Solid waste synergistic low cement paste filling material and preparation method thereof

Abstract

The solid waste synergistic low cement paste filling material provided by the invention is prepared from the following raw materials in parts by weight: 600 to 900 parts of tungsten tailing powder-based filling aggregate, 50 to 300 parts of solid waste cementing material and 200 to 400 parts of water, and the solid waste cementing material is prepared from slag powder and cement. The preparation method of the solid waste synergistic low cement paste filling material comprises the following steps: S1, weighing the tungsten tailing powder-based filling aggregate and the solid waste cementing material according to the weight part ratio, and uniformly mixing to obtain a dry material; and S2, adding water into the dry material obtained in the step S1, and uniformly mixing to obtain the solid waste synergistic low cement paste filling material. By using the tungsten tailing powder to the maximum extent, the problems of tungsten mine tailing accumulation and high filling cost are relieved; meanwhile, the steel slag, the blast furnace slag and other solid wastes are synergistically utilized, so that the comprehensive utilization difficulty of the bulk solid wastes is solved; in addition, the use of cement is greatly reduced, and carbon emission in cement production is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of mine filling, and in particular to a solid waste synergistic low-cement paste filling material and a preparation method thereof. Background Art

[0002] As a country rich in tungsten resources, my country ranks first in the world in both tungsten reserves and production. However, as environmental protection policies become increasingly stringent, the number of tailings ponds in the country will only decrease and not increase in principle starting from 2020, which poses a severe challenge to the tungsten mining industry. According to the current tungsten ore grade and mineral processing technology, about 8 tons of tungsten tailings will be produced for every ton of tungsten concentrate produced. The annual discharge of tungsten tailings is about 600,000 tons, and the total stockpile has reached about 16 million tons. Due to the fine particles and severe mudification of tungsten tailings, the resource utilization rate is extremely low. The tailings accumulation problem has become a bottleneck restricting the development of the tungsten industry and a key problem for the survival of enterprises.

[0003] In addition, the comprehensive utilization of bulk solid wastes such as steel slag and blast furnace slag in my country's steel industry is not optimistic. With the implementation of the national mandatory standard GB175-2023 "General Portland Cement", the comprehensive utilization of steel slag faces more severe challenges. The accumulation of these solid wastes not only occupies a large amount of land resources, but also causes serious pollution to the environment, and it is urgent to find an efficient solution.

[0004] In this context, it is particularly urgent to develop a filler material that can maximize the use of tungsten tailings and coordinate the treatment of steel slag and blast furnace slag. This can not only alleviate the environmental pressure caused by the accumulation of tailings and solid waste, but also effectively reduce the use of cement, reduce carbon emissions, and promote green and sustainable development. Summary of the invention

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a solid waste synergistic low-cement paste filler and a preparation method thereof, so as to solve the problems in the prior art that a large amount of tailings and solid waste generated by tungsten mines and the steel industry are seriously accumulated and difficult to be utilized as resources, which has become a bottleneck for environmental protection and economic development. The fine particles and muddy phenomenon of tungsten tailings result in a low resource utilization rate, and the comprehensive utilization of solid wastes such as steel slag and blast furnace slag also faces huge challenges. The cost of the filler is high, and there are problems such as high carbon emissions during cement production.

[0006] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0007] The first aspect of the present invention provides a solid waste synergistic low-cement paste filling material, which comprises the following raw materials in parts by weight: 600-900 parts of tungsten tailings powder-based filling aggregate, 50-300 parts of solid waste binder, and 200-400 parts of water, wherein the solid waste binder comprises slag powder and cement.

[0008] In some embodiments of the present invention, the tungsten tailings powder-based filling aggregate includes tungsten tailings powder and / or steel slag aggregate.

[0009] In some embodiments of the present invention, the solid waste binder includes steel slag powder.

[0010] In some embodiments of the present invention, the weight proportion of the slag powder is 45-90 parts.

[0011] In some embodiments of the present invention, the weight proportion of the cement is 9-45 parts; the cement is ordinary cement and / or composite cement.

[0012] In some embodiments of the present invention, the uniaxial compressive strength of the solid waste synergistic low-cement paste filler is >1 MPa.

[0013] In some embodiments of the present invention, the setting time of the solid waste synergistic low-cement paste filling material is >15h.

[0014] In some embodiments of the present invention, the weight of the tungsten tailings powder is 630-765 parts; the moisture content of the tungsten tailings powder is <10%; and the particle size range of the tungsten tailings powder is <0.15 mm.

[0015] In some embodiments of the present invention, the weight of the steel slag aggregate is 0-216 parts; the free calcium oxide content of the steel slag aggregate is <3%; the moisture content of the steel slag aggregate is <5%; and the particle size range of the steel slag aggregate is <0.8mm.

[0016] In some embodiments of the present invention, the weight of the steel slag powder is 45-99 parts; the content of free calcium oxide in the steel slag powder is <3%; and the particle size range of the steel slag powder is <45 μm.

[0017] In some embodiments of the present invention, when the tungsten tailings powder-based filling aggregate is tungsten tailings powder, it is filling aggregate A.

[0018] In some embodiments of the present invention, the tungsten tailings powder-based filling aggregate is filling aggregate B when it is tungsten tailings powder and steel slag aggregate.

[0019] In some embodiments of the present invention, when the solid waste binder is steel slag powder, slag powder and cement, it is binder A.

[0020] In some embodiments of the present invention, when the solid waste binder is slag powder and cement, it is binder B.

[0021] In some embodiments of the present invention, in the filling aggregate B, the mass ratio of the tungsten tailings powder to the steel slag aggregate is (2.9-17):1.

[0022] In some embodiments of the present invention, in the binder A, the mass ratio of the steel slag powder, slag powder and cement is (0.7-11):(2.5-8):1.

[0023] In some embodiments of the present invention, in the binder B, the mass ratio of the slag powder to cement is (1-5):1.

[0024] In some embodiments of the present invention, the filling aggregate A is combined with the binder A to obtain dry material A; the mass ratio of the filling aggregate A to the binder A in the dry material A is (4-5.7):1.

[0025] In some embodiments of the present invention, the filling aggregate B is combined with the binder B to obtain a dry material B; in the dry material B, the mass ratio of the filling aggregate B to the binder B is (9-15.7):1.

[0026] In some embodiments of the present invention, the coagulation time of the dry material A is >24h.

[0027] In some embodiments of the present invention, the slurry concentration of the dry material A is 69-78%.

[0028] In some embodiments of the present invention, the coagulation time of the dry material B is >18h.

[0029] In some embodiments of the present invention, the slurry concentration of the dry material B is 74-82%.

[0030] The second aspect of the present invention provides a method for preparing a solid waste-synergistic low-cement paste filling material, comprising the following steps:

[0031] S1. Weigh tungsten tailings powder-based filling aggregate and solid waste binder according to weight proportion, mix them evenly, and obtain dry material;

[0032] S2. Add water to the dry material obtained in step S1, mix well, and obtain a solid waste synergistic low-cement paste filling material.

[0033] In some embodiments of the present invention, the mixing in step S1 is performed by stirring with a stirrer, and the stirring time is 2-4 minutes.

[0034] In some embodiments of the present invention, the mixing in step S2 is performed by stirring with a stirrer, and the stirring time is 3-5 minutes.

[0035] The third aspect of the present invention provides the use of solid waste synergistic low-cement paste filler as a filler.

[0036] As described above, the solid waste synergistic low-cement paste filling material and the preparation method thereof of the present invention have the following beneficial effects:

[0037] (1) The tungsten tailings powder is used to the maximum extent, which can solve the problem of tungsten tailings accumulation and high filling cost after tungsten mining to a certain extent;

[0038] (2) It can help to reduce the difficulty of comprehensive utilization of bulk solid wastes such as steel slag and blast furnace slag;

[0039] (3) Significantly reduced the use of cement and reduced carbon emissions in the cement production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Shown is a flow chart for preparing the solid waste-synergistic low-cement paste filling material of the present invention. DETAILED DESCRIPTION

[0041] The solid waste synergistic low-cement paste filling material and the preparation method thereof of the present invention are described in detail below.

[0042] The solid waste-cooperative low-cement paste filling material of the present invention, on the one hand, maximizes the use of tungsten tailings powder and synergistically utilizes solid wastes such as steel slag and blast furnace slag, which can, to a certain extent, solve the problem of tungsten tailings accumulation and high filling costs after tungsten mining, and alleviate the pain point of the difficulty in comprehensive utilization of bulk solid wastes such as steel slag; on the other hand, it greatly reduces the use of cement and reduces carbon emissions in the cement production process. On this basis, the present invention is completed.

[0043] The first aspect of the present invention provides a solid waste synergistic low-cement paste filling material, which comprises the following raw materials in parts by weight: 600-900 parts of tungsten tailings powder-based filling aggregate, which can be 600-630, 630-720, 720-765, 765-810, 810-828, 828-846 or 846-900, etc. 50-300 parts of solid waste binder, which can be 50-54, 54-72, 72-90, 90-135, 135-180, 180-230, 230-270, 270-300 or 54-270, etc., and 200-400 parts of water, which can be 200-250, 250-300, 300-320, 320-350 or 350-400, etc. The uniaxial compressive strength of the solid waste synergistic low-cement paste filling material is greater than 1MPa, which can be selected as 1-1.1MPa, 1.1-1.9MPa, 1.9-2.1MPa, 2.1-2.3MPa or 2.3-3.5MPa, etc. The setting time of the solid waste synergistic low-cement paste filling material is greater than 15h, which can be selected as 15-20h, 20-24h, 24-26h, 26-29h, 29-32h or 32-37h, etc.

[0044] In the solid waste synergistic low-cement paste filling material provided by the present invention, the tungsten tailings powder comes from Hunan Xintianling Tungsten Industry Co., Ltd. The steel slag aggregate or steel slag powder comes from Baoshan Iron and Steel Co., Ltd. The slag powder comes from Shanghai Baotian New Building Materials Co., Ltd. The cement comes from Anhui Conch Cement Co., Ltd.

[0045] In the solid waste synergistic low-cement paste filling material provided by the present invention, the weight portion of the slag powder is 45-90 parts, which can be optionally 45-60 parts, 60-72 parts or 72-90 parts, etc.

[0046] In the solid waste synergistic low-cement paste filling material provided by the present invention, the weight portion of cement is 9-45 parts, which can be optionally 9-18 parts, 18-27 parts, 27-36 parts or 36-45 parts.

[0047] In the solid waste synergistic low-cement paste filling material provided by the present invention, the cement is ordinary cement and / or composite cement, and the compressive strength of the cement is 42.5 MPa.

[0048] In the solid waste synergistic low-cement paste filling material provided by the present invention, the weight proportion of the tungsten tailings powder is 630-765 parts, which can be selected as 630-720 parts or 720-765 parts; the moisture content of the tungsten tailings powder is <10%, which can be selected as 1-2%, 2-4%, 4-6%, 6-8% or 8-10%, etc.; the particle size range of the tungsten tailings powder is <0.15mm, which can be selected as 0.01-0.02mm, 0.02-0.04mm, 0.04-0.08mm, 0.08-0.1mm, 0.1-0.12mm or 0.12-0.15mm, etc.; the screening content of the tungsten tailings ore with a particle size >0.15mm is <15%. Using tungsten tailings powder to prepare the filling material and screening the particle size to less than 0.15mm not only improves the uniformity and density of the material, ensuring that the filling material is more flat and solid, but also prolongs the initial setting time, which is helpful for the construction and detail adjustment of complex shapes, reduces internal stress, and reduces the risk of shrinkage and cracking. At the same time, more complete hydration reaction enhances the bonding force and strength of the material and improves the overall durability.

[0049] In the solid waste synergistic low-cement paste filling material provided by the present invention, the weight of the steel slag aggregate is 0-216 parts, which can be 0-45 parts, 45-108 parts or 108-216 parts, etc.; the free calcium oxide content of the steel slag aggregate is less than 3%, which can be 1-2% or 2-3%; the moisture content of the steel slag aggregate is less than 5%, which can be 1-2%, 2-3%, 3-4% or 4-5%, etc.; the particle size range of the steel slag aggregate is less than 0.8mm, which can be 0.1-0.2mm, 0.2-0.3mm, 0.3-0.4mm, 0.4-0.5mm, 0.5-0.6mm, 0.6-0.7mm or 0.7-0.8mm, etc. The sieved content of the steel slag aggregate with a particle size of >0.8mm is <10%, and the sieved content of the particle size of >0.15mm is <10%. The main function of steel slag aggregate in solid waste synergistic low-cement paste filling material is to increase structural strength and stability. By controlling the particle size of steel slag aggregate to <0.8mm, it can ensure that the material is more uniform and dense, fill small gaps, reduce the risk of shrinkage and cracking after construction, and improve the durability of the filling material.

[0050] In the solid waste synergistic low-cement paste filling material provided by the present invention, the solid waste binder includes slag powder, cement and / or steel slag powder. When the solid waste binder is steel slag powder, slag powder and cement, it is binder A; the weight of the steel slag powder is 45-99 parts, which can be selected as 45-54 parts, 54-70 parts or 70-99 parts, etc.; the free calcium oxide content of the steel slag powder is <3%, which can be selected as 1-2% or 2-3%; the particle size range of the steel slag powder is <45μm, which can be selected as 1-10μm, 10-20μm, 20-30μm, 30-40μm or 40-45μm, etc.; the screening content of the steel slag powder>45μm is <2%. The role of steel slag powder in the filling material is to enhance the performance of solid waste binder. By controlling the particle size of steel slag powder to below 45μm, the reactivity of steel slag can be improved, thereby significantly improving the overall compressive strength and durability of the filling material, reducing shrinkage cracks and improving filling quality.

[0051] In the solid waste synergistic low-cement paste filling material provided by the present invention, in the binder A, the mass ratio of the steel slag powder, slag powder and cement is (0.7-11): (2.5-8): 1, which can be selected as (0.7-1.5): (2.3-8): 1, (1.5-2.5): (2.3-8): 1, (2.5-5): (2.3-8): 1, (5-11): (2.3-8): 1, (0.7-11): (2.5-4): 1 or (0.7-11): (4-8): 1, etc.

[0052] In the solid waste synergistic low-cement paste filling material provided by the present invention, when the solid waste binder is slag powder and cement, it is binder B; in the binder B, the mass ratio of the slag powder and cement is (1-5):1, which can be optionally (1-1.7):1, (1.7-3):1 or (3-5):1, etc.

[0053] In the solid waste synergistic low-cement paste filling material provided by the present invention, the tungsten tailings powder-based filling aggregate includes tungsten tailings powder and / or steel slag aggregate. When the tungsten tailings powder-based filling aggregate is tungsten tailings powder, it is filling aggregate A; when the tungsten tailings powder-based filling aggregate is tungsten tailings powder and steel slag aggregate, it is filling aggregate B; in the filling aggregate B, the mass ratio of the tungsten tailings powder to the steel slag aggregate is (2.9-17):1, which can be optionally (2.9-6.7):1 or (6.7-17):1.

[0054] In the solid waste synergistic low-cement paste filling material provided by the present invention, the filling aggregate A is combined with the binder A to obtain dry material A; in the dry material A, the mass ratio of the filling aggregate A to the binder A is (4-5.7):1, which can be optionally (4-5):1 or (5-5.7):1. When the mass ratio of the filling aggregate A to the binder A is <4.8:1, the cement content in the binder is required to be not less than 6%, and when the mass ratio is >4.8:1, the cement content in the binder is required to be not less than 12% to ensure that the compressive strength of the filling material meets the use requirements. The setting time of the dry material A is >24h; the slurry concentration of the dry material A is 69-78%, which can be optionally 69-72%, 72-75% or 75-78%.

[0055] In the solid waste synergistic low-cement paste filling material provided by the present invention, the filling aggregate B is combined with the binder B to obtain a dry material B; in the dry material B, the mass ratio of the filling aggregate B to the binder B is (9-15.7):1, which can be optionally (9-11.5):1 or (15.1-15.7):1. The tungsten tailing powder: steel slag aggregate in the filling aggregate B is inversely proportional to the filling aggregate B: binder B, that is, when the steel slag aggregate content in the filling aggregate B increases, the content of the binder B in the solid waste synergistic low-cement paste filling material can be appropriately reduced, because the addition of steel slag aggregate can significantly improve the strength of the filling material, so the amount of binder can be appropriately reduced. The setting time of the filling aggregate B is>18h; the slurry concentration of the filling aggregate B is 74-82%, which can be optionally 74-76%, 76-78%, 78-80% or 80-82%, etc.

[0056] The second aspect of the present invention provides a method for preparing a solid waste-synergistic low-cement paste filling material, comprising the following steps:

[0057] S1. Weigh tungsten tailings powder-based filling aggregate and solid waste binder according to weight proportion, mix them evenly, and obtain dry material;

[0058] S2. Add water to the dry material obtained in step S1, mix well, and obtain a solid waste synergistic low-cement paste filling material.

[0059] In the preparation method of a solid waste synergistic low-cement paste filling material provided by the present invention, step S1 is to weigh tungsten tailings powder-based filling aggregate and low-solid waste binder according to the weight ratio, mix them evenly, and obtain dry material. Specifically: after the tungsten tailings after ore dressing are dehydrated, the particle size is screened; steel slag is selected, and grinding and screening are carried out to obtain steel slag aggregate and steel slag powder respectively; filling aggregate A, filling aggregate B, binder A and binder B are prepared, and filling aggregate A and binder A are added to a mixer in proportion and stirred evenly to obtain dry material A; filling aggregate B and binder B are added to a mixer in proportion and stirred evenly to obtain dry material B.

[0060] In the method for preparing a solid waste synergistic low-cement paste filler provided by the present invention, the stirring time of dry material A or dry material B in step S1 is 2-4 minutes, and can be optionally 2-3 minutes or 3-4 minutes.

[0061] In the method for preparing a solid waste synergistic low-cement paste filler provided by the present invention, the mixing in step S2 is performed by stirring with a mixer, and the stirring time is 3-5 minutes, which can be 3-4 minutes or 4-5 minutes, etc.

[0062] The third aspect of the present invention provides the use of solid waste synergistic low-cement paste filler as a filler.

[0063] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is described in detail below in conjunction with embodiments and drawings.

[0064] In the following examples, unless otherwise specified, all reaction raw materials are commercially available products.

[0065] Unless otherwise specified, the purity of each product in each embodiment of the present invention exceeds 98%.

[0066] Example 1

[0067] The moisture content of the tungsten tailing powder used in this embodiment is less than 10%; the particle size range is less than 0.15mm, and the screening content of the tungsten tailing sand with a particle size of >0.15mm is less than 15%; the free calcium oxide content of the steel slag powder used is less than 3%; the particle size range is less than 45μm, and the screening content of the steel slag powder with a particle size of >45μm is less than 2%. The tungsten tailing powder comes from Hunan Xintianling Tungsten Industry Co., Ltd.; the steel slag powder comes from Baoshan Iron and Steel Co., Ltd.; the slag powder comes from Shanghai Baotian New Building Materials Co., Ltd.; and the cement comes from Anhui Conch Cement Co., Ltd.

[0068] The method for preparing the solid waste-synergistic low-cement paste filling material of this embodiment comprises the following steps:

[0069] S1 weighed 720kg of tungsten tailings, 18kg of cement, 54kg of steel slag powder and 90kg of slag powder, and stirred them in a mixer for 2min until they were evenly mixed to obtain dry material;

[0070] S2. Add 300 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 75%.

[0071] Example 2

[0072] The tungsten tailings sand, cement, steel slag powder and slag powder in this embodiment are the same as those in Example 1.

[0073] The method for preparing the solid waste-synergistic low-cement paste filling material of this embodiment comprises the following steps:

[0074] S1 weighed 720kg of tungsten tailings, 9kg of cement, 99kg of steel slag powder and 72kg of slag powder, and stirred them in a mixer for 2min until they were evenly mixed to obtain dry material;

[0075] S2. Add 400 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 69%.

[0076] Example 3

[0077] The tungsten tailings sand, cement, steel slag powder and slag powder in this embodiment are the same as those in Example 1.

[0078] The method for preparing the solid waste-synergistic low-cement paste filling material of this embodiment comprises the following steps:

[0079] S1 weighed 765kg of tungsten tailings, 18kg of cement, 45kg of steel slag powder and 72kg of slag powder, and stirred them in a mixer for 2min until they were evenly mixed to obtain dry material;

[0080] S2. Add 250 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 78%.

[0081] Example 4

[0082] The tungsten tailings, cement and slag powder of this embodiment are the same as those of embodiment 1. The free calcium oxide content of the steel slag aggregate is less than 3%; the moisture content is less than 5%; the particle size range is less than 0.8 mm, the screening content of the steel slag aggregate with a particle size of > 0.8 mm does not exceed 10%, and the screening content of the particle size of < 0.15 mm is less than 10%.

[0083] The method for preparing the solid waste-synergistic low-cement paste filling material of this embodiment comprises the following steps:

[0084] S1 weighed 630kg of tungsten tailings, 216kg of steel slag aggregate, 9kg of cement and 45kg of slag powder, and stirred them in a mixer for 2min until they were evenly mixed to obtain dry material;

[0085] S2. Add 200 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 82%.

[0086] Example 5

[0087] The tungsten tailings sand, steel slag aggregate, cement and slag powder in this embodiment are the same as those in Example 4.

[0088] The method for preparing the solid waste-synergistic low-cement paste filling material of this embodiment comprises the following steps:

[0089] S1 weighed 720kg of tungsten tailings, 108kg of steel slag aggregate, 27kg of cement and 45kg of slag powder, and stirred them in a mixer for 2min until they were evenly mixed to obtain dry material;

[0090] S2. Add 250 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 78%.

[0091] Example 6

[0092] The tungsten tailings sand, steel slag aggregate, cement and slag powder in this embodiment are the same as those in Example 4.

[0093] The method for preparing the solid waste-synergistic low-cement paste filling material of this embodiment comprises the following steps:

[0094] S1 weighed 765kg of tungsten tailings, 45kg of steel slag aggregate, 45kg of cement and 45kg of slag powder, and stirred them in a mixer for 2min until they were evenly mixed to obtain dry material;

[0095] S2. Add 320 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 74%.

[0096] Comparative Example 1

[0097] The tungsten tailings sand and cement in this comparative example are the same as those in Example 1.

[0098] The preparation method of the solid waste synergistic low-cement paste filling material of this comparative example comprises the following steps:

[0099] S1 weighed 630kg of tungsten tailings and 270kg of cement, stirred them in a mixer for 2min, and mixed them evenly to obtain dry material;

[0100] S2. Add 250 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 78%.

[0101] Comparative Example 2

[0102] The tungsten tailings sand and cement in this comparative example are the same as those in Example 1.

[0103] The preparation method of the solid waste synergistic low-cement paste filling material of this comparative example comprises the following steps:

[0104] S1 weighed 720kg of tungsten tailings and 180kg of cement, stirred them in a mixer for 2 minutes, and mixed them evenly to obtain dry material;

[0105] S2. Add 300 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 75%.

[0106] Comparative Example 3

[0107] The tungsten tailings sand and cement in this comparative example are the same as those in Example 1.

[0108] The preparation method of the solid waste synergistic low-cement paste filling material of this comparative example comprises the following steps:

[0109] S1 weighed 765kg of tungsten tailings and 135kg of cement, stirred them in a mixer for 2 minutes, and mixed them evenly to obtain dry material;

[0110] S2. Add 400 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 69%.

[0111] Comparative Example 4

[0112] In the solid waste synergistic low-cement paste filling material of this comparative example, the particle size of tungsten tailings sand is 0.15-4mm; the steel slag powder and slag powder are the same as those in Example 1.

[0113] The preparation method of the solid waste synergistic low-cement paste filling material of this comparative example comprises the following steps:

[0114] S1 weighed 720kg of tungsten tailings, 110kg of steel slag powder and 70kg of slag powder, and stirred them in a mixer for 2min to obtain dry material;

[0115] S2. Add 300 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 75%.

[0116] Comparative Example 5

[0117] The tungsten tailings sand, steel slag powder and slag powder in this comparative example are the same as those in comparative example 4.

[0118] The preparation method of the solid waste synergistic low-cement paste filling material of this comparative example comprises the following steps:

[0119] S1 weighed 765kg of tungsten tailings, 60kg of steel slag powder and 75kg of slag powder, and stirred them in a mixer for 2 minutes to obtain dry material;

[0120] S2. Add 488 kg of water to the dry material obtained in step S1, stir with a mixer for 3 minutes, mix evenly, and obtain a solid waste synergistic low-cement paste filling material with a slurry concentration of 73%.

[0121] Performance Testing

[0122] The initial setting time of Examples 1-6 and Comparative Examples 1-3 was tested according to the requirements of GB / T 50080 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures", and the uniaxial compressive strength of Examples 1-6 and Comparative Examples 1-3 was tested according to the requirements of JGJ / T 70 "Standard for Test Methods for Basic Performance of Building Mortar", and the cost of each group of filling materials was estimated based on 50 yuan / t of tungsten tailings powder, 75 yuan / t of tungsten tailings sand, 40 yuan / t of steel slag aggregate, 265 yuan / t of cement, 50 yuan / t of steel slag powder, 100 yuan / t of slag powder and 4 yuan / t of water, and the results are shown in Table 4. The cost comparison formula for the same tungsten tailings dosage is:

[0123] Comparison of the cost of tungsten tailings with the dosage = (using solid waste binder - using pure cement binder) ÷ using pure cement binder × 100%

[0124] For example, the tungsten tailings dosage of Comparative Example 2 and Example 1 is the same as 720 kg, then the cost comparison of the same tungsten tailings dosage of Example 1 = (58.44-84.90) ÷ 84.90 × 100% = -31.17%, indicating that the filler cost of Example 1 is reduced by 31.17%.

[0125] Table 4 Performance test and cost of solid waste synergistic low cement paste filling material

[0126]

[0127] Combined with Comparative Examples 1-5 and Examples 1-6, according to the requirements of GB / T 39489 "Technical Specifications for Full Tailings Paste Filling", the uniaxial compressive strength of the paste filling material in the mine is 0.2-5MPa and the setting time is >8h, which can meet the use requirements. In particular, in Comparative Examples 1-3, pure cement is used as the binder, and the uniaxial compressive strength far exceeds the requirements of the specification, but its initial setting time is too short, which is not conducive to mine filling operations. Although the uniaxial compressive strength of Examples 1-6 is lower than that of the comparative example, its setting time exceeds 18h, which is convenient for mine filling operations, and most of the cement is replaced by steel slag and blast furnace slag. On the premise of meeting the uniaxial compressive strength, it not only prolongs the initial setting time of the filling material, but also reduces the cost of mine filling. Under the premise of adding the same content of tungsten tailings powder, the cost of the solid waste synergistic low-cement paste filling material is at least 20% lower than that of the conventional filling material using cement as a binder.

[0128] In combination with Comparative Examples 4-5 and Examples 1-6, since the particle size of the tungsten sand tailings in Examples 1-6 (<0.15mm) is smaller than the particle size of the tungsten sand tailings in Comparative Examples 4-5 (0.15-4mm), the initial setting time of the filling body of Example 1-6 is longer. The longer initial setting time can provide a longer operating time, which is helpful for filling and adjusting complex shapes; the slow setting process can reduce the internal stress of the material and reduce the risk of shrinkage cracking. Compared with Comparative Examples 4-5, Example 1-6 adds cement to the binder, so that the uniaxial compressive strength of the filling material is enhanced. The main purpose of increasing the uniaxial compressive strength is to avoid problems such as deformation, collapse and rupture of the filling material structure, which is very important for improving the filling quality and safety of mine goaf areas. Although the use of cement will increase the cost of the filling body, the present invention selects the most cost-effective solution by conducting a cost-effectiveness analysis and targeted regulation of the composition ratio and preparation method of the solid waste synergistic low-cement paste filling material, thereby ensuring a balance between economy and performance.

[0129] From the comparison between the above comparative examples and embodiments, it can be seen that the solid waste synergistic low-cement paste filling material disclosed in the present invention, under the premise of complying with national standards, adopts the method of synergistic utilization of multiple solid wastes such as tungsten tailings, steel slag, and blast furnace slag, which not only turns multiple solid wastes such as steel slag into treasure, but also reduces the cost of mine filling and reduces the use of highly polluting cement. It is in line with my country's "carbon peak and carbon neutrality", green and low-carbon, and sustainable development policies, and has significant economic benefits and social value.

[0130] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A solid waste synergistic low-cement paste filling material, characterized in that: The solid waste synergistic low-cement paste filling material comprises the following raw materials in parts by weight: 600-900 parts of tungsten tailings powder-based filling aggregate, 50-300 parts of solid waste binder, and 200-400 parts of water, wherein the solid waste binder comprises slag powder and cement.

2. The solid waste synergistic low-cement paste filling material according to claim 1, characterized in that: Includes any one or more of the following features: A1) the tungsten tailings powder-based filling aggregate comprises tungsten tailings powder and / or steel slag aggregate; A2) the solid waste binder includes steel slag powder; A3) the weight portion of the slag powder is 45-90 parts; A4) the weight portion of the cement is 9-45 parts; A5) The cement is ordinary cement and / or composite cement; A6) The uniaxial compressive strength of the solid waste synergistic low-cement paste filling material is greater than 1 MPa; A7) The setting time of the solid waste synergistic low-cement paste filling material is >15h.

3. The solid waste synergistic low-cement paste filling material according to claim 2, characterized in that: Includes any one or more of the following features: A11) the weight portion of the tungsten tailings powder is 630-765 parts; A12) the moisture content of the tungsten tailings powder is less than 10%; A13) The particle size range of the tungsten tailings powder is less than 0.15 mm; A14) the weight of the steel slag aggregate is 0-216 parts; A15) The free calcium oxide content of the steel slag aggregate is less than 3%; A16) The moisture content of the steel slag aggregate is less than 5%; A17) The particle size range of the steel slag aggregate is less than 0.8 mm; A21) the weight portion of the steel slag powder is 45-99 parts; A22) the free calcium oxide content of the steel slag powder is less than 3%; A23) The particle size range of the steel slag powder is <45 μm.

4. The solid waste synergistic low-cement paste filling material according to claim 2, characterized in that: Includes any one or more of the following features: B1) When the tungsten tailings powder-based filling aggregate described in feature A1) is tungsten tailings powder, it is filling aggregate A; B2) When the tungsten tailings powder-based filling aggregate described in feature A1) is tungsten tailings powder and steel slag aggregate, it is filling aggregate B; B3) When the solid waste binder described in feature A2) is steel slag powder, slag powder and cement, it is binder A; B4) When the solid waste binder is slag powder and cement, it is binder B.

5. The solid waste synergistic low-cement paste filling material according to claim 4, characterized in that: Includes any one or more of the following features: B21) In the filling aggregate B, the mass ratio of the tungsten tailings powder to the steel slag aggregate is (2.9-17):1; B31) In the binder A, the mass ratio of the steel slag powder, slag powder and cement is (0.7-11): (2.5-8): 1; B41) In the binder B, the mass ratio of the slag powder to cement is (1-5):1; C1) combining the filling aggregate A with the binder A to obtain dry material A; C2) The filling aggregate B is combined with the binder B to obtain dry material B.

6. The solid waste synergistic low-cement paste filling material according to claim 5, characterized in that: Includes any one or more of the following features: C11) The mass ratio of the filling aggregate A to the binder A is (4-5.7):1; C12) the coagulation time of the dry material A>24h; C13) the slurry concentration of the dry material A is 69-78%; C21) In the dry material B, the mass ratio of the filling aggregate B to the binder B is (9-15.7):1; C22) the coagulation time of the dry material B>18h; C23) The slurry concentration of the dry material B is 74-82%.

7. A method for preparing a solid waste synergistic low-cement paste filling material as claimed in any one of claims 1 to 6, characterized in that: The steps include: S1. Weigh tungsten tailings powder-based filling aggregate and solid waste binder according to weight proportion, mix them evenly, and obtain dry material; S2. Add water to the dry material obtained in step S1, mix well, and obtain a solid waste synergistic low-cement paste filling material.

8. The method for preparing the tungsten tailings sand-steel slag powder solid waste collaborative paste filling material according to claim 7, characterized in that: The mixing in step S1 is performed by stirring with a stirrer, and the stirring time is 2-4 minutes.

9. The method for preparing the tungsten tailings sand-steel slag powder solid waste cooperative paste filling material according to claim 6, characterized in that: The mixing in step S2 is performed by using a stirrer, and the stirring time is 3-5 minutes.

10. Use of the solid waste synergistic low-cement paste filling material as described in any one of claims 1 to 9 as a filling material.

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