033] (1) The filling grout of the present invention does not add cement, thus avoiding the large amount of carbon dioxide emissions generated during the cement production process. It is more environmentally friendly and economical than traditional filling grout that uses cement as the main cementing material.

[0034] (2) The raw materials used in this invention are all green and environmentally friendly, and the cost of various solid waste materials is low. The entire preparation process does not require the addition of cement, which effectively reduces the cost of coal mine backfilling mining. Furthermore, the efficient and rational use of various solid waste materials reduces surface accumulation and greatly promotes the green mining process of coal. It provides a brand-new green backfilling path for cemented backfilling mining and has broad social and economic benefits in ensuring safe and low-cost mining.

[0035] (3) The filling slurry preparation process of the present invention is simple, and the water-based epoxy resin and its curing agent can be diluted with water in any way. Therefore, the formula and preparation process can be adjusted according to different engineering scenarios such as mine filling, and it has strong adaptability and flexibility.

[0036] (4) The filling slurry of the present invention uses water-based epoxy resin and its curing agent as the main cementing material. Compared with traditional organic solvent-based resin, water-based epoxy resin is non-toxic, odorless and pollution-free, meets environmental protection requirements, and can be used in combination with multi-source solid waste materials to reduce the occupation of land resources and pollution of the environment by industrial solid waste, realize the recycling of resources, and has significant environmental benefits. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 shows the XRD diffraction pattern of the tailings used in the embodiment of the present invention;

[0039] Figure 2 is a SEM image of the tailings used in the embodiment of the present invention;

[0040] Figure 3 shows the XRD diffraction pattern of the desulfurized gypsum used in the embodiments of the present invention;

[0041] Figure 4 is a SEM image of the desulfurized gypsum used in the embodiments of the present invention;

[0042] Figure 5 shows the XRD diffraction pattern of the fly ash used in the embodiments of the present invention;

[0043] Figure 6 is a SEM image of the fly ash used in the embodiments of the present invention;

[0044] Figure 7 shows the XRD diffraction pattern of the gasification slag used in the embodiment of the present invention;

[0045] Figure 8 is a SEM image of the gasification slag used in the embodiments of the present invention;

[0046] Figure 9 is a SEM image of the filling material prepared using the filling slurry prepared in Example 1, with a scale bar of 20.0 μm;

[0047] Figure 10 is a SEM image of the filling material prepared using the filling slurry prepared in Example 1, with a scale bar of 10.0 μm;

[0048] Figure 11 is a SEM image of the filling material prepared using the filling slurry prepared in Example 1. The scale bar is 1.0 μm. Detailed Implementation

[0049] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0050] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0051] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0052] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0053] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0054] As a first aspect of the present invention, the present invention provides a multi-source solid waste filling slurry, the raw materials of which include: multi-source solid waste materials, waterborne epoxy resin, curing agent, waterborne acrylic resin and polyacrylic acid;

[0055] The raw materials of the multi-source solid waste material, by mass percentage, include: tailings 38-45%, desulfurized gypsum 18-24%, fly ash 19-24%, and gasification slag 11-15%.

[0056] The sum of the mass of the water-based epoxy resin and the curing agent is 7.5-12.5% ​​of the mass of the multi-source solid waste material;

[0057] The mass of the water-based acrylic resin is 2-5% of the mass of the multi-source solid waste material;

[0058] The mass of the polyacrylic acid is 0.5-1% of the mass of the multi-source solid waste material.

[0059] In a preferred embodiment of the present invention, the raw materials of the multi-source solid waste filling slurry further include a defoamer; the mass of the defoamer is 2% of the sum of the mass of the multi-source solid waste material, waterborne epoxy resin, curing agent, waterborne acrylic resin and polyacrylic acid dry matter.

[0060] In a preferred embodiment of the present invention, the defoamer comprises organosilicon and tributyl phosphate; the mass ratio of the organosilicon and the tributyl phosphate is 1:2.

[0061] In a preferred embodiment of the present invention, the waterborne epoxy resin is a bisphenol-type waterborne epoxy resin. Waterborne epoxy resin refers to a stable dispersion system prepared by dispersing epoxy resin in the form of particles or droplets in a dispersion medium with water as the continuous phase. That is, it is a stable dispersion system in which epoxy resin is the main component, and hydrophilic groups are introduced or emulsifiers are used to disperse the epoxy resin in water. Its main components include epoxy resin, and hydrophilic groups introduced to make the epoxy resin hydrophilic or additives such as emulsifiers used. It contains epoxy groups, hydroxyl groups, etc.

[0062] In an embodiment of the present invention, the curing agent is a curing agent for waterborne epoxy resin. That is, a substance that can react with waterborne epoxy resin to cure it, mainly including compounds such as amines and acid anhydrides, and primarily containing amine groups, carboxyl groups, etc.

[0063] As an embodiment of the present invention, the waterborne epoxy resin is the waterborne epoxy resin component in a two-component waterborne epoxy resin, and the curing agent is the curing agent component in a two-component waterborne epoxy resin.

[0064] As an embodiment of the present invention, the waterborne acrylic resin is mainly formed by the polymerization reaction of acrylate monomers and other olefin monomers, and its main components are acrylate, methacrylate, vinyl monomers and waterborne monomers.

[0065] As an embodiment of the present invention, the polyacrylic acid is a water-soluble polymer containing a large number of strongly polar groups such as carboxyl groups on its molecular chain, and its chemical formula is (C3H4O2). n .

[0066] As an embodiment of the present invention, the organosilicon is a type of organic compound containing silicon element, which has excellent heat resistance, weather resistance and water resistance, and its main structural feature is the presence of silicon oxygen bonds, etc.

[0067] As an embodiment of the present invention, the tailings are waste discharged by a mineral processing plant after grinding the ore and selecting useful components under specific economic and technical conditions. The main crystalline mineral component in the tailings is SiO2.

[0068] As an embodiment of the present invention, the desulfurized gypsum is a byproduct produced by thermal power plants, chemical enterprises and other enterprises after desulfurizing sulfur-containing flue gas under specific environmental protection technology (limestone-gypsum wet desulfurization). The main crystalline mineral component in the desulfurized gypsum is CaSO4·2H2O, and other crystalline mineral components include a small amount of CaCO3.

[0069] As an embodiment of the present invention, the fly ash refers to the fine ash collected from the flue gas after coal combustion. It is the main solid waste discharged by coal-fired power plants. The main crystalline mineral component is SiO2, and other crystalline minerals are Al2SiO5, AlPO4, and Al2O3.

[0070] In an embodiment of the present invention, the gasification slag is a solid residue formed during the incomplete combustion of coal with oxygen or oxygen-enriched air to produce CO and H2, resulting from the various physicochemical transformations of inorganic minerals in the coal, accompanied by residual carbon particles. Its main crystalline mineral component is C. 30 H 14 N4O4Zn·2H2O.

[0071] In a preferred embodiment of the present invention, the tailings have a particle size ≤ 2.5 mm.

[0072] In a preferred embodiment of the present invention, the mass percentage of the component with a particle size ≤ 4.75 mm in the gasification slag is higher than 98%.

[0073] As a second aspect of the present invention, the present invention provides a method for preparing the above-mentioned multi-source solid waste backfill slurry, comprising the following steps:

[0074] After uniformly mixing the multi-source solid waste material, water-based epoxy resin, curing agent, water-based acrylic resin and polyacrylic acid, water is added to make the mass concentration of the multi-source solid waste filling slurry 69-76%, and the mixture is stirred evenly to obtain the multi-source solid waste filling slurry.

[0075] And / or, after uniformly mixing the multi-source solid waste material, water-based epoxy resin, curing agent, water-based acrylic resin, polyacrylic acid and defoamer, water is added to the mass concentration of the multi-source solid waste filling slurry to 69-76%, and the mixture is stirred evenly to obtain the multi-source solid waste filling slurry.

[0076] In a preferred embodiment of the present invention, water is added to a mass concentration of 73-76% for the multi-source solid waste backfill slurry.

[0077] As a third aspect of the present invention, the present invention provides the application of the above-mentioned multi-source solid waste backfill slurry in mine backfilling.

[0078] The multi-source solid waste backfill slurry and its preparation method of the present invention will be further described below with reference to specific embodiments.

[0079] The raw materials used in the following examples and comparative examples were all purchased from the market, wherein:

[0080] The XRD diffraction pattern of the tailings used is shown in Figure 1, and the SEM image is shown in Figure 2. As can be seen from Figure 1, the largest diffraction peak appears between 20° and 30° in the XRD diffraction pattern, while smaller diffraction peaks exist at other angles. This indicates that the main crystalline mineral component in the tailings is SiO2, with other crystalline minerals present in smaller amounts.

[0081] As can be seen from the SEM image of the tailings in Figure 2, the microstructure of the tailings presents a relatively regular polyhedral block structure, which can provide a stable skeletal support for the filling body; and its surface has obvious uneven texture, is relatively rough, and has a large surface area, which allows the tailings to be tightly combined with the hydrated cementitious material during the formation of the filling body, promoting a stronger bond between the various parts of the filling body, and ultimately forming a whole sample with higher strength.

[0082] The XRD diffraction pattern of the desulfurized gypsum used is shown in Figure 3, and the SEM image is shown in Figure 4. As can be seen from Figure 3, the maximum diffraction peak appears between 10° and 55° in the XRD diffraction pattern, and there are other diffraction peaks, indicating that the main crystalline mineral component of the desulfurized gypsum is CaSO4·2H2O, and other crystalline mineral components contain CaCO3.

[0083] As shown in Figure 4, the SEM image of desulfurized gypsum exhibits an irregular plate-like or sheet-like structure. This structure is beneficial for their overlapping and interlocking in subsequent applications, providing structural stability and filling capacity for related material systems. Furthermore, its surface is relatively smooth, but contains some tiny pores and textures. These pores and textures increase its specific surface area, allowing desulfurized gypsum to better undergo physical adsorption and chemical reactions with other substances (such as cementing materials and additives) when used as a building material or industrial filler. This promotes the solidification and hardening process of the material and enhances its overall strength and durability.

[0084] The XRD diffraction pattern of the fly ash used is shown in Figure 5, and the SEM image is shown in Figure 6. As can be seen from Figure 5, the largest diffraction peak appears in the XRD diffraction pattern between 20° and 30°, and there are several other diffraction peaks between 30° and 45°. This indicates that the main crystalline mineral component of the fly ash is SiO2, and the other crystalline mineral components are Al2SiO5, AlPO4, and Al2O3.

[0085] As can be seen from the SEM image of fly ash in Figure 6, the microstructure of fly ash is spherical. These spherical particles have relatively smooth surfaces, vary in size, and have a porous structure. The size and shape of these pores are different, which can adsorb more hydration products to improve the strength and durability of the filling body.

[0086] The XRD diffraction pattern of the gasification slag used is shown in Figure 7, and the SEM image is shown in Figure 8. As can be seen from Figure 7, the largest diffraction peak appears only between 20° and 30° in the XRD diffraction pattern, and this is the only diffraction peak in the pattern, indicating that the gasification slag has a single mineral composition, with C as the main component. 30 H 14 N4O4Zn·2H2O;

[0087] As can be seen from the SEM image of the gasification slag in Figure 8, the microstructure of the gasification slag is irregular blocky, porous, and has a rough surface. These characteristics enable the gasification slag to have good filling properties, adsorption properties, strength support, and certain chemical reactivity in the backfill, which can improve the performance of the backfill.

[0088] The particle size statistics of the tailings and gasification slag used in the specific embodiments and comparative examples of the present invention are shown in Table 1 (where % is the mass percentage). There are no restrictions on the particle size range of other raw materials.

[0089] Table 1

[0090] The water-based epoxy resin used was epoxy emulsion HT-5150, purchased from Hubei Jinshengyuan Environmental Protection Technology Co., Ltd.

[0091] The curing agent used was curing agent G08, which was purchased from Hubei Jinshengyuan Environmental Protection Technology Co., Ltd.

[0092] In all embodiments and comparative examples, the mass ratio of waterborne epoxy resin to its curing agent is 2:1;

[0093] The water-based acrylic resin used was water-based acrylic emulsion E0504, which was purchased from Shenzhen Yoshida Chemical Co., Ltd.

[0094] The polyacrylic acid used was DL-03 polyacrylic acid, purchased from Jinan Delan Chemical Co., Ltd.

[0095] The silicone used was industrial defoamer CI-0560, purchased from Guangdong Nanhui New Materials Co., Ltd.

[0096] The tributyl phosphate used had a molecular weight of 266.31 and was purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.

[0097] Example 1

[0098] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0099] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 45%, desulfurized gypsum 20%, fly ash 20%, and gasification slag 15%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent (10% of the total mass of the multi-source solid waste materials), waterborne acrylic resin (3% of the total mass of the multi-source solid waste materials), polyacrylic acid (0.75% of the total mass of the multi-source solid waste filling materials), and organosilicon and tributyl phosphate (2% of the total dry matter mass (sum of the dry matter mass of the multi-source solid waste materials, waterborne epoxy resin, curing agent, waterborne acrylic resin, and polyacrylic acid) (mass ratio of organosilicon and tributyl phosphate is 1:2). Mix all raw materials evenly, add an appropriate amount of water and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0100] Example 2

[0101] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0102] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 43%, desulfurized gypsum 22%, fly ash 20%, and gasification slag 15%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent accounting for 10% of the total mass of the multi-source solid waste materials; waterborne acrylic resin accounting for 3% of the total mass of the multi-source solid waste materials; polyacrylic acid accounting for 0.75% of the total mass of the multi-source solid waste filling materials; and organosilicon and tributyl phosphate accounting for 2% of the total dry matter mass (mass ratio of organosilicon and tributyl phosphate is 1:2). Mix all raw materials evenly and add an appropriate amount of water to mix and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0103] Example 3

[0104] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0105] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 38%, desulfurized gypsum 24%, fly ash 24%, and gasification slag 14%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent accounting for 12.5% ​​of the total mass of the multi-source solid waste materials; waterborne acrylic resin accounting for 4% of the total mass of the multi-source solid waste materials; polyacrylic acid accounting for 1% of the total mass of the multi-source solid waste filling materials; and organosilicon and tributyl phosphate accounting for 2% of the total dry matter mass (mass ratio of organosilicon and tributyl phosphate is 1:2). Mix all raw materials evenly and add an appropriate amount of water to mix and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0106] Example 4

[0107] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0108] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 41%, desulfurized gypsum 23%, fly ash 23%, and gasification slag 13%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent (7.5% of the total mass of the multi-source solid waste materials), waterborne acrylic resin (5% of the total mass of the multi-source solid waste materials), polyacrylic acid (0.5% of the total mass of the multi-source solid waste filling materials), and organosilicon and tributyl phosphate (2% of the total dry matter mass, with a mass ratio of organosilicon and tributyl phosphate of 1:2). Mix all raw materials evenly, add an appropriate amount of water and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0109] Example 5

[0110] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0111] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 42%, desulfurized gypsum 20%, fly ash 24%, and gasification slag 14%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent accounting for 10% of the total mass of the multi-source solid waste materials; waterborne acrylic resin accounting for 2% of the total mass of the multi-source solid waste materials; polyacrylic acid accounting for 0.75% of the total mass of the multi-source solid waste filling materials; and organosilicon and tributyl phosphate accounting for 2% of the total dry matter mass (mass ratio of organosilicon and tributyl phosphate is 1:2). Mix all raw materials evenly and add an appropriate amount of water to mix and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0112] Example 6

[0113] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0114] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 45%, desulfurized gypsum 19%, fly ash 23%, and gasification slag 13%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent (12.5% ​​of the total mass of the multi-source solid waste materials), waterborne acrylic resin (3% of the total mass of the multi-source solid waste materials), polyacrylic acid (1% of the total mass of the multi-source solid waste filling materials), and organosilicon and tributyl phosphate (2% of the total dry matter mass, with a mass ratio of organosilicon and tributyl phosphate of 1:2). Mix all raw materials evenly and add an appropriate amount of water to mix and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0115] Example 7

[0116] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0117] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 44%, desulfurized gypsum 22%, fly ash 19%, and gasification slag 15%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent (7.5% of the total mass of the multi-source solid waste materials), waterborne acrylic resin (4% of the total mass of the multi-source solid waste materials), polyacrylic acid (0.5% of the total mass of the multi-source solid waste filling materials), and organosilicon and tributyl phosphate (2% of the total dry matter mass, with a mass ratio of organosilicon and tributyl phosphate of 1:2). Mix all raw materials evenly, add an appropriate amount of water, and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 74%.

[0118] Example 8

[0119] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0120] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 44%, desulfurized gypsum 18%, fly ash 23%, and gasification slag 15%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent accounting for 10% of the total mass of the multi-source solid waste materials; waterborne acrylic resin accounting for 5% of the total mass of the multi-source solid waste materials; polyacrylic acid accounting for 0.75% of the total mass of the multi-source solid waste filling materials; and organosilicon and tributyl phosphate accounting for 2% of the total dry matter mass (mass ratio of organosilicon and tributyl phosphate is 1:2). Mix all raw materials evenly and add an appropriate amount of water to mix and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0121] Example 9

[0122] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0123] Weigh the following multi-source solid waste materials by mass percentage: tailings 43%, desulfurized gypsum 22%, fly ash 24%, and gasification slag 11%. Weigh out 12.5% ​​of the total mass of the multi-source solid waste materials, waterborne epoxy resin and its curing agent, 2% of the total mass of the multi-source solid waste materials, 0.5% of the total mass of the multi-source solid waste filling materials, and 2% of the total dry matter mass of organosilicon and tributyl phosphate (the mass ratio of organosilicon and tributyl phosphate is 1:2). Mix all raw materials evenly, add an appropriate amount of water and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0124] Comparative Example 1

[0125] Same as Example 1, except that the tailings are replaced with gasification slag (i.e., tailings are not used, and the amount of gasification slag becomes 60%).

[0126] Comparative Example 2

[0127] Same as Example 1, except that the mass of desulfurized gypsum is replaced with tailings.

[0128] Comparative Example 3

[0129] Same as Example 1, except that the gasification slag is replaced with desulfurized gypsum.

[0130] Comparative Example 4

[0131] Same as Example 1, except that the mass of desulfurized gypsum is replaced with cement (ordinary Portland cement PO 42.5).

[0132] Comparative Example 5

[0133] Same as Example 1, except that the waterborne epoxy resin and its curing agent, as well as polyacrylic acid, are replaced by waterborne acrylic resin.

[0134] Comparative Example 6

[0135] Same as Example 1, except that the amount of water added is controlled to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 85%.

[0136] Comparative Example 7

[0137] A multi-source solid waste backfill slurry, the preparation steps are as follows:

[0138] Weigh out the multi-source solid waste materials according to the following mass percentages: tailings 55%, desulfurized gypsum 7%, fly ash 10%, and gasification slag 28%. Weigh out the following materials according to the following mass percentages: waterborne epoxy resin and its curing agent (5%), waterborne acrylic resin (10%), polyacrylic acid (0.25%), and organosilicon and tributyl phosphate (2%) (mass ratio of organosilicon and tributyl phosphate 1:2). Mix all raw materials evenly and add an appropriate amount of water to mix and stir to obtain a multi-source solid waste filling slurry with a mass concentration (dry matter content) of 73%.

[0139] Comparative Example 8

[0140] Same as Example 1, except that the polyacrylic acid is replaced by water-based acrylic resin.

[0141] Comparative Example 9

[0142] Same as Example 1, except that the waterborne acrylic resin is replaced by waterborne epoxy resin and its curing agent.

[0143] Comparative Example 10

[0144] Same as Example 1, except that the waterborne epoxy resin and its curing agent, as well as the waterborne acrylic resin and polyacrylic acid, are replaced by cement (ordinary silicate cement PO 42.5) in equal quantities.

[0145] Comparative Example 11

[0146] Same as Example 1, except that the same mass of organosilicon is replaced with tributyl phosphate.

[0147] Test Example 1

[0148] The filling slurries obtained in Examples 1-9 and Comparative Examples 1-11 were used to prepare filling bodies, and their compressive strength was tested. The filling body preparation method was as follows: the filling slurry was slowly poured into a pre-prepared Ф50×100mm cylindrical mold. To prevent the generation of air bubbles during the pouring process, the slurry was poured and vibrated simultaneously. The upper surface was then smoothed with a shovel. The mold was placed in a cool place and left to stand for 2 days. Then, the mold was demolded. After removing the specimen, it was covered with a disposable plastic film and left to stand at (20±5)℃ for (24±2) hours. The specimens were then numbered and demolded. After demolding, the specimens were first cured in a standard curing room (relative humidity above 92%) for 7 days, and then naturally cured in air (relative humidity 60%) for 28 days to obtain the filling body.

[0149] Figures 9-11 show SEM images of the filler prepared using the filling slurry of Example 1 at different magnifications. As can be seen from Figures 9-11, under the auxiliary bonding effect of waterborne acrylic resin and polyacrylic acid, the waterborne epoxy resin and curing agent undergo a cross-linking reaction to form a continuous three-dimensional network structure on the surface of the solid waste material. This creates an interlayer connection effect on the solid waste material, making it tightly connected and greatly reducing the voids between the solid waste materials, thereby improving the strength of the filler.

[0150] The uniaxial compressive strength of the prepared filling material was determined using the ZSC-107R rock triaxial creep system. The results are shown in Table 2.

[0151] Table 2

[0152] As shown in Table 2, comparing Example 1 and Comparative Example 1, it can be found that the strength of the backfill decreased by 66.1% after replacing the tailings with gasification slag. This is because tailings, as an important backfill aggregate, play a significant role in supporting the backfill, while gasification slag, although it can provide some macroscopic support, is less effective due to its main component being carbon. 30 H 14N4O4Zn·2H2O cannot provide SiO2 for the reaction of cementitious materials, resulting in a weaker macroscopic support effect compared to tailings. Comparing Example 1 and Comparative Example 2, it was found that replacing desulfurized gypsum with tailings reduced the strength of the backfill by 59.5%. This is because tailings particles are larger and have relatively rougher surfaces, resulting in a smaller contact area with the cementitious materials and a weaker bonding effect compared to desulfurized gypsum. Consequently, the cementitious materials cannot fully exert their bonding and reinforcing effects, leading to a decrease in backfill performance. Comparing Example 1 and Comparative Example 3, it was found that replacing gasification slag with desulfurized gypsum reduced the strength of the backfill by 59.7%. This is because gasification slag may have higher reactivity, capable of chemically reacting with water-based epoxy resins, curing agents, etc., to form a more stable structure. Desulfurized gypsum, on the other hand, has relatively lower reactivity and does not bond as tightly with other materials, thus reducing the strength of the backfill. Comparing Example 1 and Comparative Example 4, it can be found that replacing desulfurized gypsum with cement reduced the strength of the filling body by 42.5%. This is because cement has a faster hydration reaction rate, which may lead to a certain strength in the early stages. However, in multi-source solid waste filling bodies, an excessively rapid reaction may cause internal stress concentration, affecting the development of strength in the later stages. In contrast, the reaction of desulfurized gypsum is relatively slow, and it may gradually form a stable structure with other materials over a longer period of time, thus giving the filling body better long-term strength. Comparing Example 1 and Comparative Example 5, it can be found that replacing waterborne epoxy resin and its curing agent with waterborne acrylic resin reduced the strength of the filling body by 49.3%. This is because the bonding effect of waterborne acrylic resin is worse than that of waterborne epoxy resin and its curing agent combined with waterborne acrylic resin. Waterborne acrylic resin alone cannot effectively bond various solid waste materials together. Comparing Example 1 and Comparative Example 6, it can be found that when water is added, the mass concentration of the filler reaches 85%, and the filler strength decreases by 52.9%. This is because excessive water alters the hydration reaction process of various materials in the filler. For fly ash, the hydration reaction is too rapid or uneven, resulting in a loose structure of the hydration products that cannot provide sufficient strength support. Simultaneously, excessive water may also wash away some incompletely reacted cementitious substances, such as waterborne epoxy resin and its curing agent, further reducing the filler strength. Comparing Example 1 and Comparative Example 7, it can be found that Comparative Example 7, by changing the raw material dosage to exceed the scope of the claims, resulted in a 64.6% decrease in filler strength, indicating that changing the dosage range reduced the excellent effects of the filler slurry in various aspects. Comparing Example 1 and Comparative Example 8, it can be found that replacing polyacrylic acid with waterborne acrylic resin reduced the filler strength by 55.1%. This is because, compared to polyacrylic acid, the network structure formed by waterborne acrylic resin in the filler is not dense or perfect enough, failing to provide sufficient early strength and later strength growth for the filler, leading to a decrease in the mechanical properties of the filler.Comparing Example 1 and Comparative Example 9, it can be found that replacing the waterborne acrylic resin with waterborne epoxy resin and its curing agent resulted in a 45.2% decrease in the strength of the filling. This is because the waterborne epoxy resin, after curing, forms a relatively rigid three-dimensional network structure. When the filling resists external forces or changes in internal stress, this rigid structure cannot effectively absorb and disperse stress through deformation like the waterborne acrylic resin, easily leading to cracks in the filling even with small deformations, thus reducing the crack resistance and overall stability of the filling. Comparing Example 1 and Comparative Example 10, it can be found that replacing the waterborne epoxy resin and its curing agent, as well as the waterborne acrylic resin and polyacrylic acid, with cement resulted in a 75.2% decrease in the strength of the filling. This is because cement mainly binds particles through hydration products generated by the hydration reaction. The bonding between cement and particles is mainly physical adsorption and a weak chemical bond, and its bonding method is relatively simple. The bonding effect of waterborne epoxy resin and its curing agent, as well as waterborne acrylic resin and polyacrylic acid resin and polymer systems, is not as good for particles with relatively smooth surfaces or low chemical activity, resulting in reduced cohesion and integrity of the filler. Comparing Example 1 and Comparative Example 11, it can be found that replacing silicone with tributyl phosphate reduced the filler strength by 43.6%. This is because the defoaming effect of using tributyl phosphate alone is poor, resulting in more residual air bubbles inside the filler. These air bubbles increase the porosity of the filler, making the structure loose, and thus reducing the strength and stability of the filler.

[0153] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A multi-source solid waste backfill slurry, characterized in that, Raw materials include: Multi-source solid waste materials, water-based epoxy resins, curing agents, water-based acrylic resins, and polyacrylic acid; The raw materials of the multi-source solid waste material, by mass percentage, include: tailings 38-45%, desulfurized gypsum 18-24%, fly ash 19-24%, and gasification slag 11-15%. The sum of the mass of the water-based epoxy resin and the curing agent is 7.5-12.5% ​​of the mass of the multi-source solid waste material; The mass of the water-based acrylic resin is 2-5% of the mass of the multi-source solid waste material; The mass of the polyacrylic acid is 0.5-1% of the mass of the multi-source solid waste material.

2. The multi-source solid waste backfill slurry as described in claim 1, characterized in that, The raw materials for the multi-source solid waste filling slurry also include a defoamer; the mass of the defoamer is 2% of the sum of the mass of the multi-source solid waste material, waterborne epoxy resin, curing agent, waterborne acrylic resin and polyacrylic acid dry matter.

3. The multi-source solid waste backfill slurry as described in claim 2, characterized in that, The defoamer comprises organosilicon and tributyl phosphate; the mass ratio of the organosilicon and the tributyl phosphate is 1:

2.

4. The multi-source solid waste backfill slurry as described in claim 1, characterized in that, The tailings have a particle size of ≤2.5mm.

5. The multi-source solid waste backfill slurry as described in claim 1, characterized in that, The mass percentage of components with a particle size ≤ 4.75 mm in the gasification slag is higher than 98%.

6. The method for preparing multi-source solid waste backfill slurry according to any one of claims 1-5, characterized in that, Includes the following steps: After uniformly mixing the multi-source solid waste material, water-based epoxy resin, curing agent, water-based acrylic resin and polyacrylic acid, water is added to make the mass concentration of the multi-source solid waste filling slurry 69-76%, and the mixture is stirred evenly to obtain the multi-source solid waste filling slurry. And / or, after uniformly mixing the multi-source solid waste material, water-based epoxy resin, curing agent, water-based acrylic resin, polyacrylic acid and defoamer, water is added to the mass concentration of the multi-source solid waste filling slurry to 69-76%, and the mixture is stirred evenly to obtain the multi-source solid waste filling slurry.

7. The application of the multi-source solid waste backfill slurry as described in any one of claims 1-5 in mine backfilling.

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