Preparation method of solid waste-based backfill material for mine
By using industrial solid wastes such as clinker, slag, ash, and desulfurized gypsum to form cemented backfill, the problem of high energy consumption and high carbon emissions in cement has been solved, and low-cost, high-performance mine backfill materials have been prepared to meet the needs of green mine construction.
Patent Information
- Application Number
- CN202511719659.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-03-17
AI Technical Summary
In existing mine backfilling technologies, the use of cement leads to high energy consumption and high carbon emissions, making it difficult to meet the requirements of green mine construction, and there is a lack of low-cost, high-performance solid waste alternatives.
Using industrial solid wastes such as clinker, slag, ash, and desulfurized gypsum as the main raw materials, a cemented filler with good fluidity and compressive strength is formed through scientific proportioning, replacing traditional cement materials.
It has enabled the large-scale disposal and resource utilization of solid waste, reduced carbon emissions, improved the fluidity and stability of backfill, and has significant economic and environmental benefits, meeting the requirements of green mine construction.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to the field of industrial solid waste resource utilization and mine backfilling technology, specifically a method for preparing solid waste-based backfill materials for mines. Background Technology
[0002] With the transformation of mining development towards "green mining" and "circular economy," the large-scale disposal and resource utilization of mine solid waste has become a focus of industry attention. Coal gangue, as a typical mine solid waste, is prone to environmental problems such as spontaneous combustion, dust, and groundwater pollution when stored for a long time. Cemented backfilling technology is the mainstream method for treating underground goaf areas, controlling surface subsidence, and disposing of solid waste. The workability, mechanical properties, and long-term stability of its backfill directly affect mine safety and ecological benefits.
[0003] Currently, mine backfilling relies heavily on cement as a binder. Although cement is reliable, its production process is energy-intensive, generates a large amount of carbon emissions, and is costly, making it difficult to meet the requirements for green mine construction.
[0004] Therefore, the industry needs to develop low-cost, high-performance filling materials that can replace cement and use industrial solid waste as the main raw material. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing solid waste-based backfill material for mines. By combining various industrial solid wastes such as clinker, slag, ash, and desulfurized gypsum with the reasonable gradation of coal gangue, a cemented backfill body with good fluidity, compressive strength, and stability is formed, thereby realizing the large-scale disposal of solid waste and the greening of mine backfill.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a solid waste backfill material for mining, wherein the raw materials comprise, by mass percentage:
[0007] Glue solid: 11%–14%;
[0008] Coarse coal gangue powder: 25%–33%;
[0009] Fine coal gangue powder: 67%–75%;
[0010] Water: Add according to the required concentration for construction;
[0011] The adhesive is composed of the following raw materials in the indicated mass percentages:
[0012] Cooked food: 20%;
[0013] Cooked food: 20%;
[0014] Ash: 30%;
[0015] Desulfurized gypsum: 10%.
[0016] Furthermore, the clinker and desulfurized gypsum are ground together in a 95:5 ratio, with a specific surface area ≥350 m² / kg; the slag is granulated blast furnace slag, with a specific surface area ≥400 m² / kg after grinding; the slag ash is coarse ash from a power plant, with SiO2 ≥55% and Al2O3 ≈30%, and a specific surface area of 500–650 m² / kg after grinding.
[0017] Furthermore, the coarse coal gangue powder has a particle size range of 2.36 mm–4.75 mm, and the fine coal gangue powder has a particle size of less than 2.36 mm.
[0018] The present invention also provides a method for preparing the backfill material, comprising:
[0019] S1, Prepare cementitious powder by grinding clinker, slag, desulfurized gypsum and ash separately and then mixing them in a certain proportion to form cementitious powder;
[0020] S2, the cementitious powder prepared in S1 is selected in proportion and mixed with a certain proportion of coarse coal gangue powder and fine coal gangue powder to form a mixture;
[0021] S3, the proportion of water is determined according to the backfill concentration, and it is added to the solid mixture obtained in S2 and stirred evenly to obtain a solid waste base backfill material for mining.
[0022] Compared with the prior art, the beneficial effects of the present invention are:
[0023] 1. This invention uses industrial solid waste as the main raw material, which significantly reduces dependence on cement and reduces carbon emissions.
[0024] 2. This invention improves the fluidity and stability of the slurry and inhibits bleeding by optimizing the cementitious system and aggregate gradation.
[0025] 3. The present invention provides good strength development of the filling material, with a 7-day compressive strength of over 1.6 MPa and a 28-day compressive strength of over 2.55 MPa.
[0026] 4. This invention enables high-value utilization of solid wastes such as coal gangue, slag, and ash, and has significant economic and environmental benefits. Detailed Implementation
[0027] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate orientations or positional relationships based on the shown orientations or positional relationships, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0029] The present invention will now be described in detail with reference to specific embodiments, including:
[0030] Example 1:
[0031] Clinker, slag, slag ash, and desulfurized gypsum were used as cementing materials to bind coal gangue of different particle sizes to produce mine backfill material. The raw materials were weighed as follows: cementing material consisted of 20% clinker, 40% slag, 30% slag ash, and 10% desulfurized gypsum, with a cement-to-mortar ratio of 1:6; aggregate consisted of 33% coarse coal gangue particles and 67% fine coal gangue particles. The aggregate and cementing material were first mixed for 60 seconds to obtain a mixture, then water was added to a mixer and stirred for 120 seconds before being discharged, thus completing the slurry preparation.
[0032] Example 2:
[0033] Clinker, slag, slag ash, and desulfurized gypsum were used as cementing materials to bind coal gangue of different particle sizes to produce mine backfill material. The raw materials were weighed as follows: cementing material consisted of 20% clinker, 40% slag, 30% slag ash, and 10% desulfurized gypsum, with a cement-to-mortar ratio of 1:6; aggregate consisted of 25% coarse coal gangue particles and 75% fine coal gangue particles. The aggregate and cementing material were first mixed for 60 seconds to obtain a mixture, then water was added to a mixer and stirred for 120 seconds before discharging. The slurry preparation was then complete.
[0034] Example 3:
[0035] Clinker, slag, slag ash, and desulfurized gypsum were used as cementing materials to bind coal gangue of different particle sizes to produce mine backfill material. The raw materials were weighed as follows: cementing material consisted of 20% clinker, 40% slag, 30% slag ash, and 10% desulfurized gypsum, with a cement-to-mortar ratio of 1:8; aggregate consisted of 33% coarse coal gangue particles and 67% fine coal gangue particles. The aggregate and cementing material were first mixed for 60 seconds to obtain a mixture, then water was added to a mixer and stirred for 120 seconds before being discharged, thus completing the slurry preparation.
[0036] Example 4:
[0037] Clinker, slag, slag ash, and desulfurized gypsum were used as cementing materials to bind coal gangue of different particle sizes to produce mine backfill material. The raw materials were weighed as follows: cementing material consisted of 20% clinker, 40% slag, 30% slag ash, and 10% desulfurized gypsum, with a cement-to-mortar ratio of 1:8; aggregate consisted of 25% coarse coal gangue particles and 75% fine coal gangue particles. The aggregate and cementing material were first mixed for 60 seconds to obtain a mixture, then water was added to a mixer and stirred for 120 seconds before discharging. The slurry preparation was then complete.
[0038] The slurries from Examples 1-4 were injected into 40mm×40mm×40mm molds and cured for 7 days and 28 days at 20±2℃ and humidity ≥90%. The compressive strength and flowability were tested, and the results are shown in Table 1 below:
[0039]
[0040] The above results show that the backfill material provided by this invention exhibits good workability and mechanical properties under different proportions, and is suitable for mine backfilling projects.
[0041] Conclusion: This invention, through scientific formulation and process design, achieves efficient synergistic utilization of various industrial solid wastes, producing high-performance, low-cost, and environmentally friendly mine backfill materials that meet the requirements of green mining and sustainable development.
[0042] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.
Claims
1. A mine solid waste-based backfill material, characterized by, The following raw materials are used in the following mass percentages: cementitious material: 11%-14%; coarse coal gangue powder: 25%-33%; fine coal gangue powder: 67%-75%; water: added according to the construction concentration requirement; The cementitious material is composed of the following raw materials in the following mass percentages: clinker: 20%; clinker: 20%; slag ash: 30%; desulfurization gypsum: 10%.
2. The solid waste based backfill material for mines as claimed in claim 1, wherein: The clinker and the desulfurization gypsum are co-milled by a ball mill at a mass ratio of 95:5, and the specific surface area of the obtained mixed powder is not less than 350 m² / kg.
3. The solid waste based backfill material for mines as claimed in claim 1, wherein: The slag is granulated blast furnace slag, and the specific surface area after ball milling is not less than 400 m² / kg.
4. The solid waste-based backfill material for mines according to claim 1, characterized in that: The slag ash is a coarse particle powder by-product produced by a coal-fired power plant, and the SiO2 content is not less than 55%, the Al2O3 content is about 30%, and the specific surface area after milling is 500-650 m² / kg.
5. The mine solid waste-based backfill material of claim 1, wherein: The particle size of the coarse coal gangue powder ranges from 2.36 mm to 4.75 mm, and the particle size of the fine coal gangue powder is less than 2.36 mm.
6. A method of preparing a mine waste-based backfill material as claimed in claims 1-5, characterized by: The following steps are: S1: separately mill the clinker, slag, slag ash, and desulfurization gypsum, mix them in proportion to make the cementitious material; S2: dry mix the cementitious material with the coarse coal gangue powder and the fine coal gangue powder in proportion; S3: add water according to the target slurry concentration, stir until uniform, and obtain the backfill material.
7. The method of claim 6, wherein: In step S1, the clinker and the desulfurization gypsum are first mixed and milled in proportion, and the slag and the slag ash are independently milled to the specified specific surface area before being mixed.
8. The method of claim 6, wherein: In step S2, the dry mixing time is not less than 60 seconds; in step S3, the stirring time is not less than 120 seconds.